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Posted
Hi there I have a project with a PL7 micro. It is linked to a FactoryCast Card, which has a website in it for operator interface. On the IP network, there is also an Anybus module, connected to a modbus 485 rtu network. The problem is, the data from the Anybus module is sent to the PLC in words %MW200 to %MW215. There is a STL program that makes %MB400 to %MB429 roll around, one byte at a time. I am under the impression that when data is moved around in %MB400-%MB429, the data in %MW200 to %MW215 moves along, in the same orderly fashion. The question is: are those two memory area the same, linked together, or are they separate memory areas?. Also, is the boolean memory area (%M1 and so on) linked to %MB or %MW memory area? Thank you!
Posted
%MB is addressed in bytes... %MW is words... 8 bits to a byte or 16 bits to a word. So it stands to reason that byte 400 is word 200, as each word would be 2 bytes long. I haven't touched one of these in years, so I can't say with 100% certainty, but that is how I remember it. Per the IEC standard, %M (or %MX) is one bit long. As stated above, the B and W mean byte and word. So %M0 would be the first bit in %MB0, which would then also be the first 8 bits of %MW0.
Posted
From what I see in the project, it really looks like MB400 and 401 is bound to MW200, and so on. But the %M Memory seems (has to) be seperate, because the level setpoint is in %MW0, and most of the sequence bits are in %M0 to %M15, so changing the level setpoint would break havoc in the sequence. Anyone can confirm the bounding?

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