russedwards Posted August 2, 2012 Report Share Posted August 2, 2012 Hello again Thank you all for your recent help. I have certainly experienced a steep learning curve with Visilogic! I require some help with using a PID function to control the putput of one of my valves. The problem I have is that the valve is "chattering" when near to the setpoint, i.e opening and shutting very fast as the setpoint is reached. I need to slow down the operation of the output, the control does not need to be so precise - i.e control within +/- 3 mbar of the setpoint at 103 mbar, or only open again after 2 seconds of closing. I thought that I would use the PID function to sort this problem but I am really stuck. COuld anyone please help me in very simple terms, to show me how to implement the PID into my ladder? I am using MI 2 as a linearisation of a 4 to 20 mamp input ranged 0 to 1000 mbar. This is what I want to use as my process input. Set point is 103 mbar Control can be +/- 3 or 4 mbar Would like to control Output 8 with teh PID function. Thankyou in advance :) Quote Link to comment Share on other sites More sharing options...
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