![background image](http://html1.mh-extra.com/html/mmf/vm25/vm25_instruction-manual_1813941028.webp)
Set the instrument up on the measuring point, without covering the light beam range
with your fingers. To help with the positioning, the VM25 has a laser pointer which
can be switched on and off by pressing F1.
Caution: The laser beam has a radiation power of < 1 mW at 650 nm
wavelength. Never look into the light beam! It can cause permanent
damage to your eyesight!
Depending on the size of the reflective measurement point the measurement distance
can be between 0.3 and 1 m.
The measurands can be saved by pressing the ▼ key. The saved data record is auto -
matically assigned the number of the VMID measurement point on which the sensor
is placed.
6.11. Temperature Measurement
The temperature measurement is carried out together with the rotational speed mea-
surement. (Figure 35). The VM25 contains an infrared temperature sensor inside the
upper part at the back of the instrument (Figure 34)
To take a measurement, align the instrument with the relevant point. The inbuilt
laser pointer can be used to align the instrument precisely (F1 Key). The best results
can be achieved at a distance of 10 to 20 cm. The directionality of the sensor can be
seen in Figure 36.
Every infrared temperature sensor shows a dependency on the emissivity of the mea-
suring object. The VM25 is calibrated for an emission level of 1. With some materi-
als, such as Aluminum, this can cause measurement errors.
Figure 36: Field of view of the temperature sensor
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