Cyanogen281

Micrologix 1400 Binary bits (B3) acting strangly

6 posts in this topic

So I was out in the field a few days ago and encountered an issue I have never run in to before on a Micrologix 1400 using RSLogix 500. All was going well when I was checking the I/O's until I realized that although I would get an input, the virtual output (B3) would not turn on... I have encountered something similar in Siemens programming where if you accidentally have 2 coils using the same register, they act as an AND instruction. When I was completely stumped I decided to make a completely new program and just put a few inputs and a few coils in, and everything worked fine... Could this be some sort of memory overlapping issue I am having? Any advice or tips would be greatly appreciated.

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Sounds like something else is writing to it. In addition to duplicate OTEs, it could be a MOV or a COP instruction writing to B3:0. Can you post your whole program? Also is there an HMI attached to it?

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There is no HMI attatched to it at the moment. BROWNWOOD.RSS

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You are not executing the I/O map routine, or any of the ladders beyond Ladder 2. It is the only one executed by default. Add JSR instructions to execute routines 3, 4, 5, and 6.

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HA. Wow that's pretty sad. I've been doing this too long to make a rookie mistake like that. Thanks for the help Sorcerer.

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Happens to us all

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