Need help

[glovebiter]

In what form is the PID data stored on the SLC-500?

 

[rsdoran]

I am not sure what your are asking. PID is an equation which uses integers/floating integers from inputs to create a balanced output to control things like heat (heat is an example, other things can be controlled but heat many can understand).

Lets say you have a need to control the heat in an oven/dryer. When you start the heat it may have a tendency to overshoot the preset temperature, in some cases bad enough to trigger a high temp alarm/shutdown. The proportional value is used to set the temp preset, the integral to compensate for overshoot BUT sometimes this causes too much fluctuation...ie goes over too far then under temp too far, so derivative is added to tune it to maintain a balance between over and under temp range. In alot of cases tho P&I is enough to handle the situation.

I am not sure what you were asking but I think its the type format the info is retained as in the plc. Since PID usually works with integers of some sort (like a temp setting of 350 degrees F) the file type would be integer or floating integer depending and would use word files.

If you need more detailed info on PID please state it.

 

[Peter Nachtwey]

I know, I know.

I bet glovebiter is looking for...

Word 0 is status bits.
Word 1 is ...

This is in chapeter 9 of the .pdf file.

Ron, the integral gain does not compensate for overshoot. It is one of the main causes of overshoot. Think about it. All the sum of errors accumulated while getting to the setpoint must be unwound by overshooting the setpoint. The differentiator reduces oversoot and provides system damping by increasing the damping factor of the combined system and controller. The integrator reduces steady state error.