phyto sensor DE-1M Dendrometer Instructions
- June 13, 2024
- phyto-sensor
Table of Contents
phyto sensor DE-1M Dendrometer
Product Information
The DE-1M Dendrometer is a highly precise incremental LVDT-based sensor designed for monitoring micro-variations of trunk radius in the micron range. It is used for monitoring growing plants and is manufactured by Phyto-Sensor. The sensor includes a linear displacement transducer (LVDT) mounted on a special rod with a threaded end. When the rod is anchored inside the trunk, the LVDT represents the movement of the trunk surface. The output signal of the sensor follows variations in the distance between the trunk surface and the end of the rod. The DE-1M Dendrometer also features a DC powered signal conditioner. The standard cable length between the sensor and the signal conditioner is 1 meter.
Product Usage Instructions
- Select an appropriate trunk for sensor installation.
- If the tree has rough bark over the cambium, rasp it away and carefully pare down an area of about 6L x 5W cm2. If the tree has smooth bark, no preparation may be needed.
- Drill a hole with a 3.3-3.5 mm bit. It is recommended to drill slowly using a wood drill set to a low torque to prevent excessive tearing of wood fibers. The depth of the hole must be between 3 cm and 9 cm.
- Free the locking bolt and remove the rod from the carriage frame.
- Carefully screw the rod into the tree. If there is difficulty in insertion, clear the hole carefully with the drill bit.
- Once the rod is implanted, set the sensor on the rod and adjust its position. If the trunk is supposed to grow, position the probe close to the point where the spring-loaded rod just touches the trunk. If the stem is supposed to be stable, choose a point somewhere in the middle of the 10-mm stroke of the rod.
- Fix the locking bolt to secure the sensor in place.
- Secure the sensor’s cable on the trunk to prevent occasional movement of the sensor.
Introduction **
**
The DE-1 Dendrometer is a highly precise incremental LVDT-based sensor for
monitoring micro-variations of trunk radius in micron range. The DE-1
Dendrometer includes a linear displacement transducer (LVDT) mounted on a
special rod with threaded end. When the rod is anchored inside the trunk, the
LVDT represents the movement of trunk surface. Thus, the output signal follows
variations of distance between trunk surface and the end of the rod.
The DE-1M has also a DC powered signal conditioner. Standard cable length
between the sensor and the signal conditioner is 1 meter.
Plant growth and water balance affect diurnal behavior of trunk 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 DE-1M Dendrometer allows investigating effects of irrigation rate and other environmental factors on water balance and growth of plants.
Installation
- Select appropriate trunk for sensor installation.
- In trees with rough bark over the cambium, rasp it away and pare down carefully an area of about 6L x 5W cm2. In caulis and species with smooth bark, no preparation may be needed.
- Drill the hole with the 3.3-3.5 mm bits. It is recommended to drill slowly using a wood drill set to a low torque to prevent excessive tearing of wood fibers along the length of hole. The depth of hole must be 3 cm min. and 9 cm max.
- Free the locking bolt and remove the rod from the carriage frame.
- Carefully screw the rod into the tree. If there is difficulty in insertion, clear the hole carefully with the drill bit.
- Once the rod is implanted, set the sensor on the rod and adjust its position. If a trunk is supposed to grow, the rational position the probe is close to the point where the spring-loaded rod is just touch the trunk. If the stem is supposed to be stable, choose a point somewhere in the middle of the 10-mm stroke of the rod.
- Fix the locking bolt.
- Secure the sensor’s cable on a trunk to prevent occasional movement of the sensor.
Outputs
- The DE-1M has the following analog and digital outputs: Analog: 0 to 2 Vdc, or 0 to 20 mA, or 4 to 20 mA, selected by jumpers;
- Digital: RS232, or RS485, or SDI-12, or UART-TTL, selected by micro-switches.
- Only one analog output and one digital output may be active at a time.
- The appropriate positions of jumpers and switches are described below.
- First, please choose a right output cable for connecting the sensor to a datalogger. The cable must be round with four wires for analog outputs and five wires for digital outputs. The maximal diameter of the cable is 6.5 mm.
- The cable length shall not exceed 10 m for all outputs except current outputs and RS485 with about 1 km maximal length.
- Run the cable through the appropriate inlet (see Figure 1) and connect according to the desired output:
- Power wires to XT1
- Analog output to XT6
- Digital output to the appropriate contact of the terminal XT2-XT5
Select the desired type of digital output by using the selector switch as
follows:
IMPORTANT! When using an analog output, the digital selector may be in
any position except SDI – 12!
Select the desired type of analog output by appropriate position of the jumper
XP1, XP4 as follows:
XP2 jumper must be installed for the RS485 output if the sensor is the last chain in the line.
| XP2 WITH Jumper | 120 Ohm termination resistor connected |
|---|---|
| XP2 NO Jumper | No termination resistor |
XP3 changes the level of the UART TTL output.
| XP3 WITH Jumper | 3.3V logic levels |
|---|---|
| XP3 NO Jumper | 5V logic levels |
Power supply
The 7 to 30 Vdc@100 mA regulated power supply may be used for 0 to 2 V analog output, and for all digital outputs.
- Analog outputs require at least 2 seconds excitation time for producing stable output signal.
- Digital outputs transmit output signal a second after application of power.
Data logging
UART / RS232
- Baud Rate = 9600, 8 bit, parity: None, 1 stop bit.
- Decimal data format: XXXXX (mcm).
RS485
- Baud Rate = 9600, 8 bit, parity: Even, 1 stop bit.
- Protocol: Modbus RTU
Modbus register map
| Register address | Protocol address | Access | Parameter name |
|---|---|---|---|
| 30001 | 0x00 | r | Trunk radius Variation (int) |
| 30101 | 0x64 | r | Trunk radius Variation (float) |
| 40001 | 0x00 | r/w | Slave-ID (int). Default: 247 |
SDI-12
In accordance with SDI-12 Standard (version 1.3)
When using analog outputs, all possible measures for reducing instrumental errors shall be undertaken:
- Screened cables.
- Cables with low impedance.
- Twisted pair cables.
- Filtration of the signal with low cutoff frequency.
- Isolated power supply and data logger.
- Digital filtration of the signal.
Calibrations table
| V | mA | mcm |
|---|---|---|
| 0 | 4 | 0 |
| 2 | 20 | 10000 |
Calibrations equations
Specifications
- Measurement (stroke) range 0 to 10mm
- Stem diameter range Over 6 cm
- Analog linear output (selectable) 0 to 2 Vdc 4-20 mA, 0-20 mA
- Digital output (selectable) RS232, or RS485, or SDI-12, or UART-TTL
- Resolution 0.004 mm
- Operating temperature 5 to 50 ºC
- Temperature effect < 0.001 mm/ ºC
- Output auto update time 5 s
- Supply voltage 7 to 30 Vdc
- Current consumption (depends on selected outputs) 35 mA typ. (+20 mA for current output)
- Excitation time 250 ms
- Protection index IP 64
Customer Support
If you ever need assistance with your sensor, or if you just have questions or feedback, please e-mail at support@phyto-sensor.com. Please include as part of your message your name, address, phone, and fax number along with a description of your problem.
BIO INSTRUMENTS S.R.L.
20 Padurii St., Chisinau MD-2002
REPUDLIC OF MOLDOVA
Tel./Fax: +373-22-550026
info@phyto-sensor.com
www.phyto-sensor.com