User guide

6000 Series Programmer's Guide

Controlling Multiple Serial Ports

Every stand-alone 6000 Series product has two serial ports. On existing 6000 products, the

RS-232 connector (or Rx, Tx, and GND terminals on an AUX connector) is referenced as the

“COM1” serial port, and the RP240 connector is referenced as the “COM2” serial port. Newer

products have connectors labeled “COM1” (factory default function is RS-232) and “COM2”

(factory default function is RP240). New features were added in software revision 4.0 to allow

greater flexibility for the two serial ports:

• Beginning of transmission characters may now be specified (with the BOT command) for

all responses from the 6000 product.

• The XONOFF command was created to enable or disable XON/XOFF ASCII

handshaking. (XONOFF1 enables XON/XOFF, XONOFFØ disables XON/XOFF)

Defaults: XONOFF1 for the COM1 port, XONOFFØ for the COM2 port.

Controllers on a multi-drop do not support XON/XOFF; to ensure that XON/XOFF is

disabled for COM2, send the

PORT2

command followed by the

XONOFFØ

command.

• Several commands were added to control communication on both serial communication

ports on all stand-alone products (see Configuring the COM Ports below for details).

• Support for RS-485 4-wire multi-drop communication, (see RS-485 Multi-Drop, page

75, for details).

Configuring the COM Port

To control the applicable port for setting up serial communication and transmitting ASCII

text strings, use the PORT command. PORT1 selects COM1 and PORT2 selects COM2.

• Serial communication setup commands (see list below) affect the COM port selected

with the last PORT command. For example, to configure the COM2 port for 6000

language commands only (e.g., to communicate to the 6000 product over an RS-485

interface), execute the PORT2 command, then execute the DRPCHKØ command.

DRPCHK....... RP240 Check

E................. Enable Serial Communication

ECHO........... Enable Communication Echo

BOT............. Beginning of Transmission Characters

EOT............. End of Transmission Characters

EOL............. End of Line Terminating Characters

ERRBAD....... Error Prompt

ERRDEF....... Program Definition Prompt

ERRLVL....... Error Detection Level

ERRORK....... Good Prompt

XONOFF....... Enable or disable XON/XOFF

• The PORT command also selects the COM port through which the WRITE and READ

commands transmit ASCII text strings. If an RP240 is connected, the DWRITE

command (and all other RP240 commands) will affect the RP240 regardless of the PORT

command setting. If no RP240 is detected, the commands are sent to the COM2 port.

DWRITE text strings are always terminated with a carriage return.