Trimming Recorder Outputs; Preliminary Steps - GE Moisture Image 1 Series Service Manual

Trimming Recorder
Outputs

Preliminary Steps

Troubleshooting and Maintenance
The measured value of the recorder outputs can vary from the
programmed value due to load resistance tolerance (e.g. chart
recorder, display, computer interface, etc.). The Recorder Test Menu
provides a trimming feature you can use to compensate for any
variation in the recorder outputs.
To accurately trim the recorder outputs you will need a digital
multimeter capable of measuring 0 to 2-V with a resolution of
±0.0001 VDC (0.1 mV) or 0 to 20-mA with a resolution of ±0.01 mA.
(The range you use depends on your recorder output.) Most good
quality 3 1/2-digit meters are adequate for recorder output trimming.
Use the following steps to trim recorder outputs.
1. Make sure the recorder switches on the corresponding channel
card(s) are set for the correct output - current (I) or voltage (V).
Refer to Connecting the Recorder Outputs on page 1-4 to check
switch settings.
2. Disconnect the load (e.g., chart recorder, indicator) from the end
of the recorder output signal wires.
3. Attach the digital multimeter to the signal wires in series or
parallel as shown in Figures 2-3 and 2-4.
If the recorder location is very distant from the Series 1, you may
want to have one person making readings at the recorder location
and one person making readings at the meter location.
MOISTURE IMAGE
SERIES 2
POWER
Red+
DMM
Figure 2-3: Checking the Series 1 Current Outputs
Series 1
1 2 3 YES
4 5 6 NO
7 8 9
.
- 0
Red-
Chart Recorder
June 2003
2-5