Dräger Polytron 7000 Instructions For Use Manual page 20

Electrical connections
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Installing the transmitters in explosion-hazard areas of zone 2 without a
safety barrier
— Use only supply units of the device category 3.
For safety reasons, we recommend that not more than 8 transmitters be

connected to a 2-wire or 3-wire cable.
— Take care that the maximum permissible capacitance and inductance of
connections to the supply unit are not exceeded, also taking the cable into
account.
The safety-related input parameters of the transmitter are:
C = 5 nF, L = 50 µH.
i i
The category 1 marking has to be cut out from the rating-plate label. Once
the unit has been used after installation in the above manner, it may never
be installed in explosion-hazard areas of zone 0 or zone 1 (device category 1
or 2). Explosion hazard!
Installing the transmitter in non-explosion-hazard areas:
For safety reasons, we recommend that not more than 8 transmitters be

connected to a 2-wire or 3-wire cable.
If the transmitters are equipped with relay or pump modules, not more than
4 transmitters should be connected to one cable.
The second cable gland is used for the cable to the next transmitter.
The explosion-protection marking has to be removed from the transmitter.
Once the transmitter has been used after installation in this manner, it may
never be installed in explosion-hazard areas. Explosion hazard!
The following tables show permissible combinations of transmitters, supply

voltages and maximum possible cable lengths.
— The capacitance values are typical values for commercially available
shielded cables with PVC insulation. The use of cables with different capac-
ity values will result in other cable lengths.
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CAUTION
CAUTION
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