Send Value(s) - Edit Analog Point Dialog


#1

When adding or editing an Analog Input Point, the “Edit Analog Point” dialog has two check boxes and corresponding text boxes to let you set “Send Value” or “Send Values” for “Averaging Filter Weight” and “Offset and Gain” respectively.

I’m curious as to when these values would be sent to the brain, whether or not they would be “persistent” in the brain (get stored to Flash), be overwritten by later restarts, etc.

Normally, I’d set these things up in the strategy itself (for filter weights) or I’d use PAC Manager to do calibrations (offsets and gains) for analog inputs, and then save them to flash for the I/O unit in question so the calibration would persist after power interruptions or program changes, etc.

Seeing these (to me new) check boxes and text boxes in this dialog in PAC Control, I’m curious as to how and why to use them.

Reading in the newest revision of the PAC Control User’s Guide, it says they’re only good for Analog Outputs, yet they show up, (not grayed out) for my analog inputs, and, of course, they’d both logically be used for Analog Inputs.

So I’ve got a lot of questions about how to use these parts of the Edit Analog Point dialog.

Sorry if this has been covered before.

Sigmo


#2

Sorry for the slowish reply… It was a great question and we (Opto 22) discovered that the manual is wrong, so there was some time spent getting to the bottom of it and getting things corrected…

Ok, from the top…

In a nutshell what we are doing with those values is trying to remove the need to do it in PAC Manager.
We figured that it was a pretty straight forward task, why the need to use two applications when you are downloading to the I/O anyways.
In time you will see more and more of the PAC Manager settings make their way into PAC Control. (PAC Man will never go away, don’t panic, we just are allowing things to be done from PAC Control to save the extra step where and when it makes sense).
That was the thinking, so now that you know that, lets keep digging…

Because the values are ‘embedded’ in the strategy, they are saved to flash along with the charts etc (assuming you have the ‘save to flash’ option checked in PAC Control for that strategy).
‘Latter restarts’ as you call them, will simply be the controller powering up, copying the strategy from Flash to RAM and running the power up chart from Block 0. This will set up the I/O as part of that process, just as it always has done.
(Hint, if you set the values in the strategy and power cycle the controller, you will see the values as they should be in PAC Manager - as you would expect, its just a memory map location in the I/O in the end).

The how and why to use them is the same as PAC Manager, but in PAC Control.

The manual is wrong and has been corrected, they are only for Analog Inputs. NOT outputs.

So, in short, where you used to do those two functions in PAC Manager, you can now do them from PAC Control.
On the other hand, if you are comfortable doing them in PAC Manager, then just ignore that new section in PAC Control and keep doing it the way you have (and as you commented, don’t forget to save to flash in PAC Man).

If you still have questions, just ask, we have really appreciated your post, this sort of feedback is really helpful.


#3

Thank you very much!

That explains things well. I just played with all of this on a small system I have set up just for learning and experimenting at home, and it does just what you describe.

It does make sense to be able to make more of these configuration settings from within PAC Control, so it will be handy to have this available.

I’m actually running all of the latest firmware and software on this small “test” system while on the “real” system I use at work, we’re still a few revisions behind (we’re using 9.3 there). And I do notice new features in PAC Control and PAC Display when playing on the test system. Seeing some of these new features is making me lean towards updating everything at work to the latest versions of firmware on the brains and controllers, and then switching over to the latest PAC Project suite there.

What’s sort of held me back at work has been that we are using some now obsolete PID algorithms with everything working well as things are. I’d go into that, but it’s really an issue for another thread, and I believe it’s already been covered well in some existing threads on the forum.

But I may get brave and make the switch at work soon. That system runs a municipal drinking water treatment plant so it must run every day without fail, thus my reluctance to do anything too radical without making sure I’ve got all of my ducks in a row beforehand as you might imagine.

Thanks again for your followup on this for me. Even though we’ve been using Opto 22 for many years at the plant, I still consider myself rather “green” at all of this because it’s always been so easy to make things do what we needed that I haven’t explored everything nearly as much as I should. There’s always some other project that rises to the top of the to-do list.

But with a separate system to experiment and learn on, I will be encouraged to explore the possibilities further in the future. So you can expect a mixture of many years of experience with all of this mixed with many stupid “newbie” questions from me as well.

Thanks again for your help.

Sigmo