OPERATION ST80/ST80L Flow Meter
66 Fluid Components International LLC
Figure 49 – ST80/ST80L Configuration Software Modbus Tab, Serial Interface Configuration
ST80/ST80L Modbus Commands
With the Modbus protocol the instrument data is read and written via multiple register access. The following public function numbers are
defined for communication with the ST80/ST80L: 03 and 04.
Table 19 – ST80/ST80L Modbus Function Codes
03
• Flow, Temperature, Totalizer, Pressure
• Flow unit, Temperature unit, Totalizer unit, Pressure unit
• Totalizer Enable/Disable Status register
4xxxx
04
• Flow, Temperature, Totalizer, Pressure
• Flow unit, Temperature unit, Totalizer unit, Pressure unit
3xxxx
06
• Reset Totalizer counter
• Enable Totalizer
4xxxx
See Table 22 (page 72), Table 23 (page 73), and Table 24 (page 73) for Modbus engineering unit codes, exception codes, and register
information, respectively.
ST80/ST80L Process Data Registers
Two data type registers are set up in the ST80/ST80L to access the process data. One uses integer data registers (4000) and the other
uses the Daniel extension data registers (5000).
All designated registers must be read for each variable value to extract the floating-point number. Conversion must be started manually
with the 4000 registers. The Daniel extension handles the read and conversion automatically. To use the Daniel extension the master must
support the Daniel extension function.
Totalizer Description
The ST80/ST80L through the Modbus channel offers the flow Totalizer value through three different register groups organized into two
forms of floating point data types. Registers 5103 and 5104, offer the flow Totalizer as a double precision floating point value in the
Modbus Daniel extension protocol. Registers 4105, 4106, 4107, and 4108 offer the flow Totalizer as a double precision floating point value
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