thuba TMS Manuel page 17

Manual PTB 24 ATEX 1001 X
troller. The RTD is either part of an intrinsically
safe circuit or is itself built to comply with a stan-
dardized type of protection. (For example in
increased safety Ex e)
5. Installation
For installation and operation, the rules of
generally accepted engineering practice, the
provisions of IEC 60079-14: 'Electrical instal-
lations design, selection and erection' and
the instructions set out in this Manual must
be observed.
The design data given on the rating plate of
the temperature controller and safety temper-
ature limiter and any additional data provided
by the manufacturer must always be taken
into account.
5.1 General points
Temperature controllers and safety temperature
limiters are used for controlling or limiting the
temperature of electric resistance heaters in
potentially explosive atmospheres. The temper-
ature controllers and safety temperature limiters
are designed for stationary installa tion only.
5.2 Ambient temperature
To keep the surface temperature below the per-
mitted maximum, it must be ensured that the
ambient temperature remains within the range –
50 °C up to 50 °C or 60°C. The effects of any
other local heat sources (process heat) must
also be taken into account. These must not
cause an additional temperature rise in the ter-
minal box or at the thermostats.
5.3 Selecting the low setting of the safety
temperature limiter
It must be ensured that the low setting of the
safety temperature limiter is below the expected
surface temperature of the heater. Failure to
observe this point can result in malfunctioning of
the safety temperature limiter.
Edition April 2024
Copyright
Abbildung 1
Figure 1
thuba Ltd., CH-4002 Basel
11
Switzerland