Micronics U1000MKII-FM, User Manual

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U1000MKII User Manual Micronics
Page 32 Issue 3.1 July 19
4.3 Modbus (if fitted)
The Modbus RTU interface is configured via the Modbus sub menu.
•
Float byte order
–
AB CD
–
Big endian
–
MSB first.
•
The data rate can be selected in the range 1200 to 38400 baud.
•
The address can be set in the range 1 to 126.
•
Minimum Polling Rate 1000ms (1sec). Time out after 5 seconds.
•
The U1000 MKII will only respond to Modbus requests while operational, while the flow reading,
volume total, energy total, power or temperature screens are displayed.
• The instrument responds to the “read holding registers” request (CMD 03).
•
If the flow reading is invalid then the flow value will be zero.
•
If a U1000MkII-HM temperature sensor goes out of range then the value will go to -11°C
(12.2°F).
The above faults will set the relevant status bit (see page 48).
On a unit set to Imperial the temperature is in °F, Power is in BTU/s and flow in US Gallons.
The U1000 complies with the Modbus specification document:
http://www.modbus.org/docs/Modbus_Application_Protocol_V1_1b.pdf