GLX-RSS-2-300 WL User Manual
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GLX-RSS-2-300 WL Non-Contact Flow Meter
3.1. Serial RS-232 Interface
Serial RS-232 interface is implemented as standard PC full-duplex serial interface with voltage
levels adequate for direct connection to PC computer or other embedded devices used for serial
RS-232 communication.
In case the RS-232 interface is connected to standard DB-9 PC connector, TxD line (green wire)
is connected to pin 2 and RxD (yellow wire) is connected to pin 3. For proper operation of the
serial interface, additional connection of signal GND (grey wire) is required on pin 5 of the DB-9
connector.
Optionally Geolux can supply a cable with a DB-9 connector connected to the cable, but this must
be specified when ordering the sensors.
Several communication protocols are available, as well as custom ones on request. Details of
communication protocols are described in chapter 7 of this user manual.
Picture 1. Serial RS232 DB-9 Cable
3.2. Serial RS-485 Interface
Serial RS-485 interface is implemented as standard industrial half-duplex communication
interface. Communication interface is internally protected from short-circuiting and overvoltage.
Depending on the receiving device, the interface can be used with only two wires (D+ dark red
wire & D- orange wire) while in some cases ground connection (signal GND gray wire) is also
required. For more details, please consult receiver specification.
The most common communication protocol used with RS-485 interface is Modbus-RTU but other
protocols are also available. Details of communication protocols are described in chapter 7 of this
user manual.