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Lufft CHM 8k User Manual

Ceilometer
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Lufft CHM 8k Ceilometer
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  • Page 1 User Manual Lufft CHM 8k Ceilometer General Information - 1 -...

  • Page 2: Table Of Contents

    Contents General Information ........................4 Symbols used ..........................5 Safety .............................5 Standards and Directives ......................5 Safety instructions for the laser system ..................5 Requirements for the personnel ....................5 Safety instructions for transport, installation, commissioning and cleaning ......5 Description of the warnings .......................6 2.5.1 Description of warning symbols ....................6 2.5.2 Description of precautionary statements ...................6 Product labeling CHM 8k ......................7 Designated use .........................7...
  • Page 3 Operating Manual CHM 8k R1.7 / 01-2020 Structure of the NetCDF format ..................... 39 8.4.1 General ..........................39 8.4.2 Basic principles ........................39 8.4.3 File names ..........................39 8.4.4 Format structure ........................40 8.4.5 Special values of the evaluation parameters ................. 43 Status code ..........................

  • Page 4: General Information

    G. Lufft GmbH. Violations will be prosecuted. The manual was prepared with due care. No liability is assumed for damages resulting from failure to observe the information contained in the manual.

  • Page 5: Symbols Used

    • Maintenance and adjustment work on the CHM 8k may only be carried out by the service staff of G. Lufft GmbH or by the customer’s authorized and trained personnel. All maintenance work requires a technical qualification in electrical safety. •...

  • Page 6: Description Of The Warnings

    Once the CHM 8k has been installed, it must be checked. Make sure that no safety-related changes have taken place on the device. • The inner housing door may only be opened by the service staff of G. Lufft GmbH or by the customer’s authorized and trained personnel. •...

  • Page 7: Product Labeling Chm 8K

    Figure 1 Safety labeling. 2.7 Designated use The operational safety of the CHM 8k is only guaranteed if used as designated in accordance with the instructions in this operating manual. The device is designed for single phase operation on a public low-voltage network in accordance with IEC38, 6 edition, 1983.

  • Page 8: Technical Data

    Operating Manual CHM 8k R1.7 / 01-2020 3 Technical Data 3.1 Ordering information Equipment Versions Order number Description Power supply Cable length CHM 8k EU Basic 8349.01-010 230 VAC ±10% 10 m CHM 8k EU + DSL Modem 8349.11-010 230 VAC ±10% 10 m CHM 8k EU + DSL Modem 8349.11-003 230 VAC ±10%...
  • Page 9 Operating Manual CHM 8k R1.7 / 01-2020 Data interfaces Standard interfaces RS485 half-duplex (ASCII); LAN (http, (S-)FTP, NetTools) Optional interfaces DSL, RS485 full-duplex (4 wire) Electrical parameters Power supply 230 VAC ±10 % or 115 VAC ±10 % Line frequency 50 Hz, 60 Hz Max 450 VA with activated case heater (default);...
  • Page 10 (*) the combination of high temporal and range resolution over the full range is limited due to file size and processing time. Any combination of > 70MB daily NetCDF fle sizes is not supported by Lufft. Example (standard operation mode): 15 m range resolution over 10 km range with 15 s time resolution results in 17 MB daily NetCDF file sizes.

  • Page 11: Technical Description

    The CHM 8k detection system is based on an analog detection method with a 25 nm bandwidth optical filter in front of the detector. It is designed to suppress background light effectively, while being compatible with the broader emission spectrum of InGaAs laser diodes.

  • Page 12: Functional Diagram

    Operating Manual CHM 8k R1.7 / 01-2020 • Power supply 12 - 15 VDC for the electronics • Transformer 48 VCD for fans • Fan and temperature sensors • Lightning and overvoltage protection device for power cable, LAN, RS485 The functional units are of modular design, fastened separately to the inner housing and can be removed and replaced individually for servicing purposes.

  • Page 13: Function Control And Device Status

    Figure 3 Flow chart - standard measuring cycle. The functional control of the CHM 8k (measurement and evaluation) is performed by an FPGA and an OMAP processor. The logging interval (not shown here) consist of multiple measuring cycles calculated in the OMAP processor, while processes with higher time resolution of up to 1s time intervals are processed in the FPGA.

  • Page 14: Transport / Scope Of Delivery

    4 washers ISO 7093-10.5-A2 On customer’s request: • An adapter frame can be supplied, which allows the CHM 8k to be screwed to existing fastening bolts. • An angle adapter frame can be supplied, e.g. for 15° to tilt ceilometer away from direct sunlight.

  • Page 15: Installation

    Install the CHM 8k in a protected outside area. Avoid radiation from strong light sources. The sun radiation angle must be ≥ 15° to the vertical. Please request a suitable angle adapter. The distance to trees and shrubs must be selected such that leaves, and needles do not reach the light emission apertures of the device.

  • Page 16: Installing On The Foundation

    CAUTION The CHM 8k weighs 70 kg, heavy equipment may cause serious injury.  Do not attempt to move the CHM 8k without adequate help  At least two people are required to install the ceilometer Install the CHM 8k ceilometer as follows: ...
  • Page 17 Operating Manual CHM 8k R1.7 / 01-2020  Carefully lift the CHM 8k out of the polystyrene packaging or paper honeycomb packaging by hand, observing all safety regulations. (Lifting positions: Figure 7). Figure 7 Lifting positions and handle protection (edge protection profile). Onward transport options: ...

  • Page 18: Electrical Installation

    DC. The value of the isolation resistance must be above 1 MΩ. Figure 10 shows a schematic sketch of the electrical installation of the CHM 8k. The power supply (1) to the device must be connected via an external mains switch (2) which needs to be easily accessible to cut the power to the device when required.
  • Page 19 Switch off the external circuit breaker before starting the installation and secure against reconnection. The electrical connections to the CHM 8k are specified in more detail in Figure 11. Connect the mains and data cables as shown in this figure. It is recommended to include external overvoltage protection in all connections to the device to prevent damage to the connection box.
  • Page 20 Operating Manual CHM 8k R1.7 / 01-2020 1. 230 VAC supply cable (mains cable): color code: neutral conductor: blue, conductor: brown, protective conductor: green-yellow); standard length 10 m. 115 VAC supply cable (mains cable): color code: conductor black, neutral: white, protective conductor: green / green-yellow Figure 11 Electrical installation.
  • Page 21 Operating Manual CHM 8k R1.7 / 01-2020 3. Data cable (RS 485, 3 wire): A (-) conductor: yellow; B (+) conductor: green; RS485 - GND: white & brown; shielding as required: (see Figure 13); standard length 10 m. Figure 13 RS485 connection to transducer. 4.

  • Page 22: Commissioning And Decommissioning

    The CHM 8k automatically sends out standard data telegrams when the start-up procedure has been completed. It is part of the default setup and might differ for user specific CHM 8k start settings. The automatic output every 15 s is helpful to check if the communication works correctly without entering any command.

  • Page 23: Starting Up With The Lan Connection

    Readout of the laser get 16:Lifetime(h) operating hour counter Table 3 Commands for functional testing (examples). After completing the simple functional test on the CHM 8k: • Continue to operate in polling mode, or • Reset to automatic transmission mode set<SPACE><RS485Number>:Transfermode=1<CR><LF>...

  • Page 24: Shutdown

    7.4 Disposal Disposal Notice Disposal of the CHM 8k Cloud Height Meter must be in accordance with national regulations. Electrical equipment marked with this symbol may not be disposed of in European domestic or public disposal systems. Return old or end-of-life equipment to the manufacturer for disposal at no charge to the user.

  • Page 25: Communication Via Rs485 & Ethernet

    Operating Manual CHM 8k R1.7 / 01-2020 8 Communication via RS485 & Ethernet The CHM 8k supports the interfaces RS485 (see section 8.2) and Ethernet (see section 8.7) for communication with the device. Both offer the possibility of data transfer of the measured values and the configuration of the device and can be used at the same time.
  • Page 26 Operating Manual CHM 8k R1.7 / 01-2020 Parameter Short Default Range / short description value RS485 Comment 5 RS485 Additional comment field (31 characters) Comment 6 RS485 Additional comment field (31 characters) Comment 7 Additional comment field (31 characters) RS485 DateTime UTC Time in the format DD.mm.YYYY;HH:MM:SS RS485...
  • Page 27 Operating Manual CHM 8k R1.7 / 01-2020 Parameter Short Default Range / short description value RS485 NetMask 0.0.0.0 Set / request the static Netmask address NtpMode 0; 1 switch ntpd on / off NtpServer 0.0.0.0 Set / request the NTP time server address PeltierMode* 0;...
  • Page 28 Operating Manual CHM 8k R1.7 / 01-2020 Parameter Short Default Range / short description value RS485 Zenith 0 - 90 degrees (x 100) (e.g. 10.25 and 1025 RS485 0° is vertical Table 4 List of configurable parameters, can be set in service mode, format for web interface, or only in web interface available RS485 format for RS458, or only for RS485 available...
  • Page 29 Longitude: Longitude of the location, decimal, orientation to east positive, example Berlin: 13.40833 (corresponds to 13° 24' 30'' E). MaxCrossTalkChars: The number of characters the CHM 8k will ignore within the time interval “TimeOutRS485(s)” if not ended with <EOT> (04 HEX), <CR> (0D HEX), <LF> (0A HEX). The parameter is implemented to prevent the ceilometer to fall back in its standard baud rate caused by noise on unstable communication lines.

  • Page 30: Device Configuration With Rs485

    Operating Manual CHM 8k R1.7 / 01-2020 8.2 Device configuration with RS485 The user can change settings via the RS485 interface: • for controlling the measuring processes • for configuring the communication interfaces 8.2.1 Reading out a parameter A parameter can be queried with the command: get<SPACE><RS485Number>:<ParameterName><CR><LF>...

  • Page 31: Changing The Baud Rate

    The command set<SPACE><RS485Number>:Reset=1<CR><LF> instructs the internal processor to perform an immediate restart. This restart takes less than one minute. Communication with the CHM 8k is not possible during this time; any current automatic telegram output is also interrupted. The command set<SPACE><RS485Number>:ResetSettings=1<CR><LF>...

  • Page 32: Data Query Rs485

    Operating Manual CHM 8k R1.7 / 01-2020 The logging and reporting time are set to 30 seconds. The internal measuring time is always set to one second. The login and reporting time must be a multiple of one second. The command set<SPACE><RS485Number>:DateTime=DD.MM.YYYY;hh:mm:ss<CR><LF>...

  • Page 33: Automatic Output Mode

    Operating Manual CHM 8k R1.7 / 01-2020 the standard data telegram (S), extended data telegram (L) or raw data telegram (A) are called up once only. For the format of the respective data telegram, see section 8.3.3 to 8.3.5 (Table 8, Table 9, Table 12).

  • Page 34: Extended Data Telegram

    Operating Manual CHM 8k R1.7 / 01-2020 Byte Value Description 33-37 **** Cloud layer 2 <SPACE> 20 HEX 39-43 ***** Cloud layer 3 <SPACE> 20 HEX 45-48 **** Penetration depth of the laser beam in cloud layer 1 <SPACE> 20 HEX 50-53 **** Penetration depth of the laser beam in cloud layer 2...
  • Page 35 Operating Manual CHM 8k R1.7 / 01-2020 Table 4. In the extended data telegram a semicolon (3B HEX) is used as the separator instead of the space (20 HEX). Byte Value Description <STX> 20 HEX 3, 4 3B HEX 3B HEX 8-10 Output interval [s] 3B HEX...
  • Page 36 Operating Manual CHM 8k R1.7 / 01-2020 Byte Value Description 113-117 ***** Standard deviation cloud layer 1 (CBE) 3B HEX 119-123 ***** Standard deviation cloud layer 2 (CBE) 3B HEX 125-129 ***** Standard deviation cloud layer 3 (CBE) 3B HEX Standard deviation penetration depth of laser beam in cloud layer 1 131-134 **** (CDE)

  • Page 37: Raw Data Telegram

    Operating Manual CHM 8k R1.7 / 01-2020 Byte Value Description 3B HEX Quality index aerosol layer 2 3B HEX BCC; Base Cloud Cover 3B HEX TCC; Total Cloud Cover 3B HEX 235-236 Checksum (two's complement of the sum of bytes 0 to 239 expressed in hex code, excluding bytes 235 and 236) <CR>...
  • Page 38 Operating Manual CHM 8k R1.7 / 01-2020 transmission takes about 16 seconds. The automatic output of the raw data telegram is restricted to specific logging time / Baud rate combinations, as set out in Table 11 below. Baud rate no. Baud rate [bit/s] Logging time interval [dt(s)] Not possible 1,200...

  • Page 39: Additional Data Telegrams

    The ceilometer stores all the data for one day in a file or in case the ftp mode is active in 5 min files. The time used is UTC. In the standard mode (RS485), the CHM 8k transmits a raw data telegram with a single backscatter profile and all descriptive variables and attributes in the NetCDF format.

  • Page 40: Format Structure

    Number of cloud layers transmitted in telegrams and stored in NetCDF files Table 13 Dimensions in NetCDF. Global attributes Attribute Description Type Heading for graphical representation, e.g. “Lufft Berlin, CHM 8k” title text source See device_name (left for compatibility reasons) text device_name...
  • Page 41 Operating Manual CHM 8k R1.7 / 01-2020 Variables Variable Type Dim. Unit Long description Scaling time double time seconds since End time of measurement 1904-01-01 (UTC) 00:00:00.000 00:00 range float range Distance from device (independent of direction and height of installation site) range_hr float...
  • Page 42 Operating Manual CHM 8k R1.7 / 01-2020 Variables Variable Type Dim. Unit Long description Scaling c_cal float Calibration constant (c) scaling float Scaling factor (for normalization of measuring units with respect to each other) (cs) base float time Baseline height of raw signal (mainly influenced by backgroung light) (b) stddev...

  • Page 43: Special Values Of The Evaluation Parameters

    Operating Manual CHM 8k R1.7 / 01-2020 Variables Variable Type Dim. Unit Long description Scaling voltage_det short time Detector high voltage voltage_las short time Laser bias voltage 0.001 voltage_led short time Reference LED bias 0.001 voltage background_det short time Detector background signal short time Fan activity (bit 0 set =...
  • Page 44 Operating Manual CHM 8k R1.7 / 01-2020 Type Error description 00000001 Error Error: Signal quality 00000002 Error Error: Signal recording 00000004 Error Error: Signal values null or void 00000008 Error Error: Determination of mainboard version failed (APD bias) 00000010 Error Error: Create new NetCDF file 00000020 Error Error: Write / add to NetCDF error...

  • Page 45: Escalated Status Codes

    Operating Manual CHM 8k R1.7 / 01-2020 8.5.1 Escalated status codes The CHM 8k offers an additional status code. It is divided into the following eight groups: 1. Configuration 2. Data transmission and storage 3. Temperatures 4. Calculation / processing in sky condition algorithm 5.
  • Page 46 Operating Manual CHM 8k R1.7 / 01-2020 Group Hex code Error description Duration [s] xxxx xx7x New NetCDF file cannot be generated ∞ xxxx xx8x SD card not available or defective Temperatures xxxx x0xx Temperature values are in range Laser temperature outside the valid range (setpoint -3°C xxxx x2xx ...
  • Page 47 Operating Manual CHM 8k R1.7 / 01-2020 Group Hex code Error description Duration [s] Calculated PIN signal not positive, resulting in incorrect xx4x xxxx calibration xx5x xxxx PIN signal too low xx6x xxxx Values from detector signal zero or void xx7x xxxx Insufficient test pulse signal available xx8x xxxx No window pulse in receiver signal...

  • Page 48: Firmware Update

    7.2). This screen shows information about the current status of the device and the user can log in as a superuser or service user is possible. Communication with the CHM 8k via an Ethernet connection is fast, secure and system-independent. An Apache web server runs inside the device. This enables a communication and configuration platform via the web interface for processing firmware updates, quick previews of measurement results or downloading full-day NetCDF raw data.

  • Page 49: Configuring The Chm 8K (Config Tab)

    Operating Manual CHM 8k R1.7 / 01-2020 Figure 16 Web interface: NetCDF files. Figure 17 shows the content of the “Viewer” tab, displaying the existing data for the last 24 hours. Clicking the "Update" button updates the image file, however this can only be done every 5 minutes. The "BackscatterMax"...
  • Page 50 Operating Manual CHM 8k R1.7 / 01-2020 Figure 18 Web interface: Config Network (read-only, default mode) for a device with configured static IP (eth0:1 custom). Figure 19 Web interface: Config Network (superuser). Communication via RS485 & Ethernet...
  • Page 51 (Figure 21). New firmware files are packed as back-up zip files and must be uploaded in this form. New firmware versions are published on the Lufft website. A list of previously released versions is attached to this manual in section 11.2.

  • Page 52: Status And Error Messages (Process Status)

    8.7.4 Status and error messages (process status) The upper part of the “Process Status“ tab of Figure 23 is mainly used by Lufft service personnel to identify problems and faults. In the lower parts of the tab NTP- and AFD-service information might be displayed, if applicable.

  • Page 53: Time Server

    Operating Manual CHM 8k R1.7 / 01-2020 Last response [s] Specifies how many seconds ago the time server was last queried. Status error Contains an error code that indicates problems during NTP status generation. For example, the NTP daemon is not active or was started without an Ethernet connection.

  • Page 54: Afd Mode

    Operating Manual CHM 8k R1.7 / 01-2020 If the NtpMode is activated during operation and the time difference between server and CHM 8k is greater than 1000 s, no time synchronization is performed. In this case, a firmware restart or one-time manual time setting with reactivation of the NtpMode is necessary to take over the time of the time server.

  • Page 55: Telegram Via Ethernet

    Operating Manual CHM 8k R1.7 / 01-2020 [recipient] ftp://afd:eXample@192.168.1.51//home/chm_data/%h/%tY/%tm [options] priority 9 create target dir time */15 * * * * lock DOT age-limit 3600 exec -d bzip2 %s Every 15 minutes, bzip-compressed files are transferred to the ftp server in a directory specified by /home/chm_data/hostname/year/month.
  • Page 56 Operating Manual CHM 8k R1.7 / 01-2020 ncrcat is part of the nco tool set and can be downloaded from the following website: http://nco.sourceforge.net For users of the Windows operating system: The direct application of the command ncrca.exe in the Windows command line is restricted by the use of wildcards and the total length of the command line.

  • Page 57: Data Evaluation / Sky Condition Algorithm (Sca)

    9 Data Evaluation / Sky Condition Algorithm (SCA) The CHM 8k ceilometer is a laser remote sensing device with embedded algorithm for determining layers of particles and droplets in the atmosphere. The embedded algorithm is collectively referred to as the Sky Condition Algorithm (SCA).

  • Page 58: Cloud Ceilings / Cloud Base Heights

    Operating Manual CHM 8k R1.7 / 01-2020 A further processing step is performed to determine cloud heights and aerosol layers. To compensate for the reducing signal-to-noise ratio at higher altitudes, the signal is averaged with a height-depending averaging time as shown in Figure 25. At different altitudes, the time averaging varies from 15 seconds below 3 km to 300 seconds above 6 km.

  • Page 59: Parameters For Data Evaluation

    Operating Manual CHM 8k R1.7 / 01-2020 Figure 27 Evaluation process for different cloud parameters. 9.5 Parameters for data evaluation A set of parameters control the data evaluation routine. System dependent data are stored on the laser optical module (LOM). Data accessible to users are listed in Table 4 and Table 5. If the instrument is tilted to the zenith and the zenith angle is entered correctly, the cloud distance and other ranges are corrected by this angle.

  • Page 60: Mixing Layer Height

    Operating Manual CHM 8k R1.7 / 01-2020 9.9 Mixing layer height Aerosols which are detected near the ground spread in the lower air layer, where the upper limit can be defined as a planetary boundary layer (onshore) and maritime boundary layer (offshore). The lowest aerosol layer that can be identified within the boundary layer can interpreted as mixing layer height (MXL).
  • Page 61 Operating Manual CHM 8k R1.7 / 01-2020 6 okta: 7/10 – 8/10 7 okta or more, but <10/10 8 okta: 10/10 Sky obscured by fog or other meteorological phenomena Table 21 Degree of coverage, WMO code 2700 and definitions in 10 Figure 28 Degree of coverage algorithm.

  • Page 62: Sky Condition Index (Sci)

    Operating Manual CHM 8k R1.7 / 01-2020 9.11 Sky Condition Index (SCI) To better understand certain events, the Sky Condition Index is written to the extended data telegram and NetCDF files. In older CHM systems, the variable was treated as a precipitation index. Table 22 shows how the index is defined.

  • Page 63: Cleaning, Maintenance And Service Instructions

    LED must be lit. If this is not the case, this indicates an unconnected cable, a switched-off circuit breaker or defective fuses. 10.1 Cleaning The cover windows of the CHM 8k internal housing are tested for an impact energy of 1 Joule (IEC/EN 61010-1: IK06). WARNING Operating the sensor with a broken cover window may result in electric shock, which can cause serious or fatal injury.
  • Page 64 Operating Manual CHM 8k R1.7 / 01-2020 Interval Cleaning Comment / remedy Quarterly Clean the windows (Figure 29): first of all, Dishwashing liquid, water, hands with plenty of water and a little mild soap. Do not use microfiber cloths to Carefully spread some soap on the windows clean the windows! with your hands and rinse with water.

  • Page 65: Maintenance Intervals And Measures

    Table 24 lists the recommended preventive maintenance measures and the interval for regular checks. The inner sensor housing door must be opened to carry out the maintenance measure and the work therefore must be carried out by the service staff of G. Lufft GmbH or by the customer’s authorized and trained personnel.
  • Page 66 Operating Manual CHM 8k R1.7 / 01-2020 Interval Preventive maintenance measures Comment REGULAR Check the dehumidifier bag CONTAINER DRI II for By service staff only CHECKS integrity and replace if necessary At least once a Change the dehumidifier bag CONTAINER DRI II By service staff only year Approx.

  • Page 67: Appendix

    Operating Manual CHM 8k R1.7 / 01-2020 11 Appendix 11.1 CHM 8k device hardware version Revision Date of change Changes Comment REV V1 01.03.2018 First series version REV V2 01.08.2018 Update internal wiring, Update PCBs REV V3 01.08.2019 Update Mainboard REV V4 15.12.2019 Update Lasermonitor Table 25 Hardware revisions (HardwareVersion 0 means value not set)
  • Page 68 Operating Manual CHM 8k R1.7 / 01-2020 Firmware Description Released version 7. New Linux operating system (OS 18.04.1) 1.000 Sep 2018 Requires FPGA-Version 4.17 and hardware version REV V02 1. Universal RS485 address 99 introduced 2. Escalated status codes in telegrams 1 and 5 3.
  • Page 69 Operating Manual CHM 8k R1.7 / 01-2020 Firmware Description Released version 14. Minimal value of RangeDimHr set to 10 1.030 Nov. 2019 1. Remove NetCDF files at the end of a month only if zip file was 1.040 Jan. 2020 created successfully 2.

  • Page 70: Index Of Figures

    Figure 23 Web interface: Process warnings and error log. AFD and NTP status are only visible if AFD, NTP mode are set to 1....................53 Figure 24 Normalized and calibrated backscatter signals of two different CHM 8k instruments...57 Figure 25 Example of time averaging for determining cloud heights.............58 Figure 26 Cloud detection algorithm.

  • Page 71: Index Of Tables

    Operating Manual CHM 8k R1.7 / 01-2020 13 Index of Tables Table 1 Equipment versions........................8 Table 2 Technical data..........................9 Table 3 Commands for functional testing (examples)................23 Table 4 List of configurable parameters, ....................28 Table 5 List of read-only parameters, accessible via the RS485 interface; ...........28 Table 6 Correlation between baud rate # and baud rate.
  • Page 72 Index of Tables...

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