Communications Method; Modbus Communications; Communications Specifications - Omron E5AR-T User Manual

Section 7 Modbus Communications

7.1 Communications Method

■ Modbus Communications

■ Communications Specifications

7-2
Modbus communications are based on the RTU Mode of the Modbus
Protocol of Modicon Inc. (specifications: PI-MBUS-300 Revision J).
Detailed specifications for the Modbus protocol are provided below.
Supplement
Communications are implemented by creating a program on the host
computer. The descriptions in this section are therefore from the
perspective of the host computer. For example, "reading" and "writing"
refer to the host computer reading from and writing to the E5AR-T/ER-
T.
Transfer connection

Communications method

Synchronization method
Baud rate
Send code
Data length
Stop bit length
Error detection
Flow control
Interface
Retry function
Communications buffer
Communications
response send wait time
Note: Default settings are shaded.
Multi-point
RS-485 (2-wire, half duplex)
Start-stop
9.6, 19.2, or 38.4 Kbit/s
RTU (Remote Terminal Unit)
8 bits
Automatically determined by vertical parity
setting.
Vertical parity: None, even, or odd
CRC-16 (Cyclical Redundancy Check)
None
RS-485
None
217 bytes
0 to 99 ms
Default: 20 ms