Positioner Bypass

[elangovan8391]

Hi,

I am quoting with Electro-pneumatic positioner, But Cutomer has requested to provide Positioner Bypass. But i am not sure whether Bypass is applicable for Electro pneumatic Positioner, somebody please help me.

Elango

 

[gerhardl]

Please give details, else impossible to answer. (It is always possible to by-pass any technical contraption).

 

[danw2]

I've only ever seen a bypass on a pneumatic (input) positioner. The purpose is to allow for maintenance of the positioner without interrupting valve service, assuming that the input-to-output ratio (control signalutput) is 1:1, the valve is direct action, and it's not a split range operation.

The bypass selection connects the pneumatic control signal input directly to the actuator and blocks the supply air.

There's no pneumatic control signal to connect to the actuator if an electro-pneumatic positioner is taken out of service.

The conventional pneumatic bypass mode is just not available on anything but pneumatic positioners.

For proof, look at Fisher's 3582 positioner instruction manual (page 6, type number descriptions).
Link
The pneumatic 3582's all have an option for bypass whereas the 3582i, the electropneumatic model, does not have a bypass option.

 

[gerhardl]

It is till possible to bypass any technical contraption! Quite another question is if this is a commercial available solution for the one you have in mind, and details are still needed for a proper answer.

 

[danw2]

Yup

 

[elangovan8391]

Thank s guys.