4
GF U3000 V2 Ultrasonic Flowmeter
Modbus Supplement to the operating instructions
Three wire Weipu plug/
socket or block
connector
U3000
U3000
U3000
G2.2 Recommended Modbus Network Toplogy
3
MODBUS CONFIGURATION
The Modbus board supplied with the GF U3000 V2 Ultrasonic Flowmeter complies with the Modbus Application Protocol Specification
V1.1b3 and Modbus over Serial Line Specification and Implementation V1.02. Copies of these documents can be found at
https://modbus.org/docs/Modbus_Application_Protocol_V1_1b3.pdf
and
https://modbus.org/docs/Modbus_over_serial_line_V1_02.pdf
respectively.
Only the mandatory RTU mode is supported for the GF U3000 V2 Ultrasonic Flowmeter.
The Modbus specification for RTU-mode defines an 11-bit character frame containing an 8-bit character. If Parity is used, then only
one stop bit is required. If parity is not used, then two stop bits must be specified. In addition to the standard frame format, non-
standard 10-bit frames are also supported. In this case the GF U3000 V2 Ultrasonic Flowmeter will issue warnings but not prohibit
the use of these formats.
The board supports the following baud-rate and parity combinations:
Baud Rate
Data Bits
Parity
Stop Bits
300
8
E, O, N
1, 2
600
8
E, O, N
1, 2
1200
8
E, O, N
1, 2
2400
8
E, O, N
1, 2
3600
8
E, O, N
1, 2
4800
8
E, O, N
1, 2
7200
8
E, O, N
1, 2
9600
8
E, O, N
1, 2
14K4
8
E, O, N
1, 2
19K2
8
E, O, N
1, 2
28K8
8
E, O, N
1, 2
38K4
8
E, O, N
1, 2
57K6
8
E, O, N
1, 2
76K8
8
E, O, N
1, 2
115K2
8
E, O, N
1, 2
230K4
8
E, O, N
1, 2
