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For the detail information about I, AI, Q, AQ, registers address of xLogic ,refer to the RTU protocol file.
5.5.34 Modbus read write
Short description:
This function block is developed for the new Ethernet PLC which has web server built-in, if you need use
the Ethernet as master PLC, so block should be applied into the program.
For the CPU with "-N" type, the hardware version number is 1(built-in webserver type). If your CPU
hardware version is not 1 and without webserver built-in, you can still use the modbus read and modbus
write block to establish the communication.
You can get the hardware version number by Tools-> transfer-> get PLC version number.
When a high level in En, the Modbus Read Write block will be activated and the x-Messenger could
communicate with peripheral as a master via RS232 , RS485 or Ethernet interface you selected, further
the output will be switched on when the communication is established successfully. Otherwise the output
(Q pin) is keep off it means communication is failed.
A signal at input R resets output Q and disable this block at the same time
Note:
If you are using old Ethernet CPU(need deviceManger to configure the modem) without web server
built-in and you need use MODBUS through Ethernet port, then you still use MODBUS READ or MODBUS
WRITE block. The MODBUS READ WRITE( Ethernet comm type) is only for the new version Ethernet CPU.
Connection Description
Input En A high signal at En input will enable “Modbus Write” function block to be activated
Input R Reset the value read from peripheral and set the output to 0 via the R (Reset) input.
Reset has priority over En
Parameter Slave address: 1 is default .