OPTO 22 SNAP-LCM4, Руководство пользователя

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3: JUMPERS AND COMMUNICATION
SNAP-LCM4 User’s Guide 18
Configuring Ports 2 and 3
The default for COM2 and COM3 is RS-232, but these ports can also be configured as RS-485 two-wire or
four-wire. See page
19 for jumper settings to configure RS-232 or RS-485 mode.
Jumper functions and two-wire and four-wire jumper settings are shown below. Use CFG2 jumpers for COM2
and CFG3 jumpers for COM3.
Pin Connections for COM2 and COM3
Pin RS-232 RS-485 2-wire RS-485 4-wire
1 TX TX/RX + TX +
2 RX TX/RX - TX -
3 COM COM COM
4 RTS IRQ +* RX +
5 CTS IRQ -* RX -
TX = Transmit
RX = Receive
COM = Common
Ground
RTS = Request to Send
CTS = Clear to Send
IRQ = Interrupt *NOTE: For 2-wire, use pins 4 and 5 only
if you are using an interrupt (IRQ). The
IRQ function is supported in 2-wire mode
only. Use pins 4 and 5 for the IRQ wires.
RS-485 Jumper Functions
COM2 and COM3. Two-Wire and Four-Wire Jumper
COM2 = CFG2
COM3 = CFG3
Pin 1
Pin 1