Emerson ROSEMOUNT OCX 8800 - Manual (Page 53)

Instruction Manual
IM-106-880, Rev 1.0
January 2007
4-9
OCX 8800
D/A TRIM PROCEDURES O
2
D/A trim procedure using HART/AMS
Use the following procedure to perform the O
2
D/A trim procedure using the
HART communicator or AMS. Refer to the HART menu tree, Figure 4-3.
NOTE
To select a menu item, either use the up and down arrow keys to scroll to the
menu item and press the right arrow key or use the number keypad to select
the menu item number.
To return to a preceding menu, press the left arrow key.
1. From the DIAG/SERVICE menu, select D/A TRIM. The HART
communicator displays O2 D/A Trim.
2. Press the right arrow key to start the procedure. (If you wish to exit D/A
Trim with no changes, select ABORT.)
3. The HART communicator displays WARNING: Loop should be
removed from automatic control. Remove the OCX 8800 from any
automatic control loops to avoid a potentially dangerous operating
condition and press OK.
4. Remove the electronics housing cover.
5. Refer to Figure 2-5. Connect a digital multimeter to read the milliamp
output from the O
2
D/A coverter circuit. Connect the positive lead to the
AOUT1+ terminal and connect the negative lead to the AOUT1-
terminal. Then, press OK at the HART communicator.
6. The HART communicator displays Setting Fld dev output to 4 mA.
Press OK. Read the O
2
millamp output at the digital multimeter. Enter
the reading at the HART communicator and press ENTER. (Select
ABORT to exit without changes).
7. The HART communicator displays Setting Fld dev output to 20 mA.
Press OK. Read the O
2
millamp output at the digital multimeter. Enter
the reading at the HART communicator and press ENTER. (Select
ABORT to exit without changes).
8. The HART communicator displays Setting Fld dev output to 4 mA.
Press OK.
9. The HART communicator displays Fld dev output 4.00 mA equal to
reference meter? Using the up or down arrow, select 1 Yes or 2 No
and Press ENTER. If No, the process repeats from step 6.
10. The HART communicator displays Setting Fld dev output to 20 mA.
Press OK.
11. The HART communicator displays Fld dev output 20.00 mA equal to
reference meter? Using the up or down arrow, select 1 Yes or 2 No
and Press ENTER. If No, the process repeats from step 7.
12. The HART communicator displays NOTE: Loop may be returned to
automatic control.