Sets the auto zero status
GxDmmSetAutoZero(nHandle, dwAutoZeroMode, pnStatus)
Name |
Type |
Comments |
nHandle |
SHORT |
Handle for a GX2065 board. |
dwAutoZeroMode |
DWORD |
Sets the status of the Auto Zero function.0. GXDMM_AUTO_ZERO_ON: The DMM will perform an auto zero every time a measurement is taken.1. GXDMM_AUTO_ZERO_OFF: The DMM will not auto zero when a measurement is taken.2. GXDMM_AUTO_ZERO_NOW: The DMM will perform an auto zero calculation as soon as this command is received. |
pnStatus |
PSHORT |
Returned status: 0 on success, negative number on failure. |
To help maintain stability and accuracy over time and changes in temperature, the DMM periodically measures internal voltages corresponding to offsets (zero) and amplifier gains. These measurements are used in an algorithm to calculate the reading of the input signal. This process is known as auto zeroing.
When auto zero is disabled, the offset and gain measurements are not performed. This increases the measurement speed (reading rate). However, the zero and gain reference points will eventually drift resulting in less accurate readings of the input signal.
It is recommended that auto zero only be disabled for short periods of time.
An auto zero can also be forced by using the GXDMM_AUTO_ZERO_NOW mode.
The following example performs (forces) an auto zero before taking a measurement:
SHORT nHandle, nStatus;
DOUBLE dMeasurement;
GxDmmSetAutoZero (nHandle, GXDMM_AUTO_ZERO_NOW, &nStatus);
GxDmmMeasure(nHandle, &dMeasurement, &nStatus);
GxDmmGetAutoZero, GxDmmSetFunction, GxDmmSetAperture, GxDmmSetRange, GxDmmGetRange, GxDmmGetErrorString