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Instruction Manual
IM-106-880C, OI
September 2009
5-13
Hazardous Area OCX 8800
COe D/A trim procedure using the LOI
Use the following procedure to perform the COe 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 COe Out. Touch the right-pointing key to
start the COe trim procedure.
NOTE
If you wish to exit D/A Trim with no changes, step through the procedure using
yes 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 COe D/A converter circuit. Connect the positive lead to
the AOUT2+ terminal and connect the negative lead to the AOUT2-
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 COe 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 COe
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 (question). Use the
right-pointing key to select the letter yes or no. Use the up- or
down-pointing key to change the letter. Then use the Enter key to input
the response. If no, the process repeats from step 7.
9. The LOI displays a Meter at 20 mA prompt (question). Use the
right-pointing key to select the letter yes or no. Use the up- or
down-pointing key to change the letter. Then use the Enter key to input
the response. If no, the process repeats from step 8.
10. When the ropiness in steps 9 and 10 are yes, 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 Hazardous Area OCX 8800 must
be removed from the automatic combustion control loop before you start the D/A trim proce-
dure.