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Old December 23rd, 2009, 02:38 PM   #1
e27978
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Micrologix 1200 after power failure

I have a microligix 1200 processor for some valve control Im trying to stop it from powering up the outputs that were on prior to power failure on start I want it to execute the program as if it were just loaded checking input conditions to prevent all the valves from opening at one time when power returns can this be done through processor status file I tried changing the mem module bits but it did not change any help would be appreciated Thanks
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Old December 23rd, 2009, 03:09 PM   #2
bernie_carlton
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You will probably have to deal with the logic itself. S:1/15 is a 'First Scan' bit and can be used to preset conditions on a power-up or program to run transition.
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Old December 23rd, 2009, 08:33 PM   #3
gmferg
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You may want to also research using "seal-in" logic versus Latch/Unlatch. I'm making an assumption here without seeing your code.

More suggestions may be provided if we can take a look at your program. Can you post it?
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Old December 24th, 2009, 12:15 AM   #4
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Quote:
Originally Posted by gmferg View Post
You may want to also research using "seal-in" logic versus Latch/Unlatch. I'm making an assumption here without seeing your code.

More suggestions may be provided if we can take a look at your program. Can you post it?

That is a good point. Real world Outputs should almost never be latched. Internal Bits can be latched, and then buffered with other conditions to decide if an output should go true. Only you know the specifics of your machine, and there exceptions to ever rule. An MCR Relay with a reset that kills all Output Power is a must on machines where un-commanded restart could cause machine damage or personnel injury.

Stu......
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Old December 27th, 2009, 02:51 AM   #5
e27978
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Dont know why but I never thought of using seal in logic insted of latch I changed program and it works fine now


Thanks to all
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