Abstract: According to an aspect, there is provided a communication system for transmitting safety information in an elevator system. The communication system comprises a first node; and a second node; wherein the first node is configured to receive first safety information from a first safety node via two parallel communication channels, to convert the received first safety information into a serial form for transmission in a first safety message over a single communication channel between the first node and the second node and to transmit the first safety message to the second node over the single communication channel; and the second node is configured to receive the first safety message and to convert the first safety information in the first safety message back into the parallel form for transmission via two parallel communication channels to a second safety node.

Abstract: A method for preventive maintenance of an elevator speed sensor system includes at least a first and a second sensor, which are independent of each other. The method includes: determining a reference distance for an elevator car travel between a first door zone and a second door zone, during the elevator car travel, defining continuously a first elevator car speed information from the first sensor and a second elevator car speed information from the second sensor, calculating a cumulative sensor system error by integrating the difference between the first elevator car speed information and the second elevator car speed information, and dividing the cumulative sensor system error with the reference distance to obtain a sensor system performance indicator.

Abstract: The present invention is about a system and method for evaluating the movement of an elevator car within a hoistway. The same is based on gathering movement data of the car by means of a rotation encoder or acceleration sensor. Since these data are counted pulses there is a need to convert them into real movement data. This conversion is calibrated automatically by comparing the movement data with a length distance being passed by the car, wherein said length distance is configured to be unchangeable over the time. Base on the exact movement results gained therewith by means of said calibration one also gets better position results of the car in the hoistway.

Abstract: According to an aspect, there is provided a communication system for transmitting safety information in an elevator system. The communication system comprises a first node; and a second node ; wherein the first node is configured to receive first safety information from a first safety node via two parallel communication channels, to convert the received first safety information into a serial form for transmission in a first safety message over a single communication channel between the first node and the second node and to transmit the first safety message to the second node over the single communication channel; and the second node is configured to receive the first safety message and to convert the first safety information in the first safety message back into the parallel form for transmission via two parallel communication channels to a second safety node.

Abstract: A method for preventive maintenance of an elevator speed sensor system includes at least a first and a second sensor, which are independent of each other. The method includes: determining a reference distance for an elevator car travel between a first door zone and a second door zone, during the elevator car travel, defining continuously a first elevator car speed information from the first sensor and a second elevator car speed information from the second sensor, calculating a cumulative sensor system error by integrating the difference between the first elevator car speed information and the second elevator car speed information, and dividing the cumulative sensor system error with the reference distance to obtain a sensor system performance indicator.

Abstract: This invention relates to a method for defining absolute position information of an elevator car. The method comprises: obtaining continuously a pulse position information of the elevator car; and defining an absolute position information of the elevator car by adding a predefined correction value to the obtained pulse position information of the elevator car. The predefined correction value indicates a drift between the obtained pulse position information of the elevator car and the actual pulse position of the elevator car. The invention also relates to a safety control unit and an elevator system performing at least partly the method.