GE DigitalFlo XGM868i, Service Manual

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DigitalFlow™ XGM868i Service Manual 47
Appendix B. Calibration and Testing with PanaView
B.4.2 Analog Inputs
Analog inputs may be added to the Model XGM868i by installing an appropriate option card in Slot 1 . This option card
contains two or four analog inputs, which are designated as A, B, C and D. Both the zero-point and full-scale values for
each input must be calibrated.
Calibration of the analog inputs requires the use of a calibrated current source. If an independent calibrated current
source is not available, one of the
Slot 0
analog outputs may be used for the calibration. During the analog input
calibration, the
Slot 0
analog output will supply the low reference, high reference, 4 mA and 20 mA signals at the
appropriate times.
IMPORTANT:
If a
Slot 0
analog output will be used to calibrate the analog inputs, the
Slot 0
analog output calibration
procedure must be completed first.
Prepare for the calibration procedure by connecting a
Slot 0
analog output (or independent calibrated current source) to
Input A
of the option card. See Figure 4 on page 12 to identify the
IN(+)
and
RTN(-)
pins for
Input A
on terminal block J2.
Note: The zero point of the analog input may be set for either 0 mA or 4 mA. However, the calibration procedure
always uses the 4 mA point, as the meter will extrapolate this value to obtain the 0 mA point.
1. In the center pane of the Calibration/Test window, double-click on Slot 1 .
2. Double-click on the desired input to open the Analog Input menu. (
Input A
will be used as an example in this
manual.)
IMPORTANT: Calibrating Inputs B, C or D is identical to calibrating Input A . However, be sure to reconnect the current
source on terminal block J2 . Refer to Figure 4 on page 12 for the correct pin numbers.
3. Double-click on the appropriate option to select the reference point to be calibrated.
Proceed to the corresponding sub-section for specific instructions on each of the options available in step 3.
B.4.2a 4 mA Option
Set the calibrated current source to 4 mA.
•
If you selected the 4 mA option in the Analog Input menu, double-click on Store to accept the current 4 mA value or
on Abort to cancel the entry. In either case, the Analog Input prompt reappears.
B.4.2b 20 mA Option
Set the calibrated current source to 20 mA.
•
If you selected the 20 mA option in the Analog Input menu, double-click on Store to accept the current 20 mA value
or on Abort to cancel the entry. In either case, the Analog Input prompt reappears.
Click [Exit Page] to return to the Slot 1 window and calibrate additional inputs/outputs, or click [Exit Page] again to
close the Calibration/Test menu.