OkiePC
Lifetime Supporting Member
From my searching of the manual in the link above:
MCR is like the old Honeywell Skip And De-energize. The MCR executes the logic inside the zone as false, as if you were to take all the conditions on the first MCR rung and put them on every rung within it the zone as "straight" logic.
The MCR is designed to turn off sections of outputs.
The ZCL is more like the SKP (skip, jump) in that it does not even process what's inside the JMP/LBL pair (Logix5/500 lingo) SKP zone (Honeywell) or ZCL zone (PLC-2). I am stating that based on this quote from the manual "When ZCL zone is false all outputs remain in their last state", not from any personal experience with the PLC-2.
I noticed in the book, in one place they show the ZCL being terminated with a MCR instruction, and in another section they bracket the ZCL zone with ZCL instructions?
MCR is like the old Honeywell Skip And De-energize. The MCR executes the logic inside the zone as false, as if you were to take all the conditions on the first MCR rung and put them on every rung within it the zone as "straight" logic.
The MCR is designed to turn off sections of outputs.
The ZCL is more like the SKP (skip, jump) in that it does not even process what's inside the JMP/LBL pair (Logix5/500 lingo) SKP zone (Honeywell) or ZCL zone (PLC-2). I am stating that based on this quote from the manual "When ZCL zone is false all outputs remain in their last state", not from any personal experience with the PLC-2.
YES, that's the preferred way to do things in my opinion. If there are many repeats, assign them to one bit and use that bit on subsequent rungs...skipping ladder logic controlling discrete real world devices is asking for trouble...it will work fine but at some point there will be confusion at the least.SkiRoy said:Is this acceptable to do to accomplish the same thing being done with the MCR in the PLC-2 program I posted?
I noticed in the book, in one place they show the ZCL being terminated with a MCR instruction, and in another section they bracket the ZCL zone with ZCL instructions?
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