Control Unit


The escalator controller is made out of programmable logic control (plc), which can be expanded with standard blocks. For a possible connection to an existing building management system, expansion modules are available with process field bus or Ethernet.

Two plc’s come in use. One on the bottom reverses station, and one on the top. Both controllers are connected via a bus. The plc on the top reverse station works as a master for the bottom one, and for the display.

The bottom plc monitors all the limit switches in the bottom area. If a fault occurs, this is reported immediately to the master controller, which takes over further processing.

Failure in the plc or a fault in the safety chain will lead to immediate shutdown of the escalator.

The top plc monitors all the limit switches in the top area and through the bottom plc all the rest remaining limit switches. Additionally, the motor protection switch, speed monitor, main and brake contactor as well as the brake release will be monitored.
If a malfunction occurs, the escalator is decelerated and stopped. The fault is displayed on the top stairs.
Additional optional functions are gathering the operating hours, counting the drive up and down, count the number of times the stop button and brakes were applied. A restoring of operational data is possible via a switch in the plc. The driving motor is driven by the plc via star or optional drives. The activation of the optional lubricator is also done via the master plc.