MEATEST, s.r.o.
M-142 Multifunction Calibrator
User Manual v54
49
Calibration mode
The multifunction calibrator includes a calibration procedure, which allows calibration of the calibrator. Zero
point and slope of the characteristics of individual generation and measurement ranges are set during the
calibration in predefined order. The calibration can only be controlled using the buttons and menu on the
calibrator.
The calibration mode includes AUTOCAL autocalibration function. This function can automatically correct the
short-term instability of zero point for voltage ranges up to 20 V. This function is not a part of the complete
calibration procedure, but it can be used to reduce the time and temperature dependent drift of zero point when
calibrating using small DC voltages and when simulating the thermocouples.
Calibration principles
The calibrator can be calibrated:
•
completely, i.e. all functions are calibrated in all recommended points
•
partially, i.e. only selected functions are calibrated in all recommended points
•
partially, i.e. only selected functions are calibrated in selected points
Complete calibration consists of all partial calibrations performed in the order defined by the calibration menu. If
an item of the calibration menu, e.g. “VOLTAGE DC” is selected, it is not necessary to calibrate all ranges
defined by the calibration algorithm. If new calibration of all ranges is not possible (e.g. the required standard is
not available), old calibration data can be confirmed, i.e. current step of the calibration can be skipped.
DC voltage
calibration is performed by setting the zero and slope of the scale in all ranges and in both signal
polarities (+ and -) (except the 1000 V range, where zero correction is not necessary).
AC voltage
calibration is performed by setting the zero and slope of the scale in all ranges at 1000 Hz (except
the 1000 V range, where the calibration is performed at 500 Hz).
DC current
calibration is performed by setting the zero and slope of the scale in all ranges and in both signal
polarities (+ and -).
AC current
calibration is performed by setting the zero and slope of the scale in all ranges at 1000 Hz (except
the 20 A, where the calibration is performed at 120 Hz).
AC and DC
power
calibration is performed by calibration of DC and AC current. The phase relationship of
voltage and current (power factor) is defined digitally and cannot be calibrated. It can only be checked. The
respective check is not included in the calibration procedure.
Resistance
calibration is performed by setting the zero and slope of the scale in all ranges. Slope of each range is
calibrated twice. In practice, 9 internal range resistances (50
to 1000 M
) must be measured and the measured
value entered into the calibrator; then the zero point of the scale is adjusted for each range. Calibration of
resistance ranges must be performed using AUXILIARY connector and cable adapter Option 70 in range 0 to
100 k
, and directly from Hi – Lo output terminals in range above 100 k
.
Capacitance
calibration is performed by setting the zero and slope of the scale in all ranges. Slope of each range
is calibrated twice. In practice, 9 internal capacitance ranges (1 nF to 100
F) must be measured and the
measured value entered into the calibrator; then zero point of the scale is adjusted for each range.
Calibration interruption can be performed in any point of the calibration
procedure. However this particular calibration influences parameters of the
calibrator.
Accuracy of the calibrator is guaranteed when full calibration was done.
