Serial Port Pin Assignment and Interface Selection
The DS100 features a DB9M serial port connector and is available in two models:
Models and Serial Port Types
- DS100R: Equipped with an RS232 serial port.
- DS100B: Offers a universal RS232/RS422/RS485 serial port.
The DS100B does not include internal terminators, which are typically required at the ends of RS422 and RS485 communication buses.
Termination circuits are available on the TB100 Terminal Block Adapter, which can be optionally supplied with the DS100B.
Pin Assignment
Pin Number |
DS100R |
DS100B |
||
|
RS232 (full-duplex op.) |
RS232 (full-duplex op.) |
RS422 (full-duplex op.) |
RS485 (half-duplex op.) |
|
|
#1 |
<No connection> |
<No connection> |
RTS- (output) |
<No connection> |
|
#2 |
RX (input) |
RX (input) |
RX- (input) |
RX- (input) |
|
#3 |
TX (output) |
TX (output) |
TX+ (output) |
TX+ (output) |
|
#4 |
<No connection> |
DTR (output) |
TX- (output) |
TX- (output) |
|
#5 |
Ground |
Ground |
Ground |
Ground |
|
#6 |
<No connection> |
DSR (input) |
RX+ (input) |
RX+ (input) |
|
#7 |
RTS (output) |
RTS (output) |
RTS+ (output) |
<No connection> |
|
#8 |
CTS (input) |
CTS (input) |
CTS+ (input) |
<No connection> |
|
#9 |
<No connection> |
<No connection> |
CTS- (input) |
<No connection> |
RS422 and RS485 Modes
The DS100B supports both RS422 and RS485 modes, with key differences in signal behavior and communication mode:
Communication Modes
- RS422 Mode:
- Operates in full-duplex mode
- The TX+/TX- and RTS+/RTS- signal pairs remain active and continuously output data
- RS485 Mode:
- Operates in half-duplex mode
- The TX+/TX- signal pair outputs data only when the DS100 is transmitting. During this time, incoming data is ignored
- When not transmitting, the TX+/TX- signal pair enters a tri-state mode, and the DS100 listens to incoming data on the RX+/RX- signal pair
Two-Wire RS485 Bus
A two-wire RS485 bus can be created by externally connecting:
- TX+ to RX+ (to form RS485+)
- TX- to RX- (to form RS485-)
This configuration can be easily achieved using the TB100 Terminal Block Adapter.
Note: RS485+ is also known as D0, A, and D+. RS485- is also known as D1, B and D-.
Interface Selection
Interface selection for the DS100B is managed through DIP switches located on the bottom of the device, next to the setup button.
- Switches 1 and 2: Used for interface selection
- Switch 3: Reserved for future use
|
Interface |
Switch 1 |
Switch 2 |
|
RS232 |
OFF |
OFF |
|
RS422 |
OFF |
ON |
|
RS485 |
ON |
ON |