ONICON Incorporated 727-447-6140
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SYSTEM-20 BTU METER
SECTION 7.0
MODBUS
MODBUS, serial interface connections are connected at terminal block TB4.
Transceiver: 2-wire, half-duplex (1/4 unit load)
MODBUS address range: 1 - 247 (Default: 017)
Data format: 8 bit Stop Bits: 1
Parity: None (Default), Odd, or Even Byte Order: ABCD
Baud rate: 4800, 9600, 19200, 38400, 57600, 76800 or 115200 (Default: 9600)
Termination: Jumper selectable 120Ω resistor (See page 15) Biasing: None
Engineering Units
Abbreviation
Engineering Units
Abbreviation
Energy Rate
Energy Total
Btu per hour x 1,000
kBtu/hr
Btu x 1,000
kBtu
Tons
Tons
Btu x 1,000,000
MBtu
Watts x 1,000
kW
Ton-hour
TonHr
Watts x 1,000 x 1,000,000
MW
Joules x 1,000,000
MJ
Volume Rate (FLow)
Watt-hours x 1,000
kWHr
Gallons per minute
GPM
Volume Total
Liters per second
L/s
Gallons
Gal
Cubic feet per minute
fT
3
/min
Liters
Liters
Cubic meters per hour
m
3
/hr
Cubic Feet
ft
3
Temperature
Cubic Meters
m
3
Degrees Fahrenheit
ºF
Degrees Celsius
ºC
Velocity (Flow velocity, Fluid speed of sound)
Feet per second
ft/s
Meters per second
m/s
Function Codes Supported
01 - Read Coil(s)
02 - Read Discreet Input(s)
03 - Read Holding Register(s)
04 - Read Input Register(s)
05 - Write Single Coil
06 - Write Single Register
08 - Diagnostic
15 - Write Multiple Coils
16 - Write Multiple Registers
17 - Report Slave ID