internal variables (virtual i/o) in CX Programmer

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I'm new to PLC programming and am interested in using virtual I/O where I might read several actual hardware inputs, set an internal bit or other variable as a consequence / output, then use those variables to decide what to do with actual hardware outputs.

Currently I'm using an SRM1, old PLC unit.  I have all the pdf manuals but I dont understand yet how to assign an address to in the symbols list to use virtual or internal i/o.  The hardware io is all compobus and has addresses such as 00.00 to 7.15 inputs, 10.00 to 17.15 for outputs.  

I see in the manual a list of the data area allocation, Work bits IR008, IR009, IR018, IR019, and IR200 to IR239.  Are these the addresses that I can use say I'd call a virtual output 200.00 in the symbols list?  I just dont know the industry nomenclature yet.

there are all the other areas too SR HR AR LR DM, TR, etc.  thanks in advance for helping a n00b

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You can use any unused IR addresses for internal bits.

You could also us the HR bits.  HR will hold status through power failure.

Stay away from SR and AR.  Those typically have a predefined use.

Download the SRM1 programming manual for more information.


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