Horner APG RX371 OCS HERX371C101 - Manual (Page 25)

MAN0924-01-EN CH.5
February 8, 2010 Page 25 of 124 # 1018
CHAPTER 5: SERIAL COMMUNICATIONS
5.1 Overview
All RX-371 OCS models provide two serial ports, which are implemented with 8-pin modular RJ45
connectors, and are labeled MJ1 and MJ2. The MJ1 serial port is normally used (although MJ2 can now
be used as well) for RX-371 OCS programming by connecting it to the COM port of a PC running Cscape.
In addition, both MJ1 and MJ2 can be used for application-specific communication, using a variety of
standard data exchange protocols.
5.2 Port
Descriptions
The MJ1 serial port contains both a half-duplex RS-485 interface and an RS-232 interface with RTS/CTS
handshaking.
The MJ2 serial port contains both a full-duplex RS-485 interface and an RS-232 interface with no
handshaking. Both the MJ1 and MJ2 RS-485 interfaces provide switchable termination and bias resistors
internally.
5.3 Wiring
Figure 5.1 along with Table 5.1and Table 5.2 show how the MJ1 and MJ2 serial port pins are assigned.
Figure 5.1: MJ Serial Port Connector
Table 5.1 – MJ1 Serial Port Pin Assignments
Pin Signal Signal Description Direction
1 RX/TX+ RS-485 Receive/Transmit Positive In/Out
2 RX/TX
− RS-485 Receive/Transmit Negative In/Out
3 CTS 1 RS-232 Clear to Send Out
4 RTS 1 RS-232 Request to Send In
5 +5* +5 VDC 60mA max Out
6 0V Ground −
7 TD 1 RS-232 Transmit Data In
8 RD 1 RS-232 Receive Data Out
Table 2 - Ports and Functions
Functions Port 1 (MJ1) Port 2 (MJ2)
RS-232
9 9
Hardware Handshaking 9 X
Programming 9 9
Ladder function controlled 9 9
Serial Downloadable
Protocols
9 9
RS 485 Half duplex 9 9
RS485 Full duplex X 9
8
1
Note: MJ1 and MJ2 look the
same but have different pin
assignments and functions.
• * +5 on RX-371 Rev E and later
• * +5 on all revisions XLt, XL6 and RX-371
Pin MJ1 Pins
Signal Direction
8 TXD OUT
7 RXD IN
6 0 V Ground
5* +5 60mA OUT
4 RTS OUT
3 CTS IN
2 RX- / TX- IN / OUT
1 RX+ / TX+ IN / OUT