Lufft CHM 15k Nimbus User manual

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1300m
1500m
Manual
Cloud Height Sensor CHM 15k

Dear User
2Revision R09, November 2016
Note
This Manual is protected by copyright. No part of the Manual may be reproduced in any way
(by photographing, photocopying, microfilm or any other technique) without the prior written
approval of G. Lufft, nor may it be processed, duplicated or disseminated with the help of elec-
tronic systems. Any offence against these rules will be prosecuted.
Proper care was used in compiling this document. No liability will be accepted in the event of
damage resulting from failure to comply with information provided herein.
Documentation number: 8350.MEP
This documentation is valid for the following instrument types:
CHM15k Nimbus series with order numbers: 8350.00, 8350.01, 8350.03, 8350.10
G. Lufft Mess- und Regeltechnik GmbH
Gutenbergstrasse 20
70736 Fellbach / Germany
Phone: [phone]
Fax: [phone]
E-mail: [email protected] (Info & Sales)
E-mail: [email protected] (Support Lufft Berlin)
Date Revision Comment
March 2014 I0 Firmware 0.723, last Jenoptik release
September 2014 R02 Firmware 0.724, Lufft design, range resolution in NetCDF available,
small corrections
December 2014 R04 Firmware 0.730, cloud algorithm optimized in precipitation cases,
parameter in RS485 / web-interface added, chapter 7-8 corrected
May 2015 R05 Firmware 0.732
October 2015 R06 Firmware 0.735, small fixes
November 2015 R07 Small fixes chapter 9, table SCI
October 2016 R08 Firmware 0.743, all chapter revised
November 2016 R09 small fixes
You are advised to read this manual carefully before you start using the
CHM15k Nimbus ceilometer.
This is necessary to ensure that you will be able to utilize all the capabilities, which have been
designed into the equipment.
This technology is subject to further development.

Content
Revision R09, November 2016 3
1 Basic Information 5
1.1 Manual Structuring & Layout Note . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Intended Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2Safety 7
2.1 Standards & Directives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 General Safety Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3 Safety Notes Regarding the Laser System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4 Requirements on Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.5 Safety Notes Regarding Transportation, Installation, Commissioning & Cleaning . . . . . 8
2.6 Safety Labelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.6.1 User Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.6.2 CHM 15k. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3TechnicalData 11
4 Technical Description 15
4.1 Setup of CHM 15k. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.2 Functional units in inner casing space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.2.1 Functional Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.2.2 Measuring and monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5 Transportation & Scope of Delivery 19
6 Installation 21
6.1 Installing the CHM 15k . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.1.1 Preparatory Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.1.2 Installation on the Mounting Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.2 Electrical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7 Starting Up & Shutting Down 27
7.1 Starting Up with serial connection RS485 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.2 Starting up with LAN connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.3 Shutting Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.4 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8 Communication RS485 & Ethernet 31
8.1 List of configurable instrument parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.2 Instrument Configuration using RS 485 interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
8.2.1 Reading a parameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
8.2.2 Setting a parameter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
8.2.3 Change in Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
8.2.4 Reboot, restart and reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
8.2.5 Changing the logging time dt(s), date & time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
8.3 Data Queries RS485. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
8.3.1 Polling Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
8.3.2 Automatic Output Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
8.3.3 Standard Data Telegram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
8.3.4 Extended Data Telegram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.3.5 Raw Data Telegram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
8.3.6 User configured data telegrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
8.4 NetCDF Format Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Content
4 Revision R09, November 2016
8.4.2 Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.4.3 File Names. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.4.4 Format Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
8.5 Service Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
8.6 Firmware Update. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
8.7 Communication via Ethernet - Web-Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
8.7.1 Time Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
8.8 AFD Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
8.9 Telegram over Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
8.10 NetCDF file tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
9 Data Evaluation/ Sky Condition Algorithm (SCA) 65
9.1 Laser remote sensing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
9.2 Data preprocessing and averaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
9.3 Backscatter data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
9.4 Cloud ceilings/ cloud base heights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
9.5 Cloud Penetration Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
9.6 Parameters for data evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
9.7 Determination of Maximum Detection Range (MXD) . . . . . . . . . . . . . . . . . . . . . . . . . 68
9.8 Vertical optical range (VOR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
9.9 Precipitation and haze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
9.10 Mixed layer height. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
9.11 Cloud amount/ cloud cover (BCC / TCC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
9.12 Sky condition index (SCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
10 Cleaning, Maintenance & Service Instructions 73
10.1 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
10.2 Maintenance Intervals & Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
11 DataClient - Terminal software for CHM 15k 77
11.1 Software Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
11.2 Convention for the file names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
11.3 Start dialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
11.4 Communication tab. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
11.5 Raw Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
11.6 Telegram & Cloud Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
11.7 Service Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
11.8 Service & Software Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
11.9 General available controls or indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
11.10 Autostart and command line parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
11.11 DataClient Software Versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Annex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
List of Illustrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
List of Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99
Declaration of Conformity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100

Basic Information
Revision R09, November 2016 5
1 Basic Information
This User Manual provides the information that is required to operate the CHM 15k Cloud Height
Meter.
1.1 Manual Structuring & Layout Note
The Manual consists of eleven chapters, each page indicating the chapter title in its headline.
The bottom line of each page contains the details of the revision state, date of issue and page
number. In the appendix a content list of the service manual, a list of software releases for this
manual revision and a configuration example is applied.
1.2 Intended Use
Operating safety can only be guaranteed when the CHM 15k Cloud Height Meter is operated as
intended and in accordance with the information contained in this Manual.
The CHM 15k is only intended for single-phase operation powered by a public low-voltage distri-
bution system as stipulated in IEC38, 6th revision of 1983.
The Cloud Height Meter may be used with a maximum tilt angle setting of 20 degrees. Any angle
setting in excess of this limit will be regarded as non-conforming use! The owner (operator) will
be solely responsible in the event of damage due to non-compliance of this kind.
You are strictly prohibited from using the CHM 15k in a horizontal position.
For proper operation, scheduled cleaning and maintenance cycles must be observed (refer to
chapter 10 of this Manual or to the Service Manual).

Safety
Revision R09, November 2016 7
2Safety
2.1 Standards & Directives
To guarantee the safe operation of laser devices, all binding standards, directives
and instructions regarding laser safety and laser radiation protection must be
observed by manufacturers and users (refer to Declaration of Conformity).
The CHM 15k Cloud Height Meter is built and tested for compliance with
the following standards and directives:
1. Council Directive 2004/108/EEC
on the approximation of the laws of the Member States relating to
electromagnetic compatibility (EMC),
conforming to EN 61326 and EN 55011 standard requirements
2. Council Directive 2006/95/EEC
relating to electrical equipment designed for use within certain voltage lim-
its (73/23/EEC)
conforming to the following standards:
– EN 60825-1; Safety of laser products
– EN 61010-1; Safety requirements for electrical equipment for measure-
ment, control and laboratory use
In accordance with EN 60825-1:2007 and its inherent risk potential, the
CHM 15k qualifies as a class 1M laser device.
2.2 General Safety Measures
lAll safety notes in this User Manual, including any other applicable docu-
ments, must be duly observed and followed.
lThis User Manual must be kept within easy reach of personnel at all times.
lThe CHM 15k may only be operated with the inner door closed.
lThe CHM 15k Cloud Height Meter may not be powered by nominal volt-
ages other than 230 VAC.
2.3 Safety Notes Regarding the Laser System
There is invisible 1064-nm laser radiation emerging from the CHM 15k. It emits a
laser beam of very small divergence (< 0.5 mrad) and 90 mm beam diameter.
lDo not directly look into the beam.
lAvoid unnecessary exposure to invisible laser radiation.
lIt is strictly forbidden to use optical instruments, notably, field glasses, for
viewing the laser beam.
lClass 1M laser radiation, if viewed over an extended period of time,
may cause damage to the eyes such as glare or irritation or even full
loss of eyesight.
lMake sure the laser beam path is free from material with reflecting sur-
faces.
lFollow all instructions especially those on emergence of laser radiation (also

Safety
8 Revision R09, November 2016
refer to chapter 2.6 Safety Labelling).
2.4 Requirements on Personnel
lThe CHM 15k may only be installed and commissioned by properly trained
personnel who have received instructions on operating safety.
lMaintenance or adjustment work on the CHM 15k may only be carried by
G. Lufft GmbH service personnel or specially trained and authorized techni-
cians of the Customer.
lAnyone who is entrusted with work to install and commission the CHM 15k
must have completely read and understood this Manual.
lPersonnel working with the CHM 15k must not be in a state of fatigue or
under the influence of alcohol or medication or have physical impairments
of any kind that might temporarily or lastingly restrict their attention or
judgement.
2.5 Safety Notes Regarding Transportation, Installation, Com-
missioning & Cleaning
lFor handling, shipment or transportation, the CHM 15k must be duly pack-
aged and placed in the transporting position (refer to Fig. 5). Adequate
hoisting equipment and an appropriate means of transportation must be
used in all cases.
lOnce packaged, the CHM 15k must be secured and protected against acci-
dental shifting, mechanical shock or other similar impacts that may occur
inside the selected means of transportation, for example, by using tension
belts.
lA packaged CHM 15k must not be stacked.
lThe CHM 15k requires a footprint area of 50 x 50 cm. It must be installed
and assembled in a stable and fixed position on a suitably sized concrete
foundation. The maximum permitted inclination angle of the mounting
base is 5 mm/m.
lIf the CHM 15k is not intended to be assembled immediately, it must be
protected from external influences and securely stored.
lFor installation, the following minimum prescribed clearances must be kept
betweenthe CHM 15k and:
lPrevent irradiation from strong light sources.
lThe angle of insolation must be less or equal 15 degrees against the vertical
line. Please ask for a suiable adapter plates.
lThe assembly site must be at a great enough distance from tree plantations
or shrubbery to prevent leaves or needles restricting the cloud meter's light
outlet openings.
lAt least two persons are required for installation of the CHM 15k.
lOn completion of installation work, ensure that no safety-relevant changes
- mobile phones 2,5 m
- stationary emitters, ground stations (100 W of output power) 25 m
- a second cloud height meter (to prevent optical interferences) 10 m

Safety
Revision R09, November 2016 9
have impacted the CHM 15k during installation.
2.6 Safety Labelling
2.6.1 User Manual
Throughout this Manual the following pictograms and signal words are used:
DANGER
Warns of laser radiation
CAUTION
Warns of potential damage
NOTE
Important general note
NOTE
Important note on environmental protection

Safety
10 Revision R09, November 2016
2.6.2 CHM 15k
Product labelling is as follows (see Fig. 1):
l4 warning labels with safety notes
l1 plate with performance data
l1 "Beware of Laser Radiation" warning label
l1 type plate (rear side)
Fig. 1: Labelling
1

Technical Data
Revision R09, November 2016 11
3 Technical Data
Device versions
Order # Connection Special Color
8350.00 Ethernet, RS485 - 10m - blue/ white
8350.01 DSL, RS485 - 3m - blue/ white
8350.03 DSL prepared single cable for
DSL & RS485
red /white
8350.08 Ethernet, RS485 - 10m 8k mode red /white
8350.10 Ethernet, RS485 - 10m 120 V AC blue/ white
8350.B050 DSL, RS485 - 50m Battery backup
implemented
blue/ white
Table 1: Device versions
Measurement parameter
Measuring range 5 m - 15 km (15 – 50,000 ft)
Range Resolution 5 m (16 ft) constant measurement interval over full range
Net CDF data file:
reported range resolution
5m - 30 m in 5m steps (can be selected by user)
15 m (default value)
5 m in high resolution vector in the NetCDF file
logging time &
reporting cycle
2 s to 600 s (programmable),
standard values are: 15 s, 30 s, 60 s
Targets aerosols & clouds (droplets, ice crystals)
Measured and
target parameters
backscatter raw data
cloud base height up to 9 layers incl. penetration depth (cloud thick-
ness), max detectable range (MXD), vertical visual range (VOR), sky
condition (SCI), cloud amount (TCC, BCC),...
Measuring principle lidar (light detection and ranging)
Laser-optical parameters
Light source laser, laser protection class 1M under EN 60825-1
Wavelength 1,064 nm
Bandwidth 0.1 nm
Pulse duration 1 ... 5 ns
Pulse repetition rate (PRF) 5 – 7 kHz
Beam diameter (1/e²) expanded to: 90 mm
Laser divergence < 0.3 mrad
Table 2: Technical data

Technical Data
12 Revision R09, November 2016
Energy per pulse 7 -9 μJ
Long-time stability over 12
months (pulse repetition rate)
< 10 %
Pulse-to-pulse variance of
laser energy
< 3 %
FOV Receiver 0.45 mrad
Data interfaces
Communication interfaces RS485 & LAN
Optional: DSL, RS232 or modem V.21, V.22, V.22bis
Electrical parameters
Nominal voltage 230 VAC, ±10 %
optional: 100, 115VAC ±10 %
Line frequency 50 Hz
Min. power consumption <30 W (housing heater, blower off)
Max. power consumption 800 W in maximum (all heater are running)
Optional: Backup battery >1 hour support of integrated electronics
Table 2: Technical data

Technical Data
Revision R09, November 2016 13
Operating safety
Environmental compliance ISO 10109-11
Protection class 1
Internal protection standard IP 65
EMC EN 61326 class B
Light source Laser protection class 1M under DIN EN 60825-1
Certification CE
Operating conditions
Temperature range -40 °C to +55 °C
Rel. air humidity 0 % to 100 %
Wind 55 m/s
Physical dimensions
Dimensions of casing W x H x L = 0.5 m x 0.5 m x 1.55 m
Packed dimensions W x H x L = 0.65 m x 0.8 m x 1.67 m
Weight 70 kg (complete system)
9.5 kg (laser optical unit - heaviest spare part)
Installation requirements
Suitable low-voltage distribu-
tion systems
TN-S-system: grounded supply network, CHM 15k casing grounded,
neutral and protective conductor as separate wires
TN-C-system: CHM 15k casing grounded, neutral and protective
conductor in one single wire
Type of connection Non-detachable connection
Requirements to be met by Owner/Operator
Lightning protection External lightning protection to DIN V VDE 0185-3
Grounding Grounding system to DIN V VDE 0185-3
Requirements for outdoor
installation
- Circuit breaker to cut low-voltage power supply, installed near the
CHM 15k
- Within easy reach
- Clearly marked as a part of CHM 15k
- Back-up fuse matched to wire cross-section 6A,BorC
Table 2: Technical data

Technical Description
Revision R09, November 2016 15
4 Technical Description
The CHM 15k Cloud Height Meter is intended to measure clouds at a maximum
height of fifteen kilometers, to determine cloud layer penetration depth and ver-
tical visibility.
The measured data set is transmitted by digital standard interfaces. The CHM
15k uses the Lidar technique (Lidar: Light detection and ranging, refer to chap-
ter 9.1) to emit short light pulses into the atmosphere. These are scattered back
by aerosols and air molecules. The pulse flight time and intensity of a backscat-
tered light signal are then analyzed. Using this data as input, aerosol or cloud
layers can be assigned in terms of height and visibility levels can be determined.
The CHM 15k Nimbus working is based on a photon counting method. Com-
pared to analog measurement techniques, the benefits of this method are very
high detection accuracy and sensitiveness which makes it particularly suited for
applications using lidar technique. This equally refers to the useful signal and to
potential "noise signals", for example, background light.
Engineering design features of the CHM 15k
The CHM 15k Cloud Height Meter is:
lof compact design
loperational in climatic conditions as specified in Table 1
lof modular setup
4.1 Setup of CHM 15k
The CHM 15k is enclosed by a double-shell casing of corrosion-resistant alumin-
ium. The purpose of the outer shell is to reduce and prevent potential external
influences such as:
lsolar radiation
lwind
lrain
lsnow
from effecting the inner casing shell that carries the measuring unit. There is a
chimney effect between the outer shell and the inner shell to support this pro-
cess.
The top cover protects the inner casing shell from dirt and precipitation.
An opening for laser beam outlet and inlet is machined into this cover. A parti-
tion panel inside the top cover separates the emitter module from the receiver
module and an air deflector in the interior cover space directs the air stream
from the two fans onto the glass panels in the inner casing shell.
The inner casing shell contains all equipment parts for CHM 15k operation. The
cable ports for data line, current supply, grounding and power supply of the
external fans are designed as compression glands. For pressure equalization, the
inner casing shell includes a pressure-balancing component with a Goretex
membrane.
Integrated into the top wall of the inner casing shell is a split-area vision panel of

Technical Description
16 Revision R09, November 2016
neutral-color float glass. Both vision panels are somewhat inclined in keeping
with the Brewster angle. This ensures that laser light will suffer only minimal loss
as it passes through and the vision panels remain in an optimal condition due to
a self-cleaning effect. This effect is supported by the fans which are located on
the back panel of the equipment. The fans cut in at hourly intervals or when
there is rain or snow. The two fans are also intended to remove the heat from
the inner casing space.
For maintenance of the fans, the back wall panel of the CHM 15k has to be
removed.
The outer door provides access to the inner casing shell and the glass panels for
necessary cleaning. The outer and the inner door work on different locking
mechanisms in order to avoid personal injury and to protect the internal compo-
nents against improper acts. Persons who have not undergone any safety brief-
ing shall not open the inner door.
4.2 Functional units in inner casing space
The functional units are:
lEmitter and receiver module (laser optic module - LOM)
lCentral processing board and related components
lLaser controller module
lPower supply 12 - 15 VDC for electronics
lPower transformator 48 VDC for highly shielded outdoor fan
lBlower & heater
lLightning & overvoltage protection system for power cable, LAN, RS485,
Each functional unit is of modular setup, separately fixed to the inner casing shell
and can be individually retrieved for replacement or necessary service work.

Technical Description
Revision R09, November 2016 17
4.2.1 Functional Chart
Fig. 2: Functional chart, the numbers in brackets corresponds to the
numbering in the spare parts list (refer to service manual).
Figure 2 shows clearly that the "Main controller" is the central unit that monitors
and controls all the sensors in operation.
Laser
[59]
Laser controller module
[60]
Main controller
[1]
Power supply
12 - 15 VDC
[54]
Trigger board
[6]
APD unit
[29]
LAN,
DSL
Surge arrester
ethernet [42] or DSL (opt) Temperature sensor
[57]
Temperature sensor
[58]
Fan
[45]
Surge arrester serial
[48] + [49]
12V supply
Signal line
Communication line
Laser/ LED beam
Legend
RS 485
Heater on LOM
[4]
Ref LED
[7]
Battery (opt)

Technical Description
18 Revision R09, November 2016
4.2.2 Measuring and monitoring
The process monitoring is organized inside a FPGA unit. It runs independent
from the embedded Linux running in a ARM processor.
Fig. 3: Flowchart of measuring and monitoring processes inside the FPGA.
Figure 3 shows a standard measurement cycle. On completion of each measure-
ment cycle (1s), data are checked and status parameters are evaluated. If a value
is found to be out of tolerance or if a hardware error occurs, the standard meas-
urement cycle will be re-initialized.
Cyclic standard measurement is monitored by an extra routine within the FPGA.
The state of the receiver depends on the results of monitoring noise level, supply
voltage and DC-current with and without a test pulse. Due to its internal setup,
the light source is essentially characterized by the pulse repetition rate, which
may decrease because of light source aging. The pulse rate is subject to monitor-
ing. For pulse rates below 4.5 kHz, an error message is generated. The light
pulse reflection from the window panel is also analyzed to monitor the window
contamination.
All obtained values are output in an extended data telegram or inside the
NetCDF files. The standard data telegram contains approximate information
about the service code (refer to chapter 8.5).
Measurement starts (t0)
New initialization of APD
reset if necessary, trans-
Measurement and
system performance
No Yes
Measurement stops (1s),
temperatures, signal quality,
APD voltage is checked
okay?
fer of error codes and
warnings.

Transportation & Scope of Delivery
Revision R09, November 2016 19
5 Transportation & Scope of Delivery
CAUTION
Danger of damage!
The CHM 15k may only be transported and moved with the help of suit-
able lifting gear and an appropriate means of transportation.
The CHM 15k may only be loaded and transported in packaged condition
and in the transporting position (see Fig. 5).
Inside its shipping container, the CHM 15k must be adequately protected
against slipping, shock, stroke or other mechanical impacts.
The scope of delivery includes:
lCHM 15k Cloud Height Meter
lDrilling template
lFastener components
4 S12 wallplug/ anchor (e.g. from Fischer)
4 DIN 571-10 x 140-ZN screws
4 ISO 7093-10.5-KST/PA washers
4 ISO 7093-10.5-A2 washers
lUser manual and device software
If requested by the customer, an adapter frame can be delivered together with
the equipment to allow the CHM 15k to be screwed onto prepared fastening
bolts. Angle adapters, e.g. for 15° are also available upon request.
Imperial units information: Spanner/ wrench size for 4x M10 screws: 18
mm or 7/16 BSF or 3/8 Wworth. Instead of M10 screw an imperial 3/8 or
25/64 might be used together with appropriate anchors.
Please contact G. Lufft GmbH for further technical details.
Operating state at the time of CHM 15k product delivery:
For further details on operating states, consult chapter 8.
Transfer mode 1 Automatic output of standard data telegram
Device code (device) 16
Baud rate 9,600
Duration of measurement 30 seconds