Power Supply output voltage not equal to PID set voltage value

[win2023]

Hi,

My LabVIEW code was working fine that controlled the DC power supply through PID controller. But as I set the maximum voltage in PID vi to a higher value (currently 100 Volt), my output voltage given by the power supply is 85.8 volts only,I also cross checked this voltage output read by the NI VISA with the help of multi-meter that is same as output voltage read by NI VISA.

Please help me out with the following question -

Why my power supply is not able to increase the voltage output as commanded by the PID controller?

any suggestion would be appreciated?

PS - My power supply can supply maximum rated voltage of 160 volt and 10 amp current.

[billko · Accepted solution]

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@win2023 wrote:

Hi,

My LabVIEW code was working fine that controlled the DC power supply through PID controller. But as I set the maximum voltage in PID vi to a higher value (currently 100 Volt), my output voltage given by the power supply is 85.8 volts only,I also cross checked this voltage output read by the NI VISA with the help of multi-meter that is same as output voltage read by NI VISA.

Please help me out with the following question -

Why my power supply is not able to increase the voltage output as commanded by the PID controller?

any suggestion would be appreciated?

PS - My power supply can supply maximum rated voltage of 160 volt and 10 amp current.

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Are you being current limited?

[RTSLVU]

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@win2023 wrote:

Please help me out with the following question -

Why my power supply is not able to increase the voltage output as commanded by the PID controller?

any suggestion would be appreciated?

PS - My power supply can supply maximum rated voltage of 160 volt and 10 amp current.

---

Wow that's a very hard question to answer when we have neither the power supply nor code to inspect.

There could be voltage or current limits set in the supply, you could be doing something wrong in your code...

[win2023]

I have set maximum voltage to 100 Volt in PID VI. But output Voltage is not even reaching 100 Volt. Output Voltage is reaching only 86 Volt.

Note: Power supply is running at constant voltage mode.

[billko]

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@win2023 wrote:

I have set maximum voltage to 100 Volt in PID VI. But output Voltage is not even reaching 100 Volt. Output Voltage is reaching only 86 Volt.

Note: Power supply is running at constant voltage mode.

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And you confirmed that you are still in CV mode when you are setting 100 V?  Sorry, I am not suggesting you don't know what you're doing, I just want to make sure we are on the same page.

[win2023]

Hey Billko,

I just realised what was the issue. I had set maximum current that was stopping inherently the power supply to not increase the voltage beyond a particular value.

Hence, I reduced the maximum current, that increased the upper limit of the voltage in the power supply. @ Billko you were thinking in the right direction, thanks.

Thank you every one.

Discussion on this forum have always helped me.

[billko]

I think this one of, if not THE BEST, help forum of any kind that I've participated in.