REXON MOP301 Series Online Oil Moisture Tester

The MOP301 Online Oil Moisture Tester is designed for continuous, real-time monitoring of water activity (aw), temperature, and absolute moisture content (ppm) in transformer oil, lubrication oil, hydraulic oil, and diesel fuel. By utilizing oil-specific solubility parameters, it ensures accurate moisture calculation under varying conditions. This enables operators to quickly assess oil quality, detect contamination risks at an early stage, and implement effective preventive maintenance strategies to extend equipment service life and maintain reliable system performance.

Built with advanced E+E sensing technology, the MOP301 delivers excellent long-term stability, high measurement accuracy, and strong resistance to contamination in harsh environments. Its flexible design supports various probe lengths and installation methods, including optional ball valve mounting for maintenance without process interruption. Equipped with RS485 Modbus communication and the modular Sigma 05 display system, it allows seamless integration, easy configuration, and reliable data transmission, making it an ideal solution for modern industrial oil monitoring systems.

1. Accurate & Real-Time Moisture Monitoring

Measures water activity (aw), temperature, and moisture content (ppm) simultaneously, ensuring precise and reliable oil condition assessment.

2. Advanced Sensing Technology

Equipped with high-end E+E humidity sensors, offering excellent long-term stability and strong resistance to contamination.

3. Intelligent Moisture Calculation

Automatically calculates absolute water content based on oil-specific solubility parameters for higher measurement accuracy.

4. Flexible Installation & Maintenance

Supports various probe lengths and mounting options, with optional ball valve design enabling installation or removal without system shutdown.

5. Reliable Communication & Integration

Features RS485 interface with Modbus RTU protocol for stable data transmission and easy integration into existing monitoring systems.

6. Modular & Expandable System

Compatible with Sigma 05 platform, supporting multiple probes and measurands for enhanced flexibility and scalability.

7. Plug-and-Play Operation

Automatic probe recognition and quick setup reduce commissioning time and simplify operation.

8. Easy Configuration & Adjustment

Free PCS10 software allows convenient parameter setting, output scaling, and system configuration.

9. Durable in Harsh Environments

Oil-resistant cables and robust design ensure stable performance even in aggressive industrial conditions.

Measurands

Water activity (aw) / Water content (x)

Measuring range: 0 to 1 aw

Measuring range: 0 to 100000 ppm (depending on oil type)

Valid ppm output range: 0 to 100 °C

Response time: 10 minutes in still oil at 20 °C

Accuracy:

0 to 40 °C, 0 to 0.9 aw: ±0.02 aw

0 to 40 °C, 0.9 to 1 aw: ±0.025 aw

-40 to 120 °C, 0 to 1 aw: ±0.03 aw

Resolution: 0.0001 aw

Temperature

Measuring range: -40 to 120 °C          Resolution: 0.01 °C

Output

Digital interface: RS485

Protocol: Modbus RTU

Default setting: 9600 baud, even parity, 1 stop bit, address 70

Supported baud rates: 9600, 19200, 38400, 57600, 76800, 115200

Data type: 32-bit float and 16-bit integer

General

Power supply: 8 to 35 V DC

Power consumption: 40 mW

Electrical connection: M12x1, 4 poles

Protection rating: IP66 / NEMA 4

Pressure rating: 20 bar

Probe material: Stainless steel 1.4404

Cable material: Oil and fuel resistant

Working temperature:

Sensor: -40 to 125 °C

Probe: -40 to 120 °C

Cable: -40 to 120 °C

Connector: -25 to 90 °C

Storage temperature: -40 to 80 °C

Humidity: 0 to 95% RH non-condensing

EMC standard: EN 61326-1, EN 61326-2-3, FCC Part 15 Class A

Shock and vibration: EN 60068-2-6, EN 60068-2-27

Configuration: PCS10 software