Instruction Manual
DM08
5.2
Instructions on potential equalisation and cathode protection
5.2.1 Potential equalisation
The signal outputs (process outputs and the mains supply of the DM08 are galvanic isolated from
each other. The housing and the interference filter of the mains supply are connected to PE.
The electrodes and measuring electronics are related to the potential of the function earth FE of
the sensor. FE is not connected to PE, but may be connected with each other in the sensor junc-
tion box. If the sensor is grounded by using ground disks (earthing rings), these must in connected
with the function earth FE.
At a separate assembly of sensor and display electronics the outer screen of the connecting cable
is connected to the housing of the display electronics and has PE potential. The inner screens of
the electrode line are connected to FE inside the junction box of the sensor and to the mass (GND)
of the display electronics.
Details of all wirings, terminals and drawing can be found in § Electrical connection "Electrical con-
nection".
IMPORTANT!
The display electronics can only process the measuring signal interference-free if this voltage is
referenced to a fixed potential (earth).
Potential equalisation on electrically conductive pipes:
The sensor is electrically connected to the pipeline in the sense of a potential equalisation.
Thus, the pipeline is earthed, and the media and therefore the signal voltage have a solid signal
common.
Potential equalisation on electrically insulated pipes:
Technical changes reserved
-
11
-
