KROHNE H250 M10 ATEX II3D Ex t EN - Manual (Page 10)

4
ELECTRICAL CONNECTIONS
10
H250 M10
www.krohne.com 03/2011 - 4001348101- MA H250/M10-Ex-II3G-AD R01 en
Electrical connections
4.1 General notes
The signal circuits are electrically connected in the buit-in terminal compartment of the signal
converter.
Unused conduit entries should be closed using approved blind plugs and seals. Ensure that the
seals are tight.
The connecting cables should be selected according to the applicable installation standards (e.g.
EN 60079-14) and the maximum operating temperature. The outside diameter of the connecting
cables must be matched to the sealing area of the conduit entry/entries. The connecting cables
must be fixed and laid in such a way as to be sufficiently protected against damage.
Before connecting or disconnecting the electric connecting cable of the device, ensure that all of
the cables leading to the signal converter are de-energised relative to each other and to the
reference potential of the hazardous area. This also applies to earthing conductors (FE) and
equipotential bonding conductors (PA).
All cores that are not used must be securely connected to the earth potential of the hazardous
area or carefully insulated against each other and against ground (test voltage ≥ 500 V
eff
).
4.2 Power supply
The variable area flowmeter does not require any separate power supply. The required supply
for the built-in electronics is provided via the 4...20mA current output.
4.3 Inputs / outputs
The signal circuits of the variable area flowmeter may only be connected to downstream devices
or circuits that satisfy the requirements of protective extra-low voltage (PELV). The terminal
assignment of the equipment is described in the standard installation and operating
instructions.
AD_H250_M10_II3D_R01_en_4001248101_PRT.book Page 10 Wednesday, March 30, 2011 11:44 AM