Cutler-Hammer D320 PLC, User Manual

Page: 33 / 258

Chapter 3: Product Specification
21
The DIP switch located on the front of the CPU is used as a selecting switch for communication. The
DIP switches function as follows:
Switch
Number
Switch
Position
Function Diagram
Off COM1, 9,600 bps
1
On COM1, 19,200 bps
Off Off COM2, 9,600 bps
On Off COM2, 19,200 bps
Off On COM2, 38,400 bps
2 3
On On COM2, 4,800 bps
DIP1
ON
6
5
4
3
2
1
4 Not used.
Off Off Terminating resistors for RS485 communications not connected.
5 6
On On Terminating resistors for RS485 communications connected.
CAUTION:
•
The communication port can be used for an RS232 or RS485 connection. It will automatically
select between the two.
•
The terminating resistors are connected to the end of the communication line to help remove
communication interference and signal distortion when it occurs between the PLC and other
PLCs or peripherals. The terminating resistors are typically used with long communication
distances and the RS485 communication protocol.