Hach sc1000 - Manual (Page 129)

127
Troubleshooting
8.5.2 Test the input card
In the TEST/MAINT menu, every input current channel can be checked. If necessary,
each input can be adjusted as well.
The input current can be checked by setting a defined current to the according channel
and then comparing it with the displayed value. If necessary, the displayed value can be
adjusted with an offset and a factor.
To set these parameters:
1. Set the SET OFFSET value to “0” and the SET FACTOR value to “1”.
2. Set the input current to a fairly small value (1 mA for example).
3. Adjust the SET OFFSET until the displayed current meets the set current.
4. Set the input current to a fairly big value (19 mA for example).
5. Adjust the SET FACTOR value until the displayed input current meets the set input
current.
6. Cross-check the small input current.
7. Repeat the steps 1–6 until the input precision reaches a desired value.
TEST/MAINT
CURRENT INPUTS
mA INPUT INT/EXT
FUNCTION TEST
INPUT 1-4
INPUT CURRENT Displays the input current according to the current set to the corresponding channel.
SET FACTOR
Default value: 1
Adjusts the displayed input current with an factor.
SET OFFSET
Default value: 0
Adjusts the displayed input current with an offset.
OUTPUT MODE
Default value: HOLD
Decides how other members react if they try to read an input current value while the input
current card is in the function test. As the value of the input current in the function test is not
based on any measurements other members reading this value probably have to be informed
about this special situation. There are three settings: Hold, Active and Transfer.
HOLD
Another reading member does not use the current read value but uses the last value before the
output current card was in the function test mode.
ACTIVE
Another reading member uses the current value even if the output current card is in the function
test mode.
TRANSFER The reading member uses an own substitute value for its own output value.