Logix5k, Controllogix Question

It would seem to me that the Read instruction on rung 17 would execute every scan in this series of logic, but more profressional help is needed. Any help would be appreciated.

No. That will alternately execute (I assume) BTR's and BTW's. It is logic expanded a bit over the normal BTR/BTW interlocked pair, by virtue of having some FAL instructions to handle the data out and in as well.

This is obviously a Q&D (Quick and Dirty) PLC5 conversion. The XIO XIO BTW / XIO XIO BTR is very common in the PLC5 (and to some extent later rev OS SLC500) world.

Much hate by the way for taking a Logix 5000 system and pretending it is a PLC/SLC.