Hello Everyone,
I have successfully established Modbus RTU communication over RS485 between a B&R PLC (Master) and a Slave device. Currently, I can read Holding Registers correctly, and I am exchanging INT (16-bit Integer) values without any issues.
Now I would like to transfer REAL (Float) values between the Master and Slave.
My questions are:
- Does Modbus RTU support REAL (Float) data types directly?
- Since a Holding Register is 16-bit, does a REAL value require two consecutive registers (32-bit)?
- What is the recommended method in B&R Automation Studio to read and write REAL values through Modbus?
- How should the Master combine two registers into a REAL value?
- Is there any specific byte order or word order (Endian format) that I need to consider?
- Could anyone provide a simple example of mapping a REAL variable to Modbus Holding Registers and reading it on the Master side?
Example:
- Slave REAL Value = 25.75
- Holding Register 40001 = ?
- Holding Register 40002 = ?
- Master reads these two registers and converts them back to REAL.
I would appreciate any examples, documentation references, or best practices.
Thank you.
