dendrometers for small stems
SD-type dendrometer sensors are a highly precise incremental LVDT-based sensor for monitoring micro-variations of stem diameter in micron range.
- Sap flow and tree water use
- Weather stations
- Soil moisture sensors and meters
- Soil carbon monitoring
Plant growth and water balance affect diurnal behaviour of stem diameter. The growth rate depends on a vegetation stage and environmental conditions. The diurnal variations represent mostly fluctuations of water content in plants. Two diameter-based indices are commonly used for evaluating plant water status: daily contraction amplitude and trend of daily maxima. The SD-type sensor allows investigating effects of irrigation rate and other environmental factors on water balance and growth of plants.
The SD-type sensor consists of an LVDT probe mounted in special fixing brackets and a DC powered signal conditioner.
The probe is connected by a standard 1-meter cable to the waterproof box with the signal conditioner inside.
The output cable length should be specified in the order if required.
SD-5M and SD-6M models have different fixing brackets for the same 5 mm LVDT probe. The SD-5M bracket fits stems with 5 to 25 mm in diameter. The SD-6M bracket is suitable for 20 to 70 mm stems.
|Measurement Range||0 to 5 mm|
|Stem Diameter Range (mm)||SD-5M: 5 to 25 | SD-6M: 20 to 70|
|Sensitivity||0.4 V / mm|
|Noise||< 1 mV w/filter, 1 kHz cutoff|
|Output||SDI-12, RS-485, Voltage or 4..20mA|
|Supply Voltage||10 to 30 VDC|
|Power||SD-5/6M: 1.5 W max | SD-5/6Mi: 2 W max|
|Operating Temperature||0 to 50 ℃|
|Temperature Effect||< 0.02 % total stroke / ℃|
|Excitation Time||5 seconds|
|Cable length between probe and signal conditioner||1 m|
|Cable length between signal conditioner and data logger||5 m (standard) | maximum: 10 m for voltage sensors; 200 m for 4 .. 20 mA sensors|