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hotwires

Periodic MODBUS RS232 problems

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update: 

12-10-16

I take that back, I failed after two weeks of trying every conceivable configuration to implement a complete working model of serial MODBUS with read holding register and write coils  exchanges to four vision slaves over RS232 radio modems. Has anyone out here successfully setup a Unistream master to a Vision slave, serial, 232 over modems (RF), read registers (more than one) and write coils; without errors? For example sequentially reading five 16 bit integers and in next line of periodic slave table  writing a 10 bit array of coils (or a single 16 bit write register)? 9600, 1, none, must do four RHR #3 and write coils (10 but array) to four slaves all in a cyclical (periodic) fashion. I can't make it work to save my life. I really need to know if anyone else has a working UniStream to Vision serial modbus system working as expected! Now IF you only do read holding registers or only write coils THEN it works fine. However when stacking different MODBUS operations into a single slave table in periodic mode one or the other function takes precendence over it's neighbor. I had the latest version of UniLogic and UniStream firmware as of December 1st 2016. Had to table the UniStream and go to a Vision 1210 to complete my project. However I desperately want to use the UniStream as an MTU/controller  in my project.

Edited by hotwires
Fixes

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