SOMMER SMA-2 User Manual
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SOMMER SMA-2 User Manual

Snow melt analyzer
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SMA-2
Snow melt analyzer
User Manual
Setup version 3.10
2019-03-12
Sommer GmbH
All rights reserved.

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Summary of Contents for SOMMER SMA-2

  • Page 1 SMA-2 Snow melt analyzer User Manual Setup version 3.10 2019-03-12 Sommer GmbH All rights reserved.
  • Page 2 Sommer GmbH A-6842 Koblach This manual or parts of it may only be copied or passed on to third parties with written permission of Sommer GmbH. This applies to printed as well as digital issues of this manual. Sommer GmbH...
  • Page 3 CE compliance This product is in conformity with the following standards Directive 2014/35/EU EN 62368-1 EN 61010 Richtline 89/336/EEC EWG EN 61326 RoHS II Directive 2011/65/EU RoHS III Delegated Directive (EU) 2015/863...
  • Page 4 Prior to installation of equipment inform the owner of the measurement site or the authority respon- sible for it. Upon completion, secure the installation from trespassers. Maintenance and repair must be performed by trained personnel or an engineer of Sommer GmbH. Only replacement parts supplied by Sommer GmbH should be used for repairs.

  • Page 5: Table Of Contents

    1 Introduction ..........................6 2 Unpacking ............................ 7 3 Quick start ............................ 8 3.1 Installation ............................8 3.2 Connection of the SMA-2 to a computer ..................8 3.3 Sensor configuration ........................8 4 Specifications ..........................9 5 Principles of operation ........................ 10 6 Installation ..........................
  • Page 6 Appendix A Measurement values ....................45 A.1 Error and exception values ......................45 Appendix B RS-485 interface ......................46 B.1 Protocols ............................46 B.1.1 Sommer protocol ........................ 46 B.1.2 Standard protocol ....................... 47 B.2 Commands and answers ....................... 47 B.3 Error codes ............................ 49 B.4 Sommer CRC-16 ..........................

  • Page 7: Introduction

    Determination of snowpack-properties can be very challenging as they vary significantly in space and time. The SMA-2 snow melt analyzer measures the volumetric contents of ice and water and deter- mines the snow density. This is achieved by recording the complex impedance of a ribbon-shaped sen- sor that rests in the snow pack.

  • Page 8: Unpacking

    Anti-twist support, pair Control cabinet with SPA-controller Peg for anchoring Table 1: Parts list Bolts and nuts are pre-mounted. In case of missing or damaged items please contact your Sommer sales partner. The following items are available as options: Commander software...

  • Page 9: Quick Start

    3.2 Connection of the SMA-2 to a computer 1. Install the Commander software 2. Connect the SMA-2 to your computer using the USB to RS485 converter cable (Section 7.2) 3. Connect a 9…28 VDC power supply to the SMA-2 data cable 4.

  • Page 10: Specifications

    Operating temperature -35…60 °C (-31…140 °F) Storage temperature -35…60 °C (-31…140 °F) Protection rating IP 54; IP66 with SMA-2 controller in electrical cabinet Integrated protection against indirect lightning with a discharge Lightning protection capacity of 6 kA Ppp Frame material...

  • Page 11: Principles Of Operation

    The snow melt analyzer SMA-2 breaks these limitations and provides information about the snow pack by meas- uring the dielectric properties of a large snow volume. It provides relevant snow properties like density and contents of liquid water and ice.

  • Page 12: Installation

    3. There should be no boulders, trees, fences or other objects in the vicinity of the measurement spot. Any obstacle can cause snow drift and thus affect the measurement results. 4. If feasible, the SMA-2 should be installed in the direction of the main wind. This minimizes disturb- ances by snow drifts.

  • Page 13: Control Cabinet

    6.2.4 Wiring 1. Connect the SMA-sensor cable to the I1 terminal of the controller. The sensor wires are connected to the SMA-2 controller as illustrated below. Figure 2: Wiring of SMA ribbon-sensor...

  • Page 14: Power Supply

    Table 3: Connection wires of SMA ribbon-sensor 6.2.5 Power supply The SMA-2 is designed for extreme environmental conditions at remote sites with no grid connection. The sensor switches automatically into standby-mode between measurements and thus consumes only approx. 0.1 Ah per day at a typical measurement interval between 5 to 10 minutes. Thus, the device can be powered by a 12V-solar-generator mounted in the vicinity.

  • Page 15: Communication

    7 Communication 7.1 SMA-2 controller The controller of the SMA-2 triggers the measurements of the connected sensor, acquires data and calculates the snow parameters. It returns the data via RS-485 or SDI-12. 7.1.1 Connection terminals All available connection terminals are listed in...
  • Page 16 SDI-12 (from sensor) BUS 2 RS-485 A (from sensor) RS-485 B (from sensor) Ground OUT 1,2 Switched supply voltage 1 Switched supply voltage 2 Ground OUT 3,4 Switched supply voltage 3 Switched supply voltage 4 Table 4: Connection terminals of SMA-2 controller...

  • Page 17: Communication With A Pc

    7.2 Communication with a PC Communication between the SMA-2 and a PC can be established with a USB to RS-485 converter. Per- form the following steps to set up the communication between the SMA-2 and your PC: 1. Install the Commander software on your PC.
  • Page 18 7. Make sure the SMA-2 is powered and press Next. 8. Select Sensor (9600 Bd) and press Next. 9. Tick Select port and select the COM port that was assigned to the USB/RS-232 converter; then click Next.
  • Page 19 If more than one COM ports are listed and you are not sure which one to select, open the Windows Device Manager (press  and type device manager) and expand the menu Ports (COM & LPT). By unplugging and re-plugging your USB/RS-232 converter you can identify the number of the desired port.

  • Page 20: Connection To A Data Logger

    7.3 Connection to a data logger 7.3.1 RS-485 The SMA-2 can be connected to a data logger via RS-485 according to Figure Figure 5: Wiring of the SMA-2 with a data logger via RS-485...

  • Page 21: Sdi-12

    RS-485 A D0 - A/A BUS-1 A RS-485 B Table 5: Connection to a Modbus The SMA-2 does not have termination resistors and does not need BUS polarization resistors. There- fore, only a RS-485 BUS termination has to be implemented externally.

  • Page 22: Configuration

    Parameters (F2) and clicking Download parameters from device. The complete param- eter list is transferred from the sensor to your PC and displayed in the Parameters (F2) window. Now, the settings can be modified, saved in a parameter file on your PC and uploaded again to the SMA-2. See Section for a complete list of sensor settings.

  • Page 23: General Settings

    Return/Enter or can be discarded with Esc. Menus are closed with X. After closing the main menu the sensor performs an initialization. If the SMA-2 is re-powered a boot message containing the sensors firmware version and address in the RS-485 bus is displayed in the terminal window.

  • Page 24: Calibration Of Sma-Ribbon-Sensor

    3. Open the Commander software and establish a connection to the SMA-2 as described in Section 7.2. 4. Download the parameter list and open SMA, sensor table in the Technics menu. 5. For each sensor click Test sensor. The SMA-2 performs a measurement and displays the results in a pup-up window.

  • Page 25: Span Test And Adjustment

    Fasten the bolts by hand. Figure 7: Reference plate 2. In the Commander open SMA, sensor table in the Technics menu. 3. Click Test sensor. The SMA-2 performs a measurement and displays the results in a pup-up win- dow.

  • Page 26: Serial Data Output

    Attention Erroneous and exceptional data are marked by the values listed in Appendix The number of variables recorded by the SMA-2 as well as their names and configuration can be altered by adjusting Measurements, max. number and modifying the entries in Measurements, table.

  • Page 27: Rs-485 Interface

    8.6.1 System key and device number The system key and the device number are used to identify a SMA-2 sensor in a bus system. This is essential if multiple devices (SMA-2 sensors and data loggers) are operated within the same system.

  • Page 28: Waking-Up Of A Connected Data Logger

    The sync sequence is the string UU~?~? and is sent directly before a command. It is used to synchro- nize the receiving UART. Prefix The prefix is an arbitrary character; the SMA-2 uses a blank. The character is sent prior to any commu- nication. Then the time of the OP, prefix holdback is waited and the command is sent afterwards.

  • Page 29: Commands

    If a command contains the identifier W the receiving SMA-2 returns a confirmation on receipt. This command type demands a closing sequence with a valid CRC-16. If a command contains the identifier S the receiving SMA-2 does not acknowledge the receipt of the command. This command type demands no closing sequence and therefore no CRC-16.

  • Page 30: Sdi-12 Interface

    SOMMER sensors for instrument configuration, e.g., 0XRB|! to set the measurement interval. 8.7.1 SDI-12 address (E-G-A) The SMA-2 is identified with a unique address in the SDI-12 bus system. The default address is 0. 8.7.2 Measurement commands To acquire a measurement from a sensor two individual SDI-12 commands – trigger a measurement and request measurement values –...

  • Page 31: Modbus Communication

    Modbus and back to Sommer protocol. 8.9 Analog input The SMA-2 controller has four 0 … 2.5 V, 16 bit analog input ports available. These ports may be used for temperature profile or other measurements. Any auxiliary sensor can be powered by one of the switched power output ports OUT 2 …...

  • Page 32: Parameter Definition

    9 Parameter definition The settings of the SMA-2 can be read and changed with the PC software Commander (see Section 8.1). Main menu Measurement trigger interval Measurement Interval Measurements, max. number Measurements, table Technics Special functions The parameters are arranged in a main menu with submenus. In the terminal program menu items are selected by entering the letter left to the label.
  • Page 33 C Measurements, max. number The number of variables the SMA-2 records. Up to 50 variables can be recorded, depending on the user’s needs. They are selected in Measurements, table. Value range Default Unit 1 … 50 D Measurements, table In the measurement table the recorded variables are selected. By default, the measurement table con-...
  • Page 34 1 and to retrieve the value 4.3, S-MEA must be set to 2. SOMMER sensor that supports the SBP-protocol (via RS-485) The sensor address is set in S-NUM, and the position of the measurement value within the output string is assigned in S-MEA.
  • Page 35 Supply voltage error Error code (internal) st-func Status of Fatal error (4 LED on SMA-2 controller) cap-beg Charging voltage of ultracapacitors before measurement cap-end Charging voltage of ultracapacitors after measurement SWE-sum Sum of SWE-values of horizontal ribbons in the snowpack...
  • Page 36 Description comma dot (default) E-C Sleep mode This parameter defines the behavior of the SMA-2 between two measurements, provided the meas- urement interval is longer than the time of the measurement itself. The following options are available: Parameter Description For MODBUS applications. The SMA-2 stays in normal mode. This option MODBUS, fast permits high data transmission rates, but increases power consumption.
  • Page 37 0…255 1 (default) E-E Sommer ID The Sommer ID is used to define stations within the Commander software. The ID is preset in the device and corresponds to its serial number. For more information please consult the Commander manual. By default the Sommer ID is set to the device’s serial number.
  • Page 38 E-G-C SDI-2 maximal duration The timeout for commands sent to SDI-12 devices connected to the SMA-2. If a SDI-12 device does not respond to a command within this time the device returns an error code (see Appendix A.1).
  • Page 39 Only available in terminal mode. Changes the SDI-12 address of a connected sensor. E-G-F SDI-2 ask for a sensor address Only available in terminal mode. Reads the SDI-12 address and its identification of a single SDI-12 sen- sor connected to the SMA-2. E-H RS 485-2 RS 485-2...
  • Page 40 Setting Description off (default) Continuous polling is inactive. Continuous polling is active. E-H-I Trig, timeout The time the SMA-2 is waiting until expected commands/answers are received via the RS485-2 inter- face. Unit Seconds Value range 3 … 250 60 (default) E-H-J Trig, sleep while timeout To reduce power consumption the MRL-7 can switch to a sleep mode between measurements.
  • Page 41 Only available in terminal mode. After activation, direct communication with a connected sensor is enabled, i.e. commands and theirs answers are exchanged over the RS485-2 interface of the SMA-2. With this mode the settings of a connected digital sensor can be read or changed.
  • Page 42 Serial data can be transmitted to a recording device automatically without a request. However, many devices demand a wake-up sequence before they can receive and process data. The SMA-2 has the option to send a sync sequence and a prefix before data are transmitted (see Section 0). The following...
  • Page 43 Unit Milliseconds Value range 0…5ˈ000 300 (default) E-I-G MODBUS, set default Only available in terminal mode. The Modbus protocol demands a defined setting, including multiple parameters. This command sets all these parameters automatically (see Appendix D.1). E-I-H MODBUS, device address Unique device address for the Modbus protocol.
  • Page 44 Special functions Device status View setup Set factory default Temp. load factory default Relaunch program F-A Device status Displays information about the sensor and the software version. F-B View setup All parameters of the SMA-2 are listed in the terminal window.
  • Page 45 F-C Set factory default All parameters are reset to factory defaults. Only available in terminal-mode. F-D Temp. load factory default Loads factory default values temporarily. Only available in terminal mode. F-E Relaunch program The device is restarted. Powering the sensor off and on again is equivalent.

  • Page 46: Appendix A Measurement Values

    Appendix A Measurement values A.1 Error and exception values Measurement data may be returned with the following values: Value Description 99999999 Positive overflow 99999998 Initialization error 99999997 Measurement error 99999996 Conversion error 99999995 Setup error 99999990 No sensor response (SDI-12 and SBP) -9999999 Negative overflow Table 9: Exceptional and error values...

  • Page 47: Appendix B Rs-485 Interface

    Appendix B RS-485 interface B.1 Protocols B.1.1 Sommer protocol The data string of the Sommer protocol has the following format: #M0001G00se01 39.5|02 6.2|03 371|04 281|07 94|3762; Header The header (#M0001G00se) identifies the data by system key, device number and string number.

  • Page 48: Standard Protocol

    CRC-16 4-digit hex number End character <CR><LF> Control characters Carriage return and Line feed Table 12: End sequence of the Sommer protocol B.1.2 Standard protocol The data string of the Standard protocol has the following format: M00_0001 39.5 Header The header (M00_0001) identifies the data by system key and device number.
  • Page 49 CRC-16 4-digit hex number End character Table 15: Structure of commands and answers Commands The following commands can be used with the SMA-2: Command Description Trigger a measurement Return measurement values _dd0cv Return a single measurement value with index dd (see Section 8.5)

  • Page 50: Error Codes

    Table 17: Error codes B.4 Sommer CRC-16 The CRC-16 (cyclic redundancy check) used in data transmission of Sommer devices is based on the ZMODEM protocol. When data are exchanged between two devices the receiving device calculates the CRC-value. This value is compared to the CRC value sent by the other device to check if the data were transmitted correctly.

  • Page 51: Appendix C Sdi-12 Interface

    This manual covers the main aspects of SDI-12 communication. Detailed information can be found at http://www.sdi-12.org. SOMMER devices with SDI-12 communication listen to standard commands as listed in the SDI-12 spec- ifications of version 1.3. Additionally, for instrument configuration a set of extended SDI-12 commands is implemented in all SOMMER sensors.

  • Page 52: Requesting Continuous Measurements

    C.2.1 Reading and writing sensor configurations The configuration parameters of a SOMMER sensor are read with the command aXRpp! and written with the command aXWpp=vvv!, with a the sensor address, pp the parameter identifier and vvv the value of the parameter.

  • Page 53: Adoption Of Settings

    Reading and writing a configuration value within a table Some SOMMER sensors are equipped with multiple transducers and their settings are listed in a table (see example below). A value within such a table is addressed by its row-index (01, 02 …) and column- index (A, B …).

  • Page 54: Appendix D Modbus

    Appendix D Modbus D.1 Modbus default settings The default settings are configured by the command MODBUS, set default: Baud rate 19ˈ200 Data bits Parity even Stop bits Flow control none Table 18: Default Modbus settings D.2 Modbus Configuration Function 06: Write single registers and Function 03: Read holding registers Register Variable Range...
  • Page 55 Function 04: Read input registers (read only) The measurement values are stored in the same sequence as listed in Section 8.5. Index Register Variable Unit / Bytes Format address value Test value Hardcoded test value 2.7519… float ice content water content density kg/m^3 Main...
  • Page 56 Run indicator status Modbus implementation 27 74 10100 version Separator " " Vendor string 53 6F 6D 6D 65 72 20 "Sommer " response Separator " " Device configuration 52 47 2D 33 30 20 20 “RG-30 “ Separator " "...

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