TI 565 PID Loop

[timsteuben]

I have a new PID Loop that produces a saturated, 32000 bits, output. The loop flags idenify the loop is running in auto mode. Forcing different values into the Set Point still results in a saturated output. If the Reverse-Acting Loop Parameter is enabled the loop output will go to 6400 bits and remain there. Does anybody have any suggestions? Thank you.

 

[rubha]

what are your pv high and low settings (LXPVH,LxPVL), also you can try and restart the loop.

 

[timsteuben]

Rubha thanks for your response. The pv high and low are the same as the upper and lower scale limits. Scaling is correct. The loop has been restarted, the internal bits show the loop is in auto. I used a previously operational loop as a model. It's odd the output stays saturated no matter what the relationship is between sp and pv. I can force different output levels.

 

[ADMIRALKEN]

A few questions:
is the loop in cascade mode?
is the loop enabled?
What is the address of your PV? wx, wy or V
Are you using Ramp/Soak?

Ken

 

[engRGW]

If this loop is a direct acting loop, and you are using external reset feedback, is it possible that this feedback is inverted?

 

[timsteuben]

Gentlemen, we have solved our issue. Initially the Process Variable was an analog input. The Loop would divide the analog input by 10. Obviously, we simply multipled the input by 10 and stored it in a register that is now used for the process variable. The trick was building a chart that allowed us to look at the Loop's variables. I'm not a TI expert, but I'm learning.