Renu Electronics GWY-00, User Manual

Page: 14 / 105

14
2.3 Communication Ports
Gateway unit has two communication ports. Both the ports have DB9 type connectors and are compatible
with RS232C, RS422, RS485 and CMOS signal levels. PLC1 (also known as COM1) and PLC2 (also known
as COM2) have exactly the same pin outs which are as shown below:
PLC1 / PLC2 ports
TX- (RS422/RS485)
DB9 Female
1
5
9
+5VDC*
*(DO NOT USE)
G N D
RX+ (RS422/RS485)
RXD (RS232C/CMOS)
TXD (RS232C)
TX+ (RS422/RS485)
TXD (CMOS)
RX- (RS422/RS485)
6
8
9
7
2
4
5
3
1
6
Pin Description
User can convert RS485 4 wire + Signal Ground system to a 2 Wire + Signal Ground system by shorting
following signals in the communication cable:
TX+
TX-
A
RX+ B
RX-
SG
SG
Note: If user has attached shield to Earth on Device end, leave the shield open on Gateway end. If user
has connected shield to Signal Ground on Device end, connect shield to Signal Ground on Gateway
end.
Upto 31 Devices can be multi-dropped on RS485 port of Gateway.
Pin Name Signal Level Description
1. TX+ RS422 / RS485 Differential Tr, also referred as TXA
2. TXD RS232 Transmit
3. RXD RS232 / CMOS Receive
4. RX+ RS422 / RS485 Differential R, also referred as RXA
5. GND - Signal Ground common to all signals.
6. +5VDC - DO NOT USE
7. TXD CMOS Transmit
8. TX- RS422 / RS485 Differential Transmit -, also referred as TXB
9. RX- RS422 / RS485 Differential Receive -, also referred as RXB