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5-1
Section
Connecting to the Host’s RS-422A/485 Port
88
CVM1/CV-series CPU Units whose model names do not have the suffix -EV
j
cannot be connected by any connection method.
6
5
9
1
PC (CPU Unit)
RS-422A
connector
Pin number
Connector
hood
1
2
3
4
5
6
7
8
9
Abbreviation
FG
SDA
SDB
–
RS
CS
RDA
–
RDB
–
(9-pin type)
NS-AL002
NT-AL001
Pin number
Abbreviation
F. Ground
SG
SDB
SDA
RDB
RDA
CSB
CSA
DIP Switch Settings
NT-AL001:
Pins 1 and 2 ON
Pins 3 to 6 OFF
NS-AL002:
Pin 4 ON
Pins 1 to 3 OFF
Link Adapter
RS-422A
terminal
block
NT-AL001
1
2
3
4
5
6
7
8
NS-AL002
1
---
3
7
2
6
---
---
7
5
3
1
8
6
4
2
Shield
To avoid an FG ground loop, do not connect the functional ground of the Link
Adapter to the shielding of the RS-422A cable.
Wiring a Memory Link Connection
Prepare the adapter cable while referring to the following diagram.
Host
RS-422A
connector
Abbreviation
Connector
hood
SDA
SDB
RS
CS
RDA
RDB
NS-AL002
NT-AL001
Pin number
Abbreviation
F. Ground
SG
SDB
SDA
RDB
RDA
CSB
CSA
DIP Switch Settings
NT-AL001:
Pins 1 and 2 ON
Pins 3 to 6 OFF
NS-AL002:
Pin 4 ON
Pins 1 to 3 OFF
Link Adapter
RS-422A
terminal
block
NT-AL001
1
2
3
4
5
6
7
8
NS-AL002
1
---
3
7
2
6
---
---
7
5
3
1
8
6
4
2
To avoid an FG ground loop, do not connect the functional ground of the Link
Adapter to the shielding of the RS-422A cable.
5-1-3 Direct 1:1 Connection to the Host’s RS-485
This section explains how to connect the NT21’s RS-232C port with the host’s
RS-485 port through a Link Adapter.
A Link Adapter (NT-AL001 or NS-AL002) is required to convert communications
methods between the RS-232C and RS-485 formats.
Reference: RS-485 can be used between the Link Adapter and host only when the 1:N NT
Link method (standard or high-speed) is selected at the host.
Connecting the NT21 to the Link Adapter (RS-232C)
The RS-232C connection between the NT21 and Link Adapter is the same
whether RS-422A or RS-485 communications are used between the Link
Adapter and host. Refer to Connecting the NT21 to the Link Adapter (RS-232C)
on page 85 for details on the RS-232C connection.
Connecting the Link Adapter to the Host (RS-485)
NT21
RS-485
(Total length
500 m max.)
Host
Link Adapter
(NT-AL001 or
NS-AL002)