Horner APG XL4 OCS - Manual (Page 25)

MAN0964-01-EN CH.5
June 29, 2012 Page 25 of 122
CHAPTER 5: SERIAL COMMUNICATIONS
5.1
Overview
All XL4 OCS models provide two serial ports, which are implemented with single 8-pin modular RJ45
connectors, and are labeled MJ1 and MJ2. The MJ1 serial port is RS-232 while the MJ2 port is RS-485.
MJ1 defaults to 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 a RS-232 interface with RTS/CTS handshaking.
The MJ2 serial port contains half-duplex RS-485 interface with no handshaking. The MJ2 RS-485
interface provides switchable termination and bias resistors internally.
5.3
Wiring and Dip Switches
5.4
RS-485 Termination
Proper RS-485 termination minimizes reflections and improves reliability.
The 485 serial port allows an internal RS-485 termination resistor to be placed across pins 1 and 2 by DIP
Switch Setting.
Only the two devices physically located at the endpoints of the RS-485 network should be terminated.
5.5
RS-485 Biasing
RS-485 biasing passively asserts a line-idle state when no device is actively transmitting, which is useful
for multi-drop RS-485 networking.
Pin Name Function Default
1 RS-485 Termination ON = Terminated OFF
2 Spare Always Off OFF
3 Factory Use Always Off OFF
Pin MJ1 Pins MJ2 Pins
Signal Direction Signal Direction
8 TXD OUT - -
7 RXD IN - -
6 0 V Ground 0 V Ground
5 +5V@60mA OUT +5V@60mA OUT
4 RTS OUT - -
3 CTS IN - -
2 - - RX- / TX- IN / OUT
1 - - RX+ / TX+ IN / OUT
MJ1/2 Serial Ports
MJ1: RS-232 w/Full
Handshaking
MJ2: RS-485 Half-Duplex
Two Serial Ports on One Modular Jack (8posn)
!
1"
!
8"
!
1 2 3
ON
DIP Switches
001XLE037-R1