Omega Engineering OMB-CHARTSCAN 1400, User Manual

Page: 113 / 273

ChartScan User’s Manual Calibration 6-9
1. Connect HI, LO, -S, and +S lines from the precision calibrator to the binding posts of the calibration
card, as indicated in the figure above.
2. Apply -4.4 VDC (minus 4.4 VDC) from the calibrator to the calibration card. Use a precision digital
multimeter to verify voltage accuracy.
Note: You can view the main unit calibration constants by typing:
C#0X QC?
… selects the main unit (chassis)
To monitor the chassis calibration voltage type:
*B
… to clear the buffer
C3,90X
… to address the backplane
T1,1,0,0X;@X
… to trigger the acquisition (Trigger LED flashes);
@X
starts acquisition
U13X
…very entry of U13X results in an updated value of voltage in counts
Voltage will appear in counts. For 4.4 volts the reading should be 32038.844 counts.
Note that
@X
can be used to start or stop the acquisition.
3. Type
G0,91X
. The Trigger LED will flash, indicating that gain calibration is in progress. When
flashing stops, the chassis gain calibration is complete.
4. Type
U2X
.
U128
should appear, indicating the unit is in calibration mode and that no error has
occurred.
5. Apply +4.4 VDC (positive 4.4 VDC) from the calibrator to the calibration card. Use a precision digital
multimeter to verify voltage accuracy.
6. Type
G0,91X
. The Trigger LED will flash, indicating that gain calibration is in progress. When
flashing stops, the chassis gain calibration is complete.
7. Type
U2X
.
U128
should appear, indicating the unit is in calibration mode and that no error has
occurred.
Response codes and meanings applicable to calibration are as follows:
Response to
U2X
Indication for Calibration Mode
U128
No error
U129
Read Failure (EEPROM Error)
U130
Write Failure (EEPROM Error)
U132
Chksum Err (EEPROM Error)
U136
Cal Err (offset, gain, or temperature
sensor out of range)
U144
Invalid password
U160
Invalid command
8. Type
EX
. The calibration mode is disabled.
9. Position the Calibration Enable/Disable Pushbutton in the “non-indent” (disable) position.
Note to
ChartScan users: Early production ChartScan units do not have a Calibration Enable/Disable Pushbutton .
For these units the calibration mode is enabled by positioning the DIP switch right-most micro-switch (#9) to the “1”
(up) position. Note that ChartScan units with the pushbutton have it located on the rear panel, as indicated in the
NetScan figure (page 6-2).
10. Remove power from the main unit and all connected devices.
11. Remove the calibration card from the chassis.
You are now ready to calibrate the signal conditioning cards as described in the following sections of this
chapter.