EES-101 Series Ultrasonic Flowmeter
Revision: 3.0.1
Page 42 of 65
9
Appendix1-Serial Interface Network Use and Communications Protocol
9.1
Overview
The transmitter has perfect communication protocol. It can also be connected to a RS-485.
Two basic schemes can be chosen for networking, i.e. the analog current output method only using the flowmeter
or the RS485 communication method via serial port directly using the flowmeter. The former is suitable to replace
dated instruments in old monitoring networks. The later is used in new monitoring network systems. It has
advantages such as low hardware investment and reliable system operation.
When the serial port communication method is directly used to implement a monitoring network system, the
address identification code (in window M46) of the flowmeter is used as network address code. Expanded
command set with [W] is used as communication protocol. Thus analog current loop and OCT output of
flowmeter can be used to control the opening of a control valve. The relay output can be used to power-on/off
other equipment. The analog input of the system can be used to input signals such as pressure and temperature.
The system provides an RTU function for flow measurement.
RS-485(0~1000m) can be directly used for data transmission link for a short distance.
The command answer mode is used in data transmission, i.e. the host device issues commands and the flowmeter
answers correspondingly.
9.2
Direct connection via RS-485 to the host device
Drawing of Upper Computer RS-485 network data acquisition system
Notices:
When the flowmeter is in flowmeter network ,the following network IDN:13(0DH ENTER), 10(0AH NEWLINE),
42(2AH*) and 38(26H&). The Network IDN is set in M46.
9.3
Communication protocol and the use
The communication protocol format used by the ultrasonic flowmeter is an expanded set of the Fuji FLV series
flowmeter protocol.
The host device requests the flowmeter to answer by sending a "command". The baud rate of
asynchronous communication (Primary station; computer system; ultrasonic flowmeter) is generally 9600BPS. A
single byte data format (10 bits): one start bit, one stop bit and 8 data bits. Check bit: NONE.
PC
RS485 turn RS232
DC+ DC-
GE
DC 10 - 36V
E UP+ UP-
E DN+ DN-
TRANSDUCER
I+ I-
4-20mA
OCT+ OCT-
OCT
OUT
RL+ RL-
RELAY
A B
RS485