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[ATR243] PID regulation to control valve with analog output

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user7736
Posts: 19
Joined: 25/02/2014, 13:37

[ATR243] PID regulation to control valve with analog output

Post by user7736 »

Hello,

I have ATR243 in application - PID with analog output. ATR243 controls pneumatic analog valve (medium is Steam so reaction is quite fast)
1. Does 'cycle time 21.' in this application is time how fast this valve gets from closed to open?
2. In this application I tried auto tuning multiple times and I get different values for PID controller (ID where quite similar all the time, but P changed a lot form ~8...40) Is there a correct time when activate auto tuning or some correct way in general?
3. There where 2 similar processes for one auto tuning worked very good, for second - controller always fluctuated its output for few % when temperature was reached.
Pixsys tecnico 1
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Re: ATR243 PID with analog output

Post by Pixsys tecnico 1 »

Hi,
- [TC] is the time that the valve need to move from completely close to completely open.

- try to launch autotuning when process is about 50% of the setpoint. Turn off the regulator and wait until process is quite stable (if regulator is off valve doesn't move), so when you power on it calculates PID values starting form a stable process.

- if output change continuously, maybe you are not using hysteresis. Check [c.HY] parameter.
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