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V570 comms with slc500 on rs232 port

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  • 2 weeks later...

Hi. Ive looked at it but dont understand.  Im new to allen bradley software. 2 things.  Do you have example of unitronics and allen bradley programs showing how to send and receive data.  Lets say in the V570 i'm using mb100-200 and it must be put into b11 on plc503 to switch outputs and wants to use b10 to get info back from plc503.

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  • MVP 2023

First, all you can do in Unitronics is put in a DF1 scan block to make it a slave.  It can't trigger any writes.  You'll have to do all the legwork in the the AB PLC with MSG blocks.


You don't get to be that specific.  If you look at the Unitronics Help, the Allen Bradley B files are mapped directly to the Unitronics MB file starting at 0.  The only problem is B0, B1, and B2 don't exist in Allen Bradley and the B3 file is the default bit file, which will start mapping at MB 768.  To further confuse things, Unitronics assumes that all AB files are 256 words long so you have to take that into account.


So Allen Bradley B11:0/0 starts at MB 2816 (11 x 256) and B10:0/0 starts at MB 2560 (10 x 256).  These locations are hard-coded with the Unitronics DF1 scan block


Clear as mud, I know.  Your best bet is to connect the two together and start playing with AB MSG blocks in their software while you're watching the Unitronics MB memory to verify where things land.


It would actually be easier to get an external DF1 to Modbus converter, which would give you more address control and allow the V570 to initiate communications.


Just my personal opinion.


Joe T. 

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