14
4.2. Bus Output (optional)
4.2.1. M-Bus (Meter-Bus)
The M-Bus (Meter-Bus) is a field bus for recording consumption data. The transmission is carried out serially on a reverse
polarity protected two-wire line.
The following measurements are transmitted:
Standardized volumetric flow [Nm
3
/h]
Mass flow [kg/h]
Temperature [°C]
Consumption reading [m
3
]
The flowmeter as M-Bus slave requires a separate supply voltage!
There is no specific topology (phase or star) prescribed for the cabling. Normal telephone cable of type J-Y(St)Y Nx2x0.8
mm can be used. A maximum of 250 meters is permitted per segment.
4.2.2. Modbus RTU
The measured values are stored as a 32Bit float value between 0x19 and 0x21. Depending on the measurement unit
selected, the measurements are saved in SI or US/GB units. The measurement unit can be changed using the configura-
tor software.
Modbus Map:
4.2.3. Data Transmission
4.2.4. Addressing
The flowmeters are factory-set to address 1. The slave address can be set via switches on the PCB.
Factory Setting
Adjustable Values
M-Bus
Modbus RTU
Baud Rate
9600
600...9600
9600...57600
Data Bits
8
8
8
Parity
NONE
None, Odd, Even None, Odd, Even
Stop Bits
1
1 or 2
1 or 2
Slave-Address 1
0...254
1...247
Register Address Protocol Address Measuring Value
SI-Unit
US/GB-Unit
30026
19
Standardized Flow
Nm/s
SFPM
30028
1B
Standardized Volumetric Flow Nm
3
/h
SCFPM
30030
1D
Temperature
°C
°F
30032
1F
Massflow
kg/h
kg/h
30034
21
Consumption reading
m
3
ft
3
1 2 3 4 5 6 7 8
1 - ON
0 - OFF
1 2 3 4 5 6 7 8
1 - ON
0 - OFF
1 2 3 4 5 6 7 8
1 - ON
0 - OFF
1 2 3 4 5 6 7 8
1 - ON
0 - OFF
1 2 3 4 5 6 7 8
1 - ON
0 - OFF
1 2 3 4 5 6 7 8
1 - ON
0 - OFF
Factory Setting:
Slave-Address = 1
Slave-Address = 255
The address set using
the configurator software
is used.
Dip-Switch for address setting
