Setting up upper & lower limits in PIDs

T3000 Software
1

Is it possible to set-up a limit for PID higher value and lower value?

Ex: We need a VFD to ramp only between 35 Hz and 50 Hz accordingly maximum & minimum values to be set/freeze at 50 & 35 respectively.

2

There are two topics that can help you:

  1. (Setting up upper & lower limits in PIDs)
    Maurice shows an example to limit the output value.

  2. (Converting 4-20ma signal to actual value using a program)
    Maurice shows an example of how to use the straight line formula to convert signals and, of course, it can be used to convert the 0% / 100% PID output to 35Hz / 50Hz (58.33% / 83.33% )

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3

I like to clip values using this MIN nested inside a MAX statement, its easy to see what’s going on.

VFD = MAX( 35 , MIN( 50 , PID1 ) )

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4

Thanks for the help Adalberto. Glad to see folks are finding the forum useful.

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