LASER PRECIPITATION MONITOR - stand alone version

Laser Precipitation Monitor Range

The new generation of high quality and reliable precipitation identification sensors

The state-of-the-art Laser Precipitation Monitor (LPM) measures the amount, intensity and type of precipitation with great accuracy. The LPM is capable of measuring particles down to 0.16 mm diameter and can provide a drop size distribution with 400 classes. The data output is available in SYNOP, METAR, NWS, and in 4678 and 4680 WMO code. The system calculates intensity, volume (as water equivalent) and the spectrum of precipitation (diameter and velocity), the reduction to visibility in precipitation (MOR) and the radar reflectivity (Z).

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FEATURES

• measures precipitation amount, intensity, type
• measures particles down to 0.16 mm diameter
• maintenance-free
• mains or battery power
• best cost / performance ratio
• for all year round use
• ability to add additional weather sensors

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OUTPUTS:

• total precipitation quantity
• particles speed / diameter
• intensity mm/h
• precipitation class (SYNOP/METAR)
• radar reflectivity (Z/R ration)
• MOR (Meteorological Optical Range) in rain

The LPM weather station version model 5.4110.10.x00 can also be used with the following sensors to provide a complete weather station:

• compact wind speed sensor
• compact wind direction sensor
• compact temperature and humidity sensor with weathershield

Please note the above sensors are available as accessories and not included in the LPM weather station version price.

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What it does

The LPM uses reliable laser-optics to detect and discriminate different kinds of precipitation including:

• drizzle (DZ)
• freezing drizzle (FZDZ
• rain (RA)
• freezing rain (FZRA)
• hail (GR)
• snow (SN)
• snow grains (SG)
• ice needles (IC)
• soft hail (GS)
• ice grains (PL)

With an integrated temperature regulated heater the LPM is suitable for all year round use. The sensor automatically compensates fluctuations of temperature or soiling of the optics. For use in harsh environmental conditions, for example in the mountains, a special model with extended heating is available.


The LPM is very cost effective and because of this it really does represent excellent value. Several national weather services are now deploying them in large numbers and several other agencies and individual customers have also bought the sensor for radar calibration or present weather detection network stations.

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Configurable Digital Outputs

With the following configurable digital outputs the LPM can be used as a precipitation monitor or as a tipping bucket type precipitation sensor:

• an electrically isolated serial interface (RS-485).
• 2 digital outputs (opto-coupler) which provide an easy connection to standard data logger systems with pulse/frequency inputs.

Examples

The function of the digital opto-coupler outputs is programmable for example:

• Output 1 - could be configured for 0.1 mm or 0.01 resp or 0.005 mm precipitation per pulse corresponding to the cumulatively measured precipitation quantity

• Output 2 - could be configured as a precipitation event monitor or as an additional event output, solid precipitation (snow, snow-grains, soft hail, hail) in conjunction with output 1.

In addition the following optional sensors can be connected to the optional measuring channels (weather station version only):

• temperature (Pt100, not available for models with extended heating)
• relative humidity (0-1 V / 0-100% relative humidity)
• wind speed (frequency 0-630 Hz)
• wind direction (serial synchronous)

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Choosing a model

The sensor can be provided in mains (100-260 VAC) or battery voltages (12-24 VDC) and includes models which can be used to accept additional sensors for wind speed and direction, temperature and humidity as well as models that allow the sensor to act as a tipping bucket rain gauge with pulse output for intensity and a relay for start and stop of rainfall.

The most important decision you need to make when ordering an LPM is to decide whether you need an LPM that has the weather station capability OR you need the additional relay / monitoring / Tipping Bucket Rain Gauge capability.

The units cannot be updated to allow a change to the other style later on.

Model Description
5.4110.00 000	A disdrometer featuring two digital outputs in addition to the normal output of the drop size distribution information. Both outputs are independent of each other. The two digital outputs that can be used to either act as relay contacts (rain / no rain) type of switching or to indicate accumulation (similar to a tipping bucket rain gauge pulse output) for connection to an appropriate device to log this....or to indicate a condition (full scale output voltage when condition exists such as a type of precipitation (snow for example) or if a fault exists (no laser output for example...) Voltages available: 24 VAC /DC or 22..30 VDC 115 VAC 230 VAC 12-24 VDC
5.4110.01.x00	As above but with extended heating (not for VDC model)
5.4110.10.x00	A disdrometer with the ability to add additional weather sensors such as wind speed, wind direction, temperature, humidity sensor to the LPM. The data from the additional sensors is modulated and output as a single weather data string for ease of data collection to a data logger or PC (optional PC software can be used to display and archive the data). This model can be useful if you wish to mainly record precipitation information but also wish to have the wind speed and direction and temp/RH info as well but do not wish to have a separate logger for this...or wish to understand the precipitation better from the additional weather parameters. The drop size distribution is still supplied in its entirety but the additional weather info is also included. Voltages available: 24 VAC /DC or 22..30 VDC 115 VAC 230 VAC 12-24 VDC
5.4110.11.x00	As above but with extended heating (not for DC model)

 

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Software

The data can be viewed on a PC via an RS-485 to RS232 connector (not included) using any HyperTerminal emulation, alternatively you can use the optional LNM-view software for easy data acquisition, storage and analysis. With this progressive Client Server architecture it is possible for several users to access the data simultaneously (multi-user ability). The software supports several instruments in parallel, the maximum number being limited only by the PC hardware.

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Laser Precipitation Monitor Specifications
Parameters for:
Distrometer - classification	440 classes (22 diameter bins and 20 speed bins)
Measuring area	46 cm2 (23.0 x 2.0 cm)
Measuring value	Precipitation
Measuring interval	Real time or 1 minute averaged outputs
Measuring value	Precipitation intensity
Precipitation
Precipitation types	drizzle (also freezing)
	rain (also freezing)
	hail
	snow
	snow grains / ice needles
	soft hail / ice grains
Precipitation output	via RS485: Synop (codes wawa 4680, ww 4677), Metar (code 4678) via data output: frequency
Particle size	0.16 to > 8 mm diameter
Particle speed	0.2 to 20 m/s
Intensity	<0.005 mm/h (drizzle) to >250 mm/h
Visibility precipitation	MOR (Meteorological Optical Range) 0 to 99.999 m
Radar reflectivity	Z= -9.9 to 99.9 dBz
Data Output
RS485	1200 to 115200 Bd potential isolation
Digital output	duplex 2 x opto couplers 24 VDC, 1 mA for precipitation amount pulses, rsp frequency for kind or presipitation, potential isolation
Output Intensity	via RS485: resolution 0.001 mm/h
Output quanitity	via RS485: resolution 0.01 mm via data output: pulses (res 0.1 mm; 0.01 mm; 0.005 mm)
Accuracies
Accuracy with quantity measured	<10% (rain, 0.5-20 mm/h) <30% (snow)
Accuracy for precipitation output (comparing with synoptic observation) wind speed < 3m/s)	drizzle >97% (Intensity > 0.01 mm/h) -rain(RA) >99% (>= 2 particles/min, no solid precipitation) -hail(GR) >95% (>= 2 particles/min) -snow (SN) >99% (no mixed precipitation) -snow grains (SG) >60% -soft hail(GS) t.b.d.
Operating temperature (optical components are equipped with integrated heating as standard)	- 40 ° C to + 70 ° C with extra heating option (available for mains voltage models) - 60 ° C to + 70 ° C 0 to 100% humidity
Available operating voltages	24 VAC / DC or 22..30 VDC (< 750 mA) 115 VAC, 15 VA 230 VAC, 15 VA 12 to 24 VDC, 600 mA
Optional additional heater	230 VAC / 150 VA
Optional inputs	PT100, 0 - 1 V, 0 - 1000 Hz Serial synchronous
Principle of operation	Laser 785 nm maximum 0.5 mW Optical power, laser class 1M
Housing and dimensions	All die-cast stainless steel 270 x 170 x 540 mm
Weight	4.8 kg 6.5 kg with optional extra heating
Protection	IP 65
EMC immunity	EN61326
EMC radiation	EN61000-4-3 EN61326 class B
Mounting Mast	48 mm to 102 mm: 1.9 to 4 inch
Accessories
PC Program  LNMView model 9.1700.99.000	Software for graphical presentation and analysis for Windows based systems
Instrument support model 4.3187.60.000	For the vibration-reduced operation of the LPM at 2 m height on an available concrete foundation (provided by the customer). The support consists of a vertical tube with firmly welded struts. Tube length: 2 m Tube diameter: 60 mm Weight: 30 kg Material: Steel, hot-dip galvanised

This range is in continuous development therefore specifications may change without prior notice.E&OE.

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Contact Biral for more information

To find out more about this instrument or to discuss your application requirements please do not hesitate to contact Biral.

• wwwmet@biral.com
• telephone to 01275 847787 (from the UK) or +44 1275 847787 (International)

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After Sales Support

Biral offers free advice and technical support for the lifetime of the instruments we sell. Once you have purchased the unit you can contact us for help:

• wwwmetsupport@biral.com
• telephone to 01275 847787 (from the UK) or +44 1275 847787 (International)

 

Product Information

• Laser Precipitation Monitor 5 4110 00 xxx.pdf
• combined_visibility_and_present_weather_sensors.pdf

Product Manuals

• 5.4110.xx.x00_LNM_V2.4x_STD_eng.pdf

Application Related Information

• Building Control brochure.pdf
• Combined visibility and present weather sensors.pdf

Scientific Papers and Articles

• LPM radar discrometer comparison.pdf
• LPM precipitation type.pdf