Using the DATA_EXCH for Explicit messaging FC 16 (Write Multiple Holding Registers) or FC 03 (Read Holding Register) from a M580 Ethernet interface.

[islam_said]

Hi Guys,

I am Trying to use DATA_EXCH block to Send Explicit Messaging over ModbusTCP to Modbus Device, to write some data to multiple registers with Function Code 16, and Read back Holding Registers with Function Code 03,

but i amn`t able to find a clear example how to do that ?, with DATA_EXCH or (READ_VAR), (WRITE_VAR)

for example Write/Send_Data to this range : 0xD000 - 0xD006 (Function Code 16)

and Read/Recieve_Data from this range: 0xD040 - 0xD042 (Function Code 3)

Can i do that Explicit Messaging with DATA_EXCH EFB over Modbus TCP ?, there are 1 example here but for Writing Single Register.

https://www.se.com/in/en/faqs/FA198507/

https://www.se.com/us/en/faqs/FA311665/

I could see that it was possible with DATA_EXCH to Explicit Messaging over Ethernet/IP to send a hole message in array to Ethernet/IP Device with CIP Protocol, and Receive the Data on another array

https://community.se.com/t5/Industrial-Automation-How-to/Ethernet-IP-Explicit-Messaging-Using-DATA-E...

Also, In this Video (Modbus Explicit Messaging using GPL), but not using  DATA_EXCH

https://www.youtube.com/watch?v=r_-tmkiAre8

Thanks to let me know if you have an example for DATA_EXCH or Write_Var, Read_Var, for sending a hole message frame over Modbus TCP, and receive the Data Record on an array, similarly to Ethernet/IP over CIP Protocol

[Marian_Pavlik · Accepted solution]

READ_VAR and WRITE_VAR function blocks are native to usage Modbus FC03 and FC16.

For periodic communication is better to use IO scanning of BMXNOE0100 module for M340 or DTM request at any Ethernet port of M580.

https://www.se.com/us/en/faqs/FA213730/ for WRITE_VAR

https://www.se.com/us/en/faqs/FA241528/ for READ_VAR