Lim Compare instruction

I'm trying to learm to write basic programs.

I just bought LogixPro software, and Phil's book.

My question is it possible to use a timer as the test in a Lim instruction to turn on a output.

I tried to do this and it does not work.

I use a counter instead and it works fine.

Am I trying something that is not posible?

When you used the timer did you use the value from the ACC(accumulator)? Example
T4:7.ACC is a word address, where the period separates the element from the word within that element. Since Timer files have 3 word elements, the address T4:7.ACC points to the Accumulator word (third word) in element 7 of Timer file T4.

It should work as long as your accumulator values are in the range of your limit settings.

Note also the LIM function allows some unique features, think about reversing your high and low limit values what will happen

Thanks that was what I needed.

I tried using T4:0.TT, T4:0.en, and T4:0.DN.

I never tried the .ACC.

Thanks I've been working on this for 2 days.

Logical instructions

Chuck, there are two basic divisions of instruction types in most PLCs. They are bit instructions, and word instructions. Some word instructions, like timers and counters, have bits that can be used in logic with bit instructions. IE T4:7/DN for the done bit on timer 7. However, as Ron pointed out, the LIM and other logical comparison instructions all operate on word level values. These may be integers, as in N7:12 or binary as in B3:25. Also, C5:8.ACC or T4:12.ACC may be used as they too are word values. Continue working with the different instructions and you will soon discover their uses. A word to the wise for AB, address such as T4:7/TT or C5:12/DN or any address where the / is used makes that address a bit address. The word addresses are complete most cases as in N7:12 but with the counters and timers their .ACC and .PRE word addresses associated with them. Good luck and come back here if you need more help.