How to use PIDE?

Hi All

I use RSlogix 5k.
Can someone give me a code snippet on how to use PIDE?
Currently i use regular PID block and i want to convert it
to PIDE.
I need it for auto tuning.

Thanks

Hi

in addition,where do i place the PID structure?
If i change the SP in the program where should i place
it.

How do i call this PID routine from a routine in a continous
taks.

many thanks

Place the PIDE instruction in either a FB or ST routine under a periodic tast. PIDE cannot be used in or called from the continuous task. You may scope the PIDE tag globally to the controller or locally to only the program under the periodic task. You can enable/disable the PIDE from a routine in the continuous task if you globally scope the PIDE tag by setting/clearing the EN bit.

There are a lot of vestigial parameters on the PIDE instruction. Some of the parameters that I actually use are:

CVROCLimit
CVManLimiting
ControlAction
and the PV,CV, SP limits or scaling

You will need to disable CVManlimiting and put the PIDE into ProgMan mode in order to use the Logix5000 autotune. Alternatively, you may want to look into RSLoop Optimzer, it can tune without upsetting your process.

Here's a screen shot of our typical implementation. Note that we do not use HandHand, OperHand, OperOperAutoMan or any of the many other control modes. If manual modes are required, our logic takes care of this on its own.

AK

Hi And thanks for the reply.

Where should i place the PID predefined data type
which i place in the regular PID routine as the first parameter?

I need the .SO and .SWM parameters

Thanks

Confusion alert!. The PID datatype applies to the Standard PID block that is the CLX analogy of the one used in the SLC/PLC family. The parameters you mention .SO and .SWM appear to relate to that function, not the PIDE function which is unique to the CLX and is only implemented in Function Block.