6
► Protect the housing against contact with flammable substances and
unintentional contact� To do so, equip the unit with suitable protection (e�g�
protective cover)�
► Do not press the pushbuttons manually; instead use another object (e�g�
ballpoint pen)�
3 Functions and features
Pressure Equipment Directive (PED): The units comply with section 3, article 3 of
the Directive 97/23/EC and must be designed and manufactured for non-super-
heated liquids of group 2 fluids in accordance with the sound engineering practice�
The unit monitors liquid media�
The unit detects the 3 process categories volumetric flow quantity, consumed
quantity and medium temperature�
Application area
Conductive liquids with the following properties:
• Conductivity: ≥ 20 µS/cm
• Viscosity: < 70 mm
2
/s at 40 °C
Operation in overload conditions can cause cavitation� Operation with
cavitation can damage the pressure-carrying parts�
► Consider the cavitation limits (→ Technical data).
4 Function
4.1 Measuring principle for volumetric flow monitoring
The magnetic-inductive measuring principle means that a magnetic field is gener-
ated in the measuring pipe via current-carrying coils� When a conductive medium
flows through the measuring pipe, the ions therein are diverted perpendicularly to
the magnetic field� Positive and negative charge carriers flow in opposite direc-
tions� The voltage induced is measured by two electrodes that are in contact with
the medium� This signal voltage is directly proportional to the average flow veloc-
ity� The volumetric flow quantity is derived from the inside pipe diameter�
