OTE stuck on with false rung

[boomdoom86]

I'm working with a 1764 Micrologix 1500 series C with RSLogix500 V9.00. I had to add some features to a purchased machine to facilitate new product models, the project quickly got out of hand. To make the program more readable, I created a series of the conditional bits for the features I added in a new subroutine.

I'm having trouble with some OTEs that are remaining energized, not only when the rung condition is false but also when the subroutine is not being scanned. These bits only have one output instruction and are not controlled by and HMI or other external device.

See attached files to note that LAD 21 JRS not being executed and LAD21 rung false for B3:7/5.

Does anyone see a mistake or have input on this matter?

 

[hd_coop]

If you don't scan a subroutine, you will never evaluate the logic which tells the OTE to turn off, the OTE will remain in its last state. This is normal behavior.

 

[boomdoom86]

Thanks Coop, exactly what I needed.