cRio-9066 Random overshoot?!

[Narmer]

Hello,

I am using cRio-9066 in order to control pressure regulators.

The pressure regulators are used to control a force applied by pneumatic cylinders.

Force feedback goes back to the controller via load cells. 

Most of the time the system works normally, however, sometimes and randomly the system overshoot to the maximum voltage value once the system is switched to run mode (i.e maximum force)

despite there is feedback from the load cells and the theoretical assigned load is still zero. 

The PID gain:

-Kc=0.002

-Ti=0.006 min.

-Td= 0.000 min.

PID-Output range (v):

-Output high=8

output low=0.1

What could be the source for this issue?

[GerdW]

Hi Narmer,

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@Narmer wrote:

What could be the source for this issue?

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Probably your VI, which you failed to attach…

[Narmer]

Thank you for your reply.

I didn't get your point, excuse my limited knowledge in control. 

[JensG69]

You only posted a picture of your front-panel. We do not know how you have programmed your PID-loop. We need to have a look at the source code (i.e. the block diagram, i.e. at your VI). Please upload this for further analysis.

Regards, Jens

[rolfk]

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@Narmer wrote:

Thank you for your reply.

I didn't get your point, excuse my limited knowledge in control. 

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What he tried to say is that there is an extremely high chance that the behaviour you observe is caused by the way you programmed your VI, but since you forgot to attach your VI, we can't help you further. And no, an image of a VI diagram is almost never enough to diagnose a problem and definitely useless to try it out on our own systems and try to debug it. And an image of a front panel is even less useful (basically not for any debugging purposes).

Compare this to the situation where you have a problem with your car. You don't make a photograph to send to your mecanicien to diagnose the failure but actually bring your car to him so he can take a look at it. Unless you crashed your car into a wall, the picture is pretty useless for him to diagnose why your car doesn't run anymore.