Omega FMA 4000 - Manual (Page 8)

2.2.3 Communication Parameters and Connections
The digital interface operates via RS485 (optional RS232) and provides access to
applicable internal data including: flow, CPU temperature reading, auto zero, total-
izer and alarm settings, gas table, conversion factors and engineering units selec-
tion, dynamic response compensation and linearization table adjustment.
Communication Settings for RS485 / RS232 communication interface:
Baud rate: ...................... 9600 baud
Stop bit: ...................... 1
Data bits: ...................... 8
Parity: ...................... None
Flow Control: ...................... None
RS485 communication interface connection:
The RS485 converter/adapter must be configured for: multidrop, 2 wire, half
duplex mode. The transmitter circuit must be enabled by TD or RTS (depending
on which is available on the converter/adapter). Settings for the receiver circuit
should follow the selection made for the transmitter circuit in order to eliminate
echo.
RS485 T(-) or R(-) ...................... pin 8 of the 15 pin “D” connector (TX-)
RS485 T(+) or R(+) ...................... pin 15 of the 15 pin “D” connector (RX+)
RS485 GND (if available) ...................... pin 9 of the 15 pin “D” connector (GND)
RS232 communication interface connection:
Crossover connection has to be established:
RS232 RX (pin 2 on the DB9 connector) ..... pin 8 of the 15 pin “D” connector (TX)
RS232 TX (pin 3 on the DB9 connector) ..... pin 15 of the 15 pin “D” connector (RX)
RS232 GND (pin 5 on the DB9 connector) ..... pin 9 of the 15 pin “D” connector (GND)
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