Campbell CS135 User manual

CS135
Ceilometer
User Guide
Issued 18.3.13
Copyright ©2012-2013 Campbell Scientific Ltd.
CSL 950

Guarantee
This equipment is guaranteed against defects in materials and workmanship.
This guarantee applies for twelve months from date of delivery. We will
repair or replace products which prove to be defective during the guarantee
period provided they are returned to us prepaid. The guarantee will not apply
to:
•Equipment which has been modified or altered in any way without the
written permission of Campbell Scientific
•Batteries
•Any product which has been subjected to misuse, neglect, acts of God or
damage in transit.
Campbell Scientific will return guaranteed equipment by surface carrier
prepaid. Campbell Scientific will not reimburse the claimant for costs incurred
in removing and/or reinstalling equipment. This guarantee and the Company’s
obligation thereunder is in lieu of all other guarantees, expressed or implied,
including those of suitability and fitness for a particular purpose. Campbell
Scientific is not liable for consequential damage.
Please inform us before returning equipment and obtain a Repair Reference
Number whether the repair is under guarantee or not. Please state the faults as
clearly as possible, and if the product is out of the guarantee period it should
be accompanied by a purchase order. Quotations for repairs can be given on
request. It is the policy of Campbell Scientific to protect the health of its
employees and provide a safe working environment, in support of this policy a
“Declaration of Hazardous Material and Decontamination” form will be
issued for completion.
When returning equipment, the Repair Reference Number must be clearly
marked on the outside of the package. Complete the “Declaration of
Hazardous Material and Decontamination” form and ensure a completed copy
is returned with your goods. Please note your Repair may not be processed if
you do not include a copy of this form and Campbell Scientific Ltd reserves
the right to return goods at the customers’ expense.
Note that goods sent air freight are subject to Customs clearance fees which
Campbell Scientific will charge to customers. In many cases, these charges are
greater than the cost of the repair.
Campbell Scientific Ltd,
Campbell Park, 80 Hathern Road,
Shepshed, Loughborough, LE12 9GX, UK
Tel: [phone]
Fax: [phone]
Email: [email protected]
www.campbellsci.co.uk

PLEASE READ FIRST
About this manual
Some useful conversion factors:
Area: 1 in2(square inch) = 645 mm2
Length: 1 in. (inch) = 25.4 mm
1 ft (foot) = 304.8 mm
1 yard = 0.914 m
1 mile = 1.609 km
Mass: 1 oz. (ounce) = 28.35 g
1 lb (pound weight) = 0.454 kg
Pressure: 1 psi (lb/in2) = 68.95 mb
Volume: 1 UK pint = 568.3 ml
1 UK gallon = 4.546 litres
1 US gallon = 3.785 litres
Recycling information
At the end of this product’s life it should not be put in commercial or domestic refuse
but sent for recycling. Any batteries contained within the product or used during the
products life should be removed from the product and also be sent to an appropriate
recycling facility.
Campbell Scientific Ltd can advise on the recycling of the equipment and in some cases
arrange collection and the correct disposal of it, although charges may apply for some
items or territories.
For further advice or support, please contact Campbell Scientific Ltd, or your local agent.
Campbell Scientific Ltd, Campbell Park, 80 Hathern Road, Shepshed, Loughborough, LE12 9GX, UK
Tel: [phone] Fax: [phone]
Email: [email protected]
www.campbellsci.co.uk

i
Contents
PDF viewers note: These page numbers refer to the printed version of this document. Use
the Adobe Acrobat® bookmarks tab for links to specific sections.
Section 1. General Information ......................................1
1.1 Manual Version..........................................................................................1
1.2 General Safety............................................................................................1
1.3 Sensor Unit Safety......................................................................................1
1.4 Laser Safety................................................................................................2
1.5 Electrical Safety .........................................................................................2
Section 2. Product Overview..........................................3
2.1 Introduction ..............................................................................................4
2.2 Optical Measurement................................................................................5
2.2.1 Optical Arrangement ......................................................................5
2.3 Internal Monitoring...................................................................................5
2.4 Specifications............................................................................................6
2.4.1 Measurement Specifications..........................................................6
2.4.2 Mechanical Specifications.............................................................6
2.4.3 Electrical Specifications ................................................................6
2.4.4 Optical Specifications....................................................................7
2.4.5 Environmental Specifications........................................................7
2.4.6 Communications Specifications ....................................................7
Section 3. Initial checks..................................................8
Section 4. Installation......................................................9
4.1 Location and Orientation..........................................................................9
4.2 Grounding.................................................................................................9
4.3 Mounting the CS135.................................................................................9
4.4 Tilt Angle................................................................................................10
4.5 Connectors and wiring............................................................................12
4.5.1 Base connectors............................................................................12
4.5.2 Wiring using supplied Campbell Scientific Cables......................13
4.5.3 USB connection............................................................................15
4.5.4 SDI-12 connection........................................................................15
4.6 Connecting the Back-up Battery.............................................................16
4.6.1 Removing the Cover....................................................................17
4.6.2 Removing the Enclosure Lid.......................................................17
4.7 Storage Information................................................................................18
Section 5. Operation......................................................19
5.1 Terminal Mode .......................................................................................19
5.1.1 Entering / Exiting the CS135 Terminal Mode.............................19
5.1.2 Terminal Mode Commands General............................................19
5.1.3 Terminal Mode Command Examples ........................................20
5.1.4 MCFG Command Message Types...............................................23
5.1.5 STATUS Command.....................................................................24
5.1.6 Message Polling...........................................................................27
5.1.7 Loading a New Operating System...............................................28
5.2 Restoring Factory Defaults.....................................................................28

ii
5.3 LED Indicator.........................................................................................29
Section 6. Messages .....................................................30
6.1 Data Messages General ..........................................................................30
6.2 CS Messages...........................................................................................30
6.3 CL31 Messages ......................................................................................42
6.4 CT25K Messages....................................................................................
52
Section 7. Maintenance.................................................57
7.1 General ...................................................................................................57
7.2 Cleaning..................................................................................................57
7.3 Removing the Cover...............................................................................
58
7.4 Removing the Enclosure Lid..................................................................
59
7.5 Diagnostic LED Indicators Within the Enclosure..................................60
7.6 Electrical Safety Testing.........................................................................
61
Figures
2-1. CS135 Ceilometer...................................................................................3
2-2. Principle of operation..............................................................................5
4-1. Mounting footprint................................................................................10
4-2. Setting the tilt angle...............................................................................11
4-3. Connector layout...................................................................................12
4-4. Cable Connections ................................................................................15
4-5. USB port ...............................................................................................16
4-6. Connecting Battery................................................................................16
4-7. Removing the cover ..............................................................................17
4-8. Removing the enclosure lid...................................................................17
5-1. Restoring factory defaults .....................................................................29
5-2. LED indicator........................................................................................29
7-1. Removing the cover ..............................................................................58
7-2. Removing the enclosure lid...................................................................59
7-3. Diagnostic LED indicators....................................................................60
Tables
1-1. Manual revisions.....................................................................................1
4-1. Function of the connector pins..............................................................13
5-1. Summary of the terminal mode commands available............................21

1
CS135 Ceilometer
1. General Information
1.1 Manual Version
Table 1.1 Manual revisions
Manual Version Revisions
1.0
Applicable to Operating System OS1 N/A
2.0
Applicable to Operating System OS2,
Top Board OS2, PSU OS1
3.0
Applicable to Operating System OS3,
Top Board OS2, PSU OS1
4.0
Applicable to Operating System OS6,
Top Board OS5, PSU OS1
1.2 General Safety
This manual provides important safety considerations for the installation,
operation and maintenance of the CS135. These safety considerations are
classified into three levels:
Warnings alert the installer or user to serious hazards.
Ignoring these warnings could result in injury or death
and/or irrevocable damage to the sensor unit.
Cautions warn of potential hazards. Ignoring these cautions
could result in the sensor being damaged and data being lost.
Notes highlight useful information in the installation, use and
maintenance of this product. These should be followed carefully in
order to gain the maximum benefit from the use of this product.
1.3 Sensor Unit Safety
The CS135 sensor has been checked for safety before leaving the factory and
contains no internally replaceable or modifiable parts.
Do not modify the CS135 unit. Such modifications will
lead to damage of the unit and could expose users to
dangerous light levels and voltages.
WARNING
CAUTION
NOTE
WARNING

CS135 Ceilometer
2
Ensure that the correct voltage supply is provided to the sensor.
1.4 Laser Safety
The CS135 sensor incorporates a laser diode which is rated as a class 3B device.
This is an embedded laser where the output from the sensor unit, through the
optics, is minimised to class 1M. This classification indicates that viewing of the
beam with the naked eye is safe but looking directly into the beam with optical
instruments, e.g. binoculars can be dangerous.
From the laser head the output has the following characteristics:
Maximum pulse energy: 73 nJ
Pulse duration: 100 ns
Pulse frequency 10 kHz
Wavelength: 905 nm
EN 60825-1:2001
The sensor is marked with the following warning:
INVISIBLE LASER RADIATION
DO NOT VIEW DIRECTLY WITH OPTICAL INSTRUMENTS
CLASS 1M LASER PRODUCT
Removing the laser module with the power applied to the
CS135 or battery connected may expose the user to
hazardous class 3B laser radiation.
No attempt should be made to operate the laser module
outside of the housing.
Check that the laser warning label on the sensor is still
visible and can be clearly read on an annual basis.
When installing the sensor avoid pointing the laser
housing towards areas where binoculars are in common
use.
1.5 Electrical Safety
As the sensor is powered from potentially hazardous mains voltages the wiring of
its power supply should only be carried out by personnel qualified to install
electrical equipment. For permanent installations outside, this usually requires a
certified electrician who is also familiar with local electrical and safety legislation.
Some general guidance is given in section 5.5, but the responsibility for the
installation lies with that installer.
CAUTION
WARNING
WARNING

User Guide
3
The unit should only be serviced by trained personnel.
Removal of electronic module covers or connectors
while the unit is powered will expose the operator to
potentially hazardous voltages and risk damage to the
sensor.
2. Product Overview
Fig 2.1 CS135 Ceilometer
NOTE
WARNING

CS135 Ceilometer
4
2.1 Introduction
The CS135 is a LIDAR (LIght Detection And Ranging). It emits short pulses of
near infra-red light into the atmosphere from a semiconductor laser. These are
scattered back by aerosols including cloud droplets. The time between
transmission of the pulse and the return signal gives the range, and therefore
height, of the scattering aerosols. The variation in the strength of the backscattered
light signal with height gives a profile of scatter coefficients and allow cloud
bases to be identified. If significant scattering is detected but there is no defined
cloud base then a vertical visibility can be calculated.
Cloud heights are calculated from the scatter profile as follows: -
Close range signal distortion is removed (the signal response is effectively
flattened).
The signal amplitude is range corrected.
This is then inverted (using the Klett inversion technique) and a cloud extinction
profile is calculated.
Likely cloud bases are estimated based upon changes in slope of the extinction
profile and an extinction threshold. This threshold is based on the extinction
coefficient and is equivalent to a visibility (MOR) of 1000m. This results in a
number of possible cloud bases at different heights.
The original flattened signal is also passed through three frequency filters to
produce three different filtered back scatter profiles. Peaks in each of these
filtered profiles are detected using thresholds based upon the filter bandwidth used
and the high frequency signal noise level. This results in another set of likely
cloud bases.
Cloud bases are reported by the sensor only when the likely cloud bases
candidates by these two methods above correlate, i.e. the peaks are seen by both
processing methods.
To report a cloud layer above a lower one the scatter coefficient first has to fall
below the extinction threshold used for cloud definitions (less a small hysteresis
offset). The scatter profile must then again meet the criteria above.
To avoid many very narrow close layers being reported when they have little
significance a minimum separation based on WMO reporting intervals is applied.
After the scatter coefficient has fallen below the threshold a new cloud base will
not be reported until it has stayed below this threshold for at least a set interval.
This interval varies, increasing with height.
If no clouds are detected the CS135 will give one of the following reports:-
•No significant backscatter.
•Full obscuration determined but no cloud base detected. This is reported if the
criteria for detecting cloud base is not met but the integrated scattering
coefficient reaches the limit of vertical visibility below 2,000 m. The height at
which this occurs is given as vertical visibility.
•Some obscuration detected but determined to be transparent is reported if
scattering is detected but no cloud is detected and the calculated vertical
visibility exceeds 2,000 m.

User Guide
5
The control system of the CS135 is divided into three modules, DSP, TOP and
PSU as follows:-
DSP is the main data processing and communications unit of the CS135.
TOP provides a number of safety shutdown features such as over and under laser
output level. It also contains the calibration circuitry and dirty windows system.
PSU controls the power supply, including battery charging and deep discharge
protection.
The CS135 has a rugged environmental enclosure that protects the instrument
from the harshest conditions and will measure the atmosphere with high stability
and repeatability.
Fig 2.2 Principle of operation
2.2 Optical Measurement
2.2.1 Optical Arrangement
The CS135 employs a novel split-lens design to increase optical signal to noise
ratio over other instruments while maintaining Class 1M eye safety by integrating
larger optics into a compact package (see Fig 2.2). This optical design provides an
alternative to traditional biaxial or common-optics designs. The optical isolation
of traditional biaxial systems is maintained to increase detector sensitivity, while
the low overlap onset height of common-optics systems is incorporated to allow
measurements at close ranges.
2.3 Internal Monitoring
The CS135 monitors a large number of parameters relevant to its performance.
These include window contamination, key voltages and currents and internal
temperature and relative humidity. Data messages, see Section 5, include this
information allowing remote diagnosis of the CS135 condition. In addition a
special status message can be polled.

CS135 Ceilometer
6
2.4 Specifications
2.4.1 Measurement Specifications
Maximum Reporting Range: 10 km / 32,800 ft
Minimum Reporting Resolution: 5 m / 15 ft
Hard Target Range Accuracy: +/- 0.25% +/- 4.6 m
Reporting Cycle: 2 to 120s
Cloud Layers Reported: Up to four layers reported, user selectable
2.4.2 Mechanical Specifications
Height: 1000 mm
Width: 330 mm
Depth: 316 mm
Total weight: 33 kg (excluding cables)
Packed weight: 58 kg
2.4.3 Electrical Specifications
Power required: Nominal 115 (106-137) or nominal 230 (216-253) VAC,
47-63 Hz, 470 W maximum in total.
The hood heater requires a maximum of 270 W.
The internal heater requires a maximum of 120 W.
The supply voltage required is specified at the time of order. If it has to be
changed later please contact Campbell Scientific for advice.
Fuses: The power supply contains two fuses as follows:
AUX fuse HBC 5 A (T)
PSU fuse HBC 500mA (T)
All fuses are 5 x 20 mm slow blow (T) and are the same for both 115 VAC and
230 VAC.
Battery: Internal 12V 2Ah battery provides 1hr measurement without the
blower/heater. The power supply is equipped with a system to prevent deep
discharge of the battery.
The CS135 uses Positive Temperature Coefficient (PTC) heaters within its design.
These heaters are self-regulating, simplifying the internal design of the sensor and
improving safety. Due to the nature of these devices the CS135 takes a higher
current during start up.
The CS135 will take up to 1 KW for the first few seconds of operation dropping
off quickly to its normal operating power over a period of a minute.
In cold environments the power consumption of the CS135 may be as high as
470 W. Also, in warmer environments it may be as low as 200 W.
The heaters within the CS135 are purely resistive which will prove advantageous
when connected to generators or when the power factor of your supply is
important.

User Guide
7
2.4.4 Optical Specifications
Pulse duration: 100 ns
Pulse frequency 10 kHz
Wavelength: 905 nm
Half-angle laser divergence: 0.35 mrad
Laser lifetime: 10 years typical
Eye safety class: 1M
2.4.5 Environmental Specifications
Standard Operating Temperature Range: -40°C to +60°C
Relative Humidity Range: 0 to 100%
IP Rating: IP 66
2.4.6 Communications Specifications
Supported serial settings
8 bits, no parity, 1 stop bit (default)
7 bits, even parity, 1 stop bit
7 bits, odd parity, 1 stop bit
Supported data rates
300 bps
600 baud
1200 baud
2400 baud
4800 baud
9600 baud
19200 baud
38400 baud
57600 baud
76800 baud
115200 baud (default)
Supported standards
RS232 full duplex (default)
RS232 half duplex
RS485 full duplex
RS485 half duplex

CS135 Ceilometer
8
Signal voltage levels
Minimum
Value Nominal Value Maximum Value
RS232 Communications
RS232 input threshold Low 0.8V 1.5V -
RS232 input threshold High - 2.0V 2.4V
RS232 input absolute maximum -15V - +15V
RS232 input resistance 12KΩ- -
RS232 output voltage low - - 0.4V
RS232 output voltage high (into
3KΩ) 4.4V - -
RS485/422 Communications
RS485/422 input threshold
voltage -0.2V - +0.2V
RS485/422 output (Unloaded) - - 5V
RS485/422 output (Load 50Ω) 2V - -
Maximum voltage at any terminal -7V - +7V
USB Service Port USB1.1 and 2.0 compatible, fixed 115200 baud.
3. Initial checks
The following steps will provide basic familiarisation with the CS135 and
perform basic functionality checks. To do these you must first remove the cover
and enclosure lid (see Sections 4.6.1 and 4.6.2) and then connect the battery (see
Section 4.6). Connect the hood heater plug once you have done these stages. See
Fig 4.3 in Section 4.5.1.
The laser will be operating as soon as the battery is
connected. It should not point in any direction where it
could be viewed with magnifying optics.
The green LED visible from above should now be flashing once every 10 seconds
(see Fig 5.2).
Connect a PC using a terminal emulation program to the USB port (Fig 4.5). The
terminal emulator should be set to 115200 baud, 8N1 bits/parity.
PC operating systems should identify the USB connection and allocate a port
number. The terminal emulator program you are using should then be set to this
port number. Older PC operating systems may need upgrading or additional
software.
The CS135 will be outputting message type 001 every 10 seconds (see Section
6.2).
Open terminal mode with the command “open 0”. You should now see the prompt
“CS135>”, Type “Status”. You will now see the sensor status information
described in Section 5.1.5. If you plan to use date/time information this should be
checked as it can drift up to ±14 seconds per day.
WARNING

User Guide
9
If the unit has been in storage or transit for more than a few months, the clock
battery may be discharged. However, it will charge from the back-up battery or
mains power.
Close terminal mode with the command “close” (it will close automatically after
10 minutes of inactivity).
If you are not installing the unit straight away you should disconnect the battery to
avoid it being discharged.
4. Installation
4.1 Location and Orientation
The CS135 measures environmental variables and is designed to be located in
harsh weather conditions. However there are a few considerations to take into
account if accurate and representative data from a site are to be obtained.
In order to reduce the service frequency with the unit, the CS135 should be placed
away from sources of contamination. More regular maintenance will be required
when the instrument is placed in areas where contamination is unavoidable or
where measurements may be safety related.
Take care that the orientation allows tilting in whatever direction is desired.
4.2 Grounding
The CS135 must be properly grounded by taking a ground wire with a minimum
cross sectional area of 16 mm2and maximum length of 10 m from the brass
grounding boss to an adequate grounding point. Figure 4.3 shows the location of
the grounding boss.
4.3 Mounting the CS135
The CS135 is designed to be bolted to a firm, level foundation. When bolting
down take care that the orientation allows tilting in whatever direction is desired.
Fig 4.1 shows the mounting footprint.
If a suitable surface does not already exist then a concrete foundation should be
constructed at least 600 mm square and 600 mm deep.
Drill four 12 mm diameter holes using the mount base as a template to a depth of
77 mm.
Clean the holes of all debris.
Place washers and nuts on the ends of the wedge anchors supplied (to protect the
threads during installation).
Hammer the wedge anchors into the holes until the start of the threads are below
the surface.
Tighten the nuts until about 25 mm of thread protrudes above the surface.

CS135 Ceilometer
10
Remove the washers and nuts from the protruding length screw. Then lower the
CS135 into place. If you plan to tilt the unit make sure it is orientated so that when
tilted in the preferred direction the window angle steepens.
Finally, secure the CS135 with the washers and nuts.
If the surface is not level and flat it may be necessary to add washers under the
base on one or more of the foundation screws.
Fig 4.1 Mounting footprint
4.4 Tilt Angle
The CS135 is designed to be tilted 6°, 12°, 18° or 24° from vertical. There are
several reasons why this might be done. In tropical regions it might be
advantageous to tilt the sensor north in the northern hemisphere and south in the
southern hemisphere to prevent the sun shining directly into it, it can reduce
problems caused by direct specular reflections from ice crystals and reduce
problems from rain or snow falling onto the window. To adjust the tilt angle
remove the bolts shown in Fig 4.2, move the CS135 to the required tilt angle and
replace them.
The CS135 has tilt sensors in both axes so that if it is not possible to provide a
level base cloud height can be compensated. This feature can be useful for mobile
or marine applications. Note that profile data is NOT compensated but tilt angles
are included in data messages.
Note that increasing the tilt angle beyond 24° can cause significant errors in
vertical visibility measurements if scatter coefficients vary significantly with
height.

User Guide
11
Fig 4.2 Setting the Tilt Angle

CS135 Ceilometer
12
4.5 Connectors and wiring
4.5.1 Base connectors
The CS135 has three connectors on its base. One is for communications, one
provides power input to the unit itself and the other one takes power from the unit
to the hood heater and blower.
Tilting the unit will provide better access to these connectors.
Fig 4.3 Connector Layout
The function of the connector pins is shown in Table 4.1.
NOTE
Groundin
g
boss