9. Appendices
VlinxMESR9xx Modbus Gateway
Page 77
Manual Documentation Number MESR9xx-1016m
MESR902T-x Serial Port Pinouts
Terminal
RS-232
Direction (RS-232)
RS-422
RS-485
A
RTS
Output
TDA (-)
Data A (-)
B
TD
Output
TDB (+)
Data B (+)
C
CTS
Input
RDA (-)
---
D
RD
Input
RDB (+)
---
E
GND
---
GND
GND
In the RS-422 mode, TX lines are outputs and RX lines are inputs. Connect the Modbus
gateway TXB(+) line to the RXB(+) line of the Modbus network, and the Modbus
gateway TXA(-) to the RXA(-) of the Modbus network.
Ground is signal ground and provides a common mode reference for the RS-422 Receiver
and Transmitters.