thuba TMS Manuel page 3

Temperature monitoring system
with Temperature Controllers and
Safety Temperature Limiters
1. Application
The tempearture monitoring sysetm with tem-
perature controllers and safety temperature lim-
iters type TMS are used in potentially explo sive
atmospheres for controlling, monitoring and lim-
iting the temperature of electric resistance heat-
ing systems during operation. The sensors
employed can be used in water , oil, air or super-
heated stream. The frameproof temperature
controller or safety temperature limiter is housed
in an «increased safety» eenclosure.
2. Definition
2.1 Temperature controller
Under normal operating conditions, the temper-
ature controller keeps the temperature be tween
the preset nominal temperature and the reclos-
ing temperature dictated by hysteresis. The user
sets the nominal temperature on the scale.
Normally no distinction is made between con-
trollers and monitors. The user is free to assign
the capillary tube thermostat either role, i.e. tem-
perature controlling or monitoring. All ther-
mostats are equipped with changeover contacts
for remote indication of the momentary operat-
ing state.
2.2 Safety temperature limiters
The safety temperature limiter prevents the tem-
perature from rising above a preset nominal trip-
ping temperature. Whenever the limiter trips, it
has to be reset manually. Resetting becomes
possible only when the temperature has fallen
about 10% below the limit value.
ZONE 1 ZONE 2 ZONE 21 ZONE 22
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