ABB TPU2000 Technical Manual page 369

6. Proper selection and installation of the physical cable medium.
7. Proper configuration of the RS 232/485 physical interface switches and dipswitches.
RS232 Configuration And Cabling
The Telebyte RS 232 section of the converter uses the following pins:
Pin 2 – Transmit Data
Pin 3 - Receive Data
Pin 7 - Ground
The RS 232 connector on the converter is a DB 25 male connector.
Depending upon the dipswitch settings, the following pins are used for transmit data control.
Pin 4 – Request To Send
Pin 5 – Clear To Send.
Although the TELEBYTE converter does use handshaking and control of the DTR signal (Pin 20), its use is not
covered in this application note.
The Telebyte converter is an actively powered device requiring attachment to a supplied power transformer. This
transformer supplies power to both ports on the unit. No additional power supplies are required for this converter
to operate.
The TELEBYTE converter has an additional dipswitch configuring the RS 232 port for DCE or DTE configuration.
Figures 2 and 3 illustrate cable pinouts to connect a PC or ABB to connect to a device. If the converter is
attached to a PC Host device or an ABB IED, a straight through cable may be used (or a 9 pin to 25 pin cable) to
attach the devices. The DTE/DCE switch must be placed in the DCE position due to the nature of RS 232
connections. If additional discussions of RS 232 are required, please consult the ABB Faxback System (610-877-
0721) or the ABB website (www.abb.com/substationautomation). Several documents are available explaining RS
232 communication. The TELEBYTE converter has a DB 25 connector whereas the ABB IED's and most
personal computers have DB 9 connectors. Figures 2 and 3 illustrate the cable connections are handshaking is
used (RTS/CTS) control or if no handshaking (data control using the Transmitted Data line) is employed.
Configuration of the data control handshaking mode is performed via the dipswitches located at the side of the
converter. Refer to Figure 1 of this document for dipswitch configuration.
TPU2000/2000R Modbus/Modbus Plus Automation Guide
TELEBYTE 245 OPTICAL ISOLATOR CONVERTER
RS 232
SW 2
RS232 RS422/485
1 2 3 4 TD RD TD RD
The 245 uses Pin 2 (TX/RX -) & Pin 14 (TX/RX +), Pin 7 is Ground
for its connections to the Two Wire RS-485 Relay.
RS 485 SWITCH
SW 1
MODE (2 wire)
1 2 3
UP DOWN UP DOWN
TRANSMIT DATA CONTROL
RTS DATA CONTROL
UP UP DOWN
X = TERMINATION RESISTOR , UP = INSERTED : DOWN = OUT
Figure 1 – Telebyte Dipswitch Settings
RS485/RS422
SW 1
DTE DCE
1 2 3 4
SW 2
4 1 2 3 4
X DOWN UP Y
UP X DOWN UP Y
Y = DON'T CARE
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