Emerson OCX 8800 instruction manual COe D/A trim procedure using HART/AMS

OCX 8800

Instruction Manual

IM-106-880, Rev 1.0 January 2007

COe D/A trim procedure using HART/AMS

Use the following procedure to perform the COe D/A trim procedure using the HART communicator or AMS. Refer to the HART menu tree, Figure 5-3.

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. Press the up or down arrow to select COe 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 2-4. Connect a digital multimeter to read the milliamp output from the COe D/A coverter circuit. Connect the positive lead to the AOUT2+ terminal and connect the negative lead to the AOUT2- terminal. Then, press OK at the HART communicator.

6.The HART communicator displays Setting Fld dev output to 4 mA. Press OK. Read the COe 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 COe 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.

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