Service
Analog Output Current Mode Calibration (Continued)
5. Read the output voltage with the DMM. Divide this number by the
measured resistor value and record this zero output (ZERO) value.
6. Set the analog output to +100% (20 mA).
Example:
Manual +FS Current Command: ANALOG 3,2
7. Read the output voltage with the DMM. Divide this number by the
measured resistor value and record this positive full scale (+FS) value.
8. Determine the offset calibration constant by subtracting the ZERO
value from the zero current point of 4 mA and divide that by the
difference of the +FS value and the ZERO value.
Offset constant = (4E-3
– ZERO) / (+FS – ZERO).
9. Use the CALZ command to send the offset calibration constant.
Example:
ZERO DMM Reading: 4.03974E-3
+FS DMM Reading: 20.0674E-3
Offset Constant Calculation: (4E-3 – 4.03974E-3) /
(20.0674E-3 – 4.03974E-3) = –0.00248
Calibration Command: CALZ 2,1,–0.00248
10. Determine the gain calibration constant by adding the +FS reading to
the inverse of the ZERO reading obtained in step 5 and dividing that
number into 16 mA. Gain constant = 16E-3 / (+FS – ZERO).
11. Use the CALG command to send the gain calibration constant.
Example:
ZERO DMM Reading: 4.03974E-3
+FS DMM Reading: 20.0674E-3
Gain Constant Calculation:
16E-3
/ (20.0674E-3 – 4.03974E-3) = 0.99827
Calibration Command: CALG 2,1,0.99827
12. Send the CALSAVE command to finalize the calibration.
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