Irrometer 200SS-X Watermark Soil Moisture Sensor without Leads

In use since 1978, the patented WATERMARK sensor is a granular matrix sensor used to measure soil water tension. Water in the soil exchanges with the proprietary matrix inside of the sensor, creating a relationship between measured resistance and soil water tension.

The sensor consists of corrosion resistant electrodes imbedded within a granular matrix, contained in a perforated stainless-steel enclosure. Power (normally 2.5 to 5V) is applied to the WATERMARK to obtain a resistance value. Reading devices use published calibrations to convert the measured resistance into centibars (cb) or kilopascals (kPa) of soil water tension.

The WATERMARK is designed to be a permanent sensor, placed in the soil to be read as needed for monitoring soil conditions. Low cost, minimal power requirements, and easy installation make this sensor ideal for battery powered IoT devices in both agriculture and landscape applications.

Features:

• Proven stable calibration
• Inexpensive and easy to install
• No maintenance
• Range of measurement from 0 to 239 cb (kPa)
• Durable construction
• Not harmed by freezing
• Compensated for soil water salinity
• Reads electrical resistance of soil moisture.

Specifications:

• Output: Variable resistance from 550 to 32000 ohms
• Dimensions: Diameter- 0.875" (22mm), Length: 3.00" (76 mm)
• Wire Leads: 20AWG x 6 in. (15 cm) - 2 leads
• Range: 0 to 239 centibar (kPa)
• Material: ABS plastic caps with stainless steel body over a hydrophilic fabric covered granular matrix with embedded stainless steel electrodes