MU300 Rev1.0 Oct20
Page 47 of 54
Flowmeter-RS485:
Chapter VIII Communication Interface and Communication Protocol
8.1
General
The flowmeter is provided with an UART protocol, and you also could operate by using
RS-485 Modbus. There are two basic structures you could choose for networking, i.e.
only applying the analog current output method or directly applying the UART
communication method of the flowmeter. The former one is applicable for replacing
the old meter in the old monitoring network, while the latter is used for the new
monitoring network, which has a lot of advantages like low hardware investment,
reliable system operation and etc.
When directly using the UART communication for the monitoring network system, you
could use the address identification code as the network address code and use the
command extending set with [W] as the communication protocol.
8.2
UART Definition
RS485/R232Converter
8.3.
Communication Protocol and its Use
The flowmeter supports HL protocol and MODBUS protocol.
8.3.1.
HL protocol
The flowmeter applies HL communication protocol. The host device would request the
flowmeter to respond after sending a “command”. Asynchronous communication baud rate
(Main station: computer system; secondary station: ultrasound flowmeter) is 9,600 BPS in
general.
Single byte data format (10 bits): One start bit, one stop bit and eight data bits. Check bit: Non.
One data character string is used for indicating the basic command, while one ENTER is used for
indicating ending the command. This command is applicable for RS232 and RS485. Common
commands are shown below:
Common Communication Commands
