Need to indirect address timers' presets

[kirk seiter]

I have a conveyor with 80 zones. Each has a timer. Since each zone timer serves the same function, I would like to be able to adjust the preset time globally. Any suggestions?

 

[Hakutsuru]

It would help if we knew what kind of PLC you had. I cant think of a way to do that in AB. The best you could do is just assign a register for the preset, and move that number into the preset of each timer. Now, in Modicon, there's no reason you couldnt just use the same register for all of the presets instead of entering an actual number.

-jeff

 

[snguyen]

What PLC or ctlr are you working with? Are for-next instructions allowed?

 

[hd_coop]

Attached is a screenshot of how we do it on one of our assembly lines. This PLC is a SLC 5/05 so it may or may not be of help to you. You would have to change the 75 in the GEQ to an 80 in your case

 

[geniusintraining]

...I cant think of a way to do that in AB...

If its a SLC then read this thread.. http://www.plctalk.net/qanda/showthread.php?t=30094

or search indexed addressing

but I would still like to know your thinking on this why would you need to change them, what is the need to change the preset?

also what type of PLC

 

[TConnolly]

Kirk, it would really help if we knew what PLC make and model you were using.

If its an AB PLC we can set it with a for/next loop. If its a ControlLogix then there are some really cool tricks we could try out.

If its an Omron then the solution is super simple.

And, as has been mentioned, a Modicon solution is really easy as well.

If its a Koyo PLC I also think that a solution similar to the Omron solution is avaialbe.

But all of this is contingent on knowing what PLC you are using.

 

[Hakutsuru]

Yeah, that doesn't really address the question at hand. That thread was about changing the time bases, not changing presets globally. But I shouldn't have to tell you that as you contributed quite a bit in there.

HD_Coop, you know you can use a for/next loop too, right? At least, you can in a PLC5, I assume its still there in the later processors. Also, in that bit of program, I can't figure out how the NEQs ever evaluate to true? When do N7:2 and N7:3 get unequal?

-jeff

 

[kirk seiter]

Im using SLC 504

 

[geniusintraining]

Yeah, that doesn't really address the question at hand.

The moral of that thread was why? Why do you want to just because you can?

Depending upon the need and the PLC there are many ways of doing things indexed would/could be one, I would like to see Alaric CLX suggestions

If I have a conveyor with 80 timers in my program, I would rethink the program…this is my question at hand

But like I said in my last post what is it that is trying to be done/accomplished?

 

[Hakutsuru]

GIT, (I may call you git, right?) My place is not to wonder why. It is but to do or die.

Seriously, whether he should be doing it is only half the question here. Its still a worthy exercise even if he has no good reason for it. And BTW, while I don't know conveyors, I can think of plenty of good reasons to be able to change a group of timers with just one setpoint.

I mean, unless you think he is a student trying to sneak a homework assignment by us and you are trying to ferret him out. In which case, I apoligize if I in any way dampened your fun.

-jeff

 

[hd_coop]

HD_Coop, you know you can use a for/next loop too, right? At least, you can in a PLC5, I assume its still there in the later processors. Also, in that bit of program, I can't figure out how the NEQs ever evaluate to true? When do N7:2 and N7:3 get unequal?

-jeff

N7:2 is modified from a Panelview.
I don't think the SLC has for/next, I see the instruction in my Logix 5 help but not Logix 500. I've never used it.

Our timers are there for tracking downtime associated with each operation on the line.

 

[geniusintraining]

GIT, (I may call you git, right?)

Yes all my friends do

Seriously, whether he should be doing it is only half the question here. Its still a worthy exercise even if he has no good reason for it. And BTW, while I don't know conveyors, I can think of plenty of good reasons to be able to change a group of timers with just one setpoint.

I dont disagree BUT...I have seen a lot of programs (not all and I am not **** compared to some here) but 80 timers in a program just for one part of that program??? this is not all of it?? I just don't like counting (no pun) on timers that much, to me this seams like it would have the possibility of being very unstable at best

I mean, unless you think he is a student trying to sneak a homework assignment by us and you are trying to ferret him out. In which case, I apoligize if I in any way dampened your fun.

No I don't think he is, I am just an *** and enjoy a good Thursday afternoon debate and you looked like you would fall into my trap

 

[TConnolly]

Here is how I would do it on a SLC.

You can build a loop in a SLC using a pointer, an ADD instruction to increment the pointer and a LBL/JMP instruction pair.

In your main routine (file 2) you will need a rung that is functionally equivalant to this one that calls a subroutine whenever it is necessary to change all of the timer presets. I used file 3 for this example.

Then you need a subroutine that is functionally equivalent to this one.

Just change the addresses in the example to meet your needs.


Don't forget to reset whatever logic triggered the global write after it is done.

 

[Hakutsuru]

No I don't think he is, I am just an *** and enjoy a good Thursday afternoon debate and you looked like you would fall into my trap

Well, I enjoy a good argument at any time of the day or night. Its more enjoyable when I know what I'm talking about and am right, but those aren't hard and fast pre-requisites.


-jeff

 

[Hakutsuru]

Alaric, what kinda fun things could we do with Control logix?

Also, I don't think this has been said, but obviously your timers need to be all together or trying any of this gets a little more messy.

-jeff