PID Block Confusion

[mthayer]

Hi everyone,

I'm trying to set up a simple function block application using a PID block for demonstration purposes. I'd like to have something like an AI block into a PID block, into whatever is necessary for the PID block to function.

I'm a process transmitter developer, and my needs are to set up a basic network showing our device in action. We'll have AI process data and a PID block in our instrument, as well as those from a SMAR IRF302 4-20mA to FF bridge (also has AI blocks and a PID).

Do I need a functioning AO block, or similar output block, to get a PID to enter the correct modes?

My end goal would be to see process data coming in off the AI from a couple of our instruments as well as a the SMAR unit, and to show one of them running through a PID block and demonstrate how things like gain can be easily modified through the PID block.

So far I haven't been able to get any PID block to leave IMan mode, which I've gathered from some research may be due to not having downstream blocks in the proper mode. I have somewhat of an AO block that I've been playing with (it's in the default fieldbus software in some of the hardware we're using, and will not be implemented in the finished firmware), but I'm not sure if it's functional. I don't seem to be able to get it to go out of OOS mode. Is this why I can't get the PID block to initialize?


I've got some other questions on modes and things, but that should be a start.

Any help is greatly appreciated.