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Online Particle Counter - QualiOPC™-OL2

Online Particle Counter - QualiOPC™-OL2
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Parent Product
Oil Particle Counters
Standards
ISO 11171
ISO 4402
ISO 4406
NAS 1638
SAE AS4059
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Online Particle Counter - QualiOPC™-OL2

The QualiOPC™-OL2 inline particle counter from Qualitest transforms fluid cleanliness monitoring from periodic bottle sampling into a continuous, always-on data stream. Installed directly in a pressurized hydraulic or lubrication circuit, the instrument counts particles across 16 simultaneous size channels and reports ISO 4406, NAS 1638, and SAE AS4059 cleanliness codes at configurable intervals as short as five seconds. Reliability engineers and maintenance teams gain the uninterrupted visibility they need to detect contamination events as they happen, rather than discovering them after a component has already worn.

The QualiOPC™ OL-2 sensor head uses a stabilized 650 nm semiconductor laser and the light-blocking (extinction) detection principle to resolve particles from 1 µm to 100 µm. A standard pressure rating of 0.2 to 10 MPa covers most hydraulic circuits; an optional 70 MPa rating accommodates high-pressure test stands and offshore hydraulics. The IP54-rated aluminium alloy enclosure, wide operating temperature range of −20 °C to 60 °C, and 8 W power draw suit permanent installation in compact machine cabinets, panel enclosures, or mobile equipment.

Built for Industry 4.0 environments, the QualiOPC™-OL2 supports RS485 (Modbus RTU), RS232, 4–20 mA analog output, Ethernet (MQTT / Modbus TCP), USB data export, and optional Bluetooth 5.0 wireless logging. This connectivity portfolio lets the counter feed contamination data directly into PLCs, DCS platforms, SCADA systems, cloud-based condition monitoring dashboards, and CMMS software without additional gateways or protocol converters. The instrument stores over 100,000 records onboard, buffering data locally through network interruptions and making it available for audit or analysis at any time.

Online Particle Counter - QualiOPC™-OL2 Applications

The QualiOPC™-OL2 serves any facility where continuous, automated fluid cleanliness data reduces maintenance cost, prevents unplanned downtime, and supports predictive maintenance programs. Its IIoT connectivity options make it a natural fit for both standalone installations and networked condition monitoring architectures.

  • Industrial Hydraulic Systems: continuous contamination monitoring of hydraulic power units, servo actuators, and proportional valve circuits where ISO 4406 cleanliness levels directly govern component service life
  • Predictive Maintenance Programs: automated, time-stamped particle count data fed to CMMS or cloud analytics platforms to track contamination trends, trigger maintenance alerts, and document filter performance over time
  • Mobile and Off-Highway Equipment: monitoring hydraulic oil condition in construction machinery, mining equipment, and agricultural vehicles during operation, using Bluetooth or RS485 to transmit data to cab-mounted displays or fleet management systems
  • Wind Turbine Gearboxes and Power Transmission: inline monitoring of gearbox lubricant to detect wear particle generation and contamination ingress before they escalate to gear or bearing damage in remote installations
  • Marine and Offshore Hydraulics: fluid cleanliness monitoring on deck cranes, steering gear, and subsea control systems where the optional 70 MPa pressure rating and corrosion-resistant enclosure meet demanding marine requirements
  • Aerospace Ground Support Equipment: cleanliness verification of hydraulic test rigs and ground support equipment to NAS 1638 and SAE AS4059 standards required by aircraft maintenance organizations
  • Oil and Gas Processing: monitoring lube oil and hydraulic fluid purity in compressors, turbines, and pumping stations; continuous data output via 4–20 mA or MQTT integrates with existing DCS infrastructure
  • Laboratory and Quality Assurance: reference measurement of fluid cleanliness codes on test benches, filtration test rigs, and incoming fluid acceptance stations using the built-in ISO 4402 and ISO 11171 calibration channels
Online Particle Counter - QualiOPC™-OL2

Standards

The QualiOPC™-OL2 supports the following international particle counting and fluid cleanliness standards, covering both the calibration of the instrument and the reporting codes applied to measurement results.

  • ISO 4406 – Hydraulic Fluid Power: Fluids – Method for Coding the Level of Contamination by Solid Particles
  • ISO 11171 – Hydraulic Fluid Power: Calibration of Automatic Particle Counters for Liquids
  • ISO 4402 – Hydraulic Fluid Power: Calibration of Liquid Automatic Particle Counters (legacy reference method, retained for cross-reference)
  • NAS 1638 – Cleanliness Requirements for Parts Used in Hydraulic Systems (National Aerospace Standard)
  • SAE AS4059 – Aerospace Fluid Power: Cleanliness Classification for Hydraulic Fluids

Online Particle Counter - QualiOPC™-OL2 Key Features

The QualiOPC™-OL2 combines a high-channel-count sensor with a full industrial connectivity suite, making it one of the most integration-ready inline particle counters available for continuous condition monitoring applications.

  • Full IIoT Connectivity Suite: Ethernet port with MQTT and Modbus TCP support, RS485 Modbus RTU multi-drop bus, RS232 direct PC interface, isolated 4–20 mA analog output, USB data export, and optional Bluetooth 5.0 — all standard on a single instrument, enabling integration with PLCs, DCS, SCADA, and cloud platforms without protocol converters
  • 16 Simultaneous Detection Channels: counts and reports particles across 16 size channels in a single pass, covering both the ISO 4402/NAS 1638 channel set (1, 2, 5, 10, 15, 25, 50, 100 µm) and the ISO 11171 calibration channel set (4µm(c) through 70µm(c)) without switching modes or reconfiguring the sensor
  • Optional 70 MPa Pressure Rating: standard inline pressure range of 0.2 to 10 MPa suits most industrial hydraulics; the optional 70 MPa rating opens the counter to high-pressure test circuits, hydraulic press systems, and offshore applications
  • 5-Second to 24-Hour Sampling Interval: configurable reporting interval from 5 seconds to 24 hours adapts the counter to both rapid transient detection during commissioning or filter evaluation and slow-change trend monitoring in long-term condition monitoring programs
  • Configurable Alarm Thresholds with Hardware Output: user-defined contamination level alarms trigger a relay output and audible buzzer, delivering a hardware signal that connects directly to machine safety circuits or PLC digital inputs for automated shutdown or alert escalation
  • Real-Time Flow Rate Monitoring with Volume Compensation: measures actual sample flow rate continuously and compensates particle concentration results automatically, preventing count errors caused by pump speed variations or pressure fluctuations in the sample circuit
  • 100,000-Record Onboard Storage: internal flash memory retains over 100,000 time-stamped measurement records through power cycles and network outages, providing a continuous local data buffer for audit trails, trend analysis, and post-incident review
  • Built-In ISO 4402 and ISO 11171 Calibration Wizard: on-instrument calibration guidance reduces the time and expertise required to verify and maintain particle size calibration traceability without external software tools
  • Optional Water Activity Sensor: an integrated water-activity (Aw) sensor option adds oil moisture content to the cleanliness measurement, enabling combined contamination and water ingress monitoring from a single inline instrument
  • Wide Environmental Range: operating temperature of −20 °C to 60 °C, storage temperature to −40 °C, and IP54 dust and splash protection support permanent installation in outdoor enclosures, mobile equipment, and harsh plant environments
  • Low Power Draw: 8 W typical consumption on DC 9 V or DC 12–36 V supply suits battery-backed panels, mobile equipment, and installations where minimizing electrical load is a design constraint

Theory and Method

Hydraulic and lubrication fluids circulating through a working system carry a continuous burden of solid particles: ingested environmental dust, metallic wear debris shed by contacting surfaces, degradation products of aged fluid, and residual contamination from manufacturing and assembly. These particles cause wear through abrasion, surface fatigue, and erosion of precision clearances in valves, pumps, and actuators. Because particle-induced wear accelerates exponentially as particle counts rise and particle sizes approach the clearance dimensions of sensitive components, detecting contamination early is the difference between a planned filter change and an unplanned pump replacement. 

The QualiOPC™-OL2 detects particles using the light-extinction (light-blocking) method standardized in ISO 11500. A beam from a stabilized 650 nm semiconductor laser passes continuously through the flowing oil sample. When a particle enters the measurement zone, it blocks or scatters a fraction of the beam, producing a transient reduction in the photodetector signal. The magnitude of this pulse is proportional to the projected cross-sectional area of the particle, which allows the instrument to classify each particle into one of 16 size channels spanning 1 µm to 100 µm. The sensor processes each pulse in real time at the 10–100 mL/min flow rate, counting particles in the ISO 11171 calibration channel set (4µm(c), 6µm(c), 14µm(c), and others) and reporting the three-number ISO 4406 cleanliness code at each measurement interval.

The instrument applies a built-in ISO 11171 calibration wizard to maintain traceability to the NIST AC Fine Test Dust reference material, ensuring that particle size classification remains consistent across measurement sessions. Flow rate is measured and compensated in real time so that variations in system flow do not distort particle concentration results. When the measured cleanliness level crosses a user-configured alarm threshold, the OL-2 activates a relay output and audible buzzer, providing a hardware signal that integrates directly with machine safety circuits or PLC inputs without requiring software polling.

Online Particle Counter - QualiOPC™-OL2 Technical Specifications

Measurement Performance

Parameter

Specification

Light Source

Semiconductor laser, 650 nm, stabilized

Detection Principle

Light-blocking (extinction) method per ISO 11500

Particle Size Range

1 µm – 100 µm (sensor-dependent)

Minimum Detectable Size

1 µm

Calibration Sensitivity

1 µm and 4 µm(c) per ISO 11171 / ISO 4402

Detection Channels

16 simultaneous channels

Counting Volume

10 mL per sample

Counting Accuracy

±0.5 pollution level

Flow Rate Range

10 – 100 mL/min (real-time monitoring with volume compensation)

Sampling Interval

5 seconds – 24 hours (user-configurable)

 

Fixed Particle Size Channels

Parameter

Specification

ISO 4402 / NAS 1638 Series (up to 8 channels)

1 µm, 2 µm, 5 µm, 10 µm, 15 µm, 25 µm, 50 µm, 100 µm

ISO 11171 Series ("c" calibration set, up to 8 channels)

4 µm(c), 4.6 µm(c), 6 µm(c), 10 µm(c), 14 µm(c), 21 µm(c), 38 µm(c), 70 µm(c)

 

Cleanliness Standards Reported

Parameter

Specification

International Standards

ISO 4406, ISO 4402, ISO 11171, NAS 1638, SAE AS4059

 

Physical and Environmental

Parameter

Specification

Online Test Pressure

0.2 – 10 MPa (standard); optional up to 70 MPa

Sample Temperature

0 – 80 °C

Operating Temperature

−20 °C to 60 °C

Storage Temperature

−40 °C to 85 °C

Enclosure

High-strength aluminium alloy

Ingress Protection

IP54

Power Supply

DC 9 V or DC 12 – 36 V

Power Consumption

≤ 8 W (typical)

 

Display and Storage

Parameter

Specification

Display

3.5″ color TFT-LCD, 320 × 480 px

Internal Storage

≥ 100,000 records (onboard flash)

External Storage

USB Type-A host port, FAT32, up to 128 GB

 

Communication Interfaces

Interface

Specification

RS485

Modbus RTU · up to 1 Mbps · multi-drop bus, up to 32 nodes

RS232

Direct PC connection · DB9 · configurable baud rate 9600–115200

4–20 mA

Analog output for DCS/PLC · programmable per channel · isolated

Ethernet

RJ45 · 10/100 Mbps · MQTT / Modbus TCP · remote monitoring and OTA firmware updates

USB

Type-A host port · data export to FAT32 drive · firmware upgrade

Bluetooth 5.0

(Optional) Wireless logging to tablet or phone · Android and iOS app

 

 

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Oil Particle Counters