kubler articles

Absolute and Safe Positioning

Kubler 3/1/2018

Absolute and Safe PositioningNew standards apply since September 2017 for all passenger and cargo elevators. Focus is set on increased safety for elevator users, installers, inspection personnel and service technicians. The demands placed on the elevators industry have increased accordingly. The automation specialist Kubler is the right partner here. The Company has been supplying for many years its encoders to elevator manufacturers. The sensors manufacturer now developed a new measuring system for absolute and safe shaft copying.

Nothing can be left to chance when it comes to safety of persons. This is why passenger and cargo elevators are subjected to particularly stringent standards. In buildings, elevators must operate perfectly and reliably, as nothing is worse than an elevator "standing still," especially for people depending on it. Their main task is to reach the desired floor accurately and to transmit the elevator user a good and safe feeling during the trip. Especially in this branch, the balance between technique and safety is of prime importance. Not least, elevators are today the safest means of transport in the world. 

Exact elevator car positioning

Kubler's linear measuring system is mounted directly on the elevator car. It ensures permanent absolute position measurement, which is required, among others, for the accurate approach at the desired floor. Thanks to the absolute position feedback, no referencing trip is required after a power outage, as absolute position values are available at any time with a 1 mm resolution over the whole travel height of up to 392 meters. The slip-free measurement is another advantage of the direct mounting.

Continuous elevator operation can lead to possible measuring errors due to vibrations or dynamic rope effects. This has absolutely no effect on the linear measuring system, which always guarantees the absolute position of the elevator car. Moreover, the absolute position feedback allows realizing in a simple and uncomplicated way many safety functions required by standards EN81-20 and EN81-50. The absolute position feedback makes additional magnetic switches serving as position references unnecessary. Therefore, the measuring system of this automation specialist contributes to the reduction of overall costs in the elevator shaft. As for all sensors of this manufacturer, focus has been set on robustness for this measuring system. 
 
Setting new compactness standards

Having already developed compact encoder solutions intended for elevator motors such as bearingless encoders for external rotor motors, Kubler also took this important feature into consideration when developing its shaft copying system. According to the manufacturer, it is today the most compact measuring system for absolute shaft copying (135 x 45 x 33 mm). This system can be used without any problem in tightest installation spaces for retrofits, modernizations, e.g. in existing buildings/elevator shafts or for new installations. The compact housing and the robust stainless steel tape that is led through the housing both contribute to the almost noiseless operation of the system.

Nothing is worse than a complex and long installation. The simple installation of this measuring system is an absolutely unique selling feature. The system is supplied as a mounting set consisting among others of two fastening angles, the rolled-up stainless steel tape and a spring element required for pretensioning the tape in the shaft pit. The fastening angles are mounted directly on the elevator rail in the areas of the shaft head and shaft pit. The robust stainless steel tape (V2A) is simply suspended at the shaft head with a snap hook contained in the mounting set and fastened with a spring element in the shaft pit.

The stainless steel tape is directly led through the sensor housing. This ensures highest reliability and functionality In comparison to other measuring systems, Kubler's measuring system for shaft copying requires no additional fastening elements or the like for the installation of the system. In addition, the very robust stainless steel tape forgives scratches or kinks made during installation. It is also insensitive to magnetic screwdrivers. The measuring system is installed in a few minutes. This saves time and money. 
 
The suitable solution for every requirement

This measuring system is designed for travel heights up to 392 meters with a resolution of 1 mm. Therefore, it is the suitable solution for absolute and safe shaft copying for 99.9 % of all elevators worldwide. The measuring system adapts to the requirements of every elevator type and of every situation. The manufacturer offers the elevator branch three combination possibilities with the suitable interfaces (SSI, CAN, CANopen, RS485, CANopen Lift):

-LEB, Basic variant
-LES, Safe variant
-LES, Safe variant + evaluation unit + UCM module 
 
Advantage for the customer: In its Safe variant, this measuring system can be integrated quickly and easily in any safety concept with or without additional components. The customer receives exactly what he defined. Elevators must become even safer. This runs like a common thread through the whole elevator system. Every component must be integrated in the suitable safety concept. The easiest way for the customer is when the single components are already certified. Otherwise, the safety concept must be submitted up to the smallest component to the TUV. This leads to enormous time expenditure and can cause delays for the acceptance and commissioning of the complete system/elevator system. The shaft copying system in the corresponding Safe variants makes the compliance of elevators with the high requirements of standards easier.

In the event of an error in the complete system, the elevator is set in a safe operating state by the triggering of the corresponding safety function. In addition to saving time and costs, the use of such a SIL3-certified and TUV-approved system ensures more user safety and more confidence in the elevator plant.