I am using the AB7839, ethernet adapter to Modbus RTU. How is the memory buffer address mapped to the Modbus register number? In other words how do I assign data to particular modbus register number that the user on the Modbus side can point to to read the data?
For example if I have output data in AB7839 memory address 020h 021h, how do I assign it to Modbus register 30001?
Hello @hhaider ,
the modbus registers are already mapped to memory addresses you can see the modbus mapping in the modbus RTU network guide section3.3
Thanks.
But I do not see any memory memory mapping for the 10000 and 30000 Modbus registers in that table?
Hi hhaider,
Both holding 40000 and input registers 30000 are available. The user guide is providing the Modbus register number you will need to just use the correct offset. The same applies for coils with10000 offset.
I recommend taking a look at the examples here:Modbus Function Code 04 | Read Input Registers | Simply Modbus Software