ZSTM-3 Soil Moisture, EC and Temperature Sensor
ZSTM-3
The ZSTM-3 is a soil sensor that measures soil moisture, electrical conductivity (EC) and temperature from a single probe, using frequency domain reflectometry (FDR) for moisture and an AC bridge for EC. It is supplied in the UK by MetSensor UK.
- ✓ Measures soil moisture, EC and temperature simultaneously
- ✓ FDR sensing for moisture (0-100% volumetric), AC bridge for EC
- ✓ Selectable EC ranges: 0-5,000 / 0-10,000 / 0-20,000 μS/cm
- ✓ Anti-corrosion alloy electrode, IP68 rated probe
- ✓ EC temperature compensation across 0-50°C
- ✓ Multiple output options: 0-2V, 4-20mA, RS485 Modbus
Specifications
| Measurement principle | FDR (frequency domain reflectometry) for moisture; AC bridge for EC |
|---|---|
| Soil moisture range | 0-100% volumetric moisture content |
| Moisture resolution | 0.03% (0-50%); 1% (50-100%) |
| Moisture accuracy | ±2% (0-50%); ±3% (50-100%) |
| EC range | 0-5,000 / 0-10,000 / 0-20,000 μS/cm (selectable) |
| EC resolution | 10 μS/cm (0-10,000 range); 50 μS/cm (10,000-20,000 range) |
| EC accuracy | ±3% (0-10,000 μS/cm); ±5% (10,000-20,000 μS/cm) |
| Temperature range | -40 to +80°C |
| Temperature resolution | 0.1°C |
| Temperature accuracy | ±0.5°C |
| EC temperature compensation | 0-50°C range |
| Power supply | 3.6-30V DC |
| Power consumption | 6 mA @ 24V DC |
| Output signals | 0-2V (impedance 0Ω); 4-20mA (load <500Ω); RS485 Modbus |
| Operating temperature | -40 to +85°C |
| Protection grade | IP68 |
| Probe material | Anti-corrosion alloy electrode |
| Sealing material | Black flame-retardant epoxy resin |
| Electrode length | 70 mm |
| Cable length | 2 m |
| Dimensions | 45 x 15 x 145 mm |
| Signal Output detail | Voltage 0-2V (0Ω impedance); Current 4-20mA (<500Ω load); RS485 Modbus |
| Conductivity Range | 0-5000, 0-10000, or 0-20000 µS/cm options |
| Soil Temperature Range | -40 to 80°C, resolution 0.1°C, accuracy ±0.5°C |
Applications
- Orchard, tea garden, vineyard irrigation monitoring
- Cash crop irrigation monitoring
- Water-saving agriculture
- Greenhouse control
- Precision agriculture
- Grain storage environments
- Sewage treatment facilities
Frequently asked questions
What three parameters does the ZSTM-3 measure?+
Soil moisture, soil electrical conductivity (EC) and soil temperature, from a single probe.
What EC ranges are available?+
Selectable ranges of 0-5,000, 0-10,000 or 0-20,000 μS/cm.
Why does the ZSTM-3 need EC temperature compensation?+
Electrical conductivity readings vary with temperature; the sensor compensates automatically across a 0-50°C range for more consistent EC readings.
What is the IP rating of the ZSTM-3 probe?+
IP68, suitable for direct burial in soil.
More in Weather Sensors
View all Weather Sensors →
ZCL3 Ceilometer (Laser Lidar Ceilometer)
ZCL3
ZWS100 Piezoelectric Rain Sensor
ZWS100 (optional ZWS10G with GPS/4G)
ZWS640 All-in-One Compact Weather Sensor
ZWS640
ZWS620 All-in-One Compact Weather Sensor
ZWS620 (optional ZWS62G with GPS/4G)
ZWS800 All-in-One Compact Weather Sensor
ZWS800
ZWS700 All-in-One Compact Weather Sensor
ZWS700 (optional ZWS70G with GPS/4G)