fisher dvc6020f relay b

[readfoot]

The company I work build valves and actuators.
I believe we are purchasing the wrong relays on fisher dvc6020f positioners.
We are calibrating the positioners using hart 375 communicator.
We cannot reverse the 4-20ma signal so the valve is closed at 4milliamps instead of open.
There are relays a,b and c.
Is there a way using the 375 communicator to reverse the 4-20ma signal or is that the purpose of the different relays available.

 

[JLSeagull]

Before looking at what can be done with the positioner consider the actuator. For most common rising stem valves, Fisher sells mechanically different actuators, one that pushes down to close or a different model that pushes up to close.

If you plug the communicator onto the DVC you should see all available things that can be selected. I used a laptop with AMS software for this task instead of the hand held communicator. The laptop lets you see everything at once. You should also see the choices in a manual that can be downloaded from the web.

The problem with reversing the action on a positioner is that you establish one failure position for loss of the electrical signal that is opposite the air failure. Selecting the right actuator is better.

 

[ilan7]

The positioner is design for 90 deg movment of the actuator. The normal position is that the positioner got 4 ma it send the actuator to the fail position (Close or open) and for 20ma the actuator will be at the full open (or Close) position. If from some reason you need it the other way, it can be done by using the HART communicator and changing the Feed Back connection to be backword.
Go: ONLINE ==> Setup ==> Basic Setup ==> Manual Setup ==> Press & Actuator ==> Feed back Connection
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