Ab Slc 5/05

Working on a large alarm project. Was wondering if there is a
limit on timer usage/max number of timers supported.

How big of a 5/05?

It only depends on how many words your particular model 5/05 has; i.e. 16K or 32K or 64K of memory and knowing timers consume three user words of memory.

I think that this is what you're asking ...

the just-getting-started timer file (number "T4") will hold up to 256 timers ... those timers will be addressed T4:0 through T4:255 ...

if you need more than that, you can create a new timer file (example: "T9") which will hold another 256 timers ... T9:0 through T9:255 ... and so on - and so on ... UNTIL (as Flopro said) your processor runs out of memory ...