Lift operating panels with CANopen interface
Holger Klaus, Hans & Jos. Kronenberg (E-Mail: firstname.lastname@example.org)
Lift operating panels include control devices and display modules. The customer has to connect them with large effort via numerous parallel wires. A fast and easy installation of the operating panels is often impossible.
Solutions and concepts for a direct bus connection of lift operating panels have been discussed for a long time. Partial solutions have been achieved by the definition of a standard connector assignment for the connection of car operating panels. Thus at least the car operating panel could be delivered completely pre-wired and with a pluggable connecting cable. In the lift sector, bus systems are used in many manufacturer-specific ways. If assembly groups of different producers were to be combined to a common lift construction, a uniform standard for a bus system has always been missing. By the definition of the CANopen application profile for lift control systems CANopen CiA-417 a uniform standard has finally been achieved. Hans & Jos. Kronenberg (www. kronenberg.de) have intensively contributed to the definition of this CANopen application profile and have developed a corresponding CANopen device especially for lift operating panels.
The CANopen CBK1 controller can be used in car operating panels and landing stations. It comprises eight inputs and outputs. Up to 16 extensions CBE1 with each eight further inputs and outputs can be connected. The extensions are either available with connectors or with screw terminals. The device disposes of two serial interfaces for the control of devices. Thus for example two digital displays can be controlled without occupying an output.
The existing connectors and connecting cables for the pre-wiring of pushbutton elements have been taken over. Alternatively insulation displacement connectors are used. An advantage is that the different customer-specific wiring with common cathode (active high) or common anode (active low) are no longer necessary. Also the common signal line for input and output (call line) can be removed. Input and output are separated at the 3-pole connector. This does not have any influence on the pushbutton elements and their wiring, but it permits the free assignment of in- and output. Thus it is possible to connect an overload illuminated field and a key switch to a 3-pole connector. Another advantage is the trouble-free realization of the acoustic pushbutton acknowledgement at call acceptance as required by the DIN EN 81-70 (German Industry Standard). This is difficult to realise with conventional wiring. A buzzer with different functions of acoustic acknowledgement is integrated in the default controller.
The wiring of a lift installation can be very large, especially in a big lift group. Corresponding EMC-failures can be experienced. Therefore operational reliability has been given great importance within the design. The CAN network is galvanically separated from the remaining electronic and a CAN choke is used. Each assembly group CBK and CBE includes a self-resetting input fuse and the outputs are short-circuit proof. The parameter settings are additionally saved in an exchangeable EEPROM. Thus the parameters can be assigned to other assembly groups or parameter changes can be carried out by exchanging the EEPROMs.
A project, in which the panels were employed, was the renovation of some lift groups with up to 15 floors in Cologne Seeberg, Germany. Operating panels with high protection against vandalism were requested. The landing stations were required with call pushbuttons, four travel continuation arrows and additionally two floor indicators and a key switch. By means of the CANopen controller the assembly groups on the operating panel could be controlled without any problem. The two displays were connected serially and the remaining components were wired to the eight in- and outputs. Additional CBE1 I/O-extensions were necessary in the car operating panel due to the high number of floors.
At this project the CANopen devices have proven themselves. The parameterization and the connection to the control were simple and uncomplicated. After the completion of the operating panels and the control, subsequent changes requested by the customer could still be made fast and without any problem.Projects like this show that due to the CANopen standard completely wired and parameterised lift operating panels can be integrated into the lift easily.
Source: CAN Newsletter Special Lift 2005 (www.can-cia.org/newsletter)