Pac Control Retain offset and gain after uploading

[mickaBooh]

Hi All,

Suppose I have a strategy uploaded to my R2 controller (from Pac Control). I then open Pac Manager, navigate to an analog input point and set the offset and gain using the tools shown below (this works great btw). Then sometime later, I make a change to the strategy and upload it which reset the offset and gain making me to have to recalibrate.

Is there a way can I upload a new strategy without resetting the offset and gain values? In the past, I’ve have figured out the offset and gain and add them directly to the point in Pac Control, but this is a bit cumbersome and doesn’t compensate for any changes in the system. Is there a better way to do this or is there a preferred method for dealing with this?

Thanks
Kevin

[Beno]

Have not used it, but I believe that this is the exact reason offset and gain were added to PAC Control.

Have you tested doing it this way?

[mickaBooh]

I have, but it requires knowing what the calibration values are when before sending the updated strategy to the customer. Over time, the gain many drift so what it is when we first deploy may not be be the same when we update a year or so later. Ideally, I am looking for a way to update the strategy without changing the gain, or have a simple mechanism to replace the value after the upload.

[Beno]

Something does not sound right here…
It was my understanding that if the ‘Send Values’ option is not checked in PAC Control for that analog point then nothing is sent and so whats on the I/O unit stays put when you do a strategy download…
Your saying that’s not the case? You are seeing the offset and gain get reset to zero on every strategy download?

Have you saved the I/O config to flash via PAC Manager?

The very end of this thread is how I have handed this sort of thing in the past (to be clear, that post talks about PID config on the I/O rack, but it should be the same as the gain and offset).

PID On I/O UNIT

Leeveney, The answer to your question is the answer to a different question… The REAL question is; how do you have the PID set up on the I/O unit? IF your input and output are on the same I/O unit AND your P, I, D and Setpoint are not calculated or adjusted by the strategy in any way, AND if you have the I/O unit configuration saved to flash, then your PID loop will run as long as the I/O unit has power. In fact, if the unit powers off and then back up, and your PID loop is set to auto, then…

Skip down to the last two screenshots and read around them.

[mickaBooh]

I’m going to walk back just a bit. I have not tried this using the Send Value gain. In the past I’ve set the gain on the point using the Actual and Scaled values. Let me try a few things and I’ll post back with my results.
Thanks Ben,
Kevin

[mickaBooh]

Ben,
You are absolutely correct. It seems that if Send Values is checked, the offset and gain will be written during upload. With it unchecked, the offset and gain values are retained in the controller. This is a good thing.
Thanks
Kevin

[jelectron]

This absolutely works, something else is wrong (Send values)

[Beno]

Awsome. Thanks for getting back to the forums with the result.

So now if you save your settings to flash either manually via PAC Manager, or programmatically via PAC Control and back up the I/O rack to file (in case of lighting strike taking out the unit and you need to clone it) you should be up and running for a very long time.

[jelectron]

That was fast, done.