User`s manual

Western Reserve Controls, Inc. 1782-JDC User’s Manual
16
4.3 Serial Port Connector
The ASCII devices are connected to the JDC via a 3-wire or 5-wire communications cable.
See your ASCII device’s User Manual for details on the proper connections.
The RX and TX designators are referenced with respect to the JDC.
Table 4-3 RS-232/485 Connector Signals
Pin #
Designator
(RS232/RS485)
RS232
Signal
RS485
Signal
3 RX/SG- Receive Signal -
2 TX/SG+ Transmit Signal +
1 GND Ground Shield
Table 4-4 RS-422 Connector Signals
Pin # Designator
RS422
Signal
5 TX- Transmit -
4 TX+ Transmit +
3 GND Ground
2 RX- Receive -
1 RX+ Receive +
4.4 DeviceNet Configuration
DeviceNet specifications provide for a maximum network distances for the main trunk line and
drop lines, depending upon the baud rate used on the network. See Table 4-5
Table 4-5 Maximum Network Cable Lengths
Trunk Line Length Drop Length
Maximum Distance Maximum Cumulative
Baud Rate Meters Feet Meters Feet Meters Feet
125k baud 500 m 1640 ft 6 m 20 ft 156 m 512 ft.
250k baud 250 m 820 ft 6 m 20 ft 78 m 256 ft.
500k baud 100 m 328 ft 6 m 20 ft 39 m 128 ft.
4.4.1 DeviceNet Network Termination
A DeviceNet system must be terminated at each end of the trunk line. The host controller
and the last JDC or other DeviceNet device on the network must always be terminated to
eliminate reflections, even if only two nodes are present. The DeviceNet specifications for the
terminating resistor are: