DF4 Fruit and Vegetable Dendrometer

DF fruit and vegetable dendrometers are specially designed to measureme on fruit bodies of different sizes and shapes. This design allows for stable fixation of the fruit in the dendrometer frame without affecting fruit growth. Depending on the model and conditions of installation, the dendrometer frame can be flexibly attached to the branch/shoot from which a fruit hangs. This installation prevents any straining on the branch/shoot, thus avoiding damage to the fruit being measured.

The DF series comprises four different models:
The models DF5 and DF6 come with a quick-mount fruit holder in which the fruit is easily installed and measured.  Fruit growth is directly measured without mechanical magnification of the respective measuring range (11 and 25 mm). The fruit growth data collected by these models are precise to the nearest micrometer and are therefore suitable for tracking even the finest growth responses.

The DF4 model, on the other hand, comes with a completely different measuring and installation method. Instead of being fixed in a frame, the fruit is clamped in a movable claw. The advantages of this movable claw include quick, easy installation and a notable mechanically magnified measuring range of up to 130 mm. This range is suitable for many types of fruit and thus allows maintenance-free, absolute measurement of a fruit throughout the growth and ripening process.

    DF4, easy installation and maintenance-free measurement through a claw mechanism, large measuring range of 130 mm for large and fast-growing fruits (e.g. apple, orange, peach, tomato, ...)
    DF5: with a measuring range of 11 mm for small fruits (e.g. cherries, grapes).
    DF6: larger measuring range of 25 mm for medium-sized and fast-growing fruits (e.g. plums, nuts, tangerines, apricots)

Advantages

• Suitable for diameters between 0 and 3 cm (DF5), 0 und 5 cm (DF6), or 0 and 13 cm (DF4)
• Solutions for larger diameters on request
• No extra weight load on the fruit   
• Records when ripening occurs in the case of soft fruit and vegetable varieties
• Injury-free installation
• Minimal pressure on the measuring point 
• Maximum stability against wind, snow, falling branches and fruit
• Reliable measurement value

Specific to the DF5 & DF6 models

• Direct micrometer-precise measurement of fruit growth, without mechanical magnification of the respective measuring range (11 and 25 mm).
  
• DF6 with extended measuring range; reduced maintenance effort (i.e. longer time interval between readjustment of the dendrometer frame) for fast-growing species
  
• Specific to the DF4 model
• Mechanically greatly magnified measuring range of up to 130 mm, maintenance-free (no readjustment necessary) measurement of the absolute fruit diameter throughout the fruit formation process.

Limits
    Not suitable for fruits that are too soft (e.g. ripe raspberries)

Technical data

Sensor model name
    

Fruit & Vegetable Dendrometer
Type DF4   

Fruit & Vegetable Dendrometer
Type DF5   

Fruit & Vegetable Dendrometer
Type DF6

Scope of application
    Medium-/large-sized and fast-growing fruit    small-sized fruit    Small- to medium-sized, fast-growing fruit

Suitable for fruit diameter
    10 – 130 mm    0 – 30 mm    5 – 50 mm

Special features/limitations
    

Quick and easy installation with the fruit gripper.

Mechanically greatly magnified measuring range of 130 mm.

Maintenance-free (no readjustment necessary) measurement of the absolute fruit diameter.   

Quick and easy installation with quick-mount fruit holder.

Extended measuring range for medium-sized, fast-growing fruits.

Direct, micrometer-accurate measurement of fruit growth.   

Quick and easy installation with quick-mount fruit holder.

Extended measuring range for medium-sized, fast-growing fruits.

Direct, micrometer-accurate measurement of fruit growth.

Measurement range
130 mm linear (full range, FS)
11.0 mm linear
25.4 mm linear

Resolution
   
Data logger dependent e.g.:
CR300 series: 0.15 µm

Dendrometer logger DL18: 2.5 µm
   
Data logger dependent e.g.:
CR300 series: 0.01 µm

Dendrometer logger DL18: 0.2 µm

Data logger dependent e.g.:
CR300 series: 0.03 µm
Dendrometer logger DL18: 0.5 µm

Accuracy

Dendrometer dependent: max. ± 0.8% of the measured value (stable offset)
Data logger dependent e.g.:
CR300 series: ± (0.1% of the measured value + 3.5 µm)
Dendrometer logger DL18: ± (0.1% of the measured value + 5.5 µm)
Dendrometer dependent: max. ± 4.5% of the measured value (stable offset)
Data logger dependent e.g.:
CR300 series: ± (0.04% of the measured value + 0.3 µm)
Dendrometer logger DL18: ± (0.1% of the measured value + 0.45 µm)
Dendrometer dependent: max. ± 1.97% of the measured value (stable offset)
Data logger dependent e.g.:
CR300 series: ± (0.04% of the measured value + 0.6 µm)
Dendrometer logger DL18: ± (0.1% of the measured value + 1 µm)

Output signal  

Analogue, 0V to 80% of Vex (excitation supply voltage)
Analogue, 0V to Vex (excitation supply voltage)
Analogue, 0V to Vex (excitation supply voltage)

Temperature drift of the sensor
   
< 0.015% of FS/°C in the whole measurement range
   
< 0.2 µm/°C in the whole measurement range
   
< 0.2 µm/°C in the whole measurement range

Linearity
   
< 1%
< 1%
< 0.7%

Operational conditions
    

All Models:
normal outdoor field conditions, -25 to 70 °C, 0 to 100% relative air humidity
    

All Models:
normal outdoor field conditions, -25 to 70 °C, 0 to 100% relative air humidity
    

All Models:
normal outdoor field conditions, -25 to 70 °C, 0 to 100% relative air humidity

Weight (sensor without cable)
   
48 g
15 g
33 g

Power supply

Vex (! stabilized !) 0.5 to 10 VDC,
Power consumption max. 0.28 µWh per measurement
    

Vex (! stabilized !) 0.5 to 10 VDC,
Power consumption max. 0.28 µWh per measurement
    

Vex (! stabilized !) 0.5 to 10 VDC,
Power consumption max. 0.28 µWh per measurement

Material

Stainless steel and aluminium
Stainless steel and aluminium
Stainless steel and aluminium

Sensor cable length

5 m, extendable on request to max. 100 m
5 m, extendable on request to max. 100 m
5 m, extendable on request to max. 100 m