Plastic or lined piping
Ground disks must always be used with
non-conductive piping materials if com-
pensation currents flow through the fluid.
They can irreparably damage the refer-
ence electrode within a short time due to
electrochemical corrosion.
Such conditions occur especially if:
• the piping is insulated with electrically
non-conductive materials and
• the piping is made of fibreglass or PVC
through which flow highly concentrated
acids and alkalis.
Caution!
Danger from damage due to electro-
chemical corrosion!
• Note the corrosion resistance of the
ground disks!
• Note the electrochemical potential se-
ries in cases where the ground disks
and the measuring electrodes are
made of different material.
Equalising currents in ungrounded metal pipes /
Grounding in an area with severe interference
The fluid may be grounded. In order to
make the most of the electromagnetic
compatibility (EMC) of the Promag 33,
it is advisable to provide two flange-to-
flange links and to connect them jointly
with the transmitter housing to ground
potential.
6 mm² Cu
Ground disks: appr. 3 mm thick
ba009y27
Fig. 28
Potential equalisation with plastic
or lined pipings.
6 mm² Cu
ba009y28
Fig. 29
Potential equalisation with
– equalising currents,
– in areas with severe
interference
Caution!
Promag 33 4 Electrical Connection
Endress+Hauser 29
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