Omega FMG70B Series, User Manual

Page: 8 / 24

Construction and function
- 8 - M-5575/0416
3 Construction and function
Components:

Housing:
The housing consists of aluminum die
casting and has the IP65 degree of
protection.

Electrical connection:
The electrical connection is made via 5-pin
plug M12x1.

Operation / flow indicator LED.

Process connection:
The process connections are available in
different sizes.

Type plate (sticker).
Construction:
The measuring tube with its earthing sleeves and electrodes
passes through the housing and forms the external process
connection of the FMG70B.
A magnetic field for the measurement process is generated
inside the sensor housing, which also contains the sensor
and signal conditioning circuitry.
The two stainless steel electrodes are located in the middle
of the measuring tube between the earthing sleeves.
The FMG70B does not need any moving parts to make measurements. The inside of the
measuring tube is completely open, allowing the fluid to flow unhindered through the
measuring tube.
Function:
The magnetic inductive flow sensor operates in accordance with the principle of induction, i.e.
a DC voltage is generated by the movement of a conductor in a magnetic field:
The measuring tube of the FMG70B is located in a
magnetic field (B).
An electrically conductive liquid (Q) flows through the
measuring tube. The positive and negative charge
carriers are deflected in opposite directions.
A voltage perpendicular to the magnet field is
generated and picked up by the two electrodes.
The resulting induced voltage is proportional to the
mean flow velocity of the liquid.
The electronics of the FMG70B converts the induced
voltage to a flow-proportional frequency signal.