Soil Moisture Sensor SMT100 Truebner

Name: Soil Moisture Sensor SMT100 Truebner
SKU: SMT100
Availability: InStock

Original price was: €165,00Current price is: €149,00.

Compact, functional and robust: The glass fiber reinforced circuit board enables a cost-effective design and easy installation thanks to the blade shape. The housing and cable are waterproof. Different communication protocols are available as well as a version with analogue output.

Interface

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Item number: SMT100 Categories: Professional, Truebner

The of TRUEBNER developed and manufactured SMT100 combines the advantages of a cheap FDR sensor with the accuracy of a TDR measurement. As with a TDR, the dielectric constant of the ground is determined from the signal propagation time and, as with FDR, this is converted into an easily measurable frequency. In contrast to FDR, a capacity is not simply determined, but the transit time is converted into a frequency via a ring oscillator. The resulting frequency (>100 MHz) is high enough so that measurements can also be taken in clayey soil.

The SMT has a large measuring range. It is maintenance-free and frost-resistant. With its short measuring time and the low influence of salinity, it is suitable for continuous use.

Specifications

Accuracy	Volumetric water content (VW): With factory calibration up to ± 3% (VW) in mineral soils with an average salinity of 0 to 50% VW With soil-specific calibration up to ± 1% (VW) Temperature: Typically ± 0,2°C, max. ± 0,4°C over the entire measuring range Analog version ± 0,8°C Additional readings (digital version only): Raw data dielectric permittivity
Resolution	0,1% in volumetric water content or better 0,01°C or better (analogue version 0,2°C)
Measuring range	0 to 60% volumetric water content (up to 100% volumetric water content with limited accuracy Temperature: -40 to +80°C (analogue version -40 to +60°C)
interface variants	RS485 with TBUS/ASCII RS485 with Modbus SDI-12 Low voltage UART Analogue 0 – 10V Analog 0 – 3V (for OpenSprinkler) Analog individual (please inquire) With the analog version, the power supply must be 2V higher than the interface voltage
Power Supply	4-24 V DC, up to 40 mA during measurement (Analog version 12 – 24 V DC for 0 – 10 V output signal) Measuring time digital versions: less than 50 ms Measuring time analogue versions: less than 500 ms
cable length	10 m
Dimensions	approx. 18,2 cm x 3 cm x 1,2 cm
Compatibility with data loggers	Any data logger with suitable power supply and RS485 interface (TBUS/ASCII, Modbus), SDI-12 or analog input Free PC logger software on request

installation:

Install the SMT100 in the root region, horizontally, upright, so that one edge is on top. Simply sticking it into the ground is possible, but will result in inaccurate values.
The temperature sensor is in the black cap and should therefore also be underground.
Please also note that correct measurement is not possible in material that contains a lot of air, e.g. gravel.

Downloads:
SMT100_Flyer_A4_english
SMT100_Flyer_A4_english

NEW: SMT100 4-20mA: Replacement for the MAS-1

Note: To operate on OpenSprinkler 3.x you need either:
a) das “Analog Sensor Board” and the variant “Analog 0-3V” or
b) the “Truebner RS485 Adapter” and the SMT100 variant “RS485 Modbus”

For the OSPi There are two options, depending on the version:
a) If the analog interface is soldered onto the board, then it can be connected in the “Analog 0-3V” variant or
b) a USB RS485 adapter
In general we recommend for the OSPi the SMT50.

For both you need an adapted OpenSprinklerfirmware.

When using the A2D adapter, the actual humidity can NOT be recorded, this is only possible with the “Analog Sensor Board” or “RS485 Adapter” or OSPi via the analog inputs or via a new RS485-USB adapter

Note 3: The “Analog Individual” variant allows you to define the range of the analog output voltage. Since the power supply must be at least 4V, this is the lowest value. Inquire about the desired area beforehand.

Note 4: The protocols of the RS485 variants can be changed via software, the analogue versions can no longer be changed.

Weight	0,5 kg
Interface	Low voltage UART, RS485 with Modbus, RS485 with TBUS/ASCII, SDI-12, Analog: 0-10 V, Analog: 0-3 V, Analog individual, 4-20mA MAS-1 replacement