Teledyne 460H 2.4.4 RS232/RS485 Serial Communications Port, 3 Serial Port Pins, Label

2.4.4 RS232/RS485 Serial Communications Port

A bi-directional RS232/485 Serial Port Interface is provided that can be used for data acquisition and instrument control. All that is required to use this interface is a computer with a serial communications port (COM port) and terminal software. Three pins are provided on the I/O connector for serial communications as shown in Table 2-3.

	Table 2-3 Serial Port Pins
Label	Description
SERIAL TX	Serial Transmit (RS485 – A)
SERIAL RX	Serial Receive (RS485 – B)
SERIAL GND	Serial Ground (RS232 Only)

The Serial Port can be configured for either RS232 or RS485. The standard factory configuration is RS232. For direct connection to a PC or Laptop, RS232 should be used. For a permanent connection into a data acquisition system, RS485 is recommended because it has better noise immunity and is more reliable when communicating over longer distances. See Appendix A for details on changing the Serial Port configuration.

Figure 2-5 below shows typical connections using RS232 and RS485. Note that the RS485 connection does not use the SERIAL GND pin.

DB9-FEMALE

SERIAL GND

SERIAL RX

SERIAL TX

	RS232
SERIAL TX	RS485-A
SERIAL RX	RS485-B

RS485

Figure 2-5 Typical RS232 and RS485 Connections

See Chapter 5 for information on the Serial Communications protocol used by the M460H.

P/N 03662D Teledyne API Model 460H O3 Monitor Operator Manual - Page 17