WO2005005930A1

WO2005005930A1 - Integrated senor

Info

Publication number: WO2005005930A1
Application number: PCT/IB2004/051084
Authority: WO
Inventors: Wilhelmus F. J. Fojntijn; Nicolaas Lambert; Adrianus J. M. Denissen
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2003-07-09
Filing date: 2004-07-01
Publication date: 2005-01-20

Abstract

An integrated circuit with embedded condition monitor is provided. Said integrated circuit comprises at least one sensor (100) for sensing at least one condition, at least one memory (200) for storing the sensing data of said at least one sensor (100) and a processor means (300) for processing the data stored in said memory (200) in order to condense said data. Accordingly, an embedded condition monitor is provided on an integrated circuit with an associated memory to directly store the sensed data without having to forward this data to an external device. The data stored in the memory can be analysed offline. In a separate process, the processor means is used to condense the data stored in said memory so that more data representing a longer sensed time period can be stored in the memory.

Description

INTEGRATED SENOR

FIELD OF THE INVENTION The invention relates to an integrated circuit with embedded condition monitor as well as to a method for condition monitoring.

BACKGROUND OF THE INVENTION The monitoring of environmental parameters and conditions like temperature, pressure, altitude, acceleration, velocity or the like are important in a plurality of applications. One of these applications is the well-known black-box as used in airplanes to constantly record the relevant data of the airplane like the flight-velocity, the rate of climbing and descending, or the like. Typically, these systems have a predetermined capacity to store data. Therefore, usually only the most recent data are stored. In case of a crash, the stored data are read out in order to determine the cause for the crash. In DE 196 33 286 Al a security system for a airplane is described. A plurality of electronic cameras are distributed throughout the plane in order to visually record the inside of the plane. These cameras are connected via data lines to a central recording medium to record the data thereof. However, the recording medium can only store a predetermined amount of data and therefore a predetermined recorded time period. Furthermore, valuable data can be lost if the data lines between the central recording medium and the distributed cameras are destroyed before the cameras are destroyed and stop recoding. In US 6,208,247 Bl a wireless integrated sensor network is disclosed. The sensors are capable of detecting vibration, infrared radiation, sound or other physical signals indicative of an intruder or condition to be monitored over a wide area. Each network node comprises a sensor, a digital signal processor, a microprocessor and a wireless transceiver for communication with other network nodes. The output data of the sensors are analysed and compared to a stored profile. According to the comparison result the microprocessor switches from a power conserving state to a high power operating state. The microprocessor decides which action is to be taken, i.e. whether to perform more signal processing and analysis, to activate the transmitter, to transmit the result of the analysed data, to transmit the raw signal data or to do nothing. If the analysed data appears to be interesting, this data is transmitted via the wireless transceiver. Merely a memory buffer is provided in the network node for processing purposes and no data is stored permanently in the node. However, the danger exists, that, when one of the receiving stations is damaged, the data transmitted by the network node are lost. Usually, the data of the last seconds or milliseconds before and after an event represent crucial and important data. Therefore, it is desirable to be able, to detect and record this particular data. The above mentioned problem is also known from productions plants, which need to be monitored. Typically, a plurality of distributed sensors are used, which are connected to a central data storage. Therefore, the capacity of the central data storage limits the amount of sensors that can be used. In particular, it is useful, especially when accidents occur, to have a fine grained grid of sensors scattered throughout the system to be monitored. However, constantly monitoring the system by means of the above sensors from a central location is not cost effective, since a great amount of data will be gathered during the years of production. Furthermore, it is also not possible to select just a few of said plurality of sensors and record there data, because it is never known beforehand which sensor will deliver the most valuable data and the amount of data from all combined sensors is too huge to transport and to process effectively and efficiently. Moreover, at some violent events the stream of valuable data from the sensors may be cut off before the sensors itself stop sensing. Accordingly, the same situation occurs as mentioned above, namely that extremely valuable data of a violent event is lost, because the data lines between the sensors and the central units are destroyed before the sensors stop sensing.

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a condition monitor which is able to record monitored conditions over a long period of time and which can be used independently of any central storages. This object is solved by an integrated circuit with embedded condition monitor according to claim 1 and a method for condition monitoring according to claim 12. Therefore, an integrated circuit with embedded condition monitor is provided. Said integrated circuit comprises at least one sensor 100 for sensing at least one condition, at least one memory 200 for storing the sensed data of said at least one sensor 100 and a processor means 300 for processing the data stored in said memory 200 in order to condense said data. Accordingly, an embedded condition monitor is provided on an integrated circuit with an associated memory to directly store the sensed data without having to forward this data to an external device. The data stored in the memory can be analysed offline. In a separate process, the processor means is used to condense the data stored in said memory so that more data representing a longer sensed time period can be stored in the memory. According to an aspect of the invention, the integrated circuit further comprises a communication means 400 for enabling the integrated circuit to communicate with external devices. The data stored in the memory 200 can be accessed by external devices, in order to analyse the data offline. According to a further aspect of the invention, the communication means is adapted to perfonn a wireless communication with external devices, thereby simplifying the access to the data stored in the memory 200. By providing the integrated circuit with a wireless communication means for retrieving the data stored in the memory, it is possible to encase the integrated circuit more robustly, so that it is better protected especially in cases of accidents or other violent events. According to still a further aspect of the invention, the communication means comprises a RF -module for transmitting and receiving RF-signals. According to a preferred aspect of the invention, the communication means can transmit an identification of the integrated circuit. Accordingly, it is easier to find and identify the integrated circuit especially after violent events. According to a further aspect of the invention, the integrated circuit comprises a power storage means for supplying power to the integrated circuit. According to a further aspect of the invention, said RF-module receives an external RF-signal and transforms this signal into electrical energy, which can be stored in the power storage means. Therefore, electrical energy can be transferred wirelessly to the integrated circuit. According to a further aspect of the invention, the power storage means comprises a battery, thereby providing an easy power supply for the integrated circuit. According to still a further aspect of the invention, the integrated circuit comprises at least one solar cell. Therefore, the integrated circuit is independent of external power supplies as well as a life time of a battery. According to a further aspect of the invention, said memory comprises a nonvolatile random access memory, in particular magneto resistive random access memory. The invention also relates to a method for condition monitoring of an integrated circuit with embedded condition monitor. At least one condition is sensed and the data thereof is stored. In a separate process, the stored data is processed in order to condense said data. The invention is based on the idea to combine a sensor, a memory and a processor into an autonomous device that can perform a separate condensing process on the data stored in the memory. Further aspects of the invention are described in the dependent claims. These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWING Fig. 1 shows an integrated circuit according to the first embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 shows a schematic representation of an integrated circuit or sensor device according to a first embodiment. The integrated circuit comprises a sensor 100, a nonvolatile memory 200, a processor 300 and a RF-module 400. The sensor may be any sensor, which can be integrated with or embedded into an integrated circuit. The non- volatile memory 200 is preferably a non- volatile magneto-resistive random access memory NVRAM. The integrated circuit may comprise a battery for insuring the power supply of the integrated circuit. The RF-module 400 may comprise a specific RF tag, so that the integrated circuit can be found and identified easily. The data stored in the memory 200 can be easily retrieved via the RF module 400. The sensing data of the sensor 100 are directly written into the memory 200. A separate condensing process may be started from time to time, i.e. either timed or event driven, e.g. if the memory is full, thus, the processor 300 is only active during these processing. This separate process is performed by the processor 300 in order to integrate or condense the measurements or sensing data of the sensor 100 stored in the memory 200. For instance, the oldest sub-second measurements are averaged over the second measurements, the second value is stored and the sub-second measurements are discarded. The oldest second values are averaged over a minute, the minute value is stored and the second values are discarded. This can be continued for minutes into hours from hours into days, from days into weeks, from weeks into months and from months into years. Spike values may be ignored if the sensor is not reliable or stored if the sensor is reliable. Accordingly, very detailed historic data can be provided in the memory 200. If a plurality of such process monitors are distributed over an area to be monitored, a huge number of locations in the process can be monitored without an additional burden on the transport and processing infrastructure, thus reducing the costs thereof. Having detailed historic data facilitates the tracing of problems as well as the reconstruction of accidents and near accidents so that the safety of the monitored environment can be significantly increased. By condensing the data stored in the memory 200, a significant amount of memory space is saved. Furthermore, the intermittent nature of the condensing process performed by the processor 300 also saves power. Since the sensors are not connected to a central storage but have their own embedded memories, the sensors can keep recording even if the central store is destroyed. In such a case, these sensors with their embedded memories are the only possibility to retrieve data from internal processes about the event leading to the accident. Special care should be taken with the packaging of the integrated circuit. It is especially important that the IC are packed robustly, so that they are protected against any accidents, violent events or hostile environments. Usually, only a part of the sensor will be sticking out of a thick shell of the sensor device. One possible implementation of these sensors are in a chemical process plant, where a plurality robustly encased sensor devices are scattered throughout the plant. These sensor devices are constantly monitoring parameters like the temperature, pressure or flows at selected locations in the process, but merely a small number of these sensor devices are used for the day to day running of the plant. Most of them are just recording the respective parameters until something special happens, i.e. a routine maintenance, a near accident or an accident. In such cases selected sensor devices may be checked, especially those in the vicinity of problem spots. After an explosion or another kind of accident, the search for scattered sensor devices may be performed using an RF scanner. All sensor devices being arranged in the damage section are identified via their RF tags and the data recorded in their memories 200 are retrieved via the RF module 400 by an external wireless communication device. From the identification of each sensor device the exact original location of each of said sensor devices (which are probably found scattered all over the place) can be reconstructed, since the exact location of each sensor device was stored from before the accident for later examination in case of an accident. From the data collected in the sensor devices as well as their positions where they were found after an accident a very detailed historic picture can be constructed regarding the situation at the location where the accident happened. This will lead valuable data for answering the questions of what happened and how it can be prevented in future. The condensing process as performed by the processor 300 can focus onto different aspects, namely on a historic picture and on recording special events as spikes or the like (e.g. discontinuities, rapid changes). However, spikes due to an uncharacterised change of the recorded parameters have to be evaluated carefully, since it has to be determined whether this spike is originated from a malfunctioning sensor or whether any irregular event has happened. The data from similar devices in the vicinity may be used to assess what caused an unusual reading. Preferably, a special part of the memory may be reserved for special events or strange occurrences. For example, the memory 200 may be divided into three different parts, wherein these parts have different sizes. Data will be stored in the first part until this part is full. Then the condensing process is performed on this data so that one value is deduced representing the values stored in the first part of the memory 200. This will be repeated until the second part of the memory is full as well, and the condensing process is performed on the data in said second part in order to derive one value representing this data. Accordingly, the condensing process will only be performed when the first part of the memory or the second part of the memory is full. However, this will lead to an unbalanced load of the memory. Alternative ways to organize and balance the memory are also possible. The above described sensing devices may be used as distributed black-box for example in chemical plants, as disaster recording in plains or cars. However, they can also be used in medical sensing. Since the sensors are integrated on a single chip, the size of these sensors as well as the memory can be significantly reduced, so that they may be placed into a capsule together with a battery. This capsule may be swallowed by a person, so that the sensing device may record several parameters or conditions when travelling through the stomach and digestive system of a patient. When the capsule naturally leaves the body of the patient, the recorded data may be wirelessly retrieved. This can for example be done by arranging an RF sensor in the seat of a toilet. The sampling rate of the sensor can be adapted to the particular situation in which the data needs to be measured. This can be set beforehand or be adapted (increased or reduced) during operation, e.g. according to changes in the sensed parameters or according to the available battery power. By implementing the above described condensing process old data is not thrown away but condensed into one value representing an integrated value of the detected data for a predetermined time period. Accordingly, the time period of valuable measurements can be extended without missing any relevant data. The power supply of the sensor device can be implemented as a battery, an accumulator, or a solar cell or a combination thereof. In particular the combination of a solar cell and an accumulator is very useful, since such a sensor device would be independent of external power supplies and could function for years. Alternatively, an accumulator may be used which can be recharged by the RF module by transforming an external RF signal into electrical energy. Alternatively, the memory may be implemented as a battery backed SRAM. Thoimh this is not a preferred implementation . in some cases like an integrated battery, this might be acceptable. Apart from the above mentioned implementations, the sensor device according to the invention may also be applied in any monitoring environment where small independent sensor devices are useful. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. In the device claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Furthermore, any reference signs in the claims shall not be construed as limiting the scope of the claims.

Claims

CLAIMS:

1. Integrated circuit with embedded condition monitor, comprising: at least one sensor (100) for sensing at least one predetermined condition; at least one memory (200) for storing the sensing data of said at least one sensor (100), and a processor means (300) for processing the data stored in said memory (200), in order to condense said data.

2. Integrated circuit according to claim 1, further comprising: a communication means (400) for enabling the integrated circuit to communicate with external devices.

3. Integrated circuit according to claim 2, wherein said communication means (400) is adapted to perform a wireless communication with external devices.

4. Integrated circuit according to claim 1, wherein said communication means (400) comprises a RF-module (400) for transmitting and receiving RF-signals.

5. Integrated circuit according to claim 2 or 3, wherein said communication means (400) is adapted to transmit an identification signal.

6. Integrated circuit according to claim 4, further comprising: a power storage means for supplying power to the integrated circuit.

7. Integrated circuit according to claim 6, wherein said RF module is adapted to receive an external RF-signal and to transform this signal into electrical energy.

8. Integrated circuit according to claim 6, wherein said power storage means comprises a battery.

9. Integrated circuit according to claim 6, further comprising at least one solar cell.

10. Integrated circuit according to claim 1, wherein said memory (200) is implemented as a non- volatile memory.

11. Integrated circuit according to claim 10, wherein said non- volatile memory (200) comprises a non-volatile magneto resistive random access memory.

12. Method for condition monitoring with an integrated circuit with embedded condition monitor, comprising the steps of: sensing at least one condition; storing of the sensing data, and processing the stored data in order to condense said data.