Access Automation
Control electronics
Electronic control system
(click to enlarge)
On a tonnage and volume basis steel is the biggest raw product purchased but in dollar terms the electronic control equipment, weighing only a few kilos, makes up a greater proportion of the overall cost of a cable car.
One of the attractions of the cable car for the engineering mind is the interaction of the mechanical machine with the electronic controls. Many of the cable cars use a programme logic controller or PLC. For example a 10-stop cable car has gates, timers, and very complex control systems to govern the ramping speed up and down the rail.
COP Outcome development and evaluation
The design of the electronic systems is subcontracted to a specialist firm. Over the years Access Automation has developed, in partnership with this firm, a robust safe control system specific to their needs.
The mechanical fail-safe systems are backed up with electronic monitoring. In addition to the two mechanical safety brake systems positioned on the cable car itself, there is an electronic speed monitoring system located on the winch. This monitors the speed of the winch, which pulls the cable car up and down the hill. So if the car starts to over-speed, the electronics will be activated, and if necessary also the mechanical back up safety systems. There are other proactive safety systems. For example when the car is coming in to the landing the computer checks that it is slowing down in the correct manner. The systems have evolved through experience; there are no regulations or standards governing them. They cost a little extra money but Access Automation puts a high priority on safety .
