GE CTF878, User & Service Manual

Page: 36 / 72

Calibration 3-5
February 2009
Calibrating Analog Inputs
The Analog Input calibration procedure consists of calibrating the
analog input zero point (0 or 4 mA) and the full scale point (20 mA).
Note:
Calibrating analog inputs requires use of a current source.
Calibrated analog outputs may be used as a current source.
To calibrate an Analog Input, proceed as above, select the desired
Calibrate AnalogIn option, and press [
ENTER
]. The screen appears as
in Figure 3-5 below. Step through the options using the arrow keys.
Figure 3-5: Calibrate Analog Input Window
1.
The first prompt asks you to set the low input (0 or 4 mA).
a.
Press
[ENTER]
to open the text box.
b.
Use the numeric keys to enter the desired value.
c.
Press
[ENTER]
to confirm your entry.
2.
Set the current source to output the current for the Low point
(0 or 4mA).
a.
Press the [
X
] arrow key to move to the Read box and press
[ENTER]
.
b.
Scroll to the Calibrate box and press [
ENTER
] to calibrate the
low point.
3.
The next prompt asks for the value to which you want to set the
high input (20 mA).
a.
Press
[ENTER]
to open the text box.
b.
Use the numeric keys to enter the desired value.
c.
Press
[ENTER]
to confirm your entry.
OK Cancel
mA
Calibrate Reset
Low
High 20 mA
Read
Read
Calibrate Analog Input
4