Bumpless valve changeover

[Eidde]

I am looking for a way to do a smooth changeover between to control valves from the DCS (Siemens Moore APACS)

 

[hacksaw]

that is a routine control requirement these days, it should be in the controller options offered by the dcs

 

[CARF]

This is a simple method:

If the valve has digital feedback (position) sensors on OPEN and CLOSE position, when change-over wait for the OPENING VALVE to give an OPEN signal. Only when this signal is received you can CLOSE the CLOSING VALVE.

A small timer (5 seconds) can smooth the operation even more.

This is a very good practice to avoid water/fluid hammer (high pressures) in the piping system.

Good luck,
CARF