SLC Overflow

SMOKE

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Join Date
May 2006
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East and West of Kaos
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475
I have read some threads on fault handeling, and reseting. Perhaps I dont understand yet.
I have some an alalog device that if the machine sits the reading will go past 32767. I dont care. As soon as the opperator moves this hydraulic device the reading is in the zone and all is well.
A previous programmer has put unlatch of s:5/0 at the start of the routine. I belive that the overflow is getting set and reset every scan and if gives me a majior fault.
Is there a way to ignore the overflow. What do I need to do.
 
Put it at the very end of ladder #2(see picture)

overflow.jpg
 
As a side note, if you have an STI in your program and it contains math that may overflow you should put an unlatch of S:5/0 at the end of the STI also. It is possible for an STI to trigger after the unlatch in the main program and before housekeeping. This is pretty unlikely but with the program scanning 100 times per second, sooner or later it will happen.

Keith
 

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