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The Rub-Block RB200DN with a PT100 temperature sensor is designed to report the misalignment of a
conveyor or elevator belt. The advantage of the Rub-Block is the fact that it will send a continuous
output signal to the PLC.
The Rub-Block emits a permanent life standby signal. If such a signal is absent, this must be investigated and if required the PT100 sensor must be replaced. As long as the Rub-Block emits a standby signal, it will also emit an emergency contact signal caused by its temperature rising, as soon as a belt touches it. Off-tracking belts running into the side of conveyor equipment will cause friction, which may cause damage to the belt, and may generate heat, fire, or a dust explosion.
The Rub-Block is very easy to install, it will be fitted on both sides of a conveyor or elevator belt.
Once the belt off-tracks and runs onto the brass plate of the Rub-Block, it will create friction and the
temperature of the Rub-Block brass plate increases. The built-in sensor detects the temperature
increase on the principle that 1°C temperature in crease results in a difference in electrical
resistance of 0,348 Ohm.
To assist in easy mounting, two types of Rbu-blocks exist:
Reactangle 100x150 mm: datasheet RB200DN (pdf)
Round 90 mm: datasheet RB100DN (pdf)
The Rub-Block can be used in the following ATEX zones:
ATEX Classification ExII 1D/1G Exi Exe Ta IIc T4°C Da Ip66 TAMB -40°C to 185°C IECEx
PT100
The electrical conductivity of metal (i.e. platinum) is based on the mobility of free electrons.
With increasing temperatures the atoms in the metal lattice of the PT100 sensor will vibrate more
vigorously and thus impede the free flow of electrons towards the positive pole of a voltage
source. This causes a barrier resistance in linear proportion to the temperature. For generating the permanent standby output signal, the PT100 emits a constant test current (ca. 1 mA) charge. The resistance of the PT100 causes a voltage drop (U = R xl) that can be analyzed.
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