KROHNE ALTOFLUX IFM4042K EEx EN - Manual (Page 6)

5
Galvanical separation of circuits:
•
The internal electrode circuit with type of protection "EEx ib" is galvanically connected to
the aluminum signal converter housing (i.e. PE potential).
•
The current output, the additional power supply and the internal field current circuit are
galvanically connected to each other.
2.1 Detailed description of the output circuits
The terminal compartment of the IFM 4042 K-EEx is, with respect to the explosion protection,
available in two versions. The version can be identified by the information that is listed on the
data plate, which is mounted on the signal converter housing.
Version A: Terminal compartment in "EEx de [ib]" with U
m
= 60 V.
The customer can decide in which type of explosion protection the output circuits - current
output, additional power supply and binary outputs (i.e. pulse and/or status outputs) - can be
driven; in type of protection "EEx ib", "EEx e" or "EEx d".
The safety-technical maximum voltage U
m
(maximum effective AC or DC voltage) of the
mains power supply system for the terminal compartment in type of protection EEx de [ib] is
restricted to 60 V. With this maximum voltage it is guaranteed that the protective components
on which the intrinsic safety of these circuits depends are not overloaded. This condition is
met if the mains power supply system satisfies the PELV requirements in accordance with
IEC 364 / IEC 536.
RESTRICTION !
•
It is not allowed to mix two different types of protection (e.g. current output in
type of protection "EEx ib" and pulse/status outputs in "EEx e" or "EEx d").
Version B: Terminal compartment in "EEx de" with Um = 250 V.
This version is intended for applications were the mains power supply system provides a
maximum safety-technical voltage of U
m
= 250 V. The terminals can either be provided with
type of protection increased safety "EEx e" according to EN 50019 or flameproof enclosure
"EEx d" conform to EN 50018. Type of protection intrinsical safety "EEx ib" is not allowed for
this version.
IMPORTANT NOTES (applicable for both versions)
•
The intrinsically safe "EEx ib" internal electrode circuit is supplied by the IFC 040-EEx
signal converter electronics unit inside the electronics compartment. This circuit is
separated from all other circuits up to a maximum voltage of U
m
= 250 V according to En
50020. The internal electrode circuit with type of protection intrinsic safety "ib" is
galvanically connected with the PE (housing potential).
•
The IFM 4042 K-EEx compact flowmeter must be incorporated within the equipotential
bonding system of the installation in the hazardous area in accordance with the standard
EN 60079-14. Therefore the internal or external M5 clamp terminal (i.e. PE) must be used.
Disconnection of the equipotential bonding system is only allowed when the flowmeter is
not energized.