Radar Moisture Meter with GR Probe (Grain & Feed) TRIME GWs

The TRIME GWs with GR probe is a robust inline TDR moisture measurement system specifically developed for continuous monitoring of moisture, conductivity and temperature in grain, animal feed and other bulk materials. It is designed for harsh environments and high temperatures (up to 130 °C continuous, 150 °C short-term), such as inside grain dryers, tower dryers, conveyor systems and difficult-to-access locations. The system consists of a measurement transducer (electronics housing) and the GR probe made of high-temperature-resistant PEEK with a 2-metre PTFE cable. The round GRr sensor features a stainless-steel cover over the temperature sensor and is available as variant Keilsonde WS2. Factory pre-configured for grain drying applications (calibration curve Cal2, CF mode, 3-second averaging).

Principle of Operation

TRIME GWs uses patented TRIME®-TDR technology (Time Domain Reflectometry) with pulse frequencies up to 1 GHz. A high-frequency electromagnetic pulse (600 MHz – 1.2 GHz) is transmitted along the waveguides of the GR probe, generating an electromagnetic field that penetrates the surrounding material. The propagation time of the reflected pulse (resolution 1 picosecond) is directly proportional to the dielectric constant, which is mainly influenced by water content. The internal processor performs up to 100 measurements per second, validates, filters and averages them, and outputs moisture (% wet basis) and temperature via analogue 0/4–20 mA signals. Temperature compensation is applied automatically (default TempComp = 0.2). Four operating modes are available: CS (cyclic without averaging), CA/CF (filtered for inhomogeneous flows), CC (cumulative total for batch processes).

Specifications

• Moisture range: 5–45 % wet basis (material-dependent)

• Accuracy: Standard deviation 0.6 % (5–20 %), 1 % (20–45 %); repeatability ±0.3 %

• Temperature range: Probe 0–127 °C (short-term 150 °C); transducer –10 … +70 °C

• Power supply: +12 … +24 V DC, approx. 3 W (~200 mA)

• Analogue outputs: 2 × 0/4–20 mA (Output 1: moisture 0–50 % adjustable; Output 2: temperature 0–100 °C or optionally conductivity/standard deviation); max. load 500 Ω

• Digital interfaces: RS485, IMP-Bus (galvanically isolated, current-loop for long-distance networks)

• Dimensions: Transducer 175 × 80 × 58 mm; probe Ø 70 × 235 mm

• Weight: 1.3 kg

• Protection class: Housing IP65 (cast aluminium); GR probe IP68

• Cable length: Standard 2.5 m (extensions available)

• Measurement cycle: Continuously adjustable averaging 1–20 s

• Calibration curves: Up to 15 user curves (Cal1–Cal15), selectable via SONO-VIEW or SONO-CONFIG software

• Internal resolution: 0.1 % in CA/CF mode

Main Application Areas

• Continuous moisture control in tower, belt and rotary grain dryers (inlet, heating zone, outlet)

• Conveyor belts, screw conveyors and bins during grain transport and storage

• Automated dryer control via PLC (multiple probes for full process optimisation)

• Batch drying processes with cumulative moisture summation (mode CC)

• Quality assurance in grain processing, feed production and storage facilities

Advantages of TRIME GWs Radar Moisture Meters

• Extremely high accuracy and repeatability (±0.3–0.6 %) even in hot and inhomogeneous material flows

• Superior to capacitive (5–40 MHz) and microwave (>2 GHz) methods – virtually unaffected by material density, colour or salinity

• Reliable operation at temperatures up to 150 °C and in abrasive environments

• Intelligent averaging and filtering for stable readings in continuous flows

• Up to 15 material-specific calibration curves with simple air/water balancing

• Robust IP65/IP68 construction, no moving parts, minimal maintenance

• Easy integration into existing PLC systems via 4–20 mA and IMP-Bus

• Automatic temperature compensation and extensive self-diagnostics

• Significant energy savings and improved grain quality through precise dryer control