RSLogix 500 - add timer online

[Agrajag 0]

I've gotten pretty familiar with RS5000. Sometimes I have to work with RS500 and some of my RS5000 habits hit a brick wall. For instance, at least twice now (*smacks head*) I've tried to install a new timer in a RS500 (SLC) program while online in remote programming or run mode via the edit process. The rungs never get accepted because the timer is not in the datatable. I end up downloading the program from offline mode to make the changes I need. Am I missing something here? Must all timers be added through offline download? If so, What other instructions must be programmed through an offline download (if there are many, please just generalize)? Thanks-a-mundo! -Russ Edited 11 Sep 2010 by Agrajag

[Mickey 71]

You can't increase the number of elements for any given data file ( e.g T4:??) online. That must be done offline then downloaded. Its good practice to have some spares for just this case. What processor do you have? Edited 11 Sep 2010 by Mickey

[Agrajag 0]

In this case, the processor is an AB SLC 5/05 1747-L551C. And thanks! Edited 11 Sep 2010 by Agrajag

[b_carlton 61]

Anything added that would increase the data table has to be done offline. I make it a point, whether in RSLogix 500 or 5000 to leave unused items in data tables. In RSLogix5000 create an array of general timers. Use them later if needed. Also be sure to have usable bits and numeric tags. They may not be very appropriately named but later on that can be corrected when time allows for an offline edit and download. It's not the instructions that cause the problem; it's the addition of new tags. I see Mickey covered the core of the problem. Edited 11 Sep 2010 by b_carlton