How is the BT8500 connected to a PLC or SCADA system?

Modbus (RTU)-RS485 is fitted as standard, with 4-20 mA and USB available as options. The instrument supports local or remote control and stores 1,000,000 records on board for later comparison.

Does the instrument have to be sent back for calibration?

No. Calibration is built in and can be carried out on site to high accuracy, which avoids shipping the unit back and saves both turnaround time and cost. This is one reason the instrument suits multi-point installations.

Can it be used at high temperature or with liquid containing bubbles?

For high-temperature duty choose the high-temperature sensor (H suffix), which raises the operating range from 5-50 °C to 5-70 °C. A de-bubbling device is available for liquid that carries entrained gas. Storage conditions are 0-50 °C and 18-80% relative humidity, non-condensing; the enclosure is rated NEMA 4X.

What is included in the standard supply?

One BT8500 controller, one BSLP sensor of the selected range (BSLP200, 400 or 750, or the high-temperature H version), and one mounting set: either the weir installation kit (FC-LPS01) or the flow meter installation kit (FD-MPS01). Tell us the industry and the properties of the liquid and we will advise on the configuration.

BT8500 Online Liquid Particle Counter

Q: How does the BT8500 measure particles in a liquid?

The BT8500 uses light obscuration. As liquid flows through the external laser sensor, particles passing the beam block light. The sensor derives particle size from the amount of light lost, and particle count from the number of beam breakages. The controller then groups the results by particle size channel and reports counts per millilitre or the total per measurement cycle.

Q: Which measurement range should I choose: 1-200, 2-400 or 2-750 μm?

Start from the particle size you most need to control. 1-200 μm suits industrial process water, parts cleaning and drinking water, where fine particles dominate, and runs at 60 mL/min. 2-400 μm covers coarser particles and suits filtration and equipment wear monitoring. 2-750 μm suits liquids with a high coarse fraction and runs at 120 mL/min. All three sensors report 2-300 μm as standard; wider reported ranges are available to order.

Q: Can the eight particle size channels be set by the user?

Yes. Eight particle size channels are fitted as standard and the size assigned to each channel is set by the user on the touchscreen. Versions with 16, 24 or 32 channels are available.

Q: What is the difference between cumulative and differential counting?

In cumulative mode the instrument counts all particles larger than a given channel size, which suits a single pass/fail threshold for a batch. In differential mode it counts particles falling between two adjacent channel sizes, which suits looking at the size distribution and identifying where the particles come from.

Q: How is the sensor cleaned and maintained?

The sensor is external and can be removed for cleaning. A sensor protection filter, a sensor cleaning kit and sample inlet/outlet tubing are supplied as standard. The controller provides live sensor alarms, fault display and maintenance prompts.

Q: Which liquids can the BT8500 monitor?

Industrial process water, parts cleaning fluid, drinking water treatment, lubricating and hydraulic fluids for wear protection, liquid-cooling loops, general fluid cleanliness monitoring, membrane filtration permeate, food and beverage process water, pharmaceutical and medical water, and process liquids in electronics manufacturing.

Light obscuration8 user-set channels1–750 μm

The BT8500 is an online liquid particle counter that measures the size and number of particles in a flowing liquid by light obscuration, continuously, 24 hours a day. A 7-inch colour touchscreen handles setup and readout, calibration is done on site, and counts reach a PLC or SCADA system over Modbus RTU/RS485 — so you can tell whether water, cleaning fluid, coolant or hydraulic fluid is still inside its cleanliness limit.

Ask for a selection recommendation Download datasheet (PDF)

BT8500 online liquid particle counter: silver NEMA 4X enclosure with a 7-inch colour touchscreen showing particle counts per size channel, and an external laser sensor on the right — BT8500 controller with BSLP series external laser sensor. The screen shows particle counts per size channel and the cumulative total; the model number is printed at the lower right of the enclosure.

Measurement principle

Light obscurationlaser sensor

Standard channels

8up to 32 optional

Flow rate

60–120mL/min

Data storage

1,000,000records

Read these four blocks first — they decide whether this instrument suits your lineAt a glance

What it measures

The size and number of particles in a flowing liquid, counted separately on 8 particle size channels and reported as particles per millilitre or as a total per measurement cycle.

How it measures

An external laser sensor sits directly in the sample line, so measurement happens as the liquid flows — no sampling bottles and no waiting for a lab result. You see how cleanliness changes over time, not a single snapshot.

Which range

Three sensors cover 1–200 μm, 2–400 μm and 2–750 μm, all reporting 2–300 μm as standard. Choose fine for water and cleaning fluid, coarser when large particles matter.

How it connects

Modbus (RTU)-RS485 as standard, with 4–20 mA and USB as options. Local touchscreen or remote control, 1,000,000 records held on board, straight into a PLC, DCS or historian.

Light obscuration: a laser beam crosses the liquid, and each particle reports its own size and countMeasurement principle

A laser beam passes through a narrow flow cell. Every particle that crosses it blocks part of the beam for a fraction of a second, and two things are read from that event: how much light was lost, which gives the particle size, and how often the beam was broken, which gives the particle count. Particles are counted one at a time, so the result is a distribution rather than an average.

Principle, simplified: a particle crossing the laser path reduces the light reaching the detector. The depth of the drop corresponds to the projected size of the particle; the number of drops corresponds to the number of particles.

01

Liquid enters the external sensor

The sensor is plumbed into the sample line. Liquid passes through the flow cell at 60 mL/min (1–200 μm and 2–400 μm) or 120 mL/min (2–750 μm), so particles cross the beam one at a time.
02

The beam is obscured — that gives the size

A 5 mW red laser diode shines through the flow cell. The larger the particle, the more light it blocks; the sensor converts the amount of light lost into particle size.
03

Break events give the count

Each obscuration is one break in the beam. Counting breaks yields the number of particles above that size threshold, filed into the configured channels.
04

The controller reports and stores

Channel values are shown live on the 7-inch touchscreen, sent out over Modbus RTU/RS485, and written to 1,000,000 on-board records.

CUMULATIVE MODE

Counts all particles larger than a given channel size — the right mode for a single pass/fail threshold on a batch.

DIFFERENTIAL MODE

Counts particles between two adjacent channel sizes — the right mode for size distribution and for locating where the particles come from.

Three sensors, one particle size scaleRange coverage

The controller is identical in every configuration; the measurement range comes from the sensor you fit. The scale below spreads 1–800 μm across a log axis: the three dark bands are the coverage of BSLP200, BSLP400 and BSLP750, and the red band is the instrument's standard reported size range. Begin with the particle size you most need to control, then leave some headroom above it.

100

200

300

400

750

BSLP200 · 1–200

BSLP400 · 2–400

BSLP750 · 2–750

Reported · 2–300

Sensor measurement range BSLP400 measurement range Standard reported size range 2–300 μm Horizontal axis: particle size / μm (log scale) Wider reported ranges available to order

BSLP200 / 200H

Range 1–200 μm at 60 mL/min. Suits industrial process water, parts cleaning and drinking water, where fine particles dominate. The H version is for high temperature.

BSLP400 / 400H

Range 2–400 μm at 60 mL/min. Choose it when fine and coarse particles both matter — filtration and equipment wear monitoring.

BSLP750 / 750H

Range 2–750 μm at 120 mL/min. Choose it when the liquid carries a lot of coarse material or you need the wider size span.

All three sensors report 2–300 μm as standard. Channel count and the size assigned to each channel are set on the touchscreen: 8 channels as standard, 16 / 24 / 32 optional.

Details that come from running continuouslyDesign notes

External sensor — cleaned without opening the controller

The sensor is separate from the controller and can be taken off for cleaning. A protection filter, cleaning kit and inlet/outlet tubing ship with it, so routine maintenance does not tie up the line.

Calibration on site, no trip to the factory

Calibration is built in and performed in place to high accuracy. That removes shipping time and scheduling, which matters most when you run several units across a plant.

7-inch colour touchscreen

Setup and readout happen on the same screen. Channel values, cumulative totals and run status are visible at the panel without a laptop alongside.

8 channels to start with, sizes you define

Eight particle size channels as standard, each size set by the user. Where you need a finer breakdown of the distribution, 16, 24 and 32 channel versions are available.

Alarms, faults and maintenance prompts

Live sensor alarms and fault display flag maintenance needs. The sensor's wider temperature tolerance reduces stoppages when the process temperature moves.

Outputs that fit existing systems

Modbus (RTU)-RS485 as standard, 4–20 mA and USB optional, local or remote control. Up to 1,000,000 records are held on board for later comparison.

NEMA 4X enclosure

12 × 10 × 6 inches and 5 kg, rated for wet and washdown environments. It mounts on a machine frame or on the wall next to the sample point.

Room for water quality parameters

pH and conductivity sensors and a de-bubbling device can be added, so one sample point reports both particle cleanliness and water chemistry.

SpecificationsTechnical data

Measurement and counting

Measurement principle	Light obscuration
Sensor	Laser sensor, 5 mW red laser diode
Signal-to-noise ratio	≥ 3 : 1
Size channels	8 as standard, size per channel user-defined; 16 / 24 / 32 optional
Measurement range	1–200 / 2–400 / 2–750 μm
Reported size range	2–300 μm
Flow rate	60 mL/min · 120 mL/min
Measurement precision	10 μm < 8% 2–10 μm < 10%
Counting unit	Particles per mL, or total particles per measurement cycle
Counting mode	Cumulative / differential
Calibration	Built in, performed on site

Electrical, mechanical, environment

Data output	Modbus (RTU)-RS485 as standard; 4–20 mA, USB optional
Control mode	Local / remote
Data storage	1,000,000 records
Display	7-inch high-resolution colour touchscreen
Power supply	100–240 VAC, 0.5 A 12 VDC, 1.67 A
Enclosure rating	NEMA 4X
Dimensions	12 × 10 × 6 in
Weight	5 kg
Operating temperature	5–50 °C 5–70 °C (H version)
Storage temperature	0–50 °C
Operating humidity	18–80% RH, non-condensing
Installation set	Weir FC-LPS01 or flow meter FD-MPS01

Figures as published by the manufacturer; confirm the configuration for your site before ordering. Range and reported size range are not the same figure: the sensor sets the measurement range, and accuracy is specified over 2–300 μm.

Certificates and complianceCE / RoHS / verification

CE marking: the instrument is declared in conformity with the European directives that apply to electrical equipment, so it can be installed and operated in EU member states.

RoHS

RoHS compliant: restricted substances in electrical and electronic equipment are held within the limits set by the directive.

CAL

Verification (calibration) certificate: issued for the particle size channels and supplied with the instrument, stating the verification result and the basis it was carried out against.

The certificate in force at the time of shipment applies. Ask us for the current copies — certificate numbers, the issuing laboratory and the verified range — for your project file.

Two mounting options — choose one when you orderInstallation

Two BT8500 mounting arrangements, left: controller on a stand with an overflow weir in an open tank; right: controller on a wall bracket above a flow meter

Weir installation — FC-LPS01

open tanks, troughs, wash baths

A stand carries an overflow weir. Liquid flows over the weir at a steady level and is drawn off from the side into the sensor. Suits open vessels where you take water from the edge of the bath; the short pipe run keeps the transport lag — and the chance of particles settling on the pipe wall — to a minimum.

Flow meter installation — FD-MPS01

pressurised lines, equipment cabinets

A flow meter with a bracket is fitted into the sample line, so you can set and read the sampling flow rate at the point of take-off. Suits pressurised pipework or equipment cabinets where there is no free surface to work from.

What the sensor needs either way

common to both

A liquid path through the external sensor with no air entrainment, and a flow rate that matches the sensor (60 mL/min or 120 mL/min). Where the liquid carries entrained gas, add a de-bubbling device.

Photos and part numbers are from the manufacturer's own material. Pipe connections, bracket fixing and stand height have to be confirmed against your site; tell us the take-off point and we will check the arrangement with you.

Ordering: the sensor sets the range, the mounting set sets the fitHow to specify

Every BT8500 uses the same controller — 7-inch touchscreen, 8 channels, Modbus RTU/RS485, 1,000,000 records. What changes is the sensor and the mounting set. Two choices, then send the exact model.

The table is wider than the screen — swipe sideways to see all columns.

Item	Sensor	Range	Flow rate	Where it suits
BT8500	BSLP200	1–200 μm	60 mL/min	Industrial process water, parts cleaning, drinking water — fine particles dominate
BT8500-H	BSLP200H	1–200 μm	60 mL/min	As above, liquid or ambient up to 70 °C
BT8500	BSLP400	2–400 μm	60 mL/min	Fine and coarse both matter — filtration, equipment wear
BT8500-H	BSLP400H	2–400 μm	60 mL/min	As above, high temperature
BT8500	BSLP750	2–750 μm	120 mL/min	High coarse fraction, or the wider size span
BT8500-H	BSLP750H	2–750 μm	120 mL/min	As above, high temperature

Mounting set — choose one

FC-LPS01	Weir installation — stand, overflow weir, pipework
FD-MPS01	Flow meter installation — flow meter, bracket, pipework

Supplied as standard

Controller	BT8500, 7-inch touchscreen, Modbus RTU/RS485
Sensor	BSLP series, selected range
Accessories	Sensor protection filter, cleaning kit, inlet/outlet tubing
Options	16 / 24 / 32 channels · 4–20 mA · USB · pH sensor · conductivity sensor · de-bubbling device

Where an online counter earns its placeApplications

Industrial process water

Watch particle levels at the point of use instead of sampling and waiting for a lab result.

Parts cleaning

Cleaning fluid carries particles off the parts. Counting them shows when the bath needs changing.

Drinking water treatment

Follow particle removal through filtration and clarify where a step stops performing.

Lubricating and hydraulic fluid

Particles are wear debris. Continuous counting catches equipment wear before it becomes a failure.

Liquid cooling loops

Coolant and cold plates foul from particles. Counting proves whether a cleaning cycle worked.

Fluid cleanliness monitoring

Trend a system against its own cleanliness limit and keep a record over time.

Membrane filtration

Particles in permeate and feed show breakthrough and the condition of the membrane.

Food and beverage

Process water and product liquid monitored for particle content on the line.

Pharmaceutical and medical water

Purified water and process liquid checked for particles where the record has to be continuous.

Electronics manufacturing

Process chemicals and rinse water held to a particle limit, batch after batch.

In the fieldInstallations

On-site liquid-cooled component flow path cleaning equipment: multiple cleaning stations run in parallel, and the BT8500 online liquid particle counter is used to monitor particle residues in the cleaning circuit to confirm whether the flushing meets the requirements

BT8500 online liquid particle counter installation on a tap water plant overflow weir: The external sensor is connected to the nearby sampling pipeline. During maintenance, you only need to remove the sensor, without moving the whole machine.

Site photos show the instrument in service; pipe routing and cabinet arrangement are specific to those installations.

Questions that come up before orderingFAQ

How does the BT8500 measure particles in a liquid?

By light obscuration. Liquid flows through the external laser sensor; particles crossing the beam block light. The sensor derives particle size from the amount of light lost and particle count from the number of beam breakages, then groups the results by size channel and reports counts per millilitre or the total per cycle.

Which measurement range should I choose: 1–200, 2–400 or 2–750 μm?

Start from the particle size you most need to control. 1–200 μm suits process water, parts cleaning and drinking water where fine particles dominate, at 60 mL/min. 2–400 μm covers coarse particles as well, for filtration and equipment wear. 2–750 μm suits liquid with a high coarse fraction and runs at 120 mL/min. All three report 2–300 μm as standard.

Can the eight particle size channels be set by the user?

Yes. Eight channels are fitted as standard and the size assigned to each channel is set on the touchscreen. Versions with 16, 24 or 32 channels are available.

What is the difference between cumulative and differential counting?

Cumulative mode counts all particles larger than a given channel size — a single pass/fail threshold for a batch. Differential mode counts particles between two adjacent channel sizes — the distribution, and where the particles come from.

How is it connected to a PLC or SCADA system?

Modbus (RTU)-RS485 is fitted as standard; 4–20 mA and USB are optional. The instrument supports local or remote control and holds 1,000,000 records on board for later comparison.

Does the instrument have to go back to the factory for calibration?

No. Calibration is built in and done on site to high accuracy, which avoids shipping the unit back and saves both time and cost — the reason it works well for multi-point installations.

How is the sensor cleaned and maintained?

The sensor is external and can be taken off for cleaning. A protection filter, cleaning kit and inlet/outlet tubing are supplied as standard. The controller shows live sensor alarms, faults and maintenance prompts.

Can it be used at high temperature, or with liquid carrying bubbles?

For high-temperature duty choose the H version, which lifts the operating range from 5–50 °C to 5–70 °C. A de-bubbling device is available for liquid with entrained gas. Storage is 0–50 °C at 18–80% RH non-condensing, and the enclosure is rated NEMA 4X.

Which liquids can it monitor?

Industrial process water, parts cleaning fluid, drinking water treatment, lubricating and hydraulic fluids, liquid-cooling loops, general fluid cleanliness monitoring, membrane filtration, food and beverage process water, pharmaceutical and medical water, and electronics process liquids.

What is in the standard supply?

One BT8500 controller, one BSLP sensor of the selected range (or its H version), and one mounting set — weir FC-LPS01 or flow meter FD-MPS01. Tell us the industry and the liquid, and we will advise on the configuration.

Does the BT8500 come with CE, RoHS and calibration certificates?

Yes. The instrument carries CE marking and is RoHS compliant, and it ships with a verification (calibration) certificate for the particle size channels. Copies with the certificate numbers and the issuing laboratory are available before you order.

Tell us the liquid and the limit — we will come back with a configurationContact

The useful details are short: what the liquid is, its temperature, whether the take-off point is a pressurised line or an open tank, and the particle size or cleanliness limit you have to meet. With those we can say which sensor and which mounting set you need, and whether the H version applies.

For distributors and OEM integrators: the controller is identical across ranges, so spares and training cover the whole family.

PHONE+86 185 1545 9750 EMAILzy@bebur.net

BT8500 datasheet (PDF)

Full specifications, sensor tables and the ordering list, in one file you can forward internally.

Open the PDF

Source: product information and photographs from the manufacturer's BT8500 page (bebur.net). Figures are reproduced as published; where a value is a recommendation rather than a specification, it is marked as one. Page updated 13 November 2026. If a specification has changed since, the manufacturer's current datasheet takes precedence.