1:N Connection To The Host's Rs-485 Port - Omron NT21 - SETUP MANUAL 10-2001 Setup Manual

Connecting to the Host's RS-422A/485 Port

5-1-5 1:N Connection to the Host's RS-485 Port

Reference:
Connecting the NT21s to the Link Adapters (RS-232C)
Connecting the Link Adapters between NT21s (RS-485)
NT-AL001
RS-422A
terminal
8
block
7
6
5
4
3
2
1
DIP Switch Settings
NT-AL001:
NS-AL002
NS-AL002:
92
This section explains how to connect the RS-232C ports of two or more NT21s
with the host's RS-485 port through Link Adapters.
NS-AL002 Link Adapters are required to convert communications methods be-
tween the RS-232C and RS-485 formats.
S The RS-485 standard 1:N NT link method can be used only when the follow-
ing Boards/Units are installed:
CS1W-SCB41 Serial Communications Board in a CS-series CS1G/H(-H)
CJ1W-SCU41 Serial Communications Unit in a CJ-series CJ1G
Serial Communications Board in a C200HX/HG/HE(-Z)E
CQM1H-SCB41 Serial Communications Board in a CQM1H
S The RS-485 high-speed 1:N NT link method can be used only when the follow-
ing Boards/Units are installed:
CS1W-SCB41 Serial Communications Board in a CS-series CS1G/H(-H)
CJ1W-SCU41 Serial Communications Unit in a CJ-series CJ1G
The RS-232C connections between the NT21s and Link Adapters in a 1:N con-
figuration is the same as the connection in a 1:1 RS-422A configuration. Refer to
Connecting the NT21 to the Link Adapter (RS-232C) on page 85 for details on
the RS-232C connections.
Link Adapter
Pin number Abbreviation
NT-AL001 NS-AL002
F. Ground
1 1
2 --- SG
SDB
3 3
4 7 SDA
5 2 RDB
6 6 RDA
7 --- CSB
8 --- CSA
Pins 1, 3, 4, and 6 ON
Pins 2 and 5 OFF
(Turn ON pin 2 to enable the
terminator in the last Unit.)
Pin 1 to 3 ON
Pin 4 OFF
(Turn ON pin 4 to enable the
terminator in the last Unit.)
To avoid an FG ground loop, connect the functional ground of only one of the
Link Adapters to the shielding of the RS-485 cable.
Link Adapter
NT21 (NT-AL001 or
NS-AL002)
RS-485
(Total length:
500 m max.)
Link Adapter
Abbreviation Pin number
NS-AL002
F. Ground
1
SG ---
SDB
3
SDA 7
RDB 2
RDA 6
CSB ---
CSA ---
DIP Switch Settings
NT-AL001: Pins 1, 3, 4, and 6 ON
Shield
Pins 2 and 5 OFF
(Turn ON pin 2 to enable the
terminator in the last Unit.)
NS-AL002: Pin 1 to 3 ON
Pin 4 OFF
(Turn ON pin 4 to enable the
terminator in the last Unit.)
Section
Host
NT-AL001
NT-AL001
1
RS-422A
connector
2
3
7
4
5
5
6
3
7
8
1
NS-AL002
5-1
8
6
4
2