Allen-Bradley SLC 500, User Manual, Page: 202 / 294

Publication 1747-UM011G-EN-P - June 2008
202
RS-232 Communication Interface
The RS-232 channel on the SLC 5/03, SLC 5/04, and SLC 5/05
processors supports various protocols:
•
Full-duplex DF1 (default)
•
Half-duplex DF1 (SCADA)
•
DH-485
•
ASCII communication
•
DF1 radio modem
•
Modbus RTU Master
The SLC and PLC products detailed in this appendix that communicate
over the RS-232 communication interface also use the DF1 serial
communication protocol. DF1 protocol delimits messages, controls
message flow, detects and signals errors, and retries after errors are
detected.
SLC 5/03, SLC 5/04, and SLC
5/05 processors and RS-232
Communication
The SLC 5/03, SLC 5/04, and SLC 5/05 processors can communicate by
means of the RS-232 communication port, channel 0. Channel 0 supports DF1
full-duplex protocol, DF1 half-duplex master and slave protocol, DH485
protocol, Modbus RTU Master communication, ASCII communication, and
DF1 radio modem protocol. Refer to your programming software user manual
for information on configuring the RS-232 communication port, channel 0.
The details of the DF1 protocols can be found in the DF1 Protocol and
Command Set Reference Manual, Publication Number 1770-6.5.16.
Channel 0 provides a minimum of 500V dc isolation between the I/O
signals and the logic ground of the SLC 5/03, SLC 5/04, and SLC 5/05
processors. The channel is a 9-pin D-shell. The table below provides a
description of each of the pins.
The D-shell is the bottom port on the SLC 5/03, SLC 5/04, and SLC 5/05
processors.
Pin Pin Name
1 DCD (Data Carrier Detect)
2 RXD (Receive Data)
3 TXD (Transmit Data)
4 DTR (Data Terminal Ready)
5 COM (Common Return [Signal Ground])
6 DSR (Data Set Ready)
7 RTS (Request to Send)
8 CTS (Clear to Send)
9 NC (No Connection)