Optical Particle Counters
A guide to the Alphasense OPC-N3 andOPC-R2 Optical Particle Counters

Contents02.

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Introduction to Alphasense
Optical Particle Counters
Taking the guessworkout of particle counting
OPC-N3 key
features and dimensions
OPC-R2 key
features and dimensions
Comparison ofOPC-N3 and OPC-R2
About AlphasenseIntroduction toAlphasense OpticalParticle Counters

OPC-R2Growing awareness of the dangers airborne particles present to health has led to anincreased need to accurately quantify particulate matter in industry, the workplace andpublic spaces. In parallel, as we gain greater insight into the impact of particle matter on
the performance and longevity of physical infrastructure, low-cost particle monitoring hascome to the fore.
Alphasense’s range of OPCs was developed hand in hand with aerosol scientists andengineered to deliver the accuracy you expect from industrial grade monitors in moreworkable size formats and at a fraction of the price.
Both the wide ranging OPC-N3 and the smaller footprint OPC-R2 provide digital outputsof PM1, PM2.5 and PM10 (and optionally PM4.25) along with a histogram of particle
count for each of up to 24 user-configured size categories. Alphasense’s proprietary flowcorrection technology ensures stable readings even in high-dust environments and is a
key factor in a number of universities and research organisations independently verifying
Alphasense OPCs as providing best-in-class performance.

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OPC-N3

Taking the guessworkout of particle counting
Unlike most low-cost particle sensors which measure particle count ina single size category and use that to estimate the volumes of others,
Alphasense OPCs measure the full range from PM1 to PM10, giving end
users reliable and repeatable data, rather than extrapolated values. This isdemonstrated in the adjacent graph.
Other features that Alphasense OPCs offer over inferior particle
counters include:• Integrated flow correction technology• Combined data from both high- and low-gain modes• Optimised fan cycling to mitigate build up of debris andreduce noise04.

OPC-N3
Key features
The OPC-N3 is a high-accuracy device capable of producing reference
station grade data for PM1, PM2.5, PM4.25 and PM10. This data ismeasured across the full size spectrum rather than calculated as in thecase of Nephelometers. With 24 user-configurable sizing categories
and a sample rate which can be set between 1 and 30 seconds, users
can configure the device to suit their specific application. With ameasurement range of 0.35-40 µm, the N3 is used in a broad range ofapplications, from MCerts certified air quality monitoring instruments toindustrial safety and offshore installations.

• Particle range

0.35 to 40 µm• Sizing Categories

24• Max particle count rate

10,000 particles per second• Flow rate

5.5 Litres / min• SizeCompact• Sample interval

1 – 30 seconds• USB and SPI interface• Patented design• Integrated Temperature and Humidity monitoring

The OPC-N3 is available in a marinised variant for marine applications
and has been successfully used within instrumentation intended for use
in explosive atmospheres.

• Standby mode for reduced power consumption• Suitable for use in MCerts certified instrumentation• 24-month warranty
For full specifications please refer to the product datasheet.

PM1 to PM1005.

High accuracy

True PM measurement

DurableSide view
3/4 view

Height: 80mm

Floor

Width: 30mm

length: 60mm

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OPC-R2Key features
The OPC-R2 is an ultra-compact, high-accuracy device capable of• Particle range

0.3 to 12.4 µm

producing reference station grade data for PM1, PM2.5, PM4.25 and• Sizing categories

16PM10. This data is measured across the full size spectrum rather than

• Max particle count rate

10,000 particles per second

calculated as in the case of Nephelometers. The R2 features 16 user-• Flow rate

0.24 Litres / minconfigurable sizing categories and a sample rate which can be set• SizeUltra-compact

between 1 and 30 seconds, allowing users to configure the device to suit

• Sample interval

1 – 30 seconds

their specific requirements. Whilst the R2 has a smaller measurement• USB and SPI interface

range and reduced flow rate compared to the N3, its small footprint• Patented designand low power consumption lend the R2 to portable, discreet and• Integrated Temperature and Humidity monitoringbattery powered installations where high accuracy is required.

• Standby mode for reduced power consumption

Frequently used in indoor air quality, personnel monitoring and• 12-month warranty

environmental applications, the R2 has established an enviable
reputation within the low-cost sensor arena.

PM1 to PM1007.

High accuracy

True PM measurement

For full specifications please refer to the product datasheet.

DurableSide view

Front three quarter view

Height: 30mm

Base view

Width: 30mm

length: 60mm

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Comparison ofOPC-N3 and OPC-R2Model

Particle range

Sizingcategories

Max particle
count rate

Flow rate

SizeSample
interval

0.35 to 40 µm

2410,000 particles
per second5.5 Litres / min

75mm x63.5mm x 60mm

1 – 30 seconds

0.3 to 12.4 µm

1610,000 particles
per second

0.24 Litres / min

72mm x21.5mm x 20.5mm(25.5mm inc inlet)

1 – 30 seconds

OPC-N3

OPC-R209.

DatasheetAbout Alphasense
Alphasense is the industry-leading manufacturer of sensors for air quality monitoring, gas detection and industrialapplications. Founded in 1996, Alphasense supplies world-leading industrial OEM manufacturers of portable andfixed industrial gas detection equipment, stack gas analysers and environmental monitoring instruments.
We continue to push the boundaries in gas sensor development and manufacturing with our state-of-the-art
automation and process equipment in our UK Centre of Excellence, driving technological advancements
in manufacturing.

www.alphasense.com+44 (0) 1376 556700

sensors.alphasense@ametek.com

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For more information, datasheets and application notes please visit
alphasense.com or contact sensors.alphasense@ametek.com