Session

class nidmm.Session(self, resource_name, id_query=False, reset_device=False, options={})[source]

This method completes the following tasks:

  • Creates a new IVI instrument driver session and, optionally, sets the initial state of the following session properties: nidmm.Session.range_check, nidmm.Session.QUERY_INSTR_STATUS, nidmm.Session.cache, nidmm.Session.simulate, nidmm.Session.record_coercions.
  • Opens a session to the device you specify for the Resource_Name parameter. If the ID_Query parameter is set to True, this method queries the instrument ID and checks that it is valid for this instrument driver.
  • If the Reset_Device parameter is set to True, this method resets the instrument to a known state. Sends initialization commands to set the instrument to the state necessary for the operation of the instrument driver.
  • Returns a ViSession handle that you use to identify the instrument in all subsequent instrument driver method calls.

Note

One or more of the referenced properties are not in the Python API for this driver.

Parameters:
  • resource_name (str) –

    Caution

    All IVI names for the Resource_Name, such as logical names or virtual names, are case-sensitive. If you use logical names, driver session names, or virtual names in your program, you must make sure that the name you use matches the name in the IVI Configuration Store file exactly, without any variations in the case of the characters in the name.

    Contains the resource_name of the device to initialize. The resource_name is assigned in Measurement & Automation Explorer (MAX). Refer to Related Documentation for the NI Digital Multimeters Getting Started Guide for more information about configuring and testing the DMM in MAX.
    Valid Syntax:
    • NI-DAQmx name
    • DAQ::NI-DAQmx name[::INSTR]
    • DAQ::Traditional NI-DAQ device number[::INSTR]
    • IVI logical name
  • id_query (bool) –

    Verifies that the device you initialize is one that the driver supports. NI-DMM automatically performs this query, so setting this parameter is not necessary. Defined Values:

    True (default) 1 Perform ID Query
    False 0 Skip ID Query
  • reset_device (bool) –

    Specifies whether to reset the instrument during the initialization procedure. Defined Values:

    True (default) 1 Reset Device
    False 0 Don’t Reset
  • options (str) –

    Specifies the initial value of certain properties for the session. The syntax for options is a dictionary of properties with an assigned value. For example:

    { ‘simulate’: False }

    You do not have to specify a value for all the properties. If you do not specify a value for a property, the default value is used.

    Advanced Example: { ‘simulate’: True, ‘driver_setup’: { ‘Model’: ‘<model number>’, ‘BoardType’: ‘<type>’ } }

    Property Default
    range_check True
    query_instrument_status False
    cache True
    simulate False
    record_value_coersions False
    driver_setup {}

Methods

abort

nidmm.Session.abort()

Aborts a previously initiated measurement and returns the DMM to the Idle state.

close

nidmm.Session.close()

Closes the specified session and deallocates resources that it reserved.

Note

This method is not needed when using the session context manager

configure_measurement_absolute

nidmm.Session.configure_measurement_absolute(measurement_function, range, resolution_absolute)

Configures the common properties of the measurement. These properties include nidmm.Session.method, nidmm.Session.range, and nidmm.Session.resolution_absolute.

Parameters:
  • measurement_function (nidmm.Function) – Specifies the measurement_function used to acquire the measurement. The driver sets nidmm.Session.method to this value.
  • range (float) –

    Specifies the range for the method specified in the Measurement_Function parameter. When frequency is specified in the Measurement_Function parameter, you must supply the minimum frequency expected in the range parameter. For example, you must type in 100 Hz if you are measuring 101 Hz or higher. For all other methods, you must supply a range that exceeds the value that you are measuring. For example, you must type in 10 V if you are measuring 9 V. range values are coerced up to the closest input range. Refer to the Devices Overview for a list of valid ranges. The driver sets nidmm.Session.range to this value. The default is 0.02 V.

    NIDMM_VAL_AUTO_RANGE_ON -1.0 NI-DMM performs an Auto Range before acquiring the measurement.
    NIDMM_VAL_AUTO_RANGE_OFF -2.0 NI-DMM sets the Range to the current nidmm.Session.auto_range_value and uses this range for all subsequent measurements until the measurement configuration is changed.
    NIDMM_VAL_AUTO_RANGE_ONCE -3.0 NI-DMM performs an Auto Range before acquiring the measurement. The nidmm.Session.auto_range_value is stored and used for all subsequent measurements until the measurement configuration is changed.

    Note

    The NI 4050, NI 4060, and NI 4065 only support Auto Range when the trigger and sample trigger are set to IMMEDIATE.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

  • resolution_absolute (float) –

    Specifies the absolute resolution for the measurement. NI-DMM sets nidmm.Session.resolution_absolute to this value. The PXIe-4080/4081/4082 uses the resolution you specify. The NI 4065 and NI 4070/4071/4072 ignore this parameter when the Range parameter is set to NIDMM_VAL_AUTO_RANGE_ON (-1.0) or NIDMM_VAL_AUTO_RANGE_ONCE (-3.0). The default is 0.001 V.

    Note

    NI-DMM ignores this parameter for capacitance and inductance measurements on the NI 4072. To achieve better resolution for such measurements, use the nidmm.Session.lc_number_meas_to_average property.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

configure_measurement_digits

nidmm.Session.configure_measurement_digits(measurement_function, range, resolution_digits)

Configures the common properties of the measurement. These properties include nidmm.Session.method, nidmm.Session.range, and nidmm.Session.resolution_digits.

Parameters:
  • measurement_function (nidmm.Function) – Specifies the measurement_function used to acquire the measurement. The driver sets nidmm.Session.method to this value.
  • range (float) –

    Specifies the range for the method specified in the Measurement_Function parameter. When frequency is specified in the Measurement_Function parameter, you must supply the minimum frequency expected in the range parameter. For example, you must type in 100 Hz if you are measuring 101 Hz or higher. For all other methods, you must supply a range that exceeds the value that you are measuring. For example, you must type in 10 V if you are measuring 9 V. range values are coerced up to the closest input range. Refer to the Devices Overview for a list of valid ranges. The driver sets nidmm.Session.range to this value. The default is 0.02 V.

    NIDMM_VAL_AUTO_RANGE_ON -1.0 NI-DMM performs an Auto Range before acquiring the measurement.
    NIDMM_VAL_AUTO_RANGE_OFF -2.0 NI-DMM sets the Range to the current nidmm.Session.auto_range_value and uses this range for all subsequent measurements until the measurement configuration is changed.
    NIDMM_VAL_AUTO_RANGE_ONCE -3.0 NI-DMM performs an Auto Range before acquiring the measurement. The nidmm.Session.auto_range_value is stored and used for all subsequent measurements until the measurement configuration is changed.

    Note

    The NI 4050, NI 4060, and NI 4065 only support Auto Range when the trigger and sample trigger are set to IMMEDIATE.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

  • resolution_digits (float) –

    Specifies the resolution of the measurement in digits. The driver sets the Devices Overview for a list of valid ranges. The driver sets nidmm.Session.resolution_digits property to this value. The PXIe-4080/4081/4082 uses the resolution you specify. The NI 4065 and NI 4070/4071/4072 ignore this parameter when the Range parameter is set to NIDMM_VAL_AUTO_RANGE_ON (-1.0) or NIDMM_VAL_AUTO_RANGE_ONCE (-3.0). The default is 5½.

    Note

    NI-DMM ignores this parameter for capacitance and inductance measurements on the NI 4072. To achieve better resolution for such measurements, use the nidmm.Session.lc_number_meas_to_average property.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

configure_multi_point

nidmm.Session.configure_multi_point(trigger_count, sample_count, sample_trigger=nidmm.SampleTrigger.IMMEDIATE, sample_interval=datetime.timedelta(seconds=-1))

Configures the properties for multipoint measurements. These properties include nidmm.Session.trigger_count, nidmm.Session.sample_count, nidmm.Session.sample_trigger, and nidmm.Session.sample_interval.

For continuous acquisitions, set nidmm.Session.trigger_count or nidmm.Session.sample_count to zero. For more information, refer to Multiple Point Acquisitions, Triggering, and Using Switches.

Parameters:
  • trigger_count (int) – Sets the number of triggers you want the DMM to receive before returning to the Idle state. The driver sets nidmm.Session.trigger_count to this value. The default value is 1.
  • sample_count (int) – Sets the number of measurements the DMM makes in each measurement sequence initiated by a trigger. The driver sets nidmm.Session.sample_count to this value. The default value is 1.
  • sample_trigger (nidmm.SampleTrigger) –

    Specifies the sample_trigger source you want to use. The driver sets nidmm.Session.sample_trigger to this value. The default is Immediate.

    Note

    To determine which values are supported by each device, refer to the LabWindows/CVI Trigger Routing section.

  • sample_interval (float in seconds or datetime.timedelta) –

    Sets the amount of time in seconds the DMM waits between measurement cycles. The driver sets nidmm.Session.sample_interval to this value. Specify a sample interval to add settling time between measurement cycles or to decrease the measurement rate. sample_interval only applies when the Sample_Trigger is set to INTERVAL.

    On the NI 4060, the sample_interval value is used as the settling time. When sample interval is set to 0, the DMM does not settle between measurement cycles. The NI 4065 and NI 4070/4071/4072 use the value specified in sample_interval as additional delay. The default value (-1) ensures that the DMM settles for a recommended time. This is the same as using an Immediate trigger.

    Note

    This property is not used on the NI 4080/4081/4082 and the NI 4050.

configure_rtd_custom

nidmm.Session.configure_rtd_custom(rtd_a, rtd_b, rtd_c)

Configures the A, B, and C parameters for a custom RTD.

Parameters:
  • rtd_a (float) – Specifies the Callendar-Van Dusen A coefficient for RTD scaling when RTD Type parameter is set to Custom in the nidmm.Session.configure_rtd_type() method. The default is 3.9083e-3 (Pt3851)
  • rtd_b (float) – Specifies the Callendar-Van Dusen B coefficient for RTD scaling when RTD Type parameter is set to Custom in the nidmm.Session.configure_rtd_type() method. The default is -5.775e-7 (Pt3851).
  • rtd_c (float) – Specifies the Callendar-Van Dusen C coefficient for RTD scaling when RTD Type parameter is set to Custom in the nidmm.Session.configure_rtd_type() method. The default is -4.183e-12 (Pt3851).

configure_rtd_type

nidmm.Session.configure_rtd_type(rtd_type, rtd_resistance)

Configures the RTD Type and RTD Resistance parameters for an RTD.

Parameters:
  • rtd_type (nidmm.RTDType) –

    Specifies the type of RTD used to measure the temperature resistance. NI-DMM uses this value to set the RTD Type property. The default is PT3851.

    Enum Standards Material TCR (α) Typical R0 (Ω) Notes  
    Callendar-Van Dusen Coefficient            
    PT3851 IEC-751 DIN 43760 BS 1904 ASTM-E1137 EN-60751 Platinum .003851 100 Ω 1000 Ω A = 3.9083 × 10–3 B = –5.775×10:sup:–7 C = –4.183×10:sup:–12 Most common RTDs
    PT3750 Low-cost vendor compliant RTD* Platinum .003750 1000 Ω A = 3.81 × 10–3 B = –6.02×10:sup:–7 C = –6.0×10:sup:–12 Low-cost RTD
    PT3916 JISC 1604 Platinum .003916 100 Ω A = 3.9739 × 10–3 B = –5.870×10:sup:–7 C = –4.4 ×10–12 Used in primarily in Japan
    PT3920 US Industrial Standard D-100 American Platinum .003920 100 Ω A = 3.9787 × 10–3 B = –5.8686×10:sup:–7 C = –4.167 ×10–12 Low-cost RTD
    PT3911 US Industrial Standard American Platinum .003911 100 Ω A = 3.9692 × 10–3 B = –5.8495×10:sup:–7 C = –4.233 ×10–12 Low-cost RTD
    PT3928 ITS-90 Platinum .003928 100 Ω A = 3.9888 × 10–3 B = –5.915×10:sup:–7 C = –3.85 ×10–12 The definition of temperature
    *No standard. Check the TCR.            
  • rtd_resistance (float) – Specifies the RTD resistance in ohms at 0 °C. NI-DMM uses this value to set the RTD Resistance property. The default is 100 (Ω).

configure_thermistor_custom

nidmm.Session.configure_thermistor_custom(thermistor_a, thermistor_b, thermistor_c)

Configures the A, B, and C parameters for a custom thermistor.

Parameters:
  • thermistor_a (float) –

    Specifies the Steinhart-Hart A coefficient for thermistor scaling when Thermistor Type is set to Custom in the nidmm.Session.ConfigureThermistorType() method. The default is 1.0295e-3 (44006).

    Note

    One or more of the referenced methods are not in the Python API for this driver.

  • thermistor_b (float) –

    Specifies the Steinhart-Hart B coefficient for thermistor scaling when Thermistor Type is set to Custom in the nidmm.Session.ConfigureThermistorType() method. The default is 2.391e-4 (44006).

    Note

    One or more of the referenced methods are not in the Python API for this driver.

  • thermistor_c (float) –

    Specifies the Steinhart-Hart C coefficient for thermistor scaling when Thermistor Type is set to Custom in the nidmm.Session.ConfigureThermistorType() method. The default is 1.568e-7 (44006).

    Note

    One or more of the referenced methods are not in the Python API for this driver.

configure_thermocouple

nidmm.Session.configure_thermocouple(thermocouple_type, reference_junction_type=nidmm.ThermocoupleReferenceJunctionType.FIXED)

Configures the thermocouple type and reference junction type for a chosen thermocouple.

Parameters:
  • thermocouple_type (nidmm.ThermocoupleType) –

    Specifies the type of thermocouple used to measure the temperature. NI-DMM uses this value to set the Thermocouple Type property. The default is J.

    B Thermocouple type B
    E Thermocouple type E
    J Thermocouple type J
    K Thermocouple type K
    N Thermocouple type N
    R Thermocouple type R
    S Thermocouple type S
    T Thermocouple type T
  • reference_junction_type (nidmm.ThermocoupleReferenceJunctionType) –

    Specifies the type of reference junction to be used in the reference junction compensation of a thermocouple measurement. NI-DMM uses this value to set the Reference Junction Type property. The only supported value is NIDMM_VAL_TEMP_REF_JUNC_FIXED.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

configure_trigger

nidmm.Session.configure_trigger(trigger_source, trigger_delay=datetime.timedelta(seconds=-1))

Configures the DMM Trigger_Source and Trigger_Delay. Refer to Triggering and Using Switches for more information.

Parameters:
  • trigger_source (nidmm.TriggerSource) –

    Specifies the trigger_source that initiates the acquisition. The driver sets nidmm.Session.trigger_source to this value. Software configures the DMM to wait until nidmm.Session.send_software_trigger() is called before triggering the DMM.

    Note

    To determine which values are supported by each device, refer to the LabWindows/CVI Trigger Routing section.

  • trigger_delay (float in seconds or datetime.timedelta) –

    Specifies the time that the DMM waits after it has received a trigger before taking a measurement. The driver sets the nidmm.Session.trigger_delay property to this value. By default, trigger_delay is NIDMM_VAL_AUTO_DELAY (-1), which means the DMM waits an appropriate settling time before taking the measurement. On the NI 4060, if you set trigger_delay to 0, the DMM does not settle before taking the measurement. The NI 4065 and NI 4070/4071/4072 use the value specified in trigger_delay as additional settling time.

    Note

    When using the NI 4050, Trigger_Delay must be set to NIDMM_VAL_AUTO_DELAY (-1).

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

configure_waveform_acquisition

nidmm.Session.configure_waveform_acquisition(measurement_function, range, rate, waveform_points)

Configures the DMM for waveform acquisitions. This feature is supported on the NI 4080/4081/4082 and the NI 4070/4071/4072.

Parameters:
  • measurement_function (nidmm.Function) –

    Specifies the measurement_function used in a waveform acquisition. The driver sets nidmm.Session.method to this value.

    WAVEFORM_VOLTAGE (default) 1003 Voltage Waveform
    WAVEFORM_CURRENT 1004 Current Waveform
  • range (float) –

    Specifies the expected maximum amplitude of the input signal and sets the range for the Measurement_Function. NI-DMM sets nidmm.Session.range to this value. range values are coerced up to the closest input range. The default is 10.0.

    For valid ranges refer to the topics in Devices.

    Auto-ranging is not supported during waveform acquisitions.

  • rate (float) –

    Specifies the rate of the acquisition in samples per second. NI-DMM sets nidmm.Session.waveform_rate to this value.

    The valid Range is 10.0–1,800,000 S/s. rate values are coerced to the closest integer divisor of 1,800,000. The default value is 1,800,000.

  • waveform_points (int) –

    Specifies the number of points to acquire before the waveform acquisition completes. NI-DMM sets nidmm.Session.waveform_points to this value.

    To calculate the maximum and minimum number of waveform points that you can acquire in one acquisition, refer to the Waveform Acquisition Measurement Cycle.

    The default value is 500.

disable

nidmm.Session.disable()

Places the instrument in a quiescent state where it has minimal or no impact on the system to which it is connected. If a measurement is in progress when this method is called, the measurement is aborted.

export_attribute_configuration_buffer

nidmm.Session.export_attribute_configuration_buffer()

Exports the property configuration of the session to the specified configuration buffer.

You can export and import session property configurations only between devices with identical model numbers.

This method verifies that the properties you have configured for the session are valid. If the configuration is invalid, NI‑DMM returns an error.

Coercion Behavior for Certain Devices

Imported and exported property configurations contain coerced values for the following NI‑DMM devices:

  • PXI/PCI/PCIe/USB‑4065
  • PXI/PCI‑4070
  • PXI‑4071
  • PXI‑4072

NI‑DMM coerces property values when the value you set is within the allowed range for the property but is not one of the discrete valid values the property supports. For example, for a property that coerces values up, if you choose a value of 4 when the adjacent valid values are 1 and 10, the property coerces the value to 10.

Related Topics:

Using Properties and Properties with NI‑DMM

Setting Properties Before Reading Properties

Note

Not supported on the PCMCIA‑4050 or the PXI/PCI‑4060.

Return type:list of int
Returns:Specifies the byte array buffer to be populated with the exported property configuration.

export_attribute_configuration_file

nidmm.Session.export_attribute_configuration_file(file_path)

Exports the property configuration of the session to the specified file.

You can export and import session property configurations only between devices with identical model numbers.

This method verifies that the properties you have configured for the session are valid. If the configuration is invalid, NI‑DMM returns an error.

Coercion Behavior for Certain Devices

Imported and exported property configurations contain coerced values for the following NI‑DMM devices:

  • PXI/PCI/PCIe/USB‑4065
  • PXI/PCI‑4070
  • PXI‑4071
  • PXI‑4072

NI‑DMM coerces property values when the value you set is within the allowed range for the property but is not one of the discrete valid values the property supports. For example, for a property that coerces values up, if you choose a value of 4 when the adjacent valid values are 1 and 10, the property coerces the value to 10.

Related Topics:

Using Properties and Properties with NI‑DMM

Setting Properties Before Reading Properties

Note

Not supported on the PCMCIA‑4050 or the PXI/PCI‑4060.

Parameters:file_path (str) – Specifies the absolute path to the file to contain the exported property configuration. If you specify an empty or relative path, this method returns an error. Default file extension: .nidmmconfig

fetch

nidmm.Session.fetch(maximum_time=datetime.timedelta(milliseconds=-1))

Returns the value from a previously initiated measurement. You must call nidmm.Session._initiate() before calling this method.

Parameters:maximum_time (float in seconds or datetime.timedelta) –

Specifies the maximum_time allowed for this method to complete in milliseconds. If the method does not complete within this time interval, the method returns the NIDMM_ERROR_MAX_TIME_EXCEEDED error code. This may happen if an external trigger has not been received, or if the specified timeout is not long enough for the acquisition to complete.

The valid range is 0–86400000. The default value is NIDMM_VAL_TIME_LIMIT_AUTO (-1). The DMM calculates the timeout automatically.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

Return type:float
Returns:The measured value returned from the DMM.

fetch_multi_point

nidmm.Session.fetch_multi_point(array_size, maximum_time=datetime.timedelta(milliseconds=-1))

Returns an array of values from a previously initiated multipoint measurement. The number of measurements the DMM makes is determined by the values you specify for the Trigger_Count and Sample_Count parameters of nidmm.Session.configure_multi_point(). You must first call nidmm.Session._initiate() to initiate a measurement before calling this method.

Parameters:
  • array_size (int) –

    Specifies the number of measurements to acquire. The maximum number of measurements for a finite acquisition is the (Trigger Count x Sample Count) parameters in nidmm.Session.configure_multi_point().

    For continuous acquisitions, up to 100,000 points can be returned at once. The number of measurements can be a subset. The valid range is any positive ViInt32. The default value is 1.

  • maximum_time (float in seconds or datetime.timedelta) –

    Specifies the maximum_time allowed for this method to complete in milliseconds. If the method does not complete within this time interval, the method returns the NIDMM_ERROR_MAX_TIME_EXCEEDED error code. This may happen if an external trigger has not been received, or if the specified timeout is not long enough for the acquisition to complete.

    The valid range is 0–86400000. The default value is NIDMM_VAL_TIME_LIMIT_AUTO (-1). The DMM calculates the timeout automatically.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

Return type:

tuple (reading_array, actual_number_of_points)

WHERE

reading_array (array.array(“d”)):

An array of measurement values.

Note

The size of the Reading_Array must be at least the size that you specify for the Array_Size parameter.

actual_number_of_points (int):

Indicates the number of measured values actually retrieved from the DMM.

fetch_waveform

nidmm.Session.fetch_waveform(array_size, maximum_time=datetime.timedelta(milliseconds=-1))

For the NI 4080/4081/4082 and the NI 4070/4071/4072, returns an array of values from a previously initiated waveform acquisition. You must call nidmm.Session._initiate() before calling this method.

Parameters:
  • array_size (int) – Specifies the number of waveform points to return. You specify the total number of points that the DMM acquires in the Waveform Points parameter of nidmm.Session.configure_waveform_acquisition(). The default value is 1.
  • maximum_time (float in seconds or datetime.timedelta) –

    Specifies the maximum_time allowed for this method to complete in milliseconds. If the method does not complete within this time interval, the method returns the NIDMM_ERROR_MAX_TIME_EXCEEDED error code. This may happen if an external trigger has not been received, or if the specified timeout is not long enough for the acquisition to complete.

    The valid range is 0–86400000. The default value is NIDMM_VAL_TIME_LIMIT_AUTO (-1). The DMM calculates the timeout automatically.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

Return type:

tuple (waveform_array, actual_number_of_points)

WHERE

waveform_array (array.array(“d”)):

Waveform Array is an array of measurement values stored in waveform data type.

actual_number_of_points (int):

Indicates the number of measured values actually retrieved from the DMM.

fetch_waveform_into

nidmm.Session.fetch_waveform_into(array_size, maximum_time=datetime.timedelta(milliseconds=-1))

For the NI 4080/4081/4082 and the NI 4070/4071/4072, returns an array of values from a previously initiated waveform acquisition. You must call nidmm.Session._initiate() before calling this method.

Parameters:
  • waveform_array (numpy.array(dtype=numpy.float64)) – Waveform Array is an array of measurement values stored in waveform data type.
  • maximum_time (float in seconds or datetime.timedelta) –

    Specifies the maximum_time allowed for this method to complete in milliseconds. If the method does not complete within this time interval, the method returns the NIDMM_ERROR_MAX_TIME_EXCEEDED error code. This may happen if an external trigger has not been received, or if the specified timeout is not long enough for the acquisition to complete.

    The valid range is 0–86400000. The default value is NIDMM_VAL_TIME_LIMIT_AUTO (-1). The DMM calculates the timeout automatically.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

Return type:

tuple (waveform_array, actual_number_of_points)

WHERE

waveform_array (numpy.array(dtype=numpy.float64)):

Waveform Array is an array of measurement values stored in waveform data type.

actual_number_of_points (int):

Indicates the number of measured values actually retrieved from the DMM.

get_cal_date_and_time

nidmm.Session.get_cal_date_and_time(cal_type)

Returns the date and time of the last calibration performed.

Note

The NI 4050 and NI 4060 are not supported.

Parameters:cal_type (int) –

Specifies the type of calibration performed (external or self-calibration).

NIDMM_VAL_INTERNAL_AREA (default) 0 Self-Calibration
NIDMM_VAL_EXTERNAL_AREA 1 External Calibration

Note

The NI 4065 does not support self-calibration.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

Return type:datetime.datetime
Returns:Indicates date and time of the last calibration.

get_dev_temp

nidmm.Session.get_dev_temp(options="")

Returns the current Temperature of the device.

Note

The NI 4050 and NI 4060 are not supported.

Parameters:options (str) – Reserved.
Return type:float
Returns:Returns the current temperature of the device.

get_last_cal_temp

nidmm.Session.get_last_cal_temp(cal_type)

Returns the Temperature during the last calibration procedure.

Note

The NI 4050 and NI 4060 are not supported.

Parameters:cal_type (int) –

Specifies the type of calibration performed (external or self-calibration).

NIDMM_VAL_INTERNAL_AREA (default) 0 Self-Calibration
NIDMM_VAL_EXTERNAL_AREA 1 External Calibration

Note

The NI 4065 does not support self-calibration.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

Return type:float
Returns:Returns the temperature during the last calibration.

get_self_cal_supported

nidmm.Session.get_self_cal_supported()

Returns a Boolean value that expresses whether or not the DMM that you are using can perform self-calibration.

Return type:bool
Returns:Returns whether Self Cal is supported for the device specified by the given session.
True 1 The DMM that you are using can perform self-calibration.
False 0 The DMM that you are using cannot perform self-calibration.

import_attribute_configuration_buffer

nidmm.Session.import_attribute_configuration_buffer(configuration)

Imports a property configuration to the session from the specified configuration buffer.

You can export and import session property configurations only between devices with identical model numbers.

Coercion Behavior for Certain Devices

Imported and exported property configurations contain coerced values for the following NI‑DMM devices:

  • PXI/PCI/PCIe/USB‑4065
  • PXI/PCI‑4070
  • PXI‑4071
  • PXI‑4072

NI‑DMM coerces property values when the value you set is within the allowed range for the property but is not one of the discrete valid values the property supports. For example, for a property that coerces values up, if you choose a value of 4 when the adjacent valid values are 1 and 10, the property coerces the value to 10.

Related Topics:

Using Properties and Properties with NI‑DMM

Setting Properties Before Reading Properties

Note

Not supported on the PCMCIA‑4050 or the PXI/PCI‑4060.

Parameters:configuration (list of int) – Specifies the byte array buffer that contains the property configuration to import.

import_attribute_configuration_file

nidmm.Session.import_attribute_configuration_file(file_path)

Imports a property configuration to the session from the specified file.

You can export and import session property configurations only between devices with identical model numbers.

Coercion Behavior for Certain Devices

Imported and exported property configurations contain coerced values for the following NI‑DMM devices:

  • PXI/PCI/PCIe/USB‑4065
  • PXI/PCI‑4070
  • PXI‑4071
  • PXI‑4072

NI‑DMM coerces property values when the value you set is within the allowed range for the property but is not one of the discrete valid values the property supports. For example, for a property that coerces values up, if you choose a value of 4 when the adjacent valid values are 1 and 10, the property coerces the value to 10.

Related Topics:

Using Properties and Properties with NI‑DMM

Setting Properties Before Reading Properties

Note

Not supported on the PCMCIA‑4050 or the PXI/PCI‑4060.

Parameters:file_path (str) – Specifies the absolute path to the file containing the property configuration to import. If you specify an empty or relative path, this method returns an error. Default File Extension: .nidmmconfig

initiate

nidmm.Session.initiate()

Initiates an acquisition. After you call this method, the DMM leaves the Idle state and enters the Wait-for-Trigger state. If trigger is set to Immediate mode, the DMM begins acquiring measurement data. Use nidmm.Session.fetch(), nidmm.Session.fetch_multi_point(), or nidmm.Session.fetch_waveform() to retrieve the measurement data.

Note

This method will return a Python context manager that will initiate on entering and abort on exit.

lock

nidmm.Session.lock()

Obtains a multithread lock on the device session. Before doing so, the software waits until all other execution threads release their locks on the device session.

Other threads may have obtained a lock on this session for the following reasons:

  • The application called the nidmm.Session.lock() method.
  • A call to NI-DMM locked the session.
  • After a call to the nidmm.Session.lock() method returns successfully, no other threads can access the device session until you call the nidmm.Session.unlock() method or exit out of the with block when using lock context manager.
  • Use the nidmm.Session.lock() method and the nidmm.Session.unlock() method around a sequence of calls to instrument driver methods if you require that the device retain its settings through the end of the sequence.

You can safely make nested calls to the nidmm.Session.lock() method within the same thread. To completely unlock the session, you must balance each call to the nidmm.Session.lock() method with a call to the nidmm.Session.unlock() method.

One method for ensuring there are the same number of unlock method calls as there is lock calls is to use lock as a context manager

with nidmm.Session('dev1') as session:
    with session.lock():
        # Calls to session within a single lock context

The first with block ensures the session is closed regardless of any exceptions raised

The second with block ensures that unlock is called regardless of any exceptions raised

Return type:context manager
Returns:When used in a with statement, nidmm.Session.lock() acts as a context manager and unlock will be called when the with block is exited

perform_open_cable_comp

nidmm.Session.perform_open_cable_comp()

For the NI 4082 and NI 4072 only, performs the open cable compensation measurements for the current capacitance/inductance range, and returns open cable compensation Conductance and Susceptance values. You can use the return values of this method as inputs to nidmm.Session.ConfigureOpenCableCompValues().

This method returns an error if the value of the nidmm.Session.method property is not set to CAPACITANCE (1005) or INDUCTANCE (1006).

Note

One or more of the referenced methods are not in the Python API for this driver.

Return type:tuple (conductance, susceptance)

WHERE

conductance (float):

conductance is the measured value of open cable compensation conductance.

susceptance (float):

susceptance is the measured value of open cable compensation susceptance.

perform_short_cable_comp

nidmm.Session.perform_short_cable_comp()

Performs the short cable compensation measurements for the current capacitance/inductance range, and returns short cable compensation Resistance and Reactance values. You can use the return values of this method as inputs to nidmm.Session.ConfigureShortCableCompValues().

This method returns an error if the value of the nidmm.Session.method property is not set to CAPACITANCE (1005) or INDUCTANCE (1006).

Note

One or more of the referenced methods are not in the Python API for this driver.

Return type:tuple (resistance, reactance)

WHERE

resistance (float):

resistance is the measured value of short cable compensation resistance.

reactance (float):

reactance is the measured value of short cable compensation reactance.

read

nidmm.Session.read(maximum_time=datetime.timedelta(milliseconds=-1))

Acquires a single measurement and returns the measured value.

Parameters:maximum_time (float in seconds or datetime.timedelta) –

Specifies the maximum_time allowed for this method to complete in milliseconds. If the method does not complete within this time interval, the method returns the NIDMM_ERROR_MAX_TIME_EXCEEDED error code. This may happen if an external trigger has not been received, or if the specified timeout is not long enough for the acquisition to complete.

The valid range is 0–86400000. The default value is NIDMM_VAL_TIME_LIMIT_AUTO (-1). The DMM calculates the timeout automatically.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

Return type:float
Returns:The measured value returned from the DMM.

read_multi_point

nidmm.Session.read_multi_point(array_size, maximum_time=datetime.timedelta(milliseconds=-1))

Acquires multiple measurements and returns an array of measured values. The number of measurements the DMM makes is determined by the values you specify for the Trigger_Count and Sample_Count parameters in nidmm.Session.configure_multi_point().

Parameters:
  • array_size (int) –

    Specifies the number of measurements to acquire. The maximum number of measurements for a finite acquisition is the (Trigger Count x Sample Count) parameters in nidmm.Session.configure_multi_point().

    For continuous acquisitions, up to 100,000 points can be returned at once. The number of measurements can be a subset. The valid range is any positive ViInt32. The default value is 1.

  • maximum_time (float in seconds or datetime.timedelta) –

    Specifies the maximum_time allowed for this method to complete in milliseconds. If the method does not complete within this time interval, the method returns the NIDMM_ERROR_MAX_TIME_EXCEEDED error code. This may happen if an external trigger has not been received, or if the specified timeout is not long enough for the acquisition to complete.

    The valid range is 0–86400000. The default value is NIDMM_VAL_TIME_LIMIT_AUTO (-1). The DMM calculates the timeout automatically.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

Return type:

tuple (reading_array, actual_number_of_points)

WHERE

reading_array (array.array(“d”)):

An array of measurement values.

Note

The size of the Reading_Array must be at least the size that you specify for the Array_Size parameter.

actual_number_of_points (int):

Indicates the number of measured values actually retrieved from the DMM.

read_status

nidmm.Session.read_status()

Returns measurement backlog and acquisition status. Use this method to determine how many measurements are available before calling nidmm.Session.fetch(), nidmm.Session.fetch_multi_point(), or nidmm.Session.fetch_waveform().

Note

The NI 4050 is not supported.

Return type:tuple (acquisition_backlog, acquisition_status)

WHERE

acquisition_backlog (int):

The number of measurements available to be read. If the backlog continues to increase, data is eventually overwritten, resulting in an error.

Note

On the NI 4060, the Backlog does not increase when autoranging. On the NI 4065, the Backlog does not increase when Range is set to AUTO RANGE ON (-1), or before the first point is fetched when Range is set to AUTO RANGE ONCE (-3). These behaviors are due to the autorange model of the devices.

acquisition_status (nidmm.AcquisitionStatus):

Indicates status of the acquisition. The following table shows the acquisition states:
0 Running
1 Finished with backlog
2 Finished with no backlog
3 Paused
4 No acquisition in progress

read_waveform

nidmm.Session.read_waveform(array_size, maximum_time=datetime.timedelta(milliseconds=-1))

For the NI 4080/4081/4082 and the NI 4070/4071/4072, acquires a waveform and returns data as an array of values or as a waveform data type. The number of elements in the Waveform_Array is determined by the values you specify for the Waveform_Points parameter in nidmm.Session.configure_waveform_acquisition().

Parameters:
  • array_size (int) – Specifies the number of waveform points to return. You specify the total number of points that the DMM acquires in the Waveform Points parameter of nidmm.Session.configure_waveform_acquisition(). The default value is 1.
  • maximum_time (float in seconds or datetime.timedelta) –

    Specifies the maximum_time allowed for this method to complete in milliseconds. If the method does not complete within this time interval, the method returns the NIDMM_ERROR_MAX_TIME_EXCEEDED error code. This may happen if an external trigger has not been received, or if the specified timeout is not long enough for the acquisition to complete.

    The valid range is 0–86400000. The default value is NIDMM_VAL_TIME_LIMIT_AUTO (-1). The DMM calculates the timeout automatically.

    Note

    One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

Return type:

tuple (waveform_array, actual_number_of_points)

WHERE

waveform_array (array.array(“d”)):

An array of measurement values.

Note

The size of the Waveform_Array must be at least the size that you specify for the Array_Size parameter.

actual_number_of_points (int):

Indicates the number of measured values actually retrieved from the DMM.

reset

nidmm.Session.reset()

Resets the instrument to a known state and sends initialization commands to the instrument. The initialization commands set instrument settings to the state necessary for the operation of the instrument driver.

reset_with_defaults

nidmm.Session.reset_with_defaults()

Resets the instrument to a known state and sends initialization commands to the DMM. The initialization commands set the DMM settings to the state necessary for the operation of NI-DMM. All user-defined default values associated with a logical name are applied after setting the DMM.

self_cal

nidmm.Session.self_cal()

For the NI 4080/4081/4082 and the NI 4070/4071/4072, executes the self-calibration routine to maintain measurement accuracy.

Note

This method calls nidmm.Session.reset(), and any configurations previous to the call will be lost. All properties will be set to their default values after the call returns.

self_test

nidmm.Session.self_test()

Performs a self-test on the DMM to ensure that the DMM is functioning properly. Self-test does not calibrate the DMM. Zero indicates success.

On the NI 4080/4082 and NI 4070/4072, the error code 1013 indicates that you should check the fuse and replace it, if necessary.

Raises SelfTestError on self test failure. Properties on exception object:

  • code - failure code from driver
  • message - status message from driver

Note

Self-test does not check the fuse on the NI 4065, NI 4071, and NI 4081. Hence, even if the fuse is blown on the device, self-test does not return error code 1013.

Note

This method calls nidmm.Session.reset(), and any configurations previous to the call will be lost. All properties will be set to their default values after the call returns.

send_software_trigger

nidmm.Session.send_software_trigger()

Sends a command to trigger the DMM. Call this method if you have configured either the nidmm.Session.trigger_source or nidmm.Session.sample_trigger properties. If the nidmm.Session.trigger_source and/or nidmm.Session.sample_trigger properties are set to NIDMM_VAL_EXTERNAL or NIDMM_VAL_TTLn, you can use this method to override the trigger source that you configured and trigger the device. The NI 4050 and NI 4060 are not supported.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

unlock

nidmm.Session.unlock()

Releases a lock that you acquired on an device session using nidmm.Session.lock(). Refer to nidmm.Session.unlock() for additional information on session locks.

Properties

ac_max_freq

nidmm.Session.ac_max_freq

Specifies the maximum frequency component of the input signal for AC measurements. This property is used only for error checking and verifies that the value of this parameter is less than the maximum frequency of the device. This property affects the DMM only when you set the nidmm.Session.method property to AC measurements. The valid range is 1 Hz-300 kHz for the NI 4070/4071/4072, 10 Hz-100 kHz for the NI 4065, and 20 Hz-25 kHz for the NI 4050 and NI 4060.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Max Frequency
  • C Attribute: NIDMM_ATTR_AC_MAX_FREQ

ac_min_freq

nidmm.Session.ac_min_freq

Specifies the minimum frequency component of the input signal for AC measurements. This property affects the DMM only when you set the nidmm.Session.method property to AC measurements. The valid range is 1 Hz-300 kHz for the NI 4070/4071/4072, 10 Hz-100 kHz for the NI 4065, and 20 Hz-25 kHz for the NI 4050 and NI 4060.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Min Frequency
  • C Attribute: NIDMM_ATTR_AC_MIN_FREQ

adc_calibration

nidmm.Session.adc_calibration

For the NI 4070/4071/4072 only, specifies the ADC calibration mode.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.ADCCalibration
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:ADC Calibration
  • C Attribute: NIDMM_ATTR_ADC_CALIBRATION

aperture_time

nidmm.Session.aperture_time

Specifies the measurement aperture time for the current configuration. Aperture time is specified in units set by nidmm.Session.aperture_time_units. To override the default aperture, set this property to the desired aperture time after calling nidmm.Session.ConfigureMeasurement(). To return to the default, set this property to NIDMM_VAL_APERTURE_TIME_AUTO (-1). On the NI 4070/4071/4072, the minimum aperture time is 8.89 usec, and the maximum aperture time is 149 sec. Any number of powerline cycles (PLCs) within the minimum and maximum ranges is allowed on the NI 4070/4071/4072. On the NI 4065 the minimum aperture time is 333 µs, and the maximum aperture time is 78.2 s. If setting the number of averages directly, the total measurement time is aperture time X the number of averages, which must be less than 72.8 s. The aperture times allowed are 333 µs, 667 µs, or multiples of 1.11 ms-for example 1.11 ms, 2.22 ms, 3.33 ms, and so on. If you set an aperture time other than 333 µs, 667 µs, or multiples of 1.11 ms, the value will be coerced up to the next supported aperture time. On the NI 4060, when the powerline frequency is 60 Hz, the PLCs allowed are 1 PLC, 6 PLC, 12 PLC, and 120 PLC. When the powerline frequency is 50 Hz, the PLCs allowed are 1 PLC, 5 PLC, 10 PLC, and 100 PLC.

Note

One or more of the referenced methods are not in the Python API for this driver.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Advanced:Aperture Time
  • C Attribute: NIDMM_ATTR_APERTURE_TIME

aperture_time_units

nidmm.Session.aperture_time_units

Specifies the units of aperture time for the current configuration. The NI 4060 does not support an aperture time set in seconds.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.ApertureTimeUnits
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Advanced:Aperture Time Units
  • C Attribute: NIDMM_ATTR_APERTURE_TIME_UNITS

auto_range_value

nidmm.Session.auto_range_value

Specifies the value of the range. If auto ranging, shows the actual value of the active range. The value of this property is set during a read operation.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Auto Range Value
  • C Attribute: NIDMM_ATTR_AUTO_RANGE_VALUE

auto_zero

nidmm.Session.auto_zero

Specifies the AutoZero mode. The NI 4050 is not supported.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.AutoZero
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Auto Zero
  • C Attribute: NIDMM_ATTR_AUTO_ZERO

buffer_size

nidmm.Session.buffer_size

Size in samples of the internal data buffer. Maximum is 134,217,727 (OX7FFFFFF) samples. When set to NIDMM_VAL_BUFFER_SIZE_AUTO (-1), NI-DMM chooses the buffer size.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Multi Point Acquisition:Advanced:Buffer Size
  • C Attribute: NIDMM_ATTR_BUFFER_SIZE

cable_comp_type

nidmm.Session.cable_comp_type

For the NI 4072 only, the type of cable compensation that is applied to the current capacitance or inductance measurement for the current range. Changing the method or the range through this property or through nidmm.Session.configure_measurement_digits() resets the value of this property to the default value.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.CableCompensationType
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Capacitance and Inductance:Cable Compensation Type
  • C Attribute: NIDMM_ATTR_CABLE_COMP_TYPE

channel_count

nidmm.Session.channel_count

Indicates the number of channels that the specific instrument driver supports. For each property for which the IVI_VAL_MULTI_CHANNEL flag property is set, the IVI engine maintains a separate cache value for each channel.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Instrument Capabilities:Channel Count
  • C Attribute: NIDMM_ATTR_CHANNEL_COUNT

current_source

nidmm.Session.current_source

Specifies the current source provided during diode measurements. The NI 4050 and NI 4060 are not supported.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Current Source
  • C Attribute: NIDMM_ATTR_CURRENT_SOURCE

dc_bias

nidmm.Session.dc_bias

For the NI 4072 only, controls the available DC bias for capacitance measurements.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Capacitance and Inductance:Advanced:DC Bias
  • C Attribute: NIDMM_ATTR_DC_BIAS

dc_noise_rejection

nidmm.Session.dc_noise_rejection

Specifies the DC noise rejection mode. The NI 4050 and NI 4060 are not supported.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.DCNoiseRejection
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:DC Noise Rejection
  • C Attribute: NIDMM_ATTR_DC_NOISE_REJECTION

driver_setup

nidmm.Session.driver_setup

This property indicates the Driver Setup string that the user specified when initializing the driver. Some cases exist where the end-user must specify instrument driver options at initialization time. An example of this is specifying a particular instrument model from among a family of instruments that the driver supports. This is useful when using simulation. The end-user can specify driver-specific options through the DriverSetup keyword in the optionsString parameter to the niDMM Init With Options.vi. If the user does not specify a Driver Setup string, this property returns an empty string.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:User Options:Driver Setup
  • C Attribute: NIDMM_ATTR_DRIVER_SETUP

freq_voltage_auto_range

nidmm.Session.freq_voltage_auto_range

For the NI 4070/4071/4072 only, specifies the value of the frequency voltage range. If Auto Ranging, shows the actual value of the active frequency voltage range. If not Auto Ranging, the value of this property is the same as that of nidmm.Session.freq_voltage_range.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Frequency Voltage Auto Range Value
  • C Attribute: NIDMM_ATTR_FREQ_VOLTAGE_AUTO_RANGE

freq_voltage_range

nidmm.Session.freq_voltage_range

Specifies the maximum amplitude of the input signal for frequency measurements.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Frequency Voltage Range
  • C Attribute: NIDMM_ATTR_FREQ_VOLTAGE_RANGE

function

nidmm.Session.function

Specifies the measurement method. Refer to the nidmm.Session.method topic in the NI Digital Multimeters Help for device-specific information. If you are setting this property directly, you must also set the nidmm.Session.operation_mode property, which controls whether the DMM takes standard single or multipoint measurements, or acquires a waveform. If you are programming properties directly, you must set the nidmm.Session.operation_mode property before setting other configuration properties. If the nidmm.Session.operation_mode property is set to WAVEFORM, the only valid method types are WAVEFORM_VOLTAGE and WAVEFORM_CURRENT. Set the nidmm.Session.operation_mode property to IVIDMM to set all other method values.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.Function
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Function
  • C Attribute: NIDMM_ATTR_FUNCTION

input_resistance

nidmm.Session.input_resistance

Specifies the input resistance of the instrument. The NI 4050 and NI 4060 are not supported.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Input Resistance
  • C Attribute: NIDMM_ATTR_INPUT_RESISTANCE

instrument_firmware_revision

nidmm.Session.instrument_firmware_revision

A string containing the instrument firmware revision number.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Instrument Identification:Instrument Firmware Revision
  • C Attribute: NIDMM_ATTR_INSTRUMENT_FIRMWARE_REVISION

instrument_manufacturer

nidmm.Session.instrument_manufacturer

A string containing the manufacturer of the instrument.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Instrument Identification:Instrument Manufacturer
  • C Attribute: NIDMM_ATTR_INSTRUMENT_MANUFACTURER

instrument_model

nidmm.Session.instrument_model

A string containing the instrument model.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Instrument Identification:Instrument Model
  • C Attribute: NIDMM_ATTR_INSTRUMENT_MODEL

instrument_product_id

nidmm.Session.instrument_product_id

The PCI product ID.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Instrument Identification:Instrument Product ID
  • C Attribute: NIDMM_ATTR_INSTRUMENT_PRODUCT_ID

io_resource_descriptor

nidmm.Session.io_resource_descriptor

A string containing the resource descriptor of the instrument.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Advanced Session Information:I/O Resource Descriptor
  • C Attribute: NIDMM_ATTR_IO_RESOURCE_DESCRIPTOR

lc_calculation_model

nidmm.Session.lc_calculation_model

For the NI 4072 only, specifies the type of algorithm that the measurement processing uses for capacitance and inductance measurements.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.LCCalculationModel
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Capacitance and Inductance:Advanced:Calculation Model
  • C Attribute: NIDMM_ATTR_LC_CALCULATION_MODEL

lc_number_meas_to_average

nidmm.Session.lc_number_meas_to_average

For the NI 4072 only, specifies the number of LC measurements that are averaged to produce one reading.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Capacitance and Inductance:Number of LC Measurements To Average
  • C Attribute: NIDMM_ATTR_LC_NUMBER_MEAS_TO_AVERAGE

logical_name

nidmm.Session.logical_name

A string containing the logical name of the instrument.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Advanced Session Information:Logical Name
  • C Attribute: NIDMM_ATTR_LOGICAL_NAME

meas_complete_dest

nidmm.Session.meas_complete_dest

Specifies the destination of the measurement complete (MC) signal. The NI 4050 is not supported. To determine which values are supported by each device, refer to the LabWindows/CVI Trigger Routing section in the NI Digital Multimeters Help.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.MeasurementCompleteDest
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Trigger:Measurement Complete Dest
  • C Attribute: NIDMM_ATTR_MEAS_COMPLETE_DEST

number_of_averages

nidmm.Session.number_of_averages

Specifies the number of averages to perform in a measurement. For the NI 4070/4071/4072, applies only when the aperture time is not set to AUTO and Auto Zero is ON. The default is 1. The NI 4050 and NI 4060 are not supported.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Advanced:Number Of Averages
  • C Attribute: NIDMM_ATTR_NUMBER_OF_AVERAGES

offset_comp_ohms

nidmm.Session.offset_comp_ohms

For the NI 4070/4071/4072 only, enables or disables offset compensated ohms.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Offset Compensated Ohms
  • C Attribute: NIDMM_ATTR_OFFSET_COMP_OHMS

open_cable_comp_conductance

nidmm.Session.open_cable_comp_conductance

For the NI 4072 only, specifies the active part (conductance) of the open cable compensation. The valid range is any real number greater than 0. The default value (-1.0) indicates that compensation has not taken place. Changing the method or the range through this property or through nidmm.Session.configure_measurement_digits() resets the value of this property to the default value.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Capacitance and Inductance:Open Cable Compensation Values:Conductance
  • C Attribute: NIDMM_ATTR_OPEN_CABLE_COMP_CONDUCTANCE

open_cable_comp_susceptance

nidmm.Session.open_cable_comp_susceptance

For the NI 4072 only, specifies the reactive part (susceptance) of the open cable compensation. The valid range is any real number greater than 0. The default value (-1.0) indicates that compensation has not taken place. Changing the method or the range through this property or through nidmm.Session.configure_measurement_digits() resets the value of this property to the default value.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Capacitance and Inductance:Open Cable Compensation Values:Susceptance
  • C Attribute: NIDMM_ATTR_OPEN_CABLE_COMP_SUSCEPTANCE

operation_mode

nidmm.Session.operation_mode

Specifies how the NI 4065 and NI 4070/4071/4072 acquire data. When you call nidmm.Session.configure_measurement_digits(), NI-DMM sets this property to IVIDMM. When you call nidmm.Session.configure_waveform_acquisition(), NI-DMM sets this property to WAVEFORM. If you are programming properties directly, you must set this property before setting other configuration properties.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.OperationMode
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Advanced:Operation Mode
  • C Attribute: NIDMM_ATTR_OPERATION_MODE

powerline_freq

nidmm.Session.powerline_freq

Specifies the powerline frequency. The NI 4050 and NI 4060 use this value to select an aperture time to reject powerline noise by selecting the appropriate internal sample clock and filter. The NI 4065 and NI 4070/4071/4072 use this value to select a timebase for setting the nidmm.Session.aperture_time property in powerline cycles (PLCs). After configuring powerline frequency, set the nidmm.Session.aperture_time_units property to PLCs. When setting the nidmm.Session.aperture_time property, select the number of PLCs for the powerline frequency. For example, if powerline frequency = 50 Hz (or 20ms) and aperture time in PLCs = 5, then aperture time in Seconds = 20ms * 5 PLCs = 100 ms. Similarly, if powerline frequency = 60 Hz (or 16.667 ms) and aperture time in PLCs = 6, then aperture time in Seconds = 16.667 ms * 6 PLCs = 100 ms.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Powerline Frequency
  • C Attribute: NIDMM_ATTR_POWERLINE_FREQ

range

nidmm.Session.range

Specifies the measurement range. Use positive values to represent the absolute value of the maximum expected measurement. The value is in units appropriate for the current value of the nidmm.Session.method property. For example, if nidmm.Session.method is set to NIDMM_VAL_VOLTS, the units are volts. The NI 4050 and NI 4060 only support Auto Range when the trigger and sample trigger is set to IMMEDIATE. NIDMM_VAL_AUTO_RANGE_ON -1.0 NI-DMM performs an Auto Range before acquiring the measurement. NIDMM_VAL_AUTO_RANGE_OFF -2.0 NI-DMM sets the Range to the current nidmm.Session.auto_range_value and uses this range for all subsequent measurements until the measurement configuration is changed. NIDMM_VAL_AUTO_RANGE_ONCE -3.0 NI-DMM performs an Auto Range before acquiring the next measurement. The nidmm.Session.auto_range_value is stored and used for all subsequent measurements until the measurement configuration is changed.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Range
  • C Attribute: NIDMM_ATTR_RANGE

resolution_absolute

nidmm.Session.resolution_absolute

Specifies the measurement resolution in absolute units. Setting this property to higher values increases the measurement accuracy. Setting this property to lower values increases the measurement speed. NI-DMM ignores this property for capacitance and inductance measurements on the NI 4072. To achieve better resolution for such measurements, use the nidmm.Session.lc_number_meas_to_average property.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Absolute Resolution
  • C Attribute: NIDMM_ATTR_RESOLUTION_ABSOLUTE

resolution_digits

nidmm.Session.resolution_digits

Specifies the measurement resolution in digits. Setting this property to higher values increases the measurement accuracy. Setting this property to lower values increases the measurement speed. NI-DMM ignores this property for capacitance and inductance measurements on the NI 4072. To achieve better resolution for such measurements, use the nidmm.Session.lc_number_meas_to_average property.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Digits Resolution
  • C Attribute: NIDMM_ATTR_RESOLUTION_DIGITS

sample_count

nidmm.Session.sample_count

Specifies the number of measurements the DMM takes each time it receives a trigger in a multiple point acquisition.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Multi Point Acquisition:Sample Count
  • C Attribute: NIDMM_ATTR_SAMPLE_COUNT

sample_interval

nidmm.Session.sample_interval

Specifies the amount of time in seconds the DMM waits between measurement cycles. This property only applies when the nidmm.Session.sample_trigger property is set to INTERVAL. On the NI 4060, the value for this property is used as the settling time. When this property is set to 0, the NI 4060 does not settle between measurement cycles. The onboard timing resolution is 1 µs on the NI 4060. The NI 4065 and NI 4070/4071/4072 use the value specified in this property as additional delay. On the NI 4065 and NI 4070/4071/4072, the onboard timing resolution is 34.72 ns and the valid range is 0-149 s. Only positive values are valid when setting the sample interval. The NI 4050 is not supported.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float in seconds or datetime.timedelta
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Multi Point Acquisition:Sample Interval
  • C Attribute: NIDMM_ATTR_SAMPLE_INTERVAL

sample_trigger

nidmm.Session.sample_trigger

Specifies the sample trigger source. To determine which values are supported by each device, refer to the LabWindows/CVI Trigger Routing section in the NI Digital Multimeters Help.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.SampleTrigger
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Multi Point Acquisition:Sample Trigger
  • C Attribute: NIDMM_ATTR_SAMPLE_TRIGGER

serial_number

nidmm.Session.serial_number

A string containing the serial number of the instrument. This property corresponds to the serial number label that is attached to most products.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Instrument Identification:Instrument Serial Number
  • C Attribute: NIDMM_ATTR_SERIAL_NUMBER

settle_time

nidmm.Session.settle_time

Specifies the settling time in seconds. To override the default settling time, set this property. To return to the default, set this property to NIDMM_VAL_SETTLE_TIME_AUTO (-1). The NI 4050 and NI 4060 are not supported.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float in seconds or datetime.timedelta
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Advanced:Settle Time
  • C Attribute: NIDMM_ATTR_SETTLE_TIME

short_cable_comp_reactance

nidmm.Session.short_cable_comp_reactance

For the NI 4072 only, represents the reactive part (reactance) of the short cable compensation. The valid range is any real number greater than 0. The default value (-1) indicates that compensation has not taken place. Changing the method or the range through this property or through nidmm.Session.configure_measurement_digits() resets the value of this property to the default value.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Capacitance and Inductance:Short Cable Compensation Values:Reactance
  • C Attribute: NIDMM_ATTR_SHORT_CABLE_COMP_REACTANCE

short_cable_comp_resistance

nidmm.Session.short_cable_comp_resistance

For the NI 4072 only, represents the active part (resistance) of the short cable compensation. The valid range is any real number greater than 0. The default value (-1) indicates that compensation has not taken place. Changing the method or the range through this property or through nidmm.Session.configure_measurement_digits() resets the value of this property to the default value.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Capacitance and Inductance:Short Cable Compensation Values:Resistance
  • C Attribute: NIDMM_ATTR_SHORT_CABLE_COMP_RESISTANCE

simulate

nidmm.Session.simulate

Specifies whether or not to simulate instrument driver I/O operations. If simulation is enabled, instrument driver methods perform range checking and call IVI Get and Set methods, but they do not perform instrument I/O. For output parameters that represent instrument data, the instrument driver methods return calculated values. The default value is False (0). Use the nidmm.Session.__init__() method to override this setting. Simulate can only be set within the InitWithOptions method. The property value cannot be changed outside of the method.

The following table lists the characteristics of this property.

Characteristic Value
Datatype bool
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:User Options:Simulate
  • C Attribute: NIDMM_ATTR_SIMULATE

specific_driver_description

nidmm.Session.specific_driver_description

A string containing a description of the specific driver.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Specific Driver Identification:Specific Driver Description
  • C Attribute: NIDMM_ATTR_SPECIFIC_DRIVER_DESCRIPTION

specific_driver_major_version

nidmm.Session.specific_driver_major_version

Returns the major version number of this instrument driver.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Version Info:Specific Driver Major Version
  • C Attribute: NIDMM_ATTR_SPECIFIC_DRIVER_MAJOR_VERSION

specific_driver_minor_version

nidmm.Session.specific_driver_minor_version

The minor version number of this instrument driver.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Version Info:Specific Driver Minor Version
  • C Attribute: NIDMM_ATTR_SPECIFIC_DRIVER_MINOR_VERSION

specific_driver_revision

nidmm.Session.specific_driver_revision

A string that contains additional version information about this specific instrument driver.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Version Info:Specific Driver Revision
  • C Attribute: NIDMM_ATTR_SPECIFIC_DRIVER_REVISION

specific_driver_vendor

nidmm.Session.specific_driver_vendor

A string containing the vendor of the specific driver.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Specific Driver Identification:Specific Driver Vendor
  • C Attribute: NIDMM_ATTR_SPECIFIC_DRIVER_VENDOR

supported_instrument_models

nidmm.Session.supported_instrument_models

A string containing the instrument models supported by the specific driver.

The following table lists the characteristics of this property.

Characteristic Value
Datatype str
Permissions read only
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Inherent IVI Attributes:Specific Driver Capabilities:Supported Instrument Models
  • C Attribute: NIDMM_ATTR_SUPPORTED_INSTRUMENT_MODELS

temp_rtd_a

nidmm.Session.temp_rtd_a

Specifies the Callendar-Van Dusen A coefficient for RTD scaling when the RTD Type property is set to Custom. The default value is 3.9083e-3 (Pt3851).

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Resistance Temperature Detector:RTD A
  • C Attribute: NIDMM_ATTR_TEMP_RTD_A

temp_rtd_b

nidmm.Session.temp_rtd_b

Specifies the Callendar-Van Dusen B coefficient for RTD scaling when the RTD Type property is set to Custom. The default value is -5.775e-7(Pt3851).

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Resistance Temperature Detector:RTD B
  • C Attribute: NIDMM_ATTR_TEMP_RTD_B

temp_rtd_c

nidmm.Session.temp_rtd_c

Specifies the Callendar-Van Dusen C coefficient for RTD scaling when the RTD Type property is set to Custom. The default value is -4.183e-12(Pt3851).

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Resistance Temperature Detector:RTD C
  • C Attribute: NIDMM_ATTR_TEMP_RTD_C

temp_rtd_res

nidmm.Session.temp_rtd_res

Specifies the RTD resistance at 0 degrees Celsius. This applies to all supported RTDs, including custom RTDs. The default value is 100 (?).

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Resistance Temperature Detector:RTD Resistance
  • C Attribute: NIDMM_ATTR_TEMP_RTD_RES

temp_rtd_type

nidmm.Session.temp_rtd_type

Specifies the type of RTD used to measure temperature. The default value is PT3851. Refer to the nidmm.Session.temp_rtd_type topic in the NI Digital Multimeters Help for additional information about defined values.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.RTDType
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Resistance Temperature Detector:RTD Type
  • C Attribute: NIDMM_ATTR_TEMP_RTD_TYPE

temp_tc_fixed_ref_junc

nidmm.Session.temp_tc_fixed_ref_junc

Specifies the reference junction temperature when a fixed reference junction is used to take a thermocouple measurement. The default value is 25.0 (°C).

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Thermocouple:Fixed Reference Junction
  • C Attribute: NIDMM_ATTR_TEMP_TC_FIXED_REF_JUNC

temp_tc_ref_junc_type

nidmm.Session.temp_tc_ref_junc_type

Specifies the type of reference junction to be used in the reference junction compensation of a thermocouple. The only supported value, NIDMM_VAL_TEMP_REF_JUNC_FIXED, is fixed.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.ThermocoupleReferenceJunctionType
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Thermocouple:Reference Junction Type
  • C Attribute: NIDMM_ATTR_TEMP_TC_REF_JUNC_TYPE

temp_tc_type

nidmm.Session.temp_tc_type

Specifies the type of thermocouple used to measure the temperature. The default value is J.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.ThermocoupleType
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Thermocouple:Thermocouple Type
  • C Attribute: NIDMM_ATTR_TEMP_TC_TYPE

temp_thermistor_a

nidmm.Session.temp_thermistor_a

Specifies the Steinhart-Hart A coefficient for thermistor scaling when the Thermistor Type property is set to Custom. The default value is 0.0010295 (44006).

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Thermistor:Thermistor A
  • C Attribute: NIDMM_ATTR_TEMP_THERMISTOR_A

temp_thermistor_b

nidmm.Session.temp_thermistor_b

Specifies the Steinhart-Hart B coefficient for thermistor scaling when the Thermistor Type proerty is set to Custom. The default value is 0.0002391 (44006).

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Thermistor:Thermistor B
  • C Attribute: NIDMM_ATTR_TEMP_THERMISTOR_B

temp_thermistor_c

nidmm.Session.temp_thermistor_c

Specifies the Steinhart-Hart C coefficient for thermistor scaling when the Thermistor Type property is set to Custom. The default value is 1.568e-7 (44006).

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Thermistor:Thermistor C
  • C Attribute: NIDMM_ATTR_TEMP_THERMISTOR_C

temp_thermistor_type

nidmm.Session.temp_thermistor_type

Specifies the type of thermistor used to measure the temperature. The default value is THERMISTOR_44006. Refer to the nidmm.Session.temp_thermistor_type topic in the NI Digital Multimeters Help for additional information about defined values.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.ThermistorType
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Thermistor:Thermistor Type
  • C Attribute: NIDMM_ATTR_TEMP_THERMISTOR_TYPE

temp_transducer_type

nidmm.Session.temp_transducer_type

Specifies the type of device used to measure the temperature. The default value is NIDMM_VAL_4_THERMOCOUPLE.

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.TransducerType
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Configuration:Measurement Options:Temperature:Transducer Type
  • C Attribute: NIDMM_ATTR_TEMP_TRANSDUCER_TYPE

trigger_count

nidmm.Session.trigger_count

Specifies the number of triggers the DMM receives before returning to the Idle state. This property can be set to any positive ViInt32 value for the NI 4065 and NI 4070/4071/4072. The NI 4050 and NI 4060 support this property being set to 1. Refer to the Multiple Point Acquisitions section of the NI Digital Multimeters Help for more information.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Multi Point Acquisition:Trigger Count
  • C Attribute: NIDMM_ATTR_TRIGGER_COUNT

trigger_delay

nidmm.Session.trigger_delay

Specifies the time (in seconds) that the DMM waits after it has received a trigger before taking a measurement. The default value is AUTO DELAY (-1), which means that the DMM waits an appropriate settling time before taking the measurement. (-1) signifies that AUTO DELAY is on, and (-2) signifies that AUTO DELAY is off. The NI 4065 and NI 4070/4071/4072 use the value specified in this property as additional settling time. For the The NI 4065 and NI 4070/4071/4072, the valid range for Trigger Delay is AUTO DELAY (-1) or 0.0-149.0 seconds and the onboard timing resolution is 34.72 ns. On the NI 4060, if this property is set to 0, the DMM does not settle before taking the measurement. On the NI 4060, the valid range for AUTO DELAY (-1) is 0.0-12.0 seconds and the onboard timing resolution is 100 ms. When using the NI 4050, this property must be set to AUTO DELAY (-1). Use positive values to set the trigger delay in seconds. Valid Range: NIDMM_VAL_AUTO_DELAY (-1.0), 0.0-12.0 seconds (NI 4060 only) Default Value: NIDMM_VAL_AUTO_DELAY

Note

One or more of the referenced values are not in the Python API for this driver. Enums that only define values, or represent True/False, have been removed.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float in seconds or datetime.timedelta
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Trigger:Trigger Delay
  • C Attribute: NIDMM_ATTR_TRIGGER_DELAY

trigger_source

nidmm.Session.trigger_source

Specifies the trigger source. When nidmm.Session._initiate() is called, the DMM waits for the trigger specified with this property. After it receives the trigger, the DMM waits the length of time specified with the nidmm.Session.trigger_delay property. The DMM then takes a measurement. This property is not supported on the NI 4050. To determine which values are supported by each device, refer to the LabWindows/CVI Trigger Routing section in the NI Digital Multimeters Help.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.TriggerSource
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Trigger:Trigger Source
  • C Attribute: NIDMM_ATTR_TRIGGER_SOURCE

waveform_coupling

nidmm.Session.waveform_coupling

For the NI 4070/4071/4072 only, specifies the coupling during a waveform acquisition.

The following table lists the characteristics of this property.

Characteristic Value
Datatype enums.WaveformCoupling
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Waveform Acquisition:Waveform Coupling
  • C Attribute: NIDMM_ATTR_WAVEFORM_COUPLING

waveform_points

nidmm.Session.waveform_points

For the NI 4070/4071/4072 only, specifies the number of points to acquire in a waveform acquisition.

The following table lists the characteristics of this property.

Characteristic Value
Datatype int
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Waveform Acquisition:Waveform Points
  • C Attribute: NIDMM_ATTR_WAVEFORM_POINTS

waveform_rate

nidmm.Session.waveform_rate

For the NI 4070/4071/4072 only, specifies the rate of the waveform acquisition in Samples per second (S/s). The valid Range is 10.0-1,800,000 S/s. Values are coerced to the closest integer divisor of 1,800,000. The default value is 1,800,000.

The following table lists the characteristics of this property.

Characteristic Value
Datatype float
Permissions read-write
Channel Based No
Resettable No

Tip

This property corresponds to the following LabVIEW Property or C Attribute:

  • LabVIEW Property: Waveform Acquisition:Waveform Rate
  • C Attribute: NIDMM_ATTR_WAVEFORM_RATE

Session