nidmm.Session methods

nidmm.Session.abort()

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

nidmm.Session.configure_ac_bandwidth(ac_minimum_frequency_hz, ac_maximum_frequency_hz)

Configures the nidmm.Session.ac_min_freq and nidmm.Session.ac_max_freq properties, which the DMM uses for AC measurements.

Parameters:
  • ac_minimum_frequency_hz (float) – Specifies the minimum expected frequency component of the input signal in hertz. This parameter affects the DMM only when you set the nidmm.Session.method property to AC measurements. NI-DMM uses this parameter to calculate the proper aperture for the measurement. The driver sets the nidmm.Session.ac_min_freq property to this value. The valid range is 1 Hz–300 kHz for the NI 4080/4081/4082 and the NI 4070/4071/4072, 10 Hz–100 Hz for the NI 4065, and 20 Hz–25 kHz for the NI 4050 and NI 4060.
  • ac_maximum_frequency_hz (float) –

    Specifies the maximum expected frequency component of the input signal in hertz within the device limits. This parameter is used only for error checking and verifies that the value of this parameter is less than the maximum frequency of the device.

    This parameter affects the DMM only when you set the nidmm.Session.method property to AC measurements. The driver sets the nidmm.Session.ac_max_freq property to this value. The valid range is 1 Hz–300 kHz for the NI 4080/4081/4082 and the NI 4070/4071/4072, 10 Hz–100 Hz for the NI 4065, and 20 Hz–25 kHz for the NI 4050 and NI 4060.
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. This parameter is ignored 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.
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. This parameter is ignored 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.
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.
nidmm.Session.configure_open_cable_comp_values(conductance, susceptance)

For the NI 4082 and NI 4072 only, configures the nidmm.Session.open_cable_comp_conductance and nidmm.Session.open_cable_comp_susceptance properties.

Parameters:
  • conductance (float) – Specifies the open cable compensation conductance.
  • susceptance (float) – Specifies the open cable compensation susceptance.
nidmm.Session.configure_power_line_frequency(power_line_frequency_hz)

Specifies the powerline frequency.

Parameters:power_line_frequency_hz (float) – Powerline Frequency specifies the powerline frequency in hertz. NI-DMM sets the Powerline Frequency property to this value.
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).
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).
nidmm.Session.configure_short_cable_comp_values(resistance, reactance)

For the NI 4082 and NI 4072 only, configures the nidmm.Session.short_cable_comp_resistance and nidmm.Session.short_cable_comp_reactance properties.

Parameters:
  • resistance (float) – Specifies the short cable compensation resistance.
  • reactance (float) – Specifies the short cable compensation reactance.
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.
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.
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.
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.
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.

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.
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.
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.
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.
nidmm.Session.get_aperture_time_info()

Returns the DMM Aperture_Time and Aperture_Time_Units.

Return type:tuple (aperture_time, aperture_time_units)

WHERE

aperture_time (float):

Specifies the amount of time the DMM digitizes the input signal for a single measurement. This parameter does not include settling time. Returns the value of the nidmm.Session.aperture_time property. The units of this property depend on the value of the nidmm.Session.aperture_time_units property. On the NI 4070/4071/4072, the minimum aperture time is 8.89 µs, and the maximum aperture time is 149 s. 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, the PLCs allowed are 1 PLC, 6 PLC, 12 PLC, and 120 PLC. When the powerline frequency is 50, the PLCs allowed are 1 PLC, 5 PLC, 10 PLC, and 100 PLC.

aperture_time_units (nidmm.ApertureTimeUnits):

Indicates the units of aperture time as powerline cycles (PLCs) or seconds. Returns the value of the nidmm.Session.aperture_time_units property.
SECONDS 0 Seconds
POWER_LINE_CYCLES 1 Powerline Cycles
nidmm.Session.get_auto_range_value()

Returns the Actual_Range that the DMM is using, even when Auto Range is off.

Return type:float
Returns:Indicates the actual_range the DMM is using. Returns the value of the nidmm.Session.auto_range_value property. The units of the returned value depend on the method.
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.
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.

Returns the recommended interval between external recalibration in Months.

Note

The NI 4050 and NI 4060 are not supported.

Return type:datetime.timedelta
Returns:Returns the recommended number of months between external calibrations.
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.
nidmm.Session.get_measurement_period()

Returns the measurement Period, which is the amount of time it takes to complete one measurement with the current configuration. Use this method right before you begin acquiring data—after you have completely configured the measurement and after all configuration methods have been called.

Return type:float
Returns:Returns the number of seconds it takes to make one measurement.

The first measurement in a multipoint acquisition requires additional settling time. This method does not include this additional time or any nidmm.Session.trigger_delay associated with the first measurement. Time required for internal measurements, such as nidmm.Session.auto_zero, is included.
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.
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.configure_open_cable_comp_values().

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

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.
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.configure_short_cable_comp_values().

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

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.
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.
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.
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
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.
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.

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.

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.

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.

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.