3: JUMPERS AND COMMUNICATION
SNAP-LCM4 User’s Guide
14
CONFIGURING SERIAL PORTS
The SNAP-LCM4 comes with four serial ports:
•
COM0 is selectable as RS-232, RS-485 half-duplex (2-wire), or RS-485 full duplex (4-wire). The default
mode is RS-232 for connection to a PC. In RS-232 mode, COM0 also supports RTS and DTR/DCD flow
control for use with modems.
•
COM1 is an Opto 22 remote I/O port (half-duplex RS-485 only).
•
COM2 and COM3 are both configurable either as RS-232 or as half- or full-duplex RS-485. The default
mode is RS-232. In RS-232 mode, COM2 and COM3 support RTS flow control only. Interrupt (IRQ)
functionality is available in RS-485 2-wire mode only.
Since most systems use the default modes, it’s not normally necessary to configure serial ports. However, if
you need to change the serial port configuration, you must open the controller and set configuration jumpers
on the serial card inside. See
for instructions.
In addition, all COM ports communicate using the following defaults:
If you need to change these defaults, use the OptoControl command Configure Port. See the
OptoControl
Command Reference
(Opto 22 form #725) for details on using the command.
Removing the Serial Card
Remove the faceplate thumbscrews and the faceplate. Carefully pull straight up on the serial card (the one
with the port connectors) to remove it.
The internal jumpers are shown in the diagram on the following page.
Baud rate = 115,200
Parity
= None
Data Bits
= 8
Stop bit
= 1
CTS
= Disabled
