MICRO/I Hardware Manual
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3 HG4G/3G, HG2G-5F
1
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3.4 External Interfaces
●
Serial Interface (COM1)
• Make sure to turn off the power to the HG4G/3G, HG2G-5F before wiring each interface or switching the
terminating resistor selector switch.
• Note that only one of the RS232C or RS422/485 interfaces can be used at same time. Wiring both interfaces will
result in failure of the HG4G/3G, HG2G-5F. Wire only the interface used.
Interface Specification
RS232C, RS422/485
Connector
D-sub 9-pin (Plug)
Screw lock bracket
Inch Screw Thread #4-40 UNC
No.
Name
I/O
Function
Communication type
1
4W-RDA/2W-A
IN/INOUT Receive Data (+) [4W]/ Send and Receive Data (+) [2W]
RS422/485
2
RD
IN
Receive Data
RS232C
3
SD
OUT
Send Data
RS232C
4
4W-SDA
OUT
Send Data (+) [4W]
RS422/485
5
SG
-
Signal Ground
-
6
4W-RDB/2W-B
IN/INOUT Receive Data (-) [4W]/ Send and Receive Data (-) [2W]
RS422/485
7
RS
OUT
Request to Send
RS232C
8
CS
IN
Clear to Send
RS232C
9
4W-SDB
OUT
Send Data (-) [4W]
RS422/485
1
5
6
9
