Delta OHM HD51.3D4R User manual



Operating manual
Ultrasonic anemometers
HD51.3D4R
HD51.3D4R-AL
www.deltaohm.com
English
Keep for future reference.
Companies / Brands of GHM

HD51.3D4R - 2 - V1.2
TABLE OF CONTENTS
1INTRODUCTION.................................................................................................... 3
2TECHNICAL SPECIFICATIONS ............................................................................... 4
3DESCRIPTION....................................................................................................... 5
4MEASURING PRINCIPLE OF WIND SPEED AND DIRECTION .................................. 6
5INSTALLATION ..................................................................................................... 7
5.1ALIGNMENT OF THE INSTRUMENT .............................................................................. 8
5.2ELECTRICAL CONNECTIONS ..................................................................................... 9
5.2.1RS232 SERIAL CONNECTION ..................................................................... 10
5.2.2RS485 SERIAL CONNECTION ..................................................................... 10
5.2.3RS422 SERIAL CONNECTION ..................................................................... 11
5.2.4ANALOG OUTPUTS CONNECTION.................................................................. 12
5.2.5CONNECTION OF HEATING SYSTEM ............................................................... 12
5.2.6AUXILIARY RS485 SERIAL OUTPUT CONNECTION .............................................. 13
5.3SERIAL OUTPUT PROTOCOL.................................................................................... 13
6CONFIGURATION................................................................................................ 14
6.1SERIAL COMMANDS ............................................................................................ 14
7ASCII PROPRIETARY MODE ................................................................................ 25
8NMEA MODE........................................................................................................ 26
9MODBUS-RTU MODE ........................................................................................... 28
10INSTRUMENT STORAGE ...................................................................................... 30
11SAFETY INSTRUCTIONS...................................................................................... 30
12ORDERING CODES .............................................................................................. 31

HD51.3D4R - 3 - V1.2
1INTRODUCTION
HD51.3D4R e HD51.3D4R-AL are 2-axes ultrasonic static anemometers with integrated
heater. The heater prevents the accumulation of snow and ice formation, allowing accurate
measurements in all environmental conditions.
HD51.3D4R-AL is equipped with an enhanced heater, for rapid defrosting, and an ano-
dized aluminum alloy housing with anti-corrosion coating that makes it possible to use the
instrument even in a particularly aggressive atmosphere (e.g., marine environment). The
anemometer satisfies the requirements of the MIL-STD-810G Method 509.6 standard (salt
fog anti-corrosion test). The high immunity to electromagnetic disturbances makes the ane-
mometer suitable for measurements in electrically noisy environments (e.g., industrial envi-
ronments, wind farms, etc.).
The anemometers measure:
•Wind speed up to 80 m/s (HD51.3D4R-AL) or 85 m/s (HD51.3D4R).
•Wind direction.
•Wind Gust.
•Atmospheric pressure (with internal sensor).
The average of wind speed and direction over a period configurable up to 10 minutes is calcu-
lated.
Available outputs:
•RS232, RS485 and RS422 isolated serial outputs with NMEA and MODBUS-RTU
standard protocols and ASCII proprietary protocol.
•Two analog outputs, for wind speed and direction or for velocity U-V cartesian compo-
nents, which are factory-configurable within 4÷20 mA (standard), 0÷1 V, 0÷5 V or
0÷10 V (to be specified when ordering).
Mounting on ∅40 mm mast. The electric connection is performed through the M23 connector
situated at the bottom of the instrument.
Power supply of the instrument (excluding heater) 12…30 Vdc. Power supply of the heater 24
Vdc.
All instrument sensors are factory-calibrated and do not require additional interventions of the
user (field calibration is not required).
The absence of moving parts minimizes the instrument maintenance.

HD51.3D4R - 4 - V1.2
2TECHNICAL SPECIFICATIONS
HD51.3D4R HD51.3D4R-AL
Wind speed
Used sensor Ultrasounds
Measuring range 0…85 m/s 0…80 m/s
Resolution 0.01 m/s
Accuracy ± 0.2 m/s or ± 2%, the greatest (0…60 m/s), ± 3% (>60 m/s)
Wind direction
Used sensor Ultrasounds
Measuring range 0…359.9°. In order to avoid oscillations of the analog output
around 0°, the extended range 0…539.9° can be set.
Resolution 0.1°
Accuracy ± 2° RMSE (wind speed > 2 m/s)
Atmospheric Pressure
Used sensor Piezoresistive
Measuring range 300…1100 hPa
Resolution 0.1 hPa
Accuracy ± 0.5 hPa @ 20 °C
General features
Instrument power supply
(excluding heater)
12…30 Vdc
Heater power supply 24 Vdc ± 10%
Instrument power consumption
(excluding heater)
60 mA @ 24 Vdc
Heater power consumption 15 W @ 24 Vdc 80 W @ 24 Vdc
Serial outputs Isolated RS232, RS485 and RS422
Communication protocols NMEA, MODBUS-RTU, ASCII proprietary
Analog outputs 2 analog outputs, for wind speed and direction or for velocity
U-V cartesian components.
Output at choice among 4…20 mA (standard, max. load 500 Ω),
0…1 V, 0…5 V and 0…10 V
The outputs are isolated from the power supply
Measurement interval From 250 ms to 1 s
Wind speed averaging interval Configurable from 1 s to 10 min
Wind Gust calculation interval Configurable from 1 s to 10 min
Electrical connection 19-pole M23 male connector
Operating temperature -40…+60 °C
Protection degree IP 66
Anti-corrosion test According to MIL-STD-810G Method 509.6
(48 hours of exposure + 48 hours of drying)
Survival speed 90 m/s 100 m/s
Weight 640 g approx. 1.4 kg approx.
Housing ASA with aluminum and
AISI 316 metal parts
Anodized aluminum alloy
and AISI 316
Installation on mast ∅40 mm external and ∅36 mm internal

HD51.3D4R - 5 - V1.2
Dimensions:
150
179 (HD51.3D4R)
188 (HD51.3D4R-AL)
40 ext.
36 int.
50
3DESCRIPTION
1. Ultrasonic sensors for the measurement of wind speed and direction.
2. Fixing clamp to Ø 40 mm mast.
3. Ø 40 mm mast.

HD51.3D4R - 6 - V1.2
4MEASURING PRINCIPLE OF WIND SPEED AND DIRECTION
Wind speed and direction are determined by measuring the time taken by ultrasonic pulses to
cover the distance from the transducer that generates the pulse to the receiving transducer.
The instrument uses 2 pairs of transducers oriented along two orthogonal axes. Detecting the
wind speed along two axes allows determining not only the intensity but also the wind direc-
tion.
The instrument measures the travel time of the ultrasonic pulse between the two transducers
of the same pair in both directions. The travel times in the two opposed directions are defined
as tA(forward direction time) and tR(reverse direction time).
If wind speed is zero, tAand tRvalues are the same. In the presence of wind, one of the two
time values is greater than the other and the comparison between the two time values allows
determining the direction and the intensity of the wind.
Measuring the travel time in both directions allows cancelling the dependence of the transmis-
sion speed of ultrasounds in the air from the environmental conditions of temperature, humid-
ity and barometric pressure.
Measurement along first axis Measurement along second axis
The travel times of the ultrasonic pulses are given by:
W
AVC
D
t+ =
W
RVC
D
t− =
Where:
D= Distance between the two transducers of the same pair
C= Sound speed
VW= Component of wind speed along the measurement axis
Measuring the two travel times allows determining the wind speed component:
⎟
⎠
⎞
⎜
⎝
⎛−⋅=
RA
Wtt
D
V11
2
U
axis
Transduce
r
Transduce
r
Transduce
r
T
ransduce
r
Vaxis

HD51.3D4R - 7 - V1.2
5INSTALLATION
To install the instrument, pass the connection cable inside the support mast and connect the
19-pole M23 female connector of the cable to the 19-pole M23 male connector situated at the
bottom of the instrument. Ensure connection stability by tightening the connector external nut.
Align the instrument (see par. 5.1), then fix it on the support mast by tightening the cable tie
at the bottom of the instrument.
21
Ø36 min
∅40
The support mast, having 40 mm maximum outer diameter and 36 mm minimum inner diame-
ter, should be positioned on a stable surface and must be connected to ground.
The HD54.3D4R-AL model must be connected to ground by means of the threaded
hole on the instrument body (see the figure above). Insert the cable lug of the
ground cable into the fixing screw and tighten the screw to the instrument body.
The instrument should be installed vertically and in an open area, far from obstructions located
in the vicinity that might alter the natural air flow. Any close objects (such as buildings, trees,
pylons, etc.) should be at a distance equal to at least ten times their height.
10 x H
H
In the presence of close objects, it is advisable to place the instrument at a height of 10 m.
Threaded hole fo
r
ground connection
(only HD35.3D4R-AL)

HD51.3D4R - 8 - V1.2
For open-space installations, the instrument can be installed using the HD2005.20 (2 m) or
HD2005.20.1 (3 m) tripod.
If the instrument is installed on a building, the height of the instrument should be at least 1.5
times the minimum value between the height of the building and the roof longest diagonal.
5.1 ALIGNMENT OF THE INSTRUMENT
The case has a reference arrow at the bottom: align the arrow with the geographical North.
If a magnetic compass is used for alignment, take into account that the geographic North dif-
fers from the magnetic North indicated by the compass. The difference, named magnetic
declination,depends on the area where the instrument was installed (for example, about 15°
in North-America and less than 3° in Europe).
If wind speed and direction values are given in polar coordinates, 0° angle corresponds to a
wind coming from North.
Take into account that the instrument measures the wind direction with respect to the reference
arrow on the housing (the instrument is not equipped with a magnetic compass for the auto-
matic compensation of the direction).
Arrow fo
r
alignement
to North
Su
pp
ortin
g
p
late
of ultrasonic sensors

HD51.3D4R - 9 - V1.2
5.2 ELECTRICAL CONNECTIONS
All connections are performed through a 19-pole M23 male connector situated at the bottom of
the instrument. The figure and the table below show numbers and function of the connector
contacts and the corresponding colors of the optional CP51.x cable wires:
Connector
pin number
CP51.x cable
wire color Symbol Description
1 White/Red Not used
2 White/Grey Not used
3 Yellow/Brown RX + Serial receive (input) positive
4 Brown/Green HEAT - Heater power supply negative
5 Violet HEAT + Heater power supply positive (24 Vdc)
6 Brown HEAT - Heater power supply negative
7 Grey/Brown HEAT + Heater power supply positive (24 Vdc)
8 Yellow GND Serial ground (isolated from V –)
9 Grey TX -
Serial transmission (output) negative
“DATA –” main RS485 output
10 White/Yellow AUX_B “DATA +” auxiliary RS485 output (D+)
11 White AUX_A “DATA –” auxiliary RS485 output (D-)
12 Black V - Instrument power supply negative
13 Green RX - Serial receive (input) negative
14 Pink/Brown OUT 1 Analog output 1 positive
15 Blue GND Analog ground (isolated from V –)
16 Red/Blue OUT 2 Analog output 2 positive
17 White/Green TX +
Serial transmission (output) positive
“DATA +” main RS485 output
18 -- Not used
19 Red V + Instrument power supply positive (12…30 Vdc)
-- Grey/Red SHIELD Cable shield
Connecto
r
Reference
Visible side
male
connector

HD51.3D4R - 10 - V1.2
5.2.1 RS232 SERIAL CONNECTION
TX-
RX+
GND
V+
V-
12345
6789
TX
PC
15
1
2
3
4
5
6
7
11 12
13
1416
17 18
19
RX
8
10
9
Lmax = 15m
V+
V-
For RS232 connection, TX-, RX+ and serial GND signals (pin 9, 3 and 8 of M23 connector) are
used, to be connected respectively to RX, TX and GND signals of RS232 port on PC (pin 2, 3
and 5 of 9-pole SubD connector). The length of RS232 cables should not exceed 15 m.
5.2.2 RS485 SERIAL CONNECTION
15
1
2
3
4
5
6
7
11 12
13
1416
17 18
19
8
10
9
DATA+
DATA-
GND
V+
V-
220Ω
220Ω ShieldShield
Lmax = 1200m
TX+
TX-
GND
V+
V-
DATA+
DATA-
Thanks to RS485 connection, multiple instruments can be connected to a multi-point network.
Instruments are connected in sequence through a twisted-pair shielded cable for signals and a
third wire for ground.
Line terminations should be placed at the two ends of the network. The cable shield should be
connected to both ends of the line.
The maximum number of devices that can be connected to the RS485 line (Bus) depends on the
load characteristics of the devices to be connected. The RS485 standard requires that the total
load does not exceed 32 unit loads. The load of an HD51.3D4R… anemometer is equal to ¼ of
unit load. If the total load is greater than 32 unit loads, divide the network into segments and
Reference
of female
connector (solder side)
Power supply
Power su
p
p
l
y
RS232 Port
PLC, datalo
gg
er o
r
RS485/USB or RS485/RS232
converter for PC
Other sensors with
RS485 output
Termination
T
ermination
Reference of female
connector (solder side)

HD51.3D4R - 11 - V1.2
add a signal repeater between a segment and the successive one. Line termination should be
applied at both ends of each segment.
The maximum length of the cable depends on the transmission speed and the cable character-
istics. Typically, the maximum length is 1200 m. The data line should be kept separated from
any power lines in order to prevent interference with the transmitted signal.
Each instrument on the network is univocally identified by an address. Multiple transmitters
with the same address should not be placed on the network.
If the instrument is connected to a data logger, the possibility to connect multiple sensors to
the network depends on the data logger capacity to manage multiple sensors.
Before connecting the instrument to the network, configure address and Baud Rate (see chap-
ter 6).
5.2.3 RS422 SERIAL CONNECTION
15
1
2
3
4
5
6
7
11 12
13
1416
17 18
19
8
10
9
V+
V-
220Ω220Ω
ShieldShield
Lmax = 1200m
TX+
RX+
TX-
RX-
GND
V+
V-
RX+
RX-
TX+
TX-
GND
220Ω220Ω
RS422 standard is used for point-to-point connection on long distances. The instrument is con-
nected to a PC/data logger through a shielded cable with two twisted pairs for signals and an
additional wire for ground. The extremities of the connections should end with line terminators.
The maximum length of the cable depends on the transmission speed and the cable character-
istics. Typically, the maximum length is 1200 m. The data lines should be kept separated from
any power lines in order to prevent interference with the transmitted signal.
Before connecting the instrument to the network, configure address and Baud Rate (see chap-
ter 6).
Power su
p
p
l
y
PLC, datalo
gg
er o
r
RS485/USB or RS485/RS232
converter for PC
Termination
T
ermination
Reference of female
connector (solder side)

HD51.3D4R - 12 - V1.2
5.2.4 ANALOG OUTPUTS CONNECTION
Connect the outputs according to one of the two schemes below, depending on the output
type, current (standard) or voltage (on request), available in the instrument. OUT 1 and
OUT 2 are associated to wind speed and direction respectively. In order to change the type of
speed and direction measurements associated to the outputs (e.g., to associate to the outputs
the U-V cartesian components), see chapter 6.
OUT 2
OUT 1
V+
V- V+
V-
15
1
2
3
4
5
6
7
11 12
13
1416
17 18
19
8
10
9A
I
1
A
I
2
GND
Current outputs are active. Load resistance: RL ≤500 Ω.
OUT 2
OUT 1
V+
V- V+
V-
15
1
2
3
4
5
6
7
11 12
13
1416
17 18
19
8
10
9
V
V
1
V
V
2
+
+
GND
Load resistance: RL ≥10 kΩ.
5.2.5 CONNECTION OF HEATING SYSTEM
The heater power supply is separated from the instrument’s main power supply.
15
1
2
3
4
5
6
7
11 12
13
1416
17 18
19
8
10
9
V+
V-
HEAT-
HEAT-
HEAT+
HEAT+
V+
V-
HEAT-
HEAT+
The heat circuit is switched on below +4 °C. After switching on, the heating is switched off
when the temperature exceeds +10 °C.
Power su
pp
l
y
Power su
pp
l
y
Reference of female
connector (solder side)
Reference o
f
female
connector (solder side)
Reference o
f
female
connector (solder side)
Inst
r
ument
power supply
Heate
r
power supply
Current out
p
uts 4…20mA
Volta
g
e out
p
uts

HD51.3D4R - 13 - V1.2
5.2.6 AUXILIARY RS485 SERIAL OUTPUT CONNECTION
The auxiliary RS485 serial output can be used as an alternative to the main serial connection
for connecting the instrument to the PC, for the configuration of the instrument via serial
commands or the use of the HD52.3D-S application software.
The advantage of the auxiliary RS485 serial output is that it is always available to receive
commands from the PC via a standard serial communication program or the HD52.3D-S appli-
cation software (the main serial output, instead, is not available if it is busy with one of the
operating protocols). Furthermore, the auxiliary RS485 serial output allows using long cables.
The auxiliary RS485 serial output does not work with the operating protocols (NMEA, MODBUS-
RTU or ASCII proprietary).
For connecting the auxiliary RS485 serial output to the PC, the optional RS51K can be used.
The kit includes the SWD10 power supply and the RS485/USB adapter with:
oscrew terminals for the connection to the CP51… cable (not included);
oUSB connector for the connection to the PC;
ojack connector for connecting the SWD10 power supply.
To use the RS51K kit, the drivers included in the HD52.3D-S software package, downloadable
from Delta OHM website, should be installed in the PC (see the guide to USB drivers installa-
tion in the Documentation section of the software package).
5.3 SERIAL OUTPUT PROTOCOL
Unless otherwise requested, at the first power up the instrument main serial output starts in
configuration mode and waits to receive the commands for setting the operating parameters
(see chapter 6) or the connection with the HD52.3D-S application software.
In this case, in order to activate an operating protocol (NMEA, MODBUS-RTU or ASCII proprie-
tary) it is necessary to set it with the appropriate serial command (CUMn, see chapter 6) or
with the aid of the HD52.3D-S application software.
If the instrument is set up to work with an operating protocol, the protocol becomes active 10
seconds after power on (in the first 10 seconds the instrument waits for a possible command
to enter configuration mode, as explained in chapter 6).
The auxiliary RS485 serial output is always in configuration mode.
Reference of female
connector (solder side) SWD10
T
o PC
RS485/USB
adapter
Power su
pp
l
y

HD51.3D4R - 14 - V1.2
6CONFIGURATION
Configuration mode allows to read the instrument general info (firmware version, serial num-
ber, …) and to set the instrument operation mode and operation parameters. The configura-
tion of the instrument can be done in two ways:
•With the aid of HD52.3D-S application software (see the instructions of the software).
•By sending serial commands (listed in paragraph 6.1) via a standard communication
program.
If a standard communication program is used, the program communication parameters should
be set as follows:
•Baud rate = 115200
•Data bits = 8
•Parity = None
•Stop bits = 2
•Flow control = None
For the configuration, the instrument can be connected to the PC:
•Via auxiliary RS485 (see paragraph 5.2.6 for the connection).
The auxiliary RS485 serial output is always in configuration mode and therefore it is al-
ways available to receive commands from the PC.
•Via RS232 (see paragraph 5.2.1 for the connection).
The instrument can receive commands from the PC via RS232 only if it is in configuration
mode (factory setting, unless otherwise requested).
If the instrument is not set in in configuration mode but in one of the available operating
modes (NMEA, MODBUS-RTU or ASCII proprietary), to enter configuration mode it is ne-
cessary to send within 10 seconds from power on (if the instrument is already pow-
ered, disconnect and reconnect the power supply) the serial command @(if a standard
communication program is used) or the request of connection with the HD52.3D-S ap-
plication software, if the application software is used.
6.1 SERIAL COMMANDS
Instrument control:
Command Reply Description
@ &| Allows entering configuration mode if the
instrument is set up in an operating mode.
It must be sent within 10 seconds from
power on.
# Info on operating mode Exits from the configuration mode activated
with the command @.
Operating Mode:
Command Reply Description
CUMn &| Sets instrument in mode:
Configuration if n=0
ASCII proprietary if n=2
NMEA if n=4
MODBUS-RTU if n=5
Default : Configuration (n=0)
RUM & n| Reads mode set in the instrument
Note 1: after sending the CUMn command, the instrument remains in configuration mode.
Power cycle the instrument to activate the set operating mode.

HD51.3D4R - 15 - V1.2
Parameters for ASCII proprietary mode:
Command Reply Description
CU2Bn &| Sets Baud Rate for ASCII proprietary
mode to:
9600 if n=3
19200 if n=4
38400 if n=5
57600 if n=6
115200 if n=7
Default : 115200 (n=7)
RU2B & n| Reads Baud Rate setting for ASCII
proprietary mode
CU2In &| Sets interface for ASCII mode to:
RS232 if n=0
RS485 if n=1
RS422 if n=2
Default : RS485 (n=1)
RU2I & n| Reads interface setting for ASCII mode
CU2Mn &| Sets parity and stop bits for ASCII mode
to:
8N1 if n=0 [No parity, 1 stop bit]
8N2 if n=1 [No parity, 2 stop bits]
8E1 if n=2 [Even parity, 1 stop bit]
8E2 if n=3 [Even parity, 2 stop bits]
8O1 if n=4 [Odd parity, 1 stop bit]
8O2 if n=5 [Odd parity, 2 stop bits]
The number of data bits is fixed to 8
Default : 8N2 (n=1)
RU2M & n| Reads current setting of parity and stop
bits for ASCII mode
CU1Dcccccc &| Sets measurements order in the string sent
in ASCII proprietary mode
In the sequence ccccccccccc, each character
identifies a measurement according to the
following correspondence:
0 ⇒Barometric Pressure
5 ⇒Wind speed (coordinates U,V)
7 ⇒Wind speed (intensity)
8 ⇒Wind Direction (Azimuth)
G ⇒Wind Gust (intensity and direction)
S ⇒Sound speed
T ⇒Sonic Temperature
E ⇒Errors
Default : 780TE
(see Note 2)
RU1D & ccccccccccc| Reads measurements order in the string
sent in ASCII proprietary mode

HD51.3D4R - 16 - V1.2
Command Reply Description
CU2Rnnnn &| Sets transmission interval of string with
measurements in ASCII proprietary mode
to nnnn seconds
The interval should range within 1 and
3600 seconds
Default : 1 second
RU2R & nnnn| Reads transmission interval of string with
measurements in ASCII proprietary mode
NOTE 2:MEASUREMENTS ORDER
In the measurement string sent by the instrument in ASCII proprietary mode, measurements
can be set in arbitrary order: one should simply indicate the desired order in the sequence of
characters "cccccc" sent by the command C1UD. The sequence of characters "cccccc" can have
a variable length up to a maximum of 16 characters.
Example: if the sequence of characters is set to 780, wind speed, wind direction and baromet-
ric pressure measurements will appear from left to right in the data string sent by the instru-
ment.
If information on error conditions is requested (E character), three numbers with the following
meaning will appear in the data string sent by the instrument:
1. First number = error code identifying the transducers and the type of error.
The number is composed by two digits. The first digit indicates the transducer that
presents the error, according to the numeration indicated in the figure:
1
2
4
3
N
Digit 0 indicates that no errors are present in the ultrasonic transducers.
The second digit of the error code indicates the type of error: 0= no errors;
1= transducer broken, electric interruption, path obstruction; Other = codes re-
served to technical service.
2. Second number = heating status: 0= off, 1= housing heating is on, 2= housing heat-
ing and transducers heating are both on.
3. Third number = number of invalid measurements.
Example: if 21 0 2 appears in correspondence to the error condition in the data string sent by
the instrument, it means that an error occurred in the transducer number 2, that the heating is
turned off and that two measurements have been rejected due to the error occurrence.
N
(
North
)
arrow
on the opposite side
V
axis
Uaxis
Y
axis
X
axis

HD51.3D4R - 17 - V1.2
Parameters for NMEA mode:
Command Reply Description
CU4Bn &| Sets Baud Rate for NMEA mode to:
2400 if n=1
4800 if n=2
9600 if n=3
19200 if n=4
38400 if n=5
57600 if n=6
115200 if n=7
Default : 4800 (n=2)
RU4B & n| Reads Baud Rate setting for NMEA mode
CU4In &| Sets interface for NMEA mode to:
RS232 if n=0
RS485 if n=1
RS422 if n=2
Default : RS485 (n=1)
RU4I & n| Reads interface setting for NMEA mode
CU4Mn &| Sets parity and stop bits for NMEA mode
to:
8N1 if n=0 [No parity, 1 stop bit]
8N2 if n=1 [No parity, 2 stop bits]
8E1 if n=2 [Even parity, 1 stop bit]
8E2 if n=3 [Even parity, 2 stop bits]
8O1 if n=4 [Odd parity, 1 stop bit]
8O2 if n=5 [Odd parity, 2 stop bits]
The number of data bits is fixed to 8
Default : 8N1 (n=0)
RU4M & n| Reads current setting of parity and stop
bits for NMEA mode
CU4Rnnn &| Sets transmission interval of string with
measurements in NMEA mode to nnn sec-
onds
The interval should range within 1 and 255
seconds
Default : 1 second
RU4R & nnn| Reads setting of transmission interval of
string with measurements in NMEA mode

HD51.3D4R - 18 - V1.2
Parameters for MODBUS-RTU mode:
Command Reply Description
CU5Annn &| Sets MODBUS address to nnn
The address should range within 1 and 247
Default : 1
RU5A & nnn| Reads the MODBUS address setting
CU5Bn &| Sets the Baud Rate for MODBUS mode to:
9600 if n=3
19200 if n=4
38400 se n=5
57600 se n=6
115200 se n=7
Default : 19200 (n=4)
RU5B & n| Reads Baud Rate setting for MODBUS
mode
CU5In &| Sets interface for MODBUS mode to:
RS232 if n=0
RS485 if n=1
RS422 if n=2
Default : RS485 (n=1)
Note: with RS232 option you can connect to PC
or datalogger 1 instrument only; option useful
to do tests without RS232/RS485 conversion.
RU5I & n| Reads interface setting for MODBUS mode
CU5Mn &| Sets parity and stop bits for MODBUS
mode to:
8N1 if n=0 [No parity, 1 stop bit]
8N2 if n=1 [No parity, 2 stop bits]
8E1 if n=2 [Even parity, 1 stop bit]
8E2 if n=3 [Even parity, 2 stop bits]
8O1 if n=4 [Odd parity, 1 stop bit]
8O2 if n=5 [Odd parity, 2 stop bits]
The number of bits is fixed to 8
Default : 8E1 (n=2)
RU5M & n| Reads the setting of parity and stop bits
for MODBUS mode
CU5Wn &| Sets waiting time after transmission in
MODBUS mode to:
Immediate reception if n=0
(violates protocol)
Waiting 3.5 characters if n=1
(respects protocol)
Default : Waiting 3.5 characters (n=1)
RU5W & n| Reads current setting of waiting time after
transmission in MODBUS mode

HD51.3D4R - 19 - V1.2
Units of measurement:
Command Reply Description
CGUVn &| Sets measuring unit of wind speed:
m/s if n=1
cm/s if n=2
km/h if n=3
knot if n=4
mph if n=5
Default : m/s (n=1)
RGUV n| Reads the wind speed measuring unit set
in the instrument
CGUTn &| Sets temperature measuring unit:
°C if n=1
°F if n=2
Default : °C (n=1)
RGUT n| Reads the temperature measuring unit set
in the instrument
CGUPn &| Sets pressure measuring unit:
mbar if n=1 [Note:1 mbar=1 hPa]
mmHg if n=2
inchHg if n=3
mmH2O if n=4
inchH2O if n=5
atm if n=6
Default : mbar (n=1)
RGUP n| Reads the pressure measuring unit set in
the instrument
General parameters:
Command Reply Description
CGHn &| Enables/disables heating:
Disables if n=0 Enables if n=1
Default : Enabled (n=1)
RGH n| Reads heating enabling state set in the in-
strument
CWCnnnn &| Sets wind speed threshold to nnnn value (in
hundredths of m/s)
Value should range within 0 and 100
hundredths of m/s (= 0…1 m/s)
Default : 20 (= 0.2 m/s)
(see Note 3)
RWC & nnnn| Reads the wind speed threshold value set in
the instrument (in hundredths of m/s)
CWaLnnn &| Sets time interval for the calculation of aver-
age speed and average direction to nnn value
Value should range within 1 and 600 s
Default : 1 s

HD51.3D4R - 20 - V1.2
Command Reply Description
RWaL & nnn| Reads the time interval for the calculation
of average speed and average direction set
in the instrument
CWaMn &| Sets the method for the calculation of
average speed and average direction:
If n=0: scalar average.
If n=1: vector average.
Default : vector average (n=1)
(see Note 4)
RWaM & n| Reads the method for the calculation of the
average speed and average direction set in
the instrument
CWgLnnn &| Sets time interval for the calculation of av-
erages in Wind Gust measurement to nnn
value
Value should range within 1 and 100 s
Default : 3 s (standard WMO value)
(see Note 6)
RWgL & nnn| Reads the time interval for the calculation
of averages in Wind Gust measurement set
in the instrument
CWgMn &| Sets the method for the calculation of
averages in Wind Gust measurement:
scalar average if n=0
vector average if n=1
Default : vector average (n=1)
Note: see the description of the command
CWaMn for the meaning of scalar average
and vector average.
RWgM & n| Reads the method for the calculation of av-
erages in Wind Gust measurement set in
the instrument
CWgOnnn &| Sets time interval for detecting the maximum
of the averages in Wind Gust measurement
to nnn value
Value should range within 1 and 600 s
Default : 60 s
(see Note 6)
RWgO & nnn| Reads the time interval for detecting the
maximum of the averages in Wind Gust
measurement set in the instrument
cor n cor| Sets the measurement rate to n measure-
ments/s
Value should range within 1 and 4
Default : 4
ror n samples per second Reads the measurement rate set in the in-
strument