Compact Logix 1769 PID Negative Output

[plc_dog]

Hello.


I am trying to figure out how to setup a PID in Control Logix 1769 Controller in a way that it would control a drive speed by sending -10V to 10V depending on the position error.


Right now it seems that the PID instruction that I setup only works one way. If the position < set point, the output % is positive. Once the position crosses the setpoint and goes past it (the position error becomes negative), the output drops to 0%.


How can I make the PID set output to negative, to correct the negative error?

 

[plc_dog]

Little correction.


The PLC is CompactLogix1769-L33ERM.

 

[VAN]

Might need to show what you've done already.

What is your PID output set at (what is the max out and min out after scaling)?
Are you just looking at the % CV?

 

[plc_dog]

[SOLVED] Compact Logix 1769 PID Negative Output

VAN,

What is your PID output set at ?

Thank you very much for this hint. I found that the CV Low Limit was 0%. Setting it to a negative value did the trick.


Much appreciated.