Operator`s manual

119 Signametrics
2. Select the ACV function, autorange. Turn freq on.
3. Apply the following AC voltages to the V, Ω + & - terminals. Check to see that the displayed reading on the
SM2042/44 is within the indicated range of readings.
Table 9-9. ACV Frequency Counter Test
Step Range Input Minimum Reading Maximum reading
1 330 mV 33 mV, 40 Hz 39.9952 Hz 40.0048 Hz
2 3.3 V 330 mV, 40 Hz 39.9952 Hz 40.0048 Hz
3 33 V 3.3 V, 40 Hz 39.9952 Hz 40.0048 Hz
4 330 V 33 V, 40 Hz 39.9952 Hz 40.0048 Hz
5 330 mV 250 mV, 100 kHz 99.996 kHz 100.004 kHz
6 33 V 25 V, 100 kHz 99.996 kHz 100.004 kHz
2. Select the ACI function, autorange. Turn freq on.
3. Apply the following AC currents to the I,4Ω + & - terminals. Check to see that the displayed reading on the
SM2040 is within the tolerance appropriate for your application (e.g. 90 day or 1 year accuracy).
Table 9-10. ACI Frequency Counter Test
Step Range Input Counter Reading Tolerance
1 3.3 mA 330 uA, 40 Hz
2 33 mA 15 mA, 40 Hz
3 330 mA 150 mA, 40 Hz
6.10 Calibration
Each SM2040 DMM uses its own SM40CAL.DAT calibration file to ensure the accuracy of its functions and
ranges. The SM40CAL.DAT file is a text file that contains the DMM identification number, calibration date, and
calibration constants for all DMM ranges. For most functions, the calibration constants are scale factor and offset
terms that solve the "y = mx + b" equation for each range An input "x" is corrected using a scale factor term "m"
and an offset term "b"; this gives the desired DMM reading, "y". Keep in mind that for ranges and functions that
are unavailable for a particular product in the SM2040 family, the calibration record contains a place-holder. An
example SM40CAL.DAT is shown:
card_id 10123 type 2044 calibration_date 06/15/1999
ad ; A/D compensation
72.0 20.0
vdc ; VDC 330mV, 3.3V, 33V, 330V ranges, offset and gain parameters
-386.0 0.99961
-37.0 0.999991
-83.0 0.999795
-8.8 1.00015
vac ; VAC 1st line - DC offset. Than offset, gain and freq each range 330mV to 250V
5.303
0.84 1.015461 23
0.0043 1.0256 23
0.0 1.02205 0
0.0 1.031386 0
idc ; IDC 3.3mA to 2.5A ranges, offset and gain
-1450.0 1.00103
-176.0 1.00602
-1450.0 1.00482
-176.0 1.00001