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1- What way I can use to control 2 PID or more with different parameters.2- How can I determine The best PID Gain values.

I have 2 flowing PID seystem with FieldPoint using PID toolkit.
when I run each PID individually it work a little bet fine.
But When I join them in same VI by one PID function as array of tow setpoint , I get unstable system for each PID. then I try to run these in the same VI and using 2 PID function, also it doesn't pork properly.
1- What way I can use to control 2 PID or more with different parameters(PIDGains,Outpu Ranges).
2- How can I determine The best PID Gain values.
 
Best Regards
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Could any one help me please:smileysad :
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wsaall

You can send a screen shot or the VI that shows how you are placing the PID VIs together or with Multichannel mode. Generally speaking, the PID VIs are designed to work separated from each other or on multichannel model without interfering with each other.

Also, just to be sure, the versions of the PID Toolkit and/or LabVIEW RT module would help to identify the problem.

Now, answering your questions:

1. To use two PID with different parameters, you have to create an array with 2 elements, where the element 0 is for the channel 0 and element 1, channel 1 correspondently. If you just provide one set of gains and/or output ranges, it will assume that you want this values to be applied to all channels. So, you can have the same value of Output Range for all channels with only one element in the array and a different PID gains for each channel.

2. To determine the best PID parameters, please refer to PID literature available for tuning PID Controllers. In the PID Manual you would give some information about it.

Hope this helps...

Barp - Control, Simulation, RTT and HIL - National Instruments
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