niDMM_ConfigureAutoZeroMode

NI-DMM C/CVI/VB

niDMM_ConfigureAutoZeroMode

ViStatus = niDMM_ConfigureAutoZeroMode(ViSession Instrument_Handle, ViInt32 Auto_Zero_Mode)

Purpose

Configures the DMM for Auto_Zero_Mode. When Auto_Zero_Mode is ON, the DMM internally disconnects the input signal and takes a zero reading. It then subtracts the zero reading from the measurement. This prevents offset voltages present on the input circuitry of the DMM from affecting measurement accuracy. When Auto_Zero_Mode is OFF, the DMM does not compensate for zero reading offset.

Parameters

Input
Name Type Description
Instrument_Handle ViSession Identifies a particular instrument session. You obtain the Instrument_Handle parameter from niDMM_init or niDMM_InitWithOptions. The default is None.
Auto_Zero_Mode ViInt32 Specifies the Auto_Zero_Mode. NI-DMM sets the NIDMM_ATTR_AUTO_ZERO attribute to this value.

ON enables Auto_Zero_Mode for each measurement. ONCE enables Auto_Zero_Mode before the next measurement. The Auto_Zero_Mode value is stored and used in subsequent measurements until the device is reconfigured.

OFF disables Auto_Zero_Mode. If you set this parameter to AUTO, NI-DMM determines whether to enable Auto Zero based on the measurement function that you configure. If you configure the NI 4070/4071/4072 for a 6½–digit and greater resolution DC measurement, NI-DMM sets Auto_Zero_Mode to ON.

For all other DC measurement configurations on the NI 4070/4071/4072, NI-DMM sets Auto_Zero_Mode to ONCE. For all AC measurements or waveform acquisitions on the NI 4070/4071/4072, NI-DMM sets Auto_Zero_Mode to OFF. For NI 4060, Auto_Zero_Mode is set to OFF when AUTO is selected.

For NI 4065 devices, Auto_Zero_Mode is always ON. Auto_Zero_Mode is an integral part of the signal measurement phase and adds no extra time to the overall measurement.

NIDMM_VAL_AUTO_ZERO_AUTO (default) -1 NI-DMM chooses the Auto Zero setting based on the configured function and resolution.
NIDMM_VAL_AUTO_ZERO_OFF  0 Disables Auto Zero.
Note  The NI 4065 does not support this setting.
NIDMM_VAL_AUTO_ZERO_ON  1 The DMM internally disconnects the input signal following each measurement and takes a zero reading. It then subtracts the zero reading from the preceding reading.
Note  For NI 4065 devices, Auto_Zero_Mode is always ON. Auto_Zero_Mode is an integral part of the signal measurement phase and adds no extra time to the overall measurement.
NIDMM_VAL_AUTO_ZERO_ONCE  2 The DMM internally disconnects the input signal following each measurement and takes a zero reading. It then subtracts the zero reading from the preceding reading.
Note  The NI 4060/4065 does not support this setting.

Return Value

Name Type Description
Status ViStatus Reports the Status of this operation. To obtain a text description of the status code, call niDMM_error_message. To obtain additional information concerning the error condition, use niDMM_GetError.