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TDT Soil Moisture Sensor (SDI-12)

Updated:2025-03-13

Brand: ACCLIMA
Model: TDT
Description: Acclima Digital TDT ? The soil moisture sensor is a soil moisture sensor that combines the accuracy of the digital time domain transmission instrument (TDT) with the low cost instrument. It can provid
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Product Details

TDT Soil Moisture Sensor (SDI-12) - Product Summary

User 's Manual

Acclima Digital TDT ® The soil moisture sensor is a soil moisture sensor that combines the accuracy of the digital time domain transmission instrument (TDT) with the low cost instrument. It can provide highly accurate soil moisture readings under all temperature and soil chemical conditions of crop growth.

This digital TDT sensor includes an improved SDI interface that can be directly connected to the Acclima Datalogger or any other third-party SDI version 1.4 compatible device. The improved SDI interface of Acclima can also automatically detect and resolve conflicts with the Acclima data recorder.

Features：

Works in all soils

Highly stable under a wide range of soil conductivity and temperature

Range of 0 -100% volumetric water content

Made with durable inert materials

low-power, battery operable

SDI-12 version 1.4 compliant

Low cost

Main parameters:

Physical
Dimensions (without cable)	20 cm x 5.33 cm x 1.5 cm
Weight (with 5m cable)	299 g
Composition	Type 304 stainless steel, crystalline-epoxy
PVC (insulation) cable	3 conductor, 22 ga PVC sheath, 5 meters
Environmental
Operating temp range	1 ?C to 50 ?C for VWC (no ice), -20 ?C to 50 ?C for the other data
Storage temp range	20 ?C to 75 ?C
Lightning and surge protection	6 kV @ 3 kA, 8/50 μs
Operating
Volumetric water content	0 to 100%
Resolution	0.06% VWC
Absolute VWC accuracy	±2% typical
VWC soil EC stability	±1% of full scale 0 to 5 dS/m BEC
Temp reporting accuracy	±2 ?C from +1 ?C to +50 ?C
EC reporting accuracy	±0.2 dS/m 0 to 5 dS/m BEC
Architectural
Technology	Waveform digitizing time domain transmissometer
Effective acquisition bandwidth	200 giga-sample/second
Propagation time resolution	picosecond
Waveform propagation resolution	1.5 mm in air, 0.16 mm in water
Waveguide length	30 cm
Permittivity to VWC calculation	Modified dielectric mixing model
Propagation waveform bandwidth	>2 GHz
Communications
Communication protocol	SDI-12 Revision 1.4
Maximum cable length	60 meters
Power
Operating Voltage Range	6–15 VDC
Listening/Sleep Mode Current	60 μA at 50 ?C
Communications Current	6 mA typical, 8 mA max
Read Moisture Comm Time	425 ms total for each read cycle
Moisture Sense Current	84 mA at 12VDC input, 98 mA at 8 VDC input, 110 mA at 6 VDC input
Moisture Sense Time	450 ms each sensing operation