Sensoray 2600 - Manual (Page 23)

2600 Family Instruction Manual 18 Chapter 4 : Serial Communication Server
Figure 16: RS-232 Wiring
4.2.1.2 RS-422 Wiring
It is standard practice to use twisted pairs for RS-422 transmit
and receive signal pairs, as shown in Figure 17. This will help
to reduce sensitivity to the common-mode noise that inevitably
results from exposure to dynamic fields.
Figure 17: RS-422, no termination
As shown in Figure 18, pins 6 and 7 may be connected together
to insert a 120 ohm termination resistor across the receive pair.
This termination resistor should typically be inserted only if
the MM com port receiver is the last node at the end of the
RS-422 network.
Figure 18: RS-422 with receiver termination
Pins 8 and 9 may be connected together (see Figure 18) to
insert a 120 ohm termination resistor across the transmit pair.
This termination resistor should typically be inserted only if
the MM com port transmitter is the last node at the end of the
RS-422 network.
Figure 19: RS-422 with transmitter termination
If termination is required on both the transmit and receive
pairs, connect together pins 6 to 7 and 8 to 9 as shown in
Figure 20.
Figure 20: RS-422, transmit and receive termination
4.2.1.3 RS-485 Wiring
RS-485 operation is supported on Revision D (and higher)
2601 modules. It is standard practice to use a twisted pair for
the bidirectional RS-485 data signal pair, as shown in Figure
21.
Figure 21: RS-485, no termination
Pins 8 and 9 may be connected together to insert a 120 ohm
termination resistor across the data pair (see Figure 22). This
termination resistor should typically be inserted only if the
MM is the last node at the end of the RS-485 network.
1
2
3
4
9
8
7
6
Remote
Device
Tx232
Rx232
MM
COM Port
Connector
GND
Cable
Shield
5
1
2
3
4
5
9
8
7
6
Remote
Device
Tx422+
Tx422-
MM
COM Port
Connector
Rx422+
Rx422-
GND
Cable
Shield
1
2
3
4
5
9
8
7
6
Remote
Device
Tx422+
Tx422-
MM
COM Port
Connector
Rx422+
Rx422-
GND
Cable
Shield
1
2
3
4
5
9
8
7
6
Remote
Device
Tx422+
Tx422-
MM
COM Port
Connector
Rx422+
Rx422-
GND
Cable
Shield
1
2
3
4
5
9
8
7
6
Remote
Device
Tx422+
Tx422-
MM
COM Port
Connector
Rx422+
Rx422-
GND
Cable
Shield
1
2
3
4
5
9
8
7
6
Remote
Device
RS485+
RS485-
MM
COM Port
Connector
GND
Cable
Shield