HC900-C70R

[FrederikVR 0]

Hellow I need to control two valves with a split range-control. One valve is fully opened and the other is 30-40% openend. Does anyone know how to do this? This is the work discription i received: Gas from V-5 flows into the first stage scrubber V-1811, where the entrained liquids are separated from gas. Compressor suction pressure is controlled via two pressure control valves PCV-120A and PCV-120B. The control mode for these valves shall be split range-control. The PCS algorithm shall be such that the open and closed analogue values can be changed by PCS engineer (not operator) as and when required. This change may be necessary for optimizing the pressure control if the compressor suction pressure will deviate from original design parameters. These valves are pneumatic operated are fail to close The Valve PCV-120B is equipped with open and close positions indicators and are connected to PCS. The PIC-120 shall control the operation of these valves so that valve PCV-120B will open first fully opened and if still need more demand the other PCV-120A will start open up to 30 to 40 %. Thanks Frederik

[DanW 41]

See David's reply on another forum here: http://www.control.c...7505#1397001915