Aloha here in Hawaii working on a Allen Bradley micro logic 1761 L32BBB controller and could use some help understanding why my ladder logic program for implementing a counter isn't working. Anyone there have experience with these and willing to chat for a bit? Bil Whaling [email protected]

 

Are there any instructions executed in the rung before the one with the counter, that halt or skip program execution? (I know that in older RSLogix5 versions, for PLC5's, an instruction called EOT could be automatically inserted in rungs. This would halt execution somewhere in the ladderfile, causing similar results.) What is the status of the bits like .CU and .DN? Do you perhaps use a counter reset (RES) instruction that is also executed every rung just after the counter? And of course the counter only counts when the rung the count-up instruction is in goes from false to true. - Theo Baarslag, IAMS Coevorden, NL > Aloha here in Hawaii working on a Allen Bradley micro logic 1761 L32BBB controller and could use some help understanding why my ladder logic > program for implementing a counter isn't working. Anyone there have experience with these and willing to chat for a bit? > > Bil Whaling [email protected]

 

Interlocking the enable to prevent counter operation would work. Also, a true condition during reset will cause the counter to reset to 1 and not zero, use an (osr) instruction to prevent the offset. In fact, the (osr) will edge trigger any output.

 

One other thought that comes to mind is if the counter address is used somewhere else in the program ? (2 counters using the same address) This could produce the symptoms described. Bob

 

Did you place this "Counter Program" in another ladder file, besides the main one? Like, made another ladder file, and entered your code? If you did... use the JSR instruction to call the ladder that the counter is implemented in? Blair