The invention relates to a method, an apparatus and a system for monitoring a time of operation of a device as described in the preambles of claims 1, 15 and 18 respectively.
U.S. Pat. No. 6,307,332 discloses a lamp life meter. The lamp is arranged in a housing, such as of an endoscope light source unit, a copying machine and a projector. The housing contains a control circuit to switch the lamp on or off. The housing has a socket which is suitable to plug into it a lifetime measurement and monitoring module. Said module contains a battery to supply other components contained in the module, such as a processor and a memory. When plugged into said socket, the module is connected to the control circuit inside the lamp housing. When the lamp is switched on the module receives a signal from the control circuit indicating that the lamp has been turned on.
According to said prior art, the hardware of a device which state is to be monitored should be adapted to receive a measuring module and to provide some signal to the module indicating said state. Such adaptation will increase the costs of manufacturing and therefore of its use. In some cases, such as for medical equipment, it may even require additional safety certification. Adaptation may be more difficult to carry out with equipment which is already in use, in particular equipment which is fixedly installed and/or virtually permanent in use, such as pumps and emergency exit lights. In some cases it may even be physically impossible or too costly to carry out such adaptation.
Further, according to the prior art, there are cases where a human being cannot discern directly if a monitored operation of the device, which is monitored, is on or off. For example, the device may be located at a location which is far from the person or difficult to access. In cases alike one cannot be certain that a signal supplied to the module is indeed indicating the state of operation of a monitored part of the device, because said part or a different part of the device may be malfunctioning, such that the monitored part is not operating in spite of being indicated to the module as operating. As a result, a user cannot detect proper operation of the device as expected and the accumulated measured on times of said operation may contain a large uncertainty, which may make the application of such module useless under certain circumstances.
Because of the existence of a large uncertainty about the measured and accumulated on time of a monitored operation of a device it is equally uncertain when to maintain the device, possibly to replace some part of the device, dependent on said measured and accumulated time.
It is an object of the invention to solve the drawbacks of the prior art as described above.
The above object of the invention is achieved by providing a method as described in claim 1.
Accordingly, the time which is measured will always be a true on time of the monitored operation of the device. By absence of uncertainty about the measured and accumulated on time of said operation, one may maintain the device more cost effectively. One may schedule maintenance better with a view on the true progress of the measured accumulated time with respect to a predetermined value before which maintenance must be carried out.
The above object of the invention is achieved also by providing an apparatus as described in claim 15.
The above object of the invention is achieved also by providing a system as described in claim 18.
The invention will become more gradually apparent from the following exemplary description in connection with the accompanying drawing. In the drawing:
The apparatus according to the invention, shown in
The monitored device 1 can be very diverse, for example, a lighting device, a pump, gear box and transportation means.
The operation of which the occurrence or activity is monitored could be a state of being switched on of the device 1 as a whole or a part thereof. However, different kinds of events of the device as a whole or of a part thereof could be monitored, such as a property or amount of activity, for example an intensity of emitted light, an intensity of emitted heat, an intensity of vibration and a magnitude of a linear or rotational speed. In
The apparatus according to the invention, shown in
The apparatus according to the invention, shown in
When a monitored operation of the device 1 is active, this activity is sensed by sensor 6, which then supplies a detection signal to a non-inverting input of comparator 8. An inverting input of comparator 8 receives a threshold signal Thr, which represents a threshold value. If the amount of activity sensed by sensor 6, which is represented by its output, exceeds the threshold value the output of the comparator will flip, in particular from a first logical state to a second logical state. Then the processor 16 will start a counter for counting clock pulses provided by the clock generator 12. Upon a reverse transition of the output of comparator 8 the processor stops counting. The count value represents a value of the time during which the monitored operation was active. The processor 16 retrieves an accumulated measured time value from memory 10. The processor 16 adds the recently counted value to the value retrieved from memory 10 to provide an updated value for the accumulated measured time. Then, processor 16 replaces the accumulated measured time value in memory 10 by the updated accumulated measured time value.
The accumulated measured time value can be retrieved also by a command from input/output part 14 and can then be supplied to the input/output part 14 for further processing, such as to be displayed. Said command may be generated at the input/output part 14, for example manually by pushing a button. Said command may also be received from an additional circuit or apparatus which is not shown in
In the diagram of the explanatory system shown in
The system shown in
The system shown in
The energy scavenger 32 is arranged to receive some kind of energy which is emitted by the monitored device 1, as indicated by the wavy arrow 34, such as heat (by a thermo-electric generator), light (by a solar cell), vibration (by a piezo-electric generator), magnetic field, electrical field and electrical voltage or current. The energy scavenger transforms the energy received from the monitored device 1 to therewith charge the energy accumulator 30. Accordingly, the sensing apparatus 6 to 12, 18 to 20, 30, 32 is self-sustained.
The energy scavenger can be arranged also to receive energy from a different source than the monitored device 1, or from both. For example, the energy scavenger can be arranged to receive and transform solar energy for charging the energy accumulator 30.
Under circumstances the energy received by the energy scavenger 32 is too small to keep the energy level or voltage Vcc of the energy accumulator at a sufficient level for supplying the sensing apparatus. In such a case, scanner 22 will not receive a proper response from the sensing apparatus upon its transmission of said demand for providing the accumulated measured time value stored in memory 10. Preferably, scanner 22 is arranged to detect such condition and to repeat its transmission of said demand by using a higher energy level than before. Then, the higher energy level of the transmission can be sufficient to charge the energy accumulator to a level which is sufficient to supply the sensing apparatus. If the scanner 22 does not receive a proper response still, it may repeat its transmission of the demand by using an even higher energy level than before, and so on. If the scanner does receive a proper response it may store the value of energy level and it may retrieve the stored energy level value for use with future transmissions for accessing the associated monitored device 1.
Under circumstances the sensor 6 and the energy scavenger 32 may be the same component. Examples thereof are a solar cell for sensing operation of a light source, and a vibration sensor for sensing the operation of a machine.
The sensing apparatus may be manufactured with most of its components, its sensor 6 inclusive, integrated in a single silicon substrate. Preferably the sensing apparatus is implemented as a tag, such as a flat self-adhesive tag, which can be adhered to the monitored device 1 or to a part thereof. For example, it can be adhered to a light source or to an armature of a lighting device.
It is observed that, within the meaning of the invention, any number of different entities or properties of the device 1 may be monitored simultaneously. In addition, a value of a monitored entity being below or beyond a threshold value can be considered as an on time of an operation or an event of the device. This allows the recording of data of the operation history of several properties of the device and thus of the device 1 general. In turn, this allows to design and apply a sophisticated maintenance scheme for such a device 1 and groups of devices.
It is also observed that data about an entity or about several entities of operation of the device 1, obtained as described, may be used to generate a feedback signal for a control apparatus which controls the device 1.
It is noted that the scope of the invention is not restricted to the embodiments and examples as described and those shown in the drawings, but that it is defined by the appended claims only.
Number | Date | Country | Kind |
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04104631.9 | Sep 2004 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB05/53065 | 9/19/2005 | WO | 3/21/2007 |