Chapter 2 Installation and Wiring
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Figure 2-6 Installation position of the step/pallet loss sensor for escalator
2 DetectionPrinciple
Each sensor (5/6) is installed in the return/driving station in the top/bottom machine room,
respectively to detect step loss. Based on signals of speed sensor A/B for the motor, the
system calculates the number of pulses of sensor A/B between two adjacent pulses of
sensor 5/6 to judge whether step/pallet loss occurs.
When a step passes, sensor 5/6 receives the signal and outputs a pulse. Set the time
interval between two adjacent pulses of sensor 5/6 as T and the pulse counting of sensor
A/B within T as X. In the case of no step loss, the X value is within a certain threshold
regardless of the escalator speed. If X exceeds the threshold, the system judges that step
loss occurs. Then the escalator stops running immediately and enters the safety state.
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If the detection principle is not suitable to the use habit of escalator
manufacturers, step loss can be monitored by using sensor 5/6 to detect the
step auxiliary wheel. The prerequisite is to ensure that the auxiliary wheel is
lost while the step gets lost in any way.
To detect whether a pallet of the moving walkway is lost, install sensor 5/6 in the machine
room, as shown in the following figure.
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