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Hello

Have some projects with V570 PLC and communicating with IO's on Modbus RTU. The shifting of communication with different Modbus Nodes are done by change of value in an MI using Store Direct function. This works fine on V570, but building the same function in a V700 PLC don't work at all. Are there som bugs in the Store Direct function on V700? The screen dump is from the ladder of V570 that is working fine.

 

StoredDirect.JPG

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  • MVP 2023
1 hour ago, Flex727 said:

Are you 100% sure power flow is passing through the compare block, MB 10, & MB 12? Is your MODBUS block actually writing to the slave?

Those questions were important. A third question: is your ladder in a subroutine? If so, is the subroutine being called in the Main Routine?

If the answers are all "yes", then post your .vlp file here for additional help.

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17 hours ago, Flex727 said:

Those questions were important. A third question: is your ladder in a subroutine? If so, is the subroutine being called in the Main Routine?

If the answers are all "yes", then post your .vlp file here for additional help.

It is yes to all, but in my frustration last evening I tried som more variations, and now I have a sequense for the communication that functions. Not so saticfied with it, because I thougt I hade controll if each Modbus block was finished before next Modbus block was trigged. In the smal examples with Modbus RTU thei are using a manual trigg of an Modbus block, and the trigger bit is RSET on the end of the Modbus block. 

180307b Vilja V700.vlp

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