Arne Posted December 19, 2021 Report Share Posted December 19, 2021 I use Visilogic and Unilogic for teaching. To be able to demonstrate PID responses using a mA source on the input (simulated process value) and a mA meter on the output, I would (also) like to run the PLC as i PID controller with no process connected. I first made such a program using the Visilogic (V570) and it worked just fine to remove all auto-tuning and to have only manual configuration of P, I, D parameters. (And the output (CV) could be sat manually as well) Then I tried to do the same with Unilogic (USP-70-x10) and this seems to be more difficult. It looks like you first have to make an auto-tuning before the PID function will work. (The Status Indicator will show zero or some other value that will prevent the PID controller from running.) I have found out that if you take the simulated process value from the mA source up and down a few times, I can "fake" a process response and make it run that way, but it is not a really good solution. Is there any possible way of programming a PID control function without auto-tuning? If it is impossible it would also be a valid answer. Then I don't need to use more time to find it out, If it can not be done or not 🙂 (I think that the problem is that the PID_Config.Status bit is not so easy to manipulate without making an auto-tuning first, and that's the reason it is difficult to run it in manual mode, without making this auto-tuning first. Hopefully I'm wrong in some way, or there is some workaround to this "problem".) Quote Link to comment Share on other sites More sharing options...
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