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The entity concept.
The Transmitter must be installed according to National Electrical Code
(ANSI-NFPA 70).
When installed in Class II locations the Transmitter shall be installed in an enclosure
with a specified ingress protections of IP6X according to IEC60529 and Dust-tight
conduit seals must be used.
Equipment that is FM-approved for intrinsic safety may be connected to barriers based
on the ENTITY CONCEPT. This concept permits interconnection of approved trans-
mitters, meters and other devices in combinations which have not been specifically
examined by FM, provided that the agency's criteria are met. The combination is then
intrinsically safe, if the entity concept is acceptable to the authority having jurisdiction
over the installation.
The entity concept criteria are as follows:
The intrinsically safe devices, other than barriers, must not be a source of power.
The maximum voltage Ui(V
which the device can receive and remain intrinsically safe, must be equal to or greater
than the voltage (Uo or V
can be delivered by the barrier.
The sum of the maximum unprotected capacitance (C
the interconnecting wiring must be less than the capacitance (C
connected to the barrier.
The sum of the maximum unprotected inductance (L
the interconnecting wiring must be less than the inductance (L
connected to the barrier.
The entity parameters Uo,V
provided by the barrier manufacturer.
5300Q502.doc
2005-12-16
) and current Ii(I
MAX
MAX
or V
) and current (Io or I
OC
t
or V
and Io,I
or I
OC
t
SC
Rev. AD
53 3 3 V 1 1 0 - I N
), and maximum power Pi(Pmax),
or I
) and the power Po which
SC
t
) for each intrinsically device and
i
) which can be safely
a
) for each intrinsically device and
i
) which can be safely
a
, and C
and L
for barriers are
t
a
a
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