The progressive
thermistor strings systems
from GeoPrecision

The digital thermistor strings from GeoPrecision are the smartest solution on the market with bidirectional low-power wireless transmission (433/915 MHz) and four types of digital sensors with differing accuracy and precision.

All thermistor strings are custom manufactured to user specifications. Position, accuracy and sensor numbers are flexible. Very cost effective solutions are possible (depending on accuracy and sensor type) The thermistor strings are manufactured according to customer requirements for overall length, number of sensors and accuracy. Temperature points are over-molded to provide long-term protection in all mediums. So the thermistor strings are fully resistance to the ingress of water (IP69).

It is possible any combination of up to 48 sensors on a 250 meter cable. The minimum distance between the sensors is 15 cm - the distance between the first two sensors could be 10 cm.

The thermistor strings from GeoPrecision are using a special 2-wire bus. Therefor all measures data are sending digital to the data loggers.

Why choose digital sensors?

The result is a high data integrity and reliability. The digital string sensors can be individually calibrated by the user. All calibration data are stored in each string sensor.

Themistor string 915 MHz - US/CANADA

Themistor string 433 MHz - EU/ASIA

Four types of sensors

Carbon Ice-Stick 433 /915 MHz (EU and US)

Bidirectional wireless communication

Battery clip holder

Dimensions of 433MHz data logger

Dimensions of 915MHz data logger

Dimensions of digital sensor

SDI-12 Converter

Model of permafrost*

Model of permafrost deformation**

Model of permafrost deformation**

Applications:

NEW features:

• NEW - 2-wire thermistor string sensors: accuracy from +/- 0.1°C to +/- 0.05°C
• NEW - 48 channels/sensors per string
• NEW - 2-wire bus for string lengths up to 250m
• NEW - flexible power supply (battery type AA):
• 1.5V Alkaline battery
• 1.5V Lithium battery
• 3.6V Lithium battery
  
• NEW - Battery holder: easy change by clip

Advantages:

small dimension of string sensors for a fast temperature reaction

• accuracy: from ±0.1 °C to ±0.05 °C
• resolution: from 0.01°C to 0.0001°C
• sensor diameter: 8 mm
• sensor length: 80 mm
• material: stainless steel tubes, DIN 1.4571 (0.1mm wall thickness)

rugged and flexible string cables, up to 100m length

• diameter: 4,2 mm
• material: PUR
• connector to data logger: M8, IP67 (connector free solutions are possible too)
• tensile load: up to 30 Kg

small thermistor string data loggers: M-LOG5W-STRING

• memory: 2048kB non-volatile, up to 500.000 measure values
• data transfer: wireless 433 MHz (EU, Asia) or 915 MHz (US)
• housing: stainless steel or POM (plastic)
• channels: up to 48 string sensors are connectable (2-wire system)
• battery holder: steel clip
• power supply: 1.5V to 3.6 Volt battery, up to 5 years running
• diameter: 20 mm
• length: 130 mm
• operating temp. range: -40°C to +85°C

Specifications:

*Source: Rasmussen, L., Zhang, W., Hollesen, J., Cable, St., Christiansen, H., Jansson, P.-E., Elberling, B.: Modelling present and future permafrost thermal regimes in Northeast Greenland. Cold Regions Science and Technology, Volume 146, February 2018, Pages 199-213
**Blikra, L.H., Christiansen, H.H.: A field-based model of permafrost-controlled rockslide deformation in northern Norway. Geomorphology, Volume 208, 1 March 2014, Pages 34-49