Modicon 984 PID help

I'm in the process of upgrading a 1998 vintage Modicon 984 system. The existing program contains a PID function block. The only PID instructions I can find in the ProWorx help files are the PCFL PID and the PID2.

The documentation for the PID2 function says that the Source block takes 21 consecutive 4xxxx addresses and the destination block takes 9 consecutive addresses. The PID function in the existing system has 41100 as the address for the source block and 41116 for the destination block which implies to me that the source block is using 16 consecutive addresses.

Can anyone point me to where I can find a description of the difference between the PID function and the PID2 function?

hi Steve,

I have the "Modicon Ladder Logic Block Library User Guide"
in front of me cat# 840 USE 101 00 Version 2.1
PID block is described in section 21.6.4 pages 452 to 457.

PM me with your fax number and I'll send you a copy.

Brian.

Thanks Brian, but I have version 2.0. The chapter you're citing describes the PCFL PID function #44. The instruction I'm looking at in the existing program looks like the PID2 instruction described in chapter 21.

Steve,

A brief look reveals,

PID uses FP (floating point) math unlike PID2

the length of the PID parameter block is 44 registers.

The first 12 registers are inputs, the next 32 are outputs.

there is a lot to this and I have never had the pleasure of using one.

Brian.

edit, Yep your right, I hope you find it.....

I have information on the PID2 in a manual data 1990

If you haven't found info on the PID2, I have old manuals that describe the PID2. I could scan it.

There is a PID instuction that predates both the PID2 and PCFLPID. It was a loadable block and originally for the 584 but also works with 984. Search for "modicon 584 PID" and u will have more luck. I found this link http://v1.graybar.com/automation/ga%5Fmanuals/ have a look in 584 processors chapter 19 PID and you will find what you need only page 19-10 onward.

note: that 584 processor manual is under "Mature Products" tab on linked web page.

That's exactly what I was looking for. Thanks Mike.