The VHS flow transmitter measures the flow using the volumetric
principle, and is suitable for fluid, viscous, lubricant media (e.g.
lubricating oil). If the material for the VHS is selected appropriately,
aqueous fluids such as soaps, pastes, and emulsions with
non-abrasive characteristics can also be measured, as long as they
have sufficient lubricity. Because of the volumetric functioning
principle, the device is almost completely independent of viscosity.

The VHS system consists of two interlacing screws which run in
opposite directions, driven by the flowing medium. A magnetically
pre-tensioned Hall sensor positioned outside the flow space detects
the screw flanks, and creates a frequency signal proportional to the
flow. Here, every pulse corresponds to a specific measured
volume. There are no magnets in the flow space.

The OMNI transducer located on the sensor has a backlit graphics
LCD display which is very easy to read, both in the dark and in
bright sunlight. The graphics display allows the presentation of
measured values and parameters in a clearly understandable form.
The measured values are displayed to 4 places, together with their
physical unit, which may also be modified by the user. The
electronics have an analog output (4..20 mA or 0..10 V) and two
switching outputs, which can be used as limit switches for
monitoring minimal or maximal, or as two-point controllers.

The switching outputs are designed as push-pull drivers, and can
therefore be used both as PNP and NPN outputs. Exceeding limit
values is signalled by a red LED which is visible over a long
distance, and by a cleartext in the display. The stainless steel case
has a hardened non-scratch mineral glass pane.

It is operated by a programming ring fitted with a magnet, so there
is no need to open the operating controls housing, and its
leakproofness is permanently ensured.

By turning the ring to right or left, it is simple to modify the
parameters (e.g. switching point, hysteresis...). To protect from
unintended programming, it can be removed, turned through 180 °
and replaced, or completely removed, thus acting as a key.