6/13/2012 9:15 AM | |
Joined: 1/28/2009 Last visit: 9/10/2024 Posts: 6849 Rating: (1365)
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Hello markpain, Disturbance signal contaminates measured value of a process by negatively has effect on it.As an example, consider several Tanks in vicinity while their temperature effects each other. As I know, feed forward is a method to counteract those effects.Command for a control valve is as follow in most of SIMATIC software control package: LMN = LMN_P +LMN_I +LMN_D + DISV You have 2 options to choose a value for DISV. 1-Choose a transfer function (mostly a first order filter) and feed the signal from measure disturbance signal to this input(DISV) of PID function. in example of tanks,disturbance signals are the temperatures for other tanks. 2-Instead of selecting a transfer function, it is possible to estimate.The procedure described in section "7.1" of this reference.It is possible to do that in SIMATIC range of products but personally I have not tried that. Hope this helps Best regards, Hamid Hosseini |
Last edited by: hdhosseini at: 6/13/2012 9:20 AM//typo |
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