VLM60 User Manual
Device description
page 4
ASTECH GmbH
1
Device description
The VLM60 is a sensor for detecting the speed of moving objects and measuring the length. It is intended for use
in industrial environments. The measuring principle is based on a correlation method. Even the slightest
movements can be detected in this way. A white light LED with focusing optics illuminates the surface of the
measuring object at an angle. Due to the oblique illumination, the surface structure is reflected into the receiving
optics and received by the primary sensor. The sensor signals are further processed in the evaluation electronics.
The
sensor
enables
2D
measurement, i.e. the movement
of a target can be measured in
both directions, x and y. The
output
of
the
velocity
components is done via two
independent
pulse generators
(encoder emulation) with two
phases each. If required, the
VLM60 can be equipped with an
additional
fieldbus interface
. A
programming interface
is used to
set the behavior of the device by
means of parameters.
Figure 1: Structure of a VLM60
The measuring device is mounted in parallel alignment at the prescribed working distance above or below the
measuring object and automatically detects its movement. The object to be measured must be placed in the
optical axis. Triggered length measurements can also be made by means of an external switching signal. In
addition to the length, the sensor can also output a quality signal "measuring rate R" (0...100%), which allows an
evaluation of the current signal acquisition. Mounting or installation should always be carried out in such a way
that the measuring rate reaches a maximum.
The VLM60 has a white light LED as the illumination source. LEDs are classified with regard to their
photobiological hazard potential; not according to the criteria of laser protection. The standard to be applied for
LEDs is EN/IEC 62471 "
Photobiological safety of lamps and lamp systems
". The LED illuminant used in the VLM60
is assigned to risk class RG-2 (moderate risk). This means that the illuminant does not pose a risk in use due to
the normal behavior of the user (i.e., turning the head away as the natural reaction when looking into a bright
light source). The following note should nevertheless be observed.
It is recommended not to look directly into the illumination source at any time, when the device is
powered on.
Machine directive 2006/42/EC
In the sense of the EU directive “2006/42/EC” the VLM60 is not a machine. Hence there is no conformity
declaration available for the device. The directive 2006/42/EC regularizes the requirements on machines. Here,
a machine is meant to be the entity of connected parts or mechanisms (see also EN 292-1, section 3.1). The
VLM60 is part of the electrical and sensor equipment of a machine. The machine manufacturer must consider
the VLM60 in its process for the declaration of conformity.