Heinrichs Messtechnik
Installation and Operation Manual PITe
Page 8 of 22
6 Mode of Operation and System Design
6.1 Mode of operation
Back in 1832, Faraday suggested utilizing the principle of electromagnetic induction for measuring
flow velocities. Though unsuccessful due to superimposed polarization effects, his experiments on the
river Thames are nonetheless regarded as the first in the field of magnetic-inductive flow
measurement.
According to Faraday’s law of electromagnetic induction, an electrical field
E
is produced in a
conductive liquid when moving through a magnetic field
B
at a velocity
v
in accordance with the vector
product E = [v x B].
A liquid at flow velocity
v
and a flow rate
Q
flows through a meter tube (4) producing a measuring-
circuit voltage
Um
at the two electrodes (E1 and E2), which are positioned at right angles to the
direction of flow and the magnetic field
B
generated by the field coils (3). The size of the measured
voltage is proportional to the mean flow velocity and thus the volume flow rate.
6.2 System configuration
The magnetic-inductive PITe-UMF2 (B) flow measurement system consists of a sensor (PITe), which
picks up an induced measuring signal from the medium flowing through the pipe with a known
diameter, and the transmitter UMF2 (B), which transforms this signal into standardized output signals
(4-20 mA or pulses).
The PITe-*** sensor can be operated with all transmitters for magnetic-inductive flow meters
manufactured by Heinrichs Messtechnik. The sensor is installed in the pipe while the transmitter is
mounted separately in the field for better access.
6.3 Installation of the transmitter
The sensor is equipped with a breakout cable and must be connected to the transmitter via a junction
box fitted during installation. The electrode cable is shielded and protected against disturbing
interferences.
The required cable length for the connection to the transmitter must be determined during ordering.
The end of the delivered break-out cable is prepared for an optimal and easy direct connection to the
transmitters junction box. A subsequent shortening or lengthening of the cable could cause EMC and/
or measurement issues if not correctly implemented, for which Heinrichs Messtechnik GmbH shall
take no responsibility.
