to use SLC-100 or MicroLogix 1500

[JeffKiper]

You shouldn't runout if memory but it all has to do with how you program. If you have a lot if math it will greatly increase the memory usage.

Are these steps going to be time or even driven? If it is time then there should be no reason to be worried about it. If the are even then you ciukd have a problem.

 

[zephxiii]

It's all time driven. Basically there are 6 modes, 5 of them has one unique output energized, the 6th having none of them energized (cool down). The order of the modes is a bit random and each mode can vary in length. And it was a routine that was given to us that we have to follow otherwise it would have been a lot simpler.

For now the approach is that LAD2 is the main ladder that steps through and calls a JSR for each step. Then Lad3-Lad118 is each step with the timer and associated output (or none). Then when the timer completes, the next rung in the main ladder starts and latches out the previous step. Eventually I will have to reset all the latches to start the cycle over but I can save that for later.

I was just concerned if it was going to run out of timers or something. This is the first time I've programmed in RSLogix and have dealt with this line of PCLs.

 

[Tharon]

You shouldn't run out of timers.

I think one Timer file holds 255 timers (right?) and you can make multiple files. T4 is the default, but you can make T10, T11, T12, etc (all just examples, don't have to use those numbers). As long as the number isn't used for another file type.

I doubt you'll run into a memory issue, unless each of these 115 steps are very large (dozens of rungs) in terms of instructions.

 

[Mickey]

I would not recommend conditional subroutines. If they are not scanned, whatever is in them will stay that way outputs on or outputs off.

 

[Lancie1]

For now the approach is that LAD2 is the main ladder that steps through and calls a JSR for each step. Then Lad3-Lad118 is each step with the timer and associated output (or none). Then when the timer completes, the next rung in the main ladder starts and latches out the previous step.

Possibly most of the timers could be replaced with only one Step Timer in the main program, with 118 time ranges or LIM comparison instructions with min and max time settings.

 

[Tharon]

Possibly most of the timers could be replaced with only one Step Timer in the main program, with 118 time ranges or LIM comparison instructions with min and max time settings.

While possible, I think it'd be an easier to understand program if you use a separate timer for each step. If memory size allows, which I think it will.

I'd hate to look at that rung for a single Timer that has 118 different branch possibilities making it true.

 

[Lancie1]

I'd hate to look at that rung for a single Timer that has 118 different branch possibilities making it true.

I don't think a rung like that would be needed. Only a single RTO timer that runs during all Steps of the process. Then each step or subroutine has a comparision LIM instruction that looks at the same Stage Timer to see if it is its turn to run.

It is a question of which comes first: the New Step, or the New Timer? Right now it seems that a Step Relay is latched on, then a New Timer is started. What if you did it the other way: run a Single Timer, looked at it to determine when the New Step starts and ends?

But yes, if these sleeping dogs are happy, then it is probably best to let them lay in peace.

 

[zephxiii]

Well as an update to this thread I finally got the software in to program the 1500. It took a while to figure out how to communicate with the 1500 and figure out the routine with downloading a program to it then connecting to it to run the program. There was some COMMS button on the controller I had to push to get it into a certain mode to communicate. Another weird thing is after i would download a program i would have to push the COMMS button and shut down then restart RSLinx.

I have nearly all the rungs and SRs written for each step. Today i made a shorter version of the program so I could figure out how to get it to repeat. I managed to figure out the MOV function to write 0s into B3 so I can reset all the latches. Then I discovered I had to reset all of the timers too. After doing both it now repeats itself over and over .

Now all i have to do is implement that into the actual program and I should be good to go.

 

[brstilson]

The SLC-100 is a long dead obsolete product. Micrologix 1100 would be the most suitable replacement.

 

[brstilson]

Well as an update to this thread I finally got the software in to program the 1500. It took a while to figure out how to communicate with the 1500 and figure out the routine with downloading a program to it then connecting to it to run the program. There was some COMMS button on the controller I had to push to get it into a certain mode to communicate. Another weird thing is after i would download a program i would have to push the COMMS button and shut down then restart RSLinx.

I have nearly all the rungs and SRs written for each step. Today i made a shorter version of the program so I could figure out how to get it to repeat. I managed to figure out the MOV function to write 0s into B3 so I can reset all the latches. Then I discovered I had to reset all of the timers too. After doing both it now repeats itself over and over .

Now all i have to do is implement that into the actual program and I should be good to go.

You would have been much better off with an 1100 or 1400. They have built-in ethernet and (most importantly) have online editing capability.

EDIT: I looked back and saw you already had the 1500 and are planning on an 1100, so never mind. You're on the right track. I kind of prefer the 1400 myself (mostly because you can set the IP address from the front panel and don't have to mess with BOOTP server), but the 1100 is also a solid platform.

 

[brstilson]

I'm not going to run into any memory limitations with the size of the program am I? The entire cycle is a week long and has 117 steps, which means 117 different timers and related things...at least with the approach I am trying.

You'll have no problem. The Micrologix can easily handle that many timers. Keep in mind, the SLC-100 platform you're used to is from the 1980's, when memory was expensive and having lots of it was a pipe dream.

 

[Lancie1]

Now all i have to do is implement that into the actual program and I should be good to go.

It would be interesting to see your solution, if you don't mind. Maybe post part of it, or a PDF print-out of the ladder files only.

 

[Helliana]

With that few inputs and outputs, you may be able to get by with one of the micro plcs allen-bradley puts out. The software is free, and i think they have ~$100 price tag.

Haven't used one myself since we have a stack of new 1100s in our parts crib, but i'd check into it if i was worried about price.

 

[zephxiii]

I attached a sample.

 

[Lancie1]

I think this is one weird program, because it uses dummy rungs that serve as indicators and not to perform actions, all outputs are re-used (double, triple, and quad-ruple coils) in many subroutines and in the main, so that it is hard to tell which Sub is actually in control of any one output at any particular time. Because the subroutines are activated and de-activated by timers, and the timers are inside the subroutines, it seems that once a sub is deactivated, that its timer will be frozen at whatever state it was in - hopefully with the DN bit enabled.

For example, in Sub 4, Run 0001, you have both an XIO and XIC in series for Timer T4:1/EN. I don't think the Outputs of this rung can ever be enabled like this. Did you mean for the first XIO to be for T4:0/EN instead? On the other hand, this routine shows up in all of the "COOL-30" subroutines, so it must be intentional. This is probably a "dummy" rung that is being used to indicate which output is being turned on in some other subroutine.

It is a cascade of all the timers, one timer starting the next. If power blinks, all active subroutine timers will reset to 0. It might be better to use RTO timers, so the cycle could be continued or restarted, if there is some problem after 3 days. Unless you have a RECOVER routine, it seems that the entire one-week cycle will be lost if the power or PLC blinks off for a 1/4 second - as it is now.