Pleiger system

[Tom749]

I use the Pleiger system now. The system is as follows. --------------------------------------------------------- PLC : CPU315-2 (Siemens) Communication : Profibus ---------------------------------------------------------- Comm. card : BI 01 (Pleiger company) Control Module : EHS-CM3 (Pleiger company) Actuator : EHS-D3-1/56 (Pleiger company) ---------------------------------------------------------- The problem is not easy to control the valve by siemens PID function. Because of the valve Dead-zone (+/-3%). For instance my destination position is the 52% from the 50% position. In order to do that I use the 2 ways as follows. Way1) At first open the valve to the 56% position to avoid the Dead-zone. Then go to the 52% position of the valve. (By the siemens PID function) Way2) use the manual command(101/102/103) by a timer. But these kinds of ways are not the perfect PID function control. Is there anyone who use this system? Thanks for your help in advance. (p.s. I attach the electric drawings) Edited March 22, 2013 by Tom749