Timers in Code Blocks

[jmracek]

I just tried adding a timer (ONDTMR) to a Program code block in my Do-More processor. It seems to function but the time counts at about 1/13th the speed of real time. The same goes for other timer instructions.  The timers do function properly in the $Main Task.
  Is there a trick or are timers just not allowed in programs?

[Controls Guy]

Do-More timers aren't RTC-based, they integrate scan-time, so if the rung with the timer isn't scanned every actual scan, they'll fall behind.  Your timer is probably in a code block that due to its execution or time-slice is only executed about every 13^th real scan.

To make them work right, you'll either need to make sure they're in code that executes every scan, at least while you're timing, or build an RTC-based one yourself (which still might expire late by up to one scan-time of the code in which it resides).

[BobO]

Timers accumulate time when the code is being executed. If they are located code that isn't executing every scan, they will drop time. There are a bunch of reasons why a timer might not be executing every scan, but I'll need more info about the program to offer an opinion.