Omron NT21 - SETUP MANUAL 10-2001 Setup Manual page 39

Connecting Link Adapters
1
2
3
4
5
Block Diagram
RS-232C side
D-SUB 9-pin Case
Fuse
6
+5 V
9
SG
3
RD
2
SD
4
RS
5
CS
7
DR
8
ER
RS-422A/485 Cable
Shield Connections
RS-232C Connector
The connector hood is connected to the RS-422A terminal block's frame ground
terminal.
Pin Signal name
1 Not used
6
7
2 Send data
8
3 Receive data
9
4 Request to send
(shorted to CS internally)
5 Clear to send
(shorted to RS internally)
6 +5 V (150 mA) input for Link
Adapter
7 Data set ready
(shorted to ER internally)
8 Data terminal ready
(shorted to DR internally)
9 Signal ground
The following diagram shows the internal block diagram of the NT-AL001-E Link
Adapter. Refer to this diagram only when wiring custom cables or connecting
devices with special interfaces.
POWER
Indicator
R
Photocoupler
RS-232C
Dr/Rec
R
When using RS-422A or RS-485 cables for long-distance communications, do
not ground the shield at both ends of the communications line because large cur-
rents can flow through the shield due to the difference in potential at the two
Code
(RS-232C Device ⇔ Link Adapter)
--- ---
RS-232C Device ← Link Adapter
SD
RS-232C Device → Link Adapter
RD
RS-232C Device ← Link Adapter
RS
RS-232C Device → Link Adapter
CS
RS-232C Device → Link Adapter
+5 V
RS-232C Device → Link Adapter
DR
RS-232C Device ← Link Adapter
ER
SG ---
RS-422A/485 Dr/Rec
Convertor
DC-DC
IS_5 V
L L REG
IS_0 V
R R R
SW1-6
SW1-3
SW1-5
R
Terminating
resistance
RS-422A Dr
Section
Signal direction
RS-422A/485 side
8 terminal block
1
FG
2
SG
3
SDB
4
SDA
2-wire/
4-wire
SW1-4
5
RDB
6
RDA
SW1-2
7
CSB
8
CSA
3-2
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