Teledyne 300M - Manual (Page 89)

Teledyne API Model 300M CO Analyzer Instruction Manual, 04033, Rev. A
9.2 A/D - D/A Calibration Procedure
Due to the stability of modern electronics, this procedure should not have to be performed more
than once a year or whenever a major sub-assembly is exchanged or whenever analog output
voltage range is changed.
To calibrate the voltage output, do the following: 4 - 20 mA current output calibration procedure
should follow after voltage calibration.
1. Press SETUP-MORE-DIAG.
2. Enter Diagnostic password and press NEXT until D/A CALIBRATION appears in the
display and press ENTR.
3. Press ADC to perform the A/D Cal.
4. The M300M display will read "ADJUST ZERO:A/D=xx.x MV." Put the probe of a
voltmeter between TP3 (AGND) and TP9 (DAC #0) on the top of the V/F card (See Drawing
00514, Appendix C).
5. The value displayed by the voltmeter should be close ( ± 2 mV) to the value on the M300M
display. If they are not close then the V/F card has probably been configured improperly.
6. Adjust the Zero pot (R27) on the V/F card until the value on the M300M display matches the
value on the voltmeter to within ± 2 mV.
NOTE
When adjusting R27, the value on the M300M display will change,
the value on the voltmeter will remain constant.
7. Press ENTR.
8. The M300M display will now read "ADJUST GAIN:A/D=xx.x MV."
9. Adjust the Span pot (R31) on the V/F card until the value on the M300M display matches the
value on the voltmeter to within ± 2 mV.
10. Press ENTR.
11. The ADC is now calibrated and the M300M will automatically calibrate all the DAC’s. This
process takes only a few seconds.
12. Press EXIT 4 times to return to the sample menu.
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