VLM320 Datasheet0 pages

VLM 320 Series
Angewandte Sensortechnik
Velocity and length sensor
Functional Description
The VLM 320 operates optically without contact, and implements the principle of the spatial filter by means of the use of a
CCD sensor. Spatial filter is the generic term used to describe a measuring principle for the non-contact determination of
the velocity and length of moving materials. The spatial filter is based on the
filtering effect of grid-like structures (grid modulation). The function of the
VLM 320 can be described as follows:
The object to be measured is reproduced through the objective onto the
CCD sensor. The CCD sensor is operated as an optical grid (no image
pickup). The object to be measured is illuminated by an integrated light
source (LED). External light disruptions are effectively suppressed with this
method.
When the object is moved, a signal frequency is generated due to grid
modulation. This frequency is proportional to the velocity at which the object
is moving. The device measures the signal frequency and converts it to a
velocity value.
There are several control circuits that enable automatic adjustment to the
most varied of materials (material surface structure and brightness).
Applications
Suitable for nearly all materials, such as metal, paper, textiles, plastics, rubber, ceramics and timber
Suitable for a wide range of products, including strips, rails, plates, foils, tubes, profiles, cables, wires, ropes, etc.
Caters for various processes such as cutting, positioning, regulation, inspection, quality control
Examples: Length and speed measurement at winders, slitting lines, coating and inspection lines; velocity
measurement in paper machines for example at paper pulp, web and paper; tube and profile length inspection and
provision of velocity signals for testing purposes; velocity regulation and cutting control for extruders
Advantages
The semiconductor chip (CCD) is used as a reference:
greatest proven long-term stability in the market,
excellent short-term stability
Measurements can be taken on virtually all surfaces,
from high-gloss to matte black, as the device adjusts
itself automatically to the task. Even surfaces that could
not be measured reliable with any optical measuring
equipment can now be measured!
Accurate measurements, even if the window is dusty, as
the reference is well protected inside the device
Compact design, best interface flexibility in the market,
including all conventional solutions from analog output to
Profibus; high-accuracy pulse output with 5 ns resolution
as standard
Input for change to standby mode
Output for hardware error and standstill/status
Safe operation (white LED light source)
Easy firmware update/upgrade via PC
Modular design: easy maintenance, new assemblies
can be used for repair or upgrade older units; light
sources and interface boards can be replaced by the
customer itself
Hardware, lighting and temperature self-diagnosis
(error codes and output)
All gauges have internal length calculation, sliding
average, synchronous-, clock- and date functionality
Direct connection of two light barriers possible
High interference immunity thanks to 100% potential
isolation and sophisticated ESD and EMC protection
Replacing of the LED and interface cards is easy for
the customer
Long service life, making the VLM 320 excellent
value for money
High quality standard, made in Germany; with 36months warranty
ASTECH Angewandte Sensortechnik GmbH
Non-contact measuring technology for length, width, distance, position, velocity, laser and CCD cameras
CTG Center for Technology and Trade, Schonenfahrerstr. 5, D-18057 Rostock, Germany
Telephone +49 (0)381 / 44073-0 fax +49 (0)381 / 44073-20 e-mail info@astech.de Internet www.astech.de