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Gob12345

Micrologix 1200 Fault S:6 "21H"

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Hi all, I have a fault on my micrologix 1200 which is stopping the PLC from going into run mode. I can connect to the plc as well as download to it but as soon as i put it into run mode the fault comes up I searched the error code (21H) and its "Bad MSG file parameter for building message" Anyone know what could be causing this? I'm pretty confident that I don't have any MSG bits in the program, I'm using rs logix 500 (if that helps) Thanks Gob12345

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Can you post your program? That way others can view your code and perhaps spot the cause of your fault.

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Ok, I've attached it to this post Any suggestions will be very much appreciated RWR_18_02_13.RSS

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The 1200 manual shows error 21H as relating to an I/O hardware failure. Is RSLogix actually showing "Bad MSG file parameter for building message" in the error window. Can you take a screen shot of the fault?

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Does this unit have a memory module? If so could there be another program installed in that module? If there is a memory module cycle power to the 1200. Then, without loading your own program, go online with the 1200 and upload its contents.

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The manual I have says this.

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Hi All, That error makes sense to something I've been informed today, someone had accidentally put 110V dc on the 24V terminals, I stripped the PLC down to find some of the pins on the power card burnt (I think the output pins of the power card) i cleaned the connections up and checked the fuses (which were fine). Other than that i cant visually see any other issue, That's obviously not to say there isn't an issue, I just don't know where to look from here. Again, any thoughts would be grateful Gob12345

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If you had burnt spots, odds are that something is damaged. You could try it with the correct power, but I wouldn't hold out much hope.

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Yeh i've tried it with the correct power and that's the position i'm in now from the top of this topic feed, I'm guessing something is damaged too but I have little experience following circuit boards through like this

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What's your time worth? It's probably more cost effective to replace it (or send it out for repair), unless you have a lot of free time and want to poke at it.

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