Temperature Limits; Gases; Dust; Cable Length - Flow vision FC01-Ex User Handbook Manual

Definitions and mounting instructions

2 .4 Temperature limits

2 .4 . 1 Gases

Maximum media temperature in zone 0 is 75°C. This value also depends on the medium used which
might limit the actually allowed temperature.
According to valid standards for use in equipment group II, category 1 (zone 0) and with
regard to avoiding potential ignition sources the temperatures of all surfaces – even with
very rare operating troubles – must not exceed 80% of the ignition temperature of an
inflammable gas, measured in °C .
Therefore the user has to take care that the temperature limits of his particular medium be expressly
stipulated in accordance with the known ignition temperature (see DIN EN 1127-1:2011, German
version, „Explosive atmospheres - Explosion prevention and protection - Part 1: Basic concepts and
methodology;" chapter 6.4.2: hot surfaces, category 1).
For applications in category 2 the special temperature limit must only be exceeded in rarely occurring
operating troubles.

2 .4 .2 Dust

The labelling temperature (T100°C...T130°C) depends on the maximum admissible medium tempe-
rature, see table in special conditions.
Therefore the user has to take care that the temperature limits be expressly stipulated by
means of the determined ignition temperature (to the method stipulated in EN 50281-2-1)
of a cloud of dust or the smouldering temperature of a dust layer of his particular medium
(see EN 50281-1-2, electrical apparatus for use in areas with inflammable dust, para 6:
temperature limitation) .

2 .5 Cable length

The monitoring head CST-Ex is connected to the flow monitor FC01-Ex by means of an 8pole, paired
connection cable with overall shield.
The shield is grounded on both sides, on the potentially explosive and the non-hazardous side, to
prevent inductive interference. To prevent any potentially inflammable currents from flowing over the
shield, it is imperative to observe the following:
Installation has to ensure to a high degree that there is equipotential bonding between
each end of the circuit . In order to ensure that the shield will not become >1 Ohm and
induce potential differences, it may be necessary to ground the shield at additional
positions .
If this is technically not possible, the max. cable length has to be restricted to 50 m (ssee DIN EN
60079-14:2003, German version, Electrical installations in hazardous areas (other than mines), section
12.2.2.3, grounding inductive systems [with example]: special case b).
FC01- Ex | Flow Meter
EX ATMOSPHERE
11