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- Series VMM
Installation of VMM
Technical changes reserved
- 13 -
Potential-free installation of the sensor:
If the pipelines cannot be grounded, due to operational reasons, the sensor must be installed
voltage free. To do this, a separate cable must be used to electrically connect these seg-
ments of the pipeline (min. 11.8 kcmil (6 mm²)).
An electrical connection occurring between the sensor and any material used for the instal-
lation must be avoided. Insulating segments must be installed between the sensor and the
pipeline (e.g. PVC pipes or similar).
Subsequently, grounding washers are used to electrically connect the media with the display
electronics. The display electronics must not be connected with the protective ground con-
ductor. This may only be done, if the auxiliary power is 24 V
DC
.
Potential equalization in separate design:
Create the potential equalization in the separate design the same as described in the above
sections. For the potential equalization, the display electronics and the sensor are connected
to each other through Pin 7 of the connecting cable.
4.2.2
Cathodic protectives
Using a cathodic protective unit to avoid corrosion, which put a voltage to the tube wall, it
must be connected to terminal FE. The boards, control panel and internal switches of the
display electronics are on the same potential as FE.
CAUTION! Electric current - comply with limits!
According to EN 61010-1:2012 all electrical circuits with „protective safety isolation with-
out any protection against contacts” must observe the following maximum voltages:
•
Maximum AC voltage (V
eff
)
33 V
•
Maximum DC voltage
60 V.
Make sure that no higher potential is connected to FE.
