Mick Posted February 6, 2018 Report Share Posted February 6, 2018 Hello, I use the PID with autonune of the Samba PLC. It doesn't work well and i don't understand why. That is my hardware set up for PID : => analog input is 4-20mA (voltage measure 4-20mA : from a 0-100V / 4-20mA converter), => analog output is 4-20mA. ( control voltage 4-20mA : to a 4-20mA / 0-5V converter) At first the PID status stayed at -11. I've read on the help file that it's could be the noise at the input, so i follow the advice by increase the high limit and decrease the low limit on the PV input. After tying a lot of different setting the autotune then PID finally works. Now, i try an auto-tune and it doesn't work anymore, two situation : - I set a wide range in the PV input : the control value go on the max value or the min value, the PID status stay at 2 - I set a smaller range in the PV input : The PID status stay at -11. For information i use on the Samba the 4 analog input, and the 2 analog output. Could the problem come from the speed between the input and the output? I need help. I try for several day to fix the problem, but i still no understand and I'need PID function on my project. My program file is to big for attach. Mick Quote Link to comment Share on other sites More sharing options...
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