Rievtech EXM-12DC-DA-R-HMI, User Manual

Page: 292 / 443

292
Parameter Slave address : 1 is default .
Communication protocol: Modbus(RTU)
Communication parameter: baud rate (BPS),Data bits, Stop bits,
Parity
，
Overtime (response time out)
Comm Type: RS232 or RS485( Communication interface of x-Messenger )
Data register Index: High Low /Low High
Command: 01 Read coils(0x)
02 Read Discrete Input(1x)
03 Read Holding Registers(4x)
04 Read Input Registers(3x)
Register start address, count
Output Q Q is set or reset depending on the communication status.
Successful communication , Q=1;
Failed communication ,Q=0;
Note: 1. Data register Index: High Low /Low High
For example, when High Low index was set, one data 0x 00 12 was read and saved to AQ, AQ= 0X0012;
however, when Low High index was set, AQ=0x 1200
Regarding Modbus RTU detail, please refer to our Modbus RTU communication protocol file for it.
Description of the function:
In the configuration of our x-Messenger communication, the x-Messenger usually serves as a slave via
Modbus RTU Protocol, and can communicate with a master directly. That’s to say, any device communicating
with x-Messenger sends command to it, and then its response will be sent out only when the x-Messenger has
received the command, Just as the below figure shows:
However, the “Modbus Read” or “Modbus Write”(next chapter will introduce it) function block would be
utilized if x-Messenger shall be required to play a role of master to communicate with other devices. As the
following figure shows:
When you put the “Modbus read” or “Modbus Write” function block in your program and make some