OPC-500 Online Particle Counter

Key Features Application Specification Measurement Principle Key Features

• High-precision laser and photoelectric transceiver components ensure measurement accuracy
• Suitable for various liquids, real-time monitoring of cleanliness levels 24/7
• Ensures safe operation of hydraulic and lubrication systems, preventing excessive contamination
• Optional online detection of oil moisture saturation level for enhanced diagnostics
• Internal storage of up to 3,000 test records
• Compact, robust, durable, intelligent, and easy to integrate
• Built-in flow estimation function ensures measurement accuracy
• Detects abnormal contamination and wear to safeguard asset operation
• Continuous and interval measurement modes are freely configurable
• Fast response with adjustable accumulation and measurement cycles
• Excellent chemical resistance and high-pressure tolerance
• Dual certification for EMC and explosion protection, ensuring long-term stable operation in harsh environments
• No moving parts or consumables, designed for a 10-year service life
• 5 kV isolated RS485 Modbus communication

Application

Suitable for liquids
Hydraulic oil, lubricating oil, insulating oil, turbine oil, engine oil, aviation kerosene, diesel fuel, ethylene glycol fire-resistant hydraulic fluid, phosphate ester hydraulic fluid, cooking oil, cutting fluids, ultrapure water, pharmaceutical solutions.

Applicable Industries
Aviation, aerospace, defense, oil, chemicals, power generation, energy, metallurgy, steel, transportation, ports, oil filtration, engineering, machinery, hydraulics, automotive, pharmaceuticals, electronics, semiconductors, research, laboratories and so on.

Specification

Measurement Principle	Light Extinction Method (Optical Blockage)
Sensing Element	Semiconductor laser, photodetector
Detection Range	1–100 μm (ISO 4402), 4–70 μm(c) (ISO 11171, GB/T 18854)
Detection Channels (8 channels)	ISO 4402: 1, 2, 5, 10, 15, 25, 50, 100 μm or ISO 11171: 4(c), 4.6(c), 6(c), 10(c), 14(c), 21(c), 38(c), 70 μm(c)
Sensitivity	ISO 4402: 1 μm ISO 11171: 4 μm(c)
Calibration Standard	ISO 4402 (ACFTD, GBW(E)120017) ISO 11171 (ISO MTD, GBW(E)120083)
Built-in Standards	ISO 4406: Grades 0–28 NAS 1638: Grades 00–12 GJB 420A, GJB 420B: Grades 000–12 GB/T 14039: Grades 0–28 SAE AS4059: Grades 000–12 GOST 17216: Grades 00–17
Measurement Accuracy	±0.5 cleanliness code (depends on flow stability)
Permissible Flow Rate	10–500 mL/min optimal at 25 mL/min)
Fluid Viscosity	≤680 cSt
Coincidence Error Limit	20,000 particles/mL
Maximum Allowable Oil Pressure	0–3 MPa (continuous), up to 5 MPa (transient peak); up to 42 MPa with optional pressure-reducing valve
Oil Line Connection Port	M10×1.0 mm internal thread
Digital Output	RS485 Modbus RTU, 2 kV isolation voltage
Operating Power Supply	DC 10–28 V, <60 mA @ DC 24 V, Max 2 W
Applicable Fluids	Lubricating oil, hydraulic oil, kerosene, reagents, water-based fluids, etc.(Phosphate ester fluids available on request)
Fluid Temperature	-20 °C to 85 °C
Ambient Temperature	-20 °C to 60 °C
Storage Temperature	-40 °C to 85 °C
Housing Material	Stainless steel (explosion-proof version) or anodized aluminum (industrial version), polycarbonate
Wetted Materials	NBR, FKM, glass, stainless steel, aluminum alloy
Dimensions	80 × 80 × 60 mm (L × W × H)
Weight	<800 g
Protection Rating (IP Rating)	IP66
Connection Cable	2 m long 5-core cable, M12×1.5-5 pin connector or M12 cable gland
Electromagnetic Compatibility (EMC)	EN 61000, EN 61326-1, EN 61326-2, EN 61326-4
Vibration Resistance	2 g
Explosion Protection Rating (Optional)	Ex ib IIC T6 Gb
Trace Moisture (Optional)	0–5000 ppm (calibrated per oil sample), accuracy ±10%
Water Activity (Optional)	0–1 aw (equivalent to 0–100% RH moisture saturation), accuracy ±3%
Oil Temperature (Optional)	-40 °C to 85 °C, accuracy ±0.5 °C

Measurement Principle

The OPC-500 online particle counter uses the light obscuration (light-scattering) principle and is calibrated using standard reference materials such as MTD (ISO Medium Test Dust, ISO 11171) or ACFTD (Air Cleaner Fine Test Dust, ISO 4402).

OPC-500 features a high-performance semiconductor laser that, via a collimating lens, directs a parallel beam into the oil detection channel inside the counter. Paired with a high-efficiency PIN photodetector serving as the signal-receiving unit, it enables real-time monitoring of particle count and contamination levels.

When no particles pass through the liquid, the detection circuit outputs a constant voltage. However, as particles move through the detection channel, they block the light beam, causing the photocurrent to weaken. Consequently, the photoelectric signal received by the photodetector also diminishes, triggering the detection circuit to output a pulse signal. Since the detection channel is narrow enough to ensure that particles in the liquid pass through one by one in sequence, each pulse detected corresponds to a single particle passing through the channel. By counting the number of pulses generated, you can accurately determine how many particles have traveled through the detection area.

The amplitude of the negative pulse is related to the particle size according to the following equation. This enables counting solid particles in oil and, based on different standards, facilitates real-time online detection and classification of liquid contamination levels.

E —— represents the voltage pulse value, in millivolts, generated as particles pass through the detection area，mV

E0 —— The voltage reference value, in mV, generated by the photoelectric detector when no particles pass through the detection area，mV

A ——  Effective receiving area of the photoelectric detector，μm2 ;

S ——  The projected area of the particle in the direction of the light beam，μm2 ;

d ——  When the particle is spherical, it represents the particle diameter, in μm.

The product also offers optional features for measuring dissolved moisture content (expressed in ppm), water activity (aw, moisture saturation RH%), and temperature. It is available under the model number OPC-500-W.

OPC-500-W measures water activity by integrating high-performance polyimide film capacitors, paired with a PT100 platinum resistance sensor, enabling real-time detection of dissolved moisture in oil. Leveraging its built-in multiple calibration coefficients for water solubility, the device accurately monitors both dissolved moisture levels in parts per million (ppm) and water activity (aw), ensuring at all times that oil moisture remains below the saturation point—and providing you with comprehensive diagnostic insights to safeguard your valuable equipment.

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