Flowserve 3400IQ User Manual

Page 19

Logix 3400IQ Digital Positioner FCD LGENIM3403-00 – 11/07

6. Activate the custom curve by selecting Custom Characterization Active in CONTROL_FLAGS. (NOTE:
Make sure that neither Quick Opening Curve nor Equal Percent Curve has been selected.)

7. Write the changes to the Logix 3400IQ digital positioner.

8. Verify the proper operation of the stroke response by incrementally writing values to FINAL_VALUE. (The
Resource block must also be OOS first.) CMD_USED, FINAL_POSITION_VALUE, and the valve response
should track the desired curve.

9. Return the valve to service by returning both MODE_BLKs back to Auto.

Characterization Retention
Once a custom curve has been loaded into the Logix 3400IQ digital positioner’s memory it is retained in the
EPROM until it is either edited or replaced. Turning Custom Characterization Active on or off now selects
between a linear response (Off), or the new custom curve (On). If either of the other two factory curves is
selected, it will overwrite the custom curve in RAM only. The custom curve will automatically be activated
again when the factory curve is deselected.

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