What's Wrong with my Timer?

I am running a compactlogix processor on RSlogix 5000.

My timer is self resetting with the XIO Timer DN bit in the same rung. This is so the calculation is done at the desired programmed frequency.

On the following rung, when the XIC Timer DN bit is "true", it should initiate the calculation. What I am finding is that the calculation is only being done every 1/10 times that the timer finishes and the done bit is true. What is causing this to be inconsistent?

Here is a screenshot of the two rungs:
http://i.imgur.com/A6jKdtp.png

Also, what is interesting to me is I have three other subroutines on this project with the same exact logic, just different tags which perform the calculation correctly and consistently.

I would verify for duplicated timers.
Also, you can try to run the timer unconditionally, and reset it by RES instruction in the calculation rung.

LiftStation_18 said:

Also, what is interesting to me is I have three other subroutines on this project with the same exact logic, just different tags which perform the calculation correctly and consistently.

Click to expand...

How do you invoke the subroutines? Maybe a condition is messing with your subroutine.

On the following rung, when the XIC Timer DN bit is "true", it should initiate the calculation. What I am finding is that the calculation is only being done every 1/10 times that the timer finishes and the done bit is true. What is causing this to be inconsistent?

Click to expand...

How have you verified that? In the picture the timer should trigger the update once every 10 seconds. Is it possible that you added 1 zero too many to the preset but you believe that it is set for 1 second?