Rievtech PR-12 Series, User Manual And Programmers Manual

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Attention:Only when Easy Ladder software station number is equal to 0
or PLC station number,you can download the program to PLC.
9.2 PR series PLC communication
PR series PLC support free port communication, MODBUS communication and CAN
communication.
Free port communication:
Free port communication is a half duplex communication based on RS-485
communication.Users can make their own communication protocol in free port
communication.Third party devices mostly support RS-485 serial communication .
The core of the free port communication are receiving and sending instructions.
RS-485 communication can not receive and send data at the same time.The RS-485
communication format includes a start bit, 7 or 8 bit characters, a parity bit,
and a stop bit.
Free port communication baud rate can be set to 1200, 2400, 4800, 9600, 19200,
38400, 57600 or 115200.Devices that meet the above conditions can communicate
with PLC.Free port mode has great flexibility.
Free port instructions:
UFP_RCV
UFP_RCV :Receive data instruction
l
PORT: Communication port.
l
TBL: Configuration table ， If the input is MB200.
MB200 is the configuration byte:
（ Instruction output ） M200.0 Communication
preparation
（ Instruction output ） M200.1 Communication
completion
（ Instruction output ） M200.2 Communication error
（ Instruction input ） M200.3 Send CRC check