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Having trouble producing any output on a PID programme

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I'm a student studying at De Montfort University and currently trying to design a PID autotune programme to heat an element. 

The programme is designed using Visilogic and is for a V350-J-TRA22 controller. 

I have managed to display the temperature detected by a thermocouple on the HMI and the programme is almost exactly the same as the one shown in the 'PID' tutorials video on the Unitronics main site but when the controller is wired to an oscilloscope there is no output of any kind. Various combinations and checks have been carried out but nothing so far has worked.

Does the autotune have to be carried out whilst the device is still connected to the PC and then the PID values entered manually or is this all done once the device has powered up automatically as it would suggest? 

I am new to Visilogic so if anyone could check over the programme (attached) to see if i have missed anything or direct me to someone who would, it would be much appreciated


test 25-30.vlp

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  • MVP 2023

I have successfully autotuned and run a PID loop without any I/O attached by varying the analog input by hand. The resulting PID values would not work in the real world, but I was able to test to make sure the PID loop was set up correctly.

The PID values can be calculated by the autotune process or you can enter them manually. You have either or both options available to you.

You don't need an oscilloscope to see analog output. Just go online and look at the MI operand attached to the analog output.

By the way, there are example projects that came with your VisiLogic installation that include an example for PID loops. Take a look at that and see if your PID is set up correctly.

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