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    178 Educational Focus Compilation

    EDUCATIONAL FOCUS: REMOTE MONITORING

    complex and detailed analysis of diagnostic information. Effective objective methods of measuring allow us to document a precise image of the lift. Monitoring

    The lift unit itself can establish communication between the lift unit and the operator or this may be initiated by the operator. In the former case, this might have been preceded by a malfunction, prompting the lift unit to communicate with the operator by means of a brief message using an SMS, fax, e-mail or directly in the diagnosis monitor. In the latter case, the operator communicates with the lift unit to call up diagnostic tools, depending upon how technically developed the lift is. Figures 1 and 2 show some examples of effective monitoring programs offering a series of status and diagnosis displays. Statistics and Database

    It is not only important to have the actual remote diagnosis facility. Statistics are also essential for making a fast assessment of all units involved. All of the data required for the lift are filed in a database including past malfunction situations and the actions taken so that the observer can get a detailed understanding of the unit’s state at the remote location. Diagnosis Tools

    Modern lift control mechanisms with their peripheral devices have a pivotal role to play in diagnosing lift units. They receive a wide array of messages on the state of a

    Figure 2

    In many areas of technology today, it is entirely natural to observe technical processes from a distance and to exert an influence on them from that location. We use all kinds of modern telecommunication equipment ranging from the simple telephone or cellular lines all the way to super-fast Internet connections to monitor and control processes. Remote diagnosis of processes is moving into all areas of modern technology ranging from automation engineering to medical science. And it’s obvious what the benefits are many. Scaling down service costs, faster reaction times to failures or even preventing failures from occurring in the first place by taking controlled preventative actions are just some of the reasons for availing yourself of the benefits of remote diagnosis. At the end of the day, it’s remote diagnosis that provides the prerequisites for doing next-generation service work.

    Systems are used in lift technology these days that make it possible to call up information on system states and exert an influence on these systems, thus constantly increasing quality and reliability. The main differences between these systems are the diagnostic tools. They start with passing on centralized alarms all the way to a

    DIAGNOSIS AT A DISTANCE

    by Peter Zdun

    Figure 1

    EDUCATIONAL FOCUS: REMOTE MONITORING

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    EDUCATIONAL FOCUS: REMOTE MONITORING

    lift unit, such as the state of the safety circuit, the position of the lift, the state of the call and display units, and a wide variety of other information. Fault Memory and the Lift Control Mechanism

    Modern control mechanisms are equipped with a fault memory that indicates the current fault state and how the fault arose. It is often extremely important to ascertain information on previous states before there is a malfunction in order to localize faults. It stands to reason that observing this fault memory is essential for doing modern diagnosis on lift units. We also should not forget that having information on a potential mal- function in the lift’s control mechanism saves time and money. The State of the Safety Circuit

    We can often draw conclusions on faults or sources of faults from the state of the safety circuit. A good example is when the technician sees that the safety contact of the cabin doors is not closed. This makes it much easier for him to zero in on the range of potential malfunctions. It’s fair to say that the safety circuit state display is an impor- tant component of remote diagnosis. The State of the Drive Unit

    Most frequency converters have diagnostic mechanisms, and the frequency converter is integrated into an overall design strategy, either through the lift control mechanism with a serial bus, such as CAN, or by means of a direct connection. Remote diagnosis enables us to set parameters and call up states in the same manner as with the operator’s control mechanism. However, it should be noted that remote parameter adjustment should be done with ut- most caution. The State of the Door Drives

    The door drive can be integrated into a diagnostic strategy just like the drive unit, and there are a series of ways to do this that are analogous to the frequency converter. Serial data exchange between the lift con- trol mechanism and door control unit is definitely a futuristic idea. This allows the exchange of com- mands, feedback, parameters and diagnostic data for remote diagnosis. Lift Performance Data

    The performance data can be ascertained when the lift is traveling. This information is passed onto a diagnosis con- trol center. For tracking these performance data, it is obvi- ously necessary to have special sensors that track the lift’s movement in the lift shaft. An example is the German- based Henning GmbH, that ascertains these data by mea- suring the acceleration in the x-, y- and z-directions and subsequently calculating the performance data as changes in acceleration and delay in the direction of

    travel, the change in velocity at creep rate, changes in path/time in order to localize rail malfunctions, and impact and jolting movements from the rail guides with analysis and documentation in conformity with the ISO18738 standard. Hence, remote diagnosis pro- vides precise and objective information on the travel- ing behavior of the lift being monitored. Door Functioning

    The method of ascertaining traveling behavior described above also enables you to ascertain door functioning. Remote diagnosis identifies malfunctions in the doors’ running behavior and allows preventative actions to be taken. For instance, this enables the replacement rollers before they break down. The Cable Load

    The appropriate sensors allow you to detect the cable load on each of the cables and passes this information onto the diagnostic tool, thus tracking the service life of the load-dependant component parts such as cables, driving discs, bearings and guides much more precisely than with simple trip counters. The State of the Peripheral Devices

    Every peripheral device, such as the light curtain and load measuring instrument, etc. (with fault detector or state control device), can be linked to remote diagnosis for visual data display.

    There is a wide range of diagnostic monitor programs being offered on the market today, although the inter- faces for these programs are not compatible with one an- other. This means that operators with lifts in operations with a variety of different lift control mechanisms may also be using a series of remote diagnosis tools. There will surely be a harmonization of interfaces in diagnostic systems in the future. In Germany, a group of leading lift component manufacturers have joined together to form a CANopen group with the idea of developing a uniform standard protocol (CANopen for lifts) for electrically net- working lift components. They will be exhibiting initial results at a joint stand at the Interlift 2003 fair in Augsburg, Germany, among them remote diagnosis systems based upon the CANopen system. Especially holistic applications, such as integrating lift components into a diagnostic system transmitting data to a remote control center including electronic documentation of the state of the lift, will be pointing the way to the future. If this system has open or standard interfaces, the user will then be able to match the diagnostic tools to the individual unit.

    Peter Zdun is the project manager for elevator controllers with Wittur AG. Zdun has worked with Wittur Germany for the last three years.

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    Escalators, although not the primary mode of transporta- tion, have become a prominent feature of many transit systems, and in terms of safety are often considered benign. However, they pose a far greater risk. Due to the logistics of typical escalator maintenance, safety is routinely com- promised – a fact that is confirmed by an accident rate that is higher than that of elevators.

    What is really disturbing are studies that suggest as few as 15% of accidents are caused by unsafe acts, which means that up to 85% could be prevented. Unfortunately, these problems are often compounded by extended oper- ating hours, intolerance for downtime and a lack of clear statistical data, promoting a “quick fix” approach to repairs where faults remain elusive, and units are returned to service only to fail again. Ultimately, accident expenses spiral as the equipment becomes less safe, satisfaction lessens as shutdowns become prevalent, and repair costs rise as problems increase in severity.

    Realizing these issues, Vertical Analysis pioneered the development of a new system designed to enhance the entire maintenance process, from upper manage- ment to the mechanic in the field. This resulted in Elevision, a real-time remote monitoring and management system for escalators, elevators and other electro-mechanical devices. The system comprises three main comp

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