using clock seconds to transition from low to high on the rung - Allen Bradley

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Forum PLC Programming Allen Bradley using clock seconds to transition from low to high on the rung

6/3/2010 12:58 AM

	klm
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using clock seconds to transition from low to high on the rung

When I practice learning a new RSLogix instruction; sometimes the instruction may require a low to high transition on the rung. (In order for the new RSLogix instruction to do, what it’s suppose to do).

I could put a XIC contact before the instruction – but then I would have

to manually toggle the XIC contact On and then OFF again, and again. Instead I use a XIC contact with an address of “ S:42/0” . The “S:42/0” is the ‘CLOCK CALENDAR SECONDS. This will toggle the XIC contact ON and OFF automatically because this is what it does naturally inside the CPU. Now the rung goes low and then high without me making it do that manually.

This technique could be used in a program to signal an alarm or indicator light ON and OFF repeatedly.

----[ S:42/0 ]-----------------------------------------( new RSLogix instruction looking for Low to High transition )-------

or maybe just a Module Output

klm

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Allen Bradley

using clock seconds to transition from low to high on the rung