2. Programming Concepts
Function Group COM Port Function
Number
Port
COM1 COM2 COM3
Communication setting holding
Slave communication address
Contents:
COM ports (COM1: RS-232, COM2: RS-485, COM3: RS-485) support communication format of
MODBUS ASCII/RTU modes. When RTU format is selected, the data length should be set as 8.
COM2 and COM3 support transmission speed up to 921kbps. COM1, COM2 and COM3 can be
used at the same time.
COM1:
Can be used in master or slave mode. Supports ASCII/RTU communication format, baudrate
(115200bps max), and modification on data length (data bits, parity bits, stop bits). D1036: COM1
(RS-232) communication protocol of master/slave PLC. (b8 - b15 are not used) Please refer to
table below for setting.
COM2:
Can be used in master or slave mode. Supports ASCII/RTU communication format, baudrate
(921kbps max), and modification on data length (data bits, parity bits, stop bits). D1120: COM2
(RS-485) communication protocol of master/slave PLC. Please refer to table below for setting.
Note: 600 bps is not available for ES2-C: V4.0 or later; 921kbps is not available for SE: V1.xx;
921kbps is available for SE: V2.00 or later.
COM3:
Can be used in master or slave mode. Supports ASCII/RTU communication format, baudrate
(921kbps max), and modification on data length (data bits, parity bits, stop bits). D1109: COM3
(RS-485) communication protocol of master/slave PLC. (b8 - b15 are not used) Please refer to
table below for setting.
Note: ES2-C does NOT come with COM3; 921kbps is not available for SE: V1.xx; 921kbps is
available for SE: V2.00 or later.
b0 Data Length
0: 7 data bits, 1: 8 data bits
(RTU supports 8 data bits only)
b1
b2
Parity bit
b4
b5
b6
b7
Baud rate