CiDRA GVF-100 Gas Volume Fraction Monitoring System - Manual (Page 53)

Copyright © 2006 CiDRA Corporation Page 9-2
20639-01 Rev 03
9.2 Transmitter Output Definitions
The following figure shows a diagram of the output portion of the
terminal board. The outputs of the transmitter are connected to
communicate between the transmitter and other equipment.
Figure 44 Transmitter Output Terminals
COMM – This denotes the connection point for serial digital
communications. Either RS232 or RS485 communications is
supported with baud rates settable between 2400 and 115200 baud (8
bits, no parity, 1 stop bit). The communications type (RS232/485) as
well as the baud rate can be set by the front panel keypad as listed in
a later section of the manual.
Note: If intermittent RS-485 communication problems are observed, it
may be necessary to put bus terminations of 120 ohms at the extreme
ends of the bus between COM+ and COM-. Should this be
necessary, follow best practices in selecting the resistor and in
connecting it reliably to the bus. However, it is a violation of Class I
Division 2 rating of the SONARtrac
TM transmitter to install the bus
termination resistor physically within this enclosure. A different
Class I Division 2 enclosure must be used to house the bus
termination resistor if the SONARtrac
TM
transmitter is installed in
a Class I Division 2 location.