voodoo functions

[baldyspate 0]

Hi: I'm trying to sort out, thin down, and document an uploaded palletizer program modified, modified... from an slc5/04. I"ve already found and deleted one "left behind" ladder in the files, and was about to weed out another when I thought that I ought to double check an assumption. In the file in question there are ADD,MUL,and MOV's involving the presets and accumulators, of counters and a timer which aren't defined anywhere else in the program. I mean not as a CTU or CTD block at the end of a conditional rung. They are just referenced as sources and destinations in the math blocks. I was about to nuke these when I thought that I'd better find out if the memory locals or some other feature of these might be assigned permanently and usable or some other (by me) unthought of way that this is possible. Appreciate your time

[Guest]

it's kind of hard to tell what's going on without seeing a copy of the program ... any chance you can post it? ... we'd be glad to take a look ...

[TConnolly 13]

It is possible to use the addresses T4:0.ACC or T4:0.PRE just as you would use any other positive integer address and C5:0.ACC and C5:0.PRE as you would use any other integer address without using the timer or counter in a timer our counter instruction. This wouldn't normally make much sense, but since you say this program has been reworked and reworked then after all that anything is possible. I have a case in one of my PLC programs where an R6:0.POS address is being used as a destination address even though the origianl usage of the R6:0 element is no longer germane to the PLC program, the HMI is still looking at it to display machine state information and the HMI has not been reworked. Its not my prefered way of doing things, but sometimes we don't always get that luxury (and it chaps at the OCD programmer inside of me ) Therefore, it wouldn't hurt to do a find all address search on all of those addresses in the program and in any attached HMI application, just to make sure its not being preserved as an intermediate register between the HMI and the current application.

[Kiwi Sparky 0]

If they arent used in PLC elsewhere, maybe referenced by HMI/SCADA. (strange that they are Counters/Timers, but you never know what someone else was thinking)

[baldyspate 0]

Thanks for the replies. You've answered my question. I can see that the math blocks in question may well effect balues elsewhere in the program, as the values are eventually moved to integer files elsewhere. Sorry, for the incovenience with giving enough info at the beginning but I'm not able to connect to the net with the laptop which accesses the palletizer plc. Thanks again.