GHM DeltaOHM HD51.3D Series, Operating Manual

Page: 35 / 42

HD51.3D…
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V2.0
10 MODBUS-RTU MODE
In MODBUS-RTU mode, the instrument sends the acquired measurements only if specifically
requested by the PC, PLC or data logger.
Communication parameters should be set in the PC or data logger as follows:
•
Baud rate: same as the setting in the instrument (default =19200)
•
Data bits: 8
•
Parity: same as the setting in the instrument (default = even)
•
Stop bits: same as the setting in the instrument (default = 1)
M
EASUREMENTS READING
(function 04h )
The Modbus function code 04h (Read Input Registers) allows reading the values measured by
the instrument. The following table lists the Input Registers available.
Modbus Input Registers
Register
number
Quantity Format
1 Instantaneous wind speed (x100) unsigned 16 bits
2 Instantaneous wind direction in degrees (x10) unsigned 16 bits
3 Sonic temperature measured by the transducers pair 2-4
(x10). See page 22 for the transducers numbering. 16 bits
4 Sonic temperature measured by the transducers pair 1-3
(x10). See page 22 for the transducers numbering. 16 bits
5 Average of the two sonic temperatures measured by the
two transducers pairs (x10) 16 bits
6 Temperature measured by Pt100 sensor (x10) 16 bits
7 Relative humidity in %RH (x10) unsigned 16 bits
8 Barometric pressure (x1000 if the unit of measurement is
atm, x10 in the other cases) unsigned 16 bits
9 Compass angle in degrees (x10) unsigned 16 bits
10 Solar radiation in W/m
2
unsigned 16 bits
11 Average wind speed (x100) unsigned 16 bits
12 Average wind direction in degrees (x10) unsigned 16 bits
13 Absolute humidity in g/m
3
(x100) unsigned 16 bits
14 Dew point temperature (x10) 16 bits
15 Wind direction in degrees (x10) with extended feature
(see page 27) unsigned 16 bits
16 Wind speed (x100) along V-axis unsigned 16 bits
17 Wind speed (x100) along U-axis unsigned 16 bits
18 Status register
bit0=1

speed measurement error
bit1=1

compass and tilt angles measurement error
bit2=1

temperature meas. error
bit3=1

humidity measurement error
bit4=1

pressure measurement error
bit5=1

solar radiation measurement error
unsigned 16 bits