Maximum outputs per rung

Hi,
I'm currently using a MicroLogic 1000 PLC to do some programming. I was told that the maximum number of outputs per rung is 5 for this particular PLC. I'm not sure how true this is. Can you please let me know what is the the maximum number of output/coils that can be used per rung for this plc? Thank you.

This seems a bit of an odd request, why would you want to drive 5+ outputs from the same logic this seems a waste of I/O.
anyway if you mean branches i.e. you use a bit of logic that is common + each branch has other logic dependant on when you want the particular output on then just put the common logic on a bit then use this bit as part of each rung for each output.
If all these outputs are on & off at the same time then just use one output to drive them all (via relays if required).
Never tried this but if you just keep adding outputs the software will tell you when you have reached the limit I suppose.

Hi,
thank you for the reply. I have converted an application which was done using Grafcet, into ladder logic hence the reason I have many outputs per rung. The initial state results in 6 outputs which are done using B3 bits. What i'm asking is if the MicroLogix 1000 PLC will permit all 6 output bits to work in one rung. I was told only 5 output bits can be used in one rung so i reduced the number of output bits per rung. Was this necessary?

No, the information you received was incorrect.

I just happened to have a Micrologix 1000 on my desk, so I tested this. I have 50 outputs on a single rung and it appears to work just fine. I don't remember what the limit is...I thought it was 32, but apparently it is more...

My ML1000 is a series E FRN 1.0...the series and firmware revision number may make a difference.

When in doubt, you can verify the rung offline and RSLogix500 will warn you if you are exceeding the limits of your PLC.

Paul

EDIT: according to the rockwell knowledgebase, the maximum number of extended branches (like shown in my screenshot) is 75. The maximum number of nested branches (upside down wedding cakes) is four, and the maximum number of instructions per rung is 128.

I don't remember the limits either for branches that are extended down but I think the limit for nested branches is seven.

Thank you so so much. I'm this information is greatly appreciated