AB Micro1400 PID AntiWind Up

dave k

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Jan 2011

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• May 29, 2018

• #1

Team,
I am using a Allen Bradley Micrologix 1400 and I think I am experiencing Anti Wind Up in my PID Instruction.
Any suggestions on how to prevent this?
Any suggestions on Best practices using PID Instruction?

My PID Instruction is on an unconditional rung and I am switching between manual and automatic modes, not sure if this is a problem?

any suggestions would be greatly appreciated.

thanks

 

cardosocea

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Nov 2016

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• May 29, 2018

• #2

What are the conditions for the switching?
What is it controlling? Speed, pressure, temperature? What is the sensor and actuator/s?

What are you observing?

 

dave k

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• May 29, 2018

• #3

I am controlling a dc motor speed so when the motor is disabled I put pid in manual and when the motor is enabled I put pid in auto mode.
the sensor is an encoder for position and speed
it appears when I am going from manual to auto the output jumps to full output and stays there for a while before it drops.

 

g.mccormick

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• May 29, 2018

• #4

When you go from manual to auto, can you set the integral to whatever the manual value was?

 

tarik1978

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• May 29, 2018

• #5

Check this thread for pid bumpless transfer
http://www.plctalk.net/qanda/showthread.php?t=114799

 

Peter Nachtwey

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• May 29, 2018

• #6

I am pretty sure what is wrong.

dave k said:

I am controlling a dc motor speed so when the motor is disabled I put pid in manual and when the motor is enabled I put pid in auto mode.
the sensor is an encoder for position and speed
it appears when I am going from manual to auto the output jumps to full output and stays there for a while before it drops.

Click to expand...

I am not surprised.
What is your set point?
How do you change your set point?

There was a similar thread a week or two ago.
Does the amplifier have velocity loop or is it a simple voltage to current amplifier?

 

rupej

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Sep 2014

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• May 29, 2018

• #7

Need more info. There should be no windup if you're in manual and writing to the output directly. Bumpless transfer is inherent from manual to auto if done correctly.