Setting PID setpoint via HMI

Hi all,

I am having some difficulties with PID controllers, in particular writing the set point via HMI. I am using RSLogix 500, CCW and I have a ML1400 and PView 800. I have the PID seemingly working, and intend the HMI to use a numeric input to change the setpoint. First of all I dont have the help files for CCW installed (no idea why) but I am using the Indicator and Write tags as the same integer, which should be linked to the bit for the setpoint in the PID yet I get nothing on the HMI, and the PID is not affected if I change the numeric entry value. Any ideas what I am doing wrong?

Regards

What register are you write to?

Can you post the .rss file ( zip it first)

I'm not real sure about rs 500, but I did a lot of setpoint changing in rs 5000 v.20. What I did was use a keypad of course on the HMI and connected it to a tag in logic as an example Cool_PID_SP, which was usually a DINT. That tag was in a move instruction and it moved the numerical value to Cool_PID.SP. This tag has to be the name of the PID. Note the dot in the second one which is an extension of the PID instructions, like .kp, .ki etc. I did a LOT of setpoint changing that way based on conditions and compare instructions in logic. If you like I'll send you a screenshot of it. LMK. Hope this helps. 500 may be a little different.

@ Mickey - Thanks for the reply, I have attempted writing and reading from the PD Data file that I crated for the PID (in this case PD10:1/2). I have been successful in writing to it in one test from within the PLC program, but the issue is interfacing with the number entry control in CCW. I beleive the tags I should be using in CCW is Indicate and Write, but there are a couple of other tags that could be important that I have overlooked?

@ Saultgeorge - Once again thanks for the reply. RS 5000 has the luxury of using tags instead of addresses which I think is the main difference. I am using Integer data files for the storage of the data, and a PD data file for the PID controllers (I think in RS5000 you dont need to create a data file for them). From my exposure to RS 5000, it seems to work a lot better as it is integrated with CCW, but not for the MicroLogic PLC's. They cant be programmed from within CCW.

You did not say which register you are writing to for your setpoint.
It should be PD10:1.SPS , in your case.

Usually you should write to an integer first check for limits then move that integer to the PID's setpoint (PD10:1.SPS)

I am not familiar with CCW software so no help there from me.

FYI, the program you posted is not calling LAD 9 ( STI is not configuredor "JSR" instruction calling it) you have the PID setup for "STI".

Sorry Mickey, I did mention it but didn't make it clear. The register I am writing to is PD10:1/2. The Rockwell literature shows a table which says preset is bit 2. I will update the software with .SPS instead and try it out when I get back to the office on Monday.

Deffiant said:

Sorry Mickey, I did mention it but didn't make it clear. The register I am writing to is PD10:1/2. The Rockwell literature shows a table which says preset is bit 2. I will update the software with .SPS instead and try it out when I get back to the office on Monday.

Click to expand...

HMMMM?

Can you post or point to the literature where it says that?

Setpoint is a whole word not a bit??

Mickey said:

HMMMM?

Can you post or point to the literature where it says that?

Setpoint is a whole word not a bit??

Click to expand...

That was a school boy error! yes it is word 2, not bit 2!

I have it working on the PLC side, just need to get the CCW side of it functioning how I want it now. Thank you!

Mickey said:

HMMMM?

Can you post or point to the literature where it says that?

Setpoint is a whole word not a bit??

Click to expand...

I assume this would be the literature the OP is talking about.



But as Mickey has stated it should be addressed PD10:1.SPS