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NRS70 Series
SECTION 5
NRS70OPS
070803 Version 1 Issue 2
www.snellwilcox.com
5.4
Connect the RS232/RS422 converter to COM1 or COM2 of the PC and connect this via RS422 cable to the 9
pin ‘D’ on the IQ modular unit. This interface is specifically designed for third party connections into the system.
This allows PC’s or any other serial device access to any of the units within the system. Every active 1RU or
3RU box has one of these ports.
N.B. Connector is a socket,
viewed from mating face.
Equivalently, this is a plug,
viewed from the rear,
cable face.
Physical Interface - RollCall RS422
For reference, the A signal
is at 0V at line idle, and
the B signal at 5V.
1
6
2
7
3
8
4
9
5
1
6
2
7
3
8
4
9
5
9-Way Ribbon connections
TxA
Pin 2
RxB
Pin 3
GND
Pin 1
TxB
Pin 7
RxA
Pin 8
Standard
Connections
9-way
Connector
FUNCTION
1
Frame Ground
2
Transmit A (Tx-)
3
Receive B (Rx+)
4
Receive Common
5
[No connection]
6
Transmit Common
7
Transmit B (Tx+)
8
Receive A (Rx-)
9
Frame Ground
N.B. The D connector on the Gateway card could
also be configured as RS485.
Selection of the interface format is by a switch on
the card.
Note that RS485 interconnections should be
pin to pin and only be used for Snell & Wilcox
RollNet applications.
DOWN i.e. towards the PCB selects RS422
UP
i.e. away from the PCB selects RS485
Switch set to RS485