Lufft SHM 31 User manual

Snow depth sensor SHM 31, V2.1
Dear User,
Please read this user manual carefully before commissioning the SHM 31 snow depth sensor. We reserve the right
to further develop this device in line with technical progress.
OTT HydroMet Fellbach GmbH
Gutenbergstrasse 20
70736 Fellbach
Germany
Phone: [phone]
Hotline: [phone]
Fax: [phone]
Email: [e-mail] (Sales, Repairs)
Email: [e-mail] (Technical Support)
This manual was published in: June 2023
Document number: 48.7230-SHM31EN
Date
Issue
Change log
30/04/2017
Rev. 1.0
Published for the first time
08/05/2018
Rev. 1.3
Sections 7 and 11 revised; various minor changes
20/06/2018
Rev. 1.4
Modbus section inserted
08/11/2018
Rev. 1.9
‘SDI-12 for v1.4’ section extended; various revisions
30/06/2023
Rev. 2.1
Safety instructions, new data telegrams, various revisions
This manual is protected by copyright. No part of this manual may be reproduced in any way (by photographing,
photocopying, etc.) or processed, duplicated or distributed using electronic systems without the written consent of
OTT HydroMet. The manual has been edited with due care. No liability is accepted for damage resulting from
failure to observe the information contained in this manual.
We reserve the right to adapt the manual in line with the device’s technical further development.

Snow depth sensor SHM 31, V2.1
Contents
1. Read before commissioning ......................................................................................................................................5
1.1 Symbols used ......................................................................................................................................................5
1.2 Safety instructions ...............................................................................................................................................5
1.3 Notes on laser safety and laser classification......................................................................................................5
1.4 Intended use........................................................................................................................................................6
1.5 Incorrect use........................................................................................................................................................6
1.6 Brand names used ..............................................................................................................................................6
2. Item names and technical data ..................................................................................................................................7
2.1. Labelling ..............................................................................................................................................................7
2.2. Technical data .....................................................................................................................................................8
2.3. Scope of delivery .................................................................................................................................................9
2.4. Additional documents and software...................................................................................................................11
3. Description of the device .........................................................................................................................................12
3.1. Basic principles of the measurement method....................................................................................................12
3.2. Introduction to assembly and commissioning ....................................................................................................12
3.3. Sensor heating ..................................................................................................................................................13
4. Generating the measured values.............................................................................................................................14
4.1. Measured values (curr, avg)..............................................................................................................................14
4.2. Normal mode .....................................................................................................................................................14
5. Assembly ...................................................................................................................................................................15
5.1. Assembly instructions........................................................................................................................................15
5.2. Assembly...........................................................................................................................................................15
6. Connections ..............................................................................................................................................................17
6.1. Connecting the device .......................................................................................................................................17
6.2. Connector pin assignment.................................................................................................................................17
6.3. Recommended cable shield connection ............................................................................................................17
6.4. Supply voltage ...................................................................................................................................................17
6.5. Data interfaces ..................................................................................................................................................17
6.6. Heating release .................................................................................................................................................17
7. Commissioning .........................................................................................................................................................18
7.1. Important information for commissioning...........................................................................................................18
7.2. Switching on ......................................................................................................................................................18
7.2.1. Settings over RS232 or RS485 ...............................................................................................................18
7.3. UMB ConfigTool.NET ........................................................................................................................................18
7.3.1. Basic installation with ConfigTool.NET and a serial interface .................................................................18
7.3.2. The SHM 31’s sensor parameters ..........................................................................................................26
8. Communication over UMB-ASCII 2.0.......................................................................................................................29
8.1. Syntax................................................................................................................................................................29
8.2. Checksum..........................................................................................................................................................29
8.3. Examples...........................................................................................................................................................29
8.4. Description of the data telegram #1 with an example ........................................................................................30
8.5. Angle adjustment...............................................................................................................................................30
8.6. Switching from UMB protocol to ASCII protocol ................................................................................................30
8.7. ASCII command overview .................................................................................................................................31
9. UMB communication ................................................................................................................................................37
9.1. Factory settings .................................................................................................................................................37
9.2. Overview of measuring channels.......................................................................................................................37
9.3. Communication in binary protocol .....................................................................................................................39
9.3.1. Data frame ..............................................................................................................................................39
9.3.2. Addressing with class ID and device ID ..................................................................................................39
9.3.3. Example of creating addresses...............................................................................................................39

Snow depth sensor SHM 31, V2.1
9.3.4. Example of a binary protocol query........................................................................................................ 39
9.3.5. Status and error codes in the UMB binary protocol................................................................................ 40
9.3.6. CRC calculation ..................................................................................................................................... 41
10. Communication in SDI-12 mode ............................................................................................................................. 42
10.1. Connector pin assignment ................................................................................................................................ 42
10.2. Settings for using SDI-12.................................................................................................................................. 42
10.3. Exiting SDI mode .............................................................................................................................................. 42
10.4. Command overview .......................................................................................................................................... 43
10.5. Setting the address........................................................................................................................................... 44
10.6. Measured data telegrams ................................................................................................................................. 44
10.6.1. Example: C and M queries of the SHM 31-UMB .................................................................................... 45
10.6.2. Buffer assignment – basic data – SHM 31-UMB .................................................................................... 45
10.7. Additional measuring commands...................................................................................................................... 46
10.8. Device identification telegram ........................................................................................................................... 47
10.9. Telegram verification......................................................................................................................................... 47
10.10. Query measured value parameter command (SDI-12 v1.4) ............................................................................ 48
10.11. Switching commands....................................................................................................................................... 49
10.11.1. Unit system changeover command ........................................................................................................ 49
10.11.2. Device reset command........................................................................................................................... 49
10.11.3. End measurement command ................................................................................................................. 50
10.11.4. Start measurement command ................................................................................................................ 50
10.11.5. Laser on command................................................................................................................................. 50
10.11.6. Laser off command................................................................................................................................. 50
10.11.7. Calibrate offset and angle command...................................................................................................... 50
10.11.8. Calibrate offset command ...................................................................................................................... 51
10.11.9. Switch on defrost heating cycle command ............................................................................................. 51
10.11.10.Switch off defrost heating cycle command ............................................................................................. 51
10.12. Parameter setting commands.......................................................................................................................... 51
10.12.1. Retrieving the current parameter setting ................................................................................................ 51
10.12.2. Setting the parameter setting ................................................................................................................. 52
11. Communication in Modbus mode........................................................................................................................... 53
11.1. Modbus connection and communication parameters........................................................................................ 53
11.2. Addressing........................................................................................................................................................ 53
11.3. Modbus functions.............................................................................................................................................. 53
11.3.1. 0x03 Read Holding Registers, 0x06 Write Single Register, 0x16 Write Multiple Registers function ...... 53
11.3.2. 0x04 Read Input Registers function ....................................................................................................... 55
12. Checking the signal quality..................................................................................................................................... 59
12.1. Application ........................................................................................................................................................ 59
13. Service, maintenance and technical support......................................................................................................... 61
13.1. Firmware update............................................................................................................................................... 61
13.2. Maintenance ..................................................................................................................................................... 61
13.3. Faults................................................................................................................................................................ 63
13.3.1. Possible indications of error on the snow depth sensor ......................................................................... 63
13.3.2. Potential interferences that may affect correct functioning..................................................................... 63
13.3.3. Error codes............................................................................................................................................. 63
13.4. UMB status codes............................................................................................................................................. 64
13.5. Disposal information – within the EU ................................................................................................................ 65
13.6. Disposal information – outside the EU.............................................................................................................. 65
13.7. Repair / maintenance........................................................................................................................................ 65
13.8. Technical support.............................................................................................................................................. 65

Read before commissioning
Snow depth sensor SHM 31, V2.1 5
1. Read before commissioning
Please read the operating manual carefully and keep it for future reference. Please note that various
components of the device and the described software may look slightly different from the figures provided in
this operating manual.
1.1 Symbols used
Warning – potential hazards for the user
Important information for correct device functioning
Reference to potential hazards for the user due to laser radiation
1.2Safety instructions
•Only adequately qualified specialists may assemble and commission the device.
•Never take measurements on or touch live parts.
•The sensor has a dead weight of approx. 2 kg and can cause injuries if dropped.
Carry the sensor with both hands to prevent the weatherproof protective hood
from sliding off the sensor.
•Parts can fall off, especially during assembly. Avoid risks by first of all transporting
and fully assembling the sensor without the hood and only putting the
weatherproof protective hood on the sensor afterwards. Ensure that no
components can come loose and fall down once installation is complete.
•The mast mount may have sharp edges due to the manufacturing process.
•Use suitable occupational safety equipment during assembly and take safety
measures to prevent injuries.
•Observe the technical data, storage conditions and operating conditions.
1.3 Notes on laser safety and laser classification
The SHM 31 is a Laser Class 2 product according to the international standard IEC 60825-
1: 2014-03. Class 2 laser products are only safe for short-time exposure of the beam to the
eyes (< 0.25 s). Prolonged exposure to the laser beam may damage the eyes. Avoid
staring into the beam or pointing it towards humans or animals. The wavelength of the
laser measuring device used here is in the red, visible spectral range. Living creatures’
natural eyelid reflex helps to ensure that no damage occurs. But you should still
deliberately turn your head away when the laser beam’s light enters your eyes. Especially
in low ambient light conditions, Laser Class 2 products can lead to temporary dazzling and
considerable distraction.

Read before commissioning
6Snow depth sensor SHM 31, V2.1
Maximum radiant output power
0.95 mW
Wavelength
635 nm
Pulse duration
>400 ps
Pulse repetition rate
320 MHz
Beam divergence
0.16 mrad x 0.6 mrad
Attention
Do not look into the laser beam or point the laser beam towards people or animals! Only
authorised, trained personnel should have access to the laser sensor.
1.4Intended use
•The device must only be operated within the range of the specified technical data.
•The device must only be used under the conditions and for the purposes it was designed
for.
•The device must not be modified or converted; its operational safety and functionality
are then no longer guaranteed.
The following basic use is considered to be intended:
•Measuring distances from fixed targets.
•Measuring snow depth as a distance from the snow surface.
•Assembling the sensor on a mast or mast bracket with the line of sight below a tilt angle
towards the ground, (also see the notes on laser safety).
•Regular cleaning, checking measured results and maintenance.
1.5 Incorrect use
If the device is not assembled correctly:
•It may not work, or may only work to a limited extent
•It may be permanently damaged
•It may fall down and hurt someone
If the device is not connected properly:
•It may not work
•It may be permanently damaged
•It may cause an electric shock under certain circumstances
1.6Brand names used
All brand names used in this manual are subject to the valid trademark rights and ownership rights of the
respective owner without restriction.

Item names and technical data
Snow depth sensor SHM 31, V2.1 7
2. Item names and technical data
Item
Item number
SHM 31 snow depth sensor
8365.30
Mast strap clamp for mast measuring up to
80 mm in diameter
8365.608-11
Mast strap clamp for mast measuring up to
300 mm in diameter
8365.609-11
Mast clamp for mast measuring up to 72 mm
in diameter
8365.610-11
Connection cable (15 m)
8365.KAB015
Reference target plate set
8365.KWK-SET
UMB ConfigTool.NET software
https://www.lufft.com/download/software-lufft-configtool-net/
Replacement sensor module
8365.30-SEN
Table 1: Item numbers
2.1. Labelling
The following stickers are attached to the product.
Figure 1: Laser warning with technical data
Figure 2: Rating plate with serial number

Item names and technical data
8Snow depth sensor SHM 31, V2.1
2.2. Technical data
Category
Name
Value
Measuring parameters
Snow depth
0 – 15 m
Accuracy
± (5 mm + 0.06%)
Repeatability
0.6 mm
Precision, reproducibility
5 mm
Signal intensity (normalised)
0 – 255
Installation
Assembly height / measuring
distance
0.1 – 16 m
Tilt angle to the vertical position
10 – 30 degrees
Data interface
RS485
-UMB binary protocol (19200 Bd, variable)
-UMB-ASCII 2.0
-Modbus RTU
-Modbus ASCII
SDI-12
-SDI-12 protocol
RS232
-UMB-ASCII 2.0 protocol (9600 Bd, fixed)
RS485 and SDI-12 share the same connectors and cannot be used in parallel. RS232 uses separate
connectors and can be operated in parallel with RS485 or SDI-12.
Data transfer
Polling: UMB, UMB-ASCII 2.0, SDI-12,
Modbus
Auto Send function: UMB-ASCII 2.0
Operating parameters
Temperature range:
Without heating:
-40°C – + 50°C
-10°C – +50°C (laser inactive < -15°C)
Rel. humidity
0 – 100%
Power supply
12 or 24 V DC, tolerance ±15%
Connected load with heating
18 W
Average consumption without
heating
0.7 W
Average consumption with 10 s
measurement interval and window
heating switched on
3.4 W
MTBF @ 25°C / 40°C
88,000 h / 50,000 h
Connection cable length while using
the RS232 interface
1
≤15 m
Safety
Laser safety
Laser Class 2 (IEC 60825-1:2014)
Protection rating
IP68
EMC
EN 61326-1:2012 (industrial standard)
EU Directive
EMC 2014/30/EU, ROHS 2011/65/EU
Size, weight
Sensor size (LxWxH)
302 x 130 x 234 mm
Sensor weight
2.35 kg
Packaging size
400 x 240 x 180 mm
Weight incl. packaging
3.4 kg
Storage conditions
Temperature; rel. humidity
T={-25°C – +70°C}; rH < 100%
Table 2 2: Technical data
1If connection cables > 15 m are used, transfer problems may occur over RS232. Additionally, the voltage
drop over the cable length must be taken into account.

Item names and technical data
Snow depth sensor SHM 31, V2.1 9
Figure 3: SHM 31 dimensions, technical drawing
2.3. Scope of delivery
Depending on the order, the delivery consists of the standard scope of delivery (see
Figure 4) and additional components (see Figure 5 to Figure 9).
Figure 4: Standard scope of delivery 8365.30, consisting of sensor, test report, quick start guide and
USB stick with additional software and documents

Item names and technical data
10 Snow depth sensor SHM 31, V2.1
SHM31
8365.30
Mast mount
8365.610-11
Connection cable
8365.KAB015
Figure 5: SHM 31 sensor, here with mast mount 8365.610-11 and
connection cable
Mast mount
8365.610-11
Figure 6: Mast mount 8365.610-11
Mast mounts with steel strap
8365.608-11
or
8365.609-11
Figure 7: Mast mount with assembly clamp and steel strap, here for
masts up to Ø = 300 mm (l = 1,000 mm)

Item names and technical data
Snow depth sensor SHM 31, V2.1 11
Connection cable
8365.KAB015
Figure 8: SHM 31 connection cable, standard length 15 m
Reference target plate set
8365.KWK-SET
Figure 9: Target plate set, consisting of black and white coloured cards
Documentation
•Quick start guide
•Test report
•Configuration overview
USB stick
Operating manual and UMB ConfigTool.NET software
2.4. Additional documents and software
The free UMB ConfigTool.NET configuration software is available on the supplied USB stick, and can be
downloaded from the website www.lufft.com. The software is available for download for the Windows and
Android operating systems. In future, it will also be available for individual Linux operating systems.
You will find the following documents and software available for download on the internet at www.lufft.com:
•Operating manual…………This document
•UMB protocol…………….Communication protocol for UMB devices
•UMB ConfigTool.NET……Communication software for UMB devices
•Firmware…………………..The device’s current firmware

Description of the device
12 Snow depth sensor SHM 31, V2.1
3. Description of the device
3.1. Basic principles of the measurement method
The SHM 31 snow depth sensor applies the phase measurement method to precisely measure distances
from objects. In the phase measurement method used here, a laser diode emits short laser pulses, which are
amplitude modulated with a defined frequency. The laser light is scattered to objects and detected with a
photo diode. Unlike the SHM 30 snow depth sensor, when using this method no continuously modulated
laser light is emitted. Instead, individual pulses that are in a fixed relationship to one another are emitted. All
in all, the advantage of the newer method is that the contrast has been improved, thereby reducing the
dependency on background light. The short pulses also mean that no speckle patterns are generated due to
the pulses’ short coherence time, which would otherwise lead to lower precision in the distance
measurement.
The emitted laser light that hits the surface is scattered back towards the sensor in small particles. This part
of the light is compared to a reference signal to measure the distance from the surface. In addition to
measuring the distance, the sensor also evaluates the signal intensity. At OTT HydroMet, the signal intensity
is normalised as a function of the distance during the production process on target plates. The method
enables a rough distinction between surfaces of different reflectivity – to differentiate between snow and
grass, for example. Another purpose of normalisation is to make the sensors comparable with one another.
More information about this can be found in the section entitled: ‘Testing and error descriptions’.
3.2. Introduction to assembly and commissioning
The snow depth sensor is mounted on a mast using the mast clamps provided. Assembly on a mast
cantilever is also possible, but not necessary. The sensor is aligned in the direction of the surface. The angle
the sensor is assembled at (tilt angle α) should be between 10 and 30 degrees to prevent snow falling from
the mast or the sensor itself from affecting the measured result. If an angle is too large, this causes the laser
beam to hit the ground at too flat an angle, which may give a vague and inconsistent distance measurement
result.
Following installation, the user performs an automatic zero measurement to measure the distance d0from
the surface, as well as the installation angle α. The measured values are stored in the internal memory as
reference values; see Figure 10 and Figure 11. An existing snow depth during device commissioning can be
manually communicated to the sensor as an offset value.
The snow depth h1is calculated according to the following formula:
ℎ1=ℎ− ℎ =ℎ−()⋅cos()
where hris the installation height at the laser exit window and mean(d) is the averaged measured distance
value.
Three interfaces are implemented in the SHM 31 snow depth sensor:
•RS485 (half duplex),
•RS232
•SDI-12
The RS232 interface can always be used at the same time as the RS485 or SDI-12 interface. The SDI-12
and RS485 interfaces use a common connection cable, so they cannot be used together. The device
configuration defines which interface is active.

Description of the device
Snow depth sensor SHM 31, V2.1 13
Figure 10: SHM 31 assembly, determining the
distance d0and angle α. h: height above ground.
Figure 11: Calculating the snow depth h1from the
difference Δdin distance and the tilt angle α.
Types of communication:
Communication over the RS232 interface takes place using the UMB-ASCII 2.0 protocol. Data telegrams can
be requested using the ‘polling method’, or an automatic transmission mode can be set.
The configuration of the RS232 interface is: 9600 baud, 8N1 (8 bit, none parity, 1 stop bit, no handshaking).
The default configuration of the RS485 interface is: 19200 baud, 8N1. This interface can be used to
communicate either using the UMB-ASCII 2.0 protocol (query or automatic transmission mode) or using the
UMB binary protocol (pure query mode). Various tools are available here for the UMB binary protocol in
particular, such as the Lufft UMB ConfigTool.NET software, as well as connection to other Lufft-specific
communication and database solutions such as SmartView.
Modbus RTU and Modbus ASCII are also available over the RS485 interface from firmware version v16.
The specifications for the SDI-12 interface can be found in section 10.
3.3. Sensor heating
The SHM 31 has two integrated heating circuits. One circuit brings the laser to the right temperature and
prevents fogging of the optical window as far as possible. One heating circuit can be parameterised and is
used in ‘defrost mode’ to de-ice the pane. Significant warming of the inner housing compared to the outside
temperature corresponds to the sensor’s normal operating behaviour.

Generating the measured values
14 Snow depth sensor SHM 31, V2.1
4. Generating the measured values
4.1. Measured values (curr, avg)
Factory setting: The current measured values are measured values averaged over 60 s. A new measurement
is performed internally every 10 s. So, for the current measured values, averages are taken and provided for
6 out of these 10 seconds.
The measured values labelled avg, min and max are output as averages over 10 minutes with the default
settings.
4.2. Normal mode
The snow depth sensor is switched on and off by connecting and disconnecting the power supply.
After the sensor is switched on, it will require a start-up time of a few seconds before communication is
possible. In the first few seconds after a restart, the sensor is ready to receive UMB commands over the
RS485 interface. This also applies if the user is using the SDI-12 protocol and ensures that it is always
possible to exit the SDI-12 mode in this way.

Assembly
Snow depth sensor SHM 31, V2.1 15
5. Assembly
5.1. Assembly instructions
Do not look into the laser beam of the SHM 31.
Do not switch on the SHM 31 until it has been assembled and aligned.
5.2. Assembly
The snow depth sensor is mounted on a mast using the mast clamps provided. The sensor is aligned in the
direction of the surface. The angle the sensor is assembled at (tilt angle α) should be between 10 and
30 degrees to prevent snow falling from the mast or the sensor itself from affecting the measured result
(Fig. 15). If an angle is too large, this causes the laser beam to hit the ground at too flat an angle, which may
give a vague and inconsistent distance measurement result. Additionally, the accuracy of the snow depth
calculation decreases at larger tilt angles due to the influence the angle measurement has.
Figure 12: SHM 31 sensors with mast clamp 8365.610-11 (top left), mast clamp
8365.608-11 (bottom left) and SHM 30 sensor with mast clamp 8365.608-11 (middle right).
During assembly, the mast clamp should first of all be firmly assembled on the mast. The sequence of
whether the connection cable should be assembled on the sensor first or whether the sensor should be
assembled on the mast clamp first using the tristar knob is not specified and depends on the local conditions.
To connect the cable, first of all loosen the three knurled screws and remove the hood. Then the cable with
the strain relief sleeve can be inserted into the recess in the side of the base plate and the connector
screwed tight; see Figure 12 and Figure 14.

Assembly
16 Snow depth sensor SHM 31, V2.1
Figure 13: Assembling the connection cable on the sensor. The
strain relief sleeve is inserted into the recess in the base plate
during cable assembly. The angle of the Amphenol connector can
be adjusted (in increments of 45°) as needed once the mounting
ring has been loosened.
Figure 14: Sensor assembled with hood. After attaching the
cable, the weatherproof protective hood is fixed again using
the three knurled screws.
The sensor can be placed on the pins of the mast clamp by means of its 360° perforated ring and locked in
place using the tristar knob. The perforated ring has a 10° grading and enables rough adjustment of the
sensor tilt.
Figure 15 shows the general installation conditions. The criterion of not aligning the sensor towards the sun
has been softened somewhat with the SHM 31, since no restrictions have yet been established regarding the
radiation power due to sunlight reflected on the snow’s surface. However, higher measurement uncertainties
cannot be ruled out where there is strong solar radiation in the high mountains.
Figure 15: Assembly direction and angle of the SHM 31
Unlike the SHM 30, the angle of the SHM 31 no longer has to be measured manually and transferred to the
sensor. The SHM 31 has a built-in tilt sensor.
In the delivery state, the reference angle is used to calculate the snow depth. The reference angle is
determined after installation along with the reference height during the zero measurement. However, the
current angle can also be used for the calculation. The corresponding measurement channels for the angles
are listed in the list of UMB channels in this manual.

Connections
Snow depth sensor SHM 31, V2.1 17
6. Connections
There is an 8-pin plug-in screw connector on the device’s housing. It is used to connect the supply voltage
and the data interface.
A connection cable measuring 15 m long is offered separately.
6.1. Connecting the device
The Amphenol C091D series connector has a locking ring (white). Loosening the ring enables variation of the
direction of the cable outlet to the notch in increments of 45°.
6.2. Connector pin assignment
Interface cable / core
SHM 31
Name
Connector pin #
Green
A_RS485
RS485 A
5
Yellow
B_RS485 / SDI-12
RS485 B / SDI-12 Data Line
2
Pink
RS232_TX
RS232 transmission line
1
Blue
RS232_RX
RS232 receiving line
6
Grey
GND
RS232 / RS485 ground
4
Red
EXT_TRIG_IN
Heating release +
3
Brown
V_IN_+
Supply voltage +
8
White
V_IN_-
Supply voltage –
SDI-12 ground
7
Table 1: SHM 31 connector pin assignment
6.3. Recommended cable shield connection
The shielding of the SHM 31’s connection cable must be connected to earth in the switch box, as there is
usually no secure, electrically conductive connection to an earthed mast via the screw joints and mast clamp.
6.4. Supply voltage
The snow depth sensor is supplied with a DC voltage of
12 V DC ±15% or 24 V DC ±15%.
6.5. Data interfaces
The device has a half-duplex, two-wire RS485 interface for measured value queries and firmware updates,
an SDI-12 interface, and an RS232 interface.
6.6. Heating release
The sensor can be configured such that the heating is only switched on after a positive voltage signal
(typically 5 – 12 V DC with 12 V DC operating voltage or 24 V DC with 24 V DC operating voltage) has been
applied. This allows the user to operate the heating in battery mode, for example, regardless of the internal
heating configuration.
Figure
16: Connection cable (schematic), designation of the
connector:
Figure 17: View of soldered connection of
the cable box with notch.

Commissioning
18 Snow depth sensor SHM 31, V2.1
7. Commissioning
7.1. Important information for commissioning
The following points must be noted:
Using the RS485 configuration over UMB
•Learn how the UMB ConfigTool.NET software works. The current version of the
software can be downloaded from the Lufft website at:
https://www.lufft.com/download/software-lufft-configtool-net/. The software contains
a Help function that provides further explanations on using the software. A quick start
guide specifically for the SHM 31 forms part of this operating manual.
Laser safety
•Do not look into the laser when the sensor is switched on. To ensure that the laser
is transmitting periodically, use a sheet of paper, for example, and hold it in the laser
beam. Observe the laser beam indirectly!
Mechanical and electrical connection
•Ensure that the SHM 31 has been connected and installed according to its intended
use.
7.2. Switching on
As soon as the SHM 31 is supplied with power, it starts its internal measuring cycle and can be addressed
over RS232, as well as over RS485 or SDI-12 – depending on the selected setting.
7.2.1. Settings over RS232 or RS485
If you would like to address the SHM 31 sensor over RS232, you can use a terminal program with the UMB-
ASCII protocol. For communication over RS485, you can choose between the UMB-ASCII 2.0 and the UMB
binary protocol. We recommend using the ConfigTool.NET software with UMB binary protocol to conveniently
set up the sensor over RS485. The setting options and parameter lists for operation over UMB-ASCII 2.0 or
UMB binary protocols are listed in the following sections.
7.3. UMB ConfigTool.NET
The ConfigTool.NET software is available for various operating system platforms. It can basically
communicate with sensors over a serial, a Bluetooth or a network interface. ConfigTool.NET allows the
following communication steps:
1. Reading out the sensor’s individual UMB channels; also see section 9
2. Automatically querying, graphically displaying and storing the measured data
3. Performing firmware updates
4. Controlling the sensor using parameter lists
5. Control commands, such as determining reference values, defrost mode, etc.
7.3.1. Basic installation with ConfigTool.NET and a serial interface
The following steps can be performed to work with the UMB ConfigTool.NET software during initial
installation:
1. Install and launch the current UMB ConfigTool.NET software
2. Preparatory settings:
a) On the ConfigTool.NET start screen, click on the ‘Settings’ cogwheel icon in the top
right-hand corner.

Commissioning
Snow depth sensor SHM 31, V2.1 19
Figure 18: Cogwheel icon to access the settings (start screen)
b) If necessary, create or select the folder that ConfigTool.NET should save the log file
for your measurements in.
c) Use the device template download function to update the list of available UMB
channels. OTT HydroMet regularly expands the list of UMB channels and updates it
with respect to the latest sensors / sensor options. An internet connection is
required for this step.
d) Confirm the changes with ‘OK’, or click on ‘Cancel’ to return to the start screen.
Figure 19:The basic settings for log files and communication with the sensor

Commissioning
20 Snow depth sensor SHM 31, V2.1
3. You can set up different workspaces in ConfigTool.NET to manage your sensor settings
and measurements. You can access the workspace options by clicking on the button in
the top left-hand corner of the start screen.
a) Click on the ‘Edit Workspaces’ icon. This creates a new workspace if no already
created workspace has been selected in the drop-down list.
b) Appropriate connection settings must be made for each new workspace. For this
example, select the ‘Serial’ connection type and your serial adapter’s corresponding
COM port.
c) Confirm the changes with ‘OK’ to go to the ‘Workspace Details’.
Figure
20: The position of the ‘Workspaces’ menu on the ConfigTool.NET main page
Figure
21: Connection settings for the current workspace