Rosemount OCX 8800, Instruction Manual

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Instruction Manual
IM-106-880, Rev 2.1
April 2017
OCX 8800
5-12
D/A TRIM
PROCEDURES - LOI
O
2
D/A trim procedure using the LOI
Use the following procedure to perform the O
2
D/A trim procedure at the LOI.
Refer to the LOI menu tree in Figure 4-4.
1. From the operating display use the left-pointing key to select the first
column submenu. Use the down-pointing key to select SYSTEM .
2. From the SYSTEM menu, use the down-pointing key to select
Input/Output . Use the right-pointing key to select the Analog
parameters list.
3. Scroll down to the item Trim O2 Out . Touch the right-pointing key to
start the O
2
trim procedure.
NOTE
If you wish to exit D/A Trim with no changes, step through the procedure using
y es responses, and enter no meter readings.
4. Remove the electronics housing cover.
5. Refer to Figure 2-6. Connect a digital multimeter to read the milliamp
output from the O
2
D/A converter circuit. Connect the positive lead to
the AOUT1+ terminal and connect the negative lead to the AOUT1-
terminal. Then, touch the
Enter key at the LOI.
6. The LOI displays 4 mA........Meter . The trim program inputs the
design-equivalent signal for a 4.00 mA output. Read the O
2
millamp
output at the digital multimeter. Use the right-pointing key to select each
digit and use the up- and down-pointing keys to change the value. When
the correct value is displayed, use the
Enter key to input the value.
7. The LOI displays 20 mA........Meter . The trim program inputs the
design-equivalent signal for a 20.00 mA output. Read the O
2
millamp
output at the digital multimeter. Use the right-pointing key to select each
digit and use the up- and down-pointing keys to change the value. When
the correct value is displayed, use the
Enter key to input the value.
8. The LOI displays a Meter at 4 mA prompt. Use the right-pointing key to
select the letter y es or n o. Use the up- or down-pointing key to change
the letter. Then use the Enter key to input the response. If n o, the
process repeats from step 7.
9. The LOI displays a Meter at 20 mA prompt. Use the right-pointing key
to select the letter y es or n o. Use the up- or down-pointing key to
change the letter. Then use the Enter key to input the response. If n o,
the process repeats from step 8.
10. When the ropiness in steps 9 and 10 are y es, the trim procedure is
complete. Exit the LOI menu and return the control loop to automatic
control.
To avoid a potentially dangerous operating condition, the OCX 8800 must be removed from
the automatic combustion control loop before you start the D/A trim procedure.