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BobLfoot

Modicon CPU Memory Map

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I am relatively new to Modicon PLC and trying to find a memory map that will help me out.  I understand the 0xxxx are output and 1xxxx are digital inputs, but in the Ab world I had S registers which contained the system clock and fault/status stuff.  Is there a document with the full register/memory map of the 434 or 534 CPUs explained.  Mr. Google and I haven't had any luck finding it yet.

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Hi, please take this Concept user manual: http://www.schneider-electric.com/download/ww/en/details/2267493-Concept-26---User-Manual/ In this manual you will find description for memory mapping. Just search for "3x" or "4x".  

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Bob,

Modicon PLCs don't have assigned status registers like the AB S-register file. Instead, the battery coil (0x) and time of day clock registers (4x) are assigned in the processor configuration. 984 ladder logic has the STAT instruction which retrieves the status words into a number of consecutive registers starting at the specified register. The number of registers varies by the PLC family. Modicon doesn't use AB style word/bit addressing for bit instructions, just the 0x and 1x bit addresses. To read bits from the status words, use the SENS instruction and remember that bit 1 is MSB and bit 16 is LSB.

(Edit) I saw you other post and realized you're working on the Quantum family with ProWORX/NxT. We only have it installed on our last working WinXP laptop. There is Instruction help under the Help menu, but it looks a bit limited. What you really need is a copy of Modicon Ladder Logic Block Library User Guide, Schneider document number 840 USE 101 00.

Mike

Edited by Mike Lamond
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