Timers on an AB ML1100

Description:

We "bake" innertubes in order to "cure" them. We have around 50 AB ML1100's and the other 50 stands are running Modicon PLCS. We have a cure and a blow time that is independent of other tubes so curing stands open and close at different times depending on the operator.
Each tube cures and then gets "blown down" and these timers have to be exact in order to prevent scrap.


Problem:

I've noticed using RSL500 and the ML1100 I'm not able to program timers on the fly. I must be in program mode in order to make the changes.

Yesterday I made changes to the 1100's to prepare them for the use of RSVIEW in order to adjust timers from a central location. As of right now the operator may hit "start1" on an operator panel and adjust cure time via plc sans laptop. They may then hit "start2" and adjust in the same manner. After I changed 5 PLCS i stopped and went home. When i got to work today they said the timers were off.. which i knew couldn't be the case since i manually entered every curing stands cure and blow times.

To my surprise when i got to the machine, the plc read fine on the little display but the times were in no way close. It read 360 sec and cured for 20 sec. It read 60 sec blow and blew for 10 sec.

I then changed the timers in the program and re-downloaded and it worked fine.

Question:
Why would the display on the plc not correspond with the actual timer if it was set manually, and has been set manually for over a year? If the display timer is not correct what is the point of having one?

Also: why would i have to manually switch this particular plcs mode to "run" or "program" and not be able to from RSL500? This is the only machine i have had this trouble with in 3 years of this mode of operation.

Thanks!

JB
Firestone USA

1. I make changes to timer's Presets all the time while monitoring a program in Run mode using RSLogix. Are you trying to change something else?

2. What 'changes' were made to the 1100's to prepare them for RSView?

3. Can you give an example of one timer? List all the program information about the timer including its preset. Also give information concerning the control in RSView which is changing the timer. This includes all information about the connection and formatting and what it shows as a value while connected.

One way to adjust on the "fly" is to use an N7 for the timer .preset.
That way the n7 can be changed anytime even if the timer is running.
As for the display, It may depend on what the display is looking at.
Is it looking at the timer preset or something else?
Maybe post your code so others can look at it also.

If you include a rung that executes every scan that includes (for example) MOV N7:1 T4:1.PRE you can then adjust N7:1 on the fly very easily and it will then set that new value into the timer preset on the next scan.

You can then point your display to show the value in N7:1 or if you want a real time feedback of the timer value, you can also include a rung: MOV T4:1.ACC N7:2 and display N7:2.

The onther option is you can do online edits with an 1100. Very handy for quick changes to things.

.

I made changes in identification and added individual i.p. addresses.

I don't have any immediate way of posting code right now. i will later, i just dont have rsl on this computer.

Any idea why the timer on the plc wouldn't correspond with actual time? anybody?

I think i may have located the problem.

I guess in my frenzy i overlooked the fact that it's mode had been switched from remote to a specific "program" or "run" mode. I should have realized it yesterday when i received a popup box indicating mode was in run and i had to manually switch it to program on the plc display. Things like that happen all the time when supervisors are changing variables before their shifts begin. I'd never hit this particular problem. I did learn that if the plc is in "run" the timers will not update until switched to "remote" .. now i just have to type up a work instruction... woohooo.

Novice mistake, but i appreciate everyone's input.

JB