Abstract: In a method of operating an electronic system (1) a first device (3) of the electronic system (1) sends a message to a second device (6) of the electronic system (1). The second device (6) receives the message, generates a first value utilizing a first function based on at least parts of the history of at least parts of messages previously received at the second device (6), and stores the first value in a memory (8) of the second device (6). The first value is compared 5 with a second value generated at the first device (3), wherein the second value utilizes a second function based on at least parts of the history of at least parts of messages previously sent from the first device (3) to the second device (6). The first and second values are evaluated, and a signal is generated if the evaluating of the first and second values indicates that the history—of the messages previously received at the second device (6) differs from the 10 history of messages previously sent from the first device (3).

Abstract: Systems for identifying and categorizing distributed devices, e.g., lighting fixtures and thermostats, is disclosed. In an embodiment, a user (200) sends a low power discovery message to devices (201) using a portable programming tool (100). The devices (201) within range respond with identification information. The portable programming tool (100) organizes the responses by proximity and sends a “flash” message to the device with the closest perceived proximity. That device responds with a visual or audible signal (202), allowing the user (200) to determine whether that device is the one intended for selection. If so, the user initiates a store routine in which identification information, including category information, is stored in one or more locations, such as, the selected device (201), the portable programming tool (100), and/or a central or local controller (1100). The identification and categorization can, for example, be used to automate load shedding and to reduce energy consumption.

Abstract: Radio frequency identification (RFID) tag assemblies and methods having an RFID semiconductor chip, a conductor and an antenna, the RFID semiconductor chip has an antenna interface mounted on a mounting surface of a mounting substrate and a predetermined operating frequency, the conductor is electrically coupled to the antenna interface of the RFID semiconductor chip, and the antenna is electrically coupled to the conductor and includes a first radiating element lying in a first plane and a second radiating element lying in a second plane that is at an angle relative to the first plane.

Abstract: This invention relates to a method and an apparatus for electronic communication between at least two communication devices. To allow reliable connection setup between the devices which are to be provided for communication at the same time as simple handling, a method according to the invention has the following steps: two communication devices intended for communication are associated with one another by means of a first coupling mechanism, and the communication between the mutually associated communication devices is performed by means of a second coupling mechanism, wherein the first coupling mechanism has a shorter range than the second coupling mechanism or is effected by means of physical contact between the communication devices.

Abstract: Disclosed methods, systems, and apparatuses remotely monitor a plurality of field assets. Device discovery may be conducted to find a communication path through a personal area network (PAN) coordinator to an operations center. A plurality of states are monitored for individual field assets of the plurality of field assets. In response to trigger events, monitored states are selectively included in data sets that may be parsed, tokenized, encoded, encrypted, and forwarded through networks to an operations center.

Abstract: A process for monitoring containers including use of a severable security lock with an radio frequency identification (RFID) antenna adapted sever upon dislocation of the lock. The process utilizes an electronic identification number to ensure security lock integrity. The process includes detecting the security lock in transit by the use of mobile and fixed transmission units at regional boundaries. Updates are provided to an event log associated with the security lock.

Abstract: Methods and systems for location detection are disclosed. One method includes a plurality of base stations of a location system obtaining information about at least one tag associated with the location system. One of the plurality of base stations is designated as a master base station for each tag. Each master base station electro-magnetically transmits beacons to each tag that the master base station has been designated as the master of. Each tag responds to the electro-magnetically transmitted beacons with an acoustic signal that identifies the tag. Multiple of the plurality of base stations, receive the acoustic signal of each tag. A location of each tag is estimated based on times of arrival of each acoustic signal of each tag at each of the multiple base stations, and based on location information of each of the multiple base stations.

Abstract: The invention concerns a contactless portable object (10, 30, 60) featuring a main radiofrequency device made up of a main chip (18, 38, 68) and a main antenna (16, 36, 66) connected together so that, when the portable object enters the magnetic field of a suitable reader, the main radiofrequency device provides power to the chip and ensures communication between the chip and the reader. According to the main characteristic of the invention, the portable object includes a secondary contactless device featuring a secondary antenna (12, 32, 62) and an electric circuit set up in such a way that, when the two antennas enter the magnetic field of a suitable reader at the same time, the amount of energy required to power the electric circuit and have it operational being less than the amount of energy required to power the main chip (18, 38, 68) and have it operational, the electric circuit is powered and makes the reading of data of the main chip impossible.

Abstract: A method and a system are described for improved reading of Radio Frequency Identification (RFID) tags using correcting codes on sets of electronic tags. A reading device requests information from each of a set of electronic tags. The information includes an identification code and a portion of a codeword, the codeword contains a coded message with identification codes of all tags in the set. The information is received from a subset of the set of tags. Portions of the codeword from the received tag information of the subset of tags are assembled. A decoding component to decode the assembled portions and to construct the coded message from the assembled portions of the codeword. Information is individually received from a remaining set of the tags in the set of tags. An enterprise system processes the received information from all tags in the set.

Abstract: A railway positioning system provides an on-board speed measurement device (6) inducing eddy currents in the wayside structure at two spots along the travelling direction, measuring the variations of the magnetic field emitted by the wayside structure and determining position and speed by correlating the 2 measured signals known from U.S. Pat. No. 5,825,177 and a wayside coded tag (1) providing a coding recognizable by the onboard speed measurement device (6). The coded tag (1) consists of a bar (4) with several slots (3) in which metal blocks (2) of different sizes are mounted. The block sizes and positions are selected to represent a coding according to Quadrature Amplitude Modulation.

Abstract: A backscatter passive wireless control system and method employs frequency coding using frequency components generated from an interrogating field using a passive nonlinear element such as a diode in a passive transponder tag. In particular, InterModulation Distortion (IMD) frequency components may be generated which are shifted in frequency from the interrogating signal to assist in backscatter detection at a receiver but are still in band, e.g., in an ISM band. The shifted frequency components may be swept or stepped over a range and passive elements in the tag encode a tag ID by selecting specific frequencies to be backscattered. A manually operated switch may couple an antenna to the transponder to allow battery free control.

Abstract: A license detector system enables a person such as a police officer to monitor vehicles on the road to ensure drivers have valid licenses. Within each valid license is an RFID tag which contains specific information and each RFID tag is able to send that information to a detector when requested. To use the system, the police officer aims the detector at a vehicle, initiates the signal to be received by the RFID tag within the license and waits to receive a signal back from the RFID tag. If a signal is received, then a valid license has been detected within the vehicle. However, if no signal or an invalid signal is received by the detector, then no one, specifically the driver of the car, has a valid license. Upon discovering such information, the police officer should be justified in stopping the vehicle and taking the necessary police action.

Abstract: A sensing device for sensing one or more conditions inside a container is provided. The sensing device comprises a radio frequency based sensor; a support for positioning the sensor in operative proximity to the inside of the container, and a pick-up coil in operative association with the sensor.

Abstract: There is provided a sensor tag device capable of detecting event data by a sensor tag all the time even when no radio wave is received, saving power supply for a microprocessor, and enlarging the radio communication distance. The sensor tag device includes generation means 6 and 7 using one or more environmental changes, power supply voltage rise control means 8, and power supply synthesis means 9, and power is supplied to a microprocessor 12 and event data is stored in the microprocessor 12 when an event, i.e., an environmental change has occurred. A power receiving circuit having a transmission/reception antenna, a built-in power receiving circuit, and the microprocessor and capable of bi-directional communication by radio waves is combined with a stab resonance RF boost circuit and a ladder boost rectification circuit.

Abstract: An information access system including an information device that is adapted for radio communication with a reader/writer, the information device having a detection data acquisition unit acquiring detection data from a sensor, a detection data storage unit holding the most recent detection data, a first receiving unit detecting the reception of an RF signal, and a first transmission unit transmitting a response signal. The reader/writer is adapted for radio communication with the information device and includes a second transmission unit transmitting the information request signal, a second receiving unit receiving the response signal, an accumulation recording unit recording the received detection data, and a detection data accumulation unit accumulating, in the accumulation recording unit, the most recent detection data, and if other detection data has not been accumulated in the accumulation recording unit, accumulating the other detection data in the accumulation recording unit.

Abstract: Disclosed methods, systems, and apparatuses remotely monitor a plurality of field assets. Device discovery is conducted to find a communication path through a master controller to an operations center. A plurality of states are monitored for individual field assets of the plurality of field assets. In response to trigger events, monitored states are selectively included in data sets that may be parsed, compressed, encrypted, and forwarded through a mesh network to an operations center.

Abstract: In one embodiment, a method and apparatus for reducing time expended on non-value added tasks during assembly of an aircraft is provided. A RFID tag reading function of a RFID tag reader integrated into user apparel is enabled. The RFID tag reader comprises a set of touch activation components integrated into the user apparel. A touch activation component in the set of touch activation components is pressed against a surface in proximity of a RFID tag associated with an aircraft component. The RFID tag reader transmits an interrogate signal to an RFID tag associated with the aircraft component. The user observes a display device coupled to the RFID tag reader integrated into the user apparel, wherein the display device displays RFID tag information received from the RFID tag in response to the interrogate signal. The RFID tag information comprises data describing the aircraft component. The user receives the RFID tag information without interrupting an assembly task.

Abstract: A system and method for preventing relay attack on a passive entry system (PES) or other passive system (PS) included within a vehicle or other entity. The relay attack prevention may be based in part on an assessment of whether the fob is able to distinguish signal strength relative to messages communicated form different antennas within the vehicle and/or amongst different signal amplitude communicated from the same antenna.

Abstract: A method for producing a proof of the presence and/or of the availability of an entity in a site over a period that is greater than or equal to a presence threshold, the method including: successively transmitting messages, the messages being generated from a secret such that the secret may be reconstituted by having the knowledge of a given number of messages that is greater than or equal to a threshold, each message being transmitted over a transmission period whose duration is chosen such that the product of the duration of the transmission period times the threshold is substantially equal to the presence threshold; comparing the secret and a secret candidate generated from messages received by the entity; the proof being produced only if the secret and the secret candidate are equal.

Abstract: The invention relates to a device for analysing radio-frequency systems. Such a device comprises means for detecting radio-frequency electromagnetic signals, and means for determining at least one analog property of the radio-frequency signal received form the reader. According to the invention, the device further comprises means for producing an electromagnetic excitation signal in order to excite the radio-frequency tag, and means for determining at least one analog property of the return signal received from the radio-frequency tag. The device permits the effective analysis of RFID systems, for example, in system-installation and error-searching situations.

Abstract: A method for tracking movements in a portable tracking apparatus includes a movement sensor. Virtual object position information is generated and local movement instructions for a user of the portable tracking apparatus is determined based on the generated virtual object position information. The local movement instructions are presented only non-visually to the user and movement of the portable tracking apparatus is determined using the movement sensor. A non-visual feedback is presented to the user of the portable tracking apparatus based on the determined movement of the portable tracking apparatus.

Abstract: An apparatus, system and techniques for determining a location of an RFID tag among a population of tags are disclosed. The system includes an RFID reader with at least one antenna port and a population of RFID tags. The population of tags can be homogenous or heterogeneous. The RFID reader varies its transmit power through one or more antenna ports resulting in a grouping of the RFID tags into clusters. In one embodiment, the reader utilizes multiple antennas to further define RFID tag clusters among the population. Each read tag is then uniquely associated with a defined cluster. Tag agents also can be provided among the population of tags facilitating definition of the clusters.

Abstract: A group proving method includes the following steps. First, a query command is broadcasted to radio frequency identification (RFID) tags, each of which responds the query command with tag identification data. Next, a first round parameter is generated and broadcasted according to the tag identification data, and each RFID tag responds the first round parameter with a first response parameter. Then, a second round parameter is generated and broadcasted according to the first response parameter, and each RFID tag determines whether the second round parameter is received in a predetermined period after the first round parameter was received and whether the first and second round parameters correspond to each other. If so, each RFID tag updates its tag key according to a random number parameter and outputs a second response parameter. Thereafter, group proving data are generated according to the above-mentioned data.

Abstract: The patient identification system of the preferred embodiments includes a transponder that is affixed to a patient and functions to communicate information that identifies the patient to a device or series of devices. The series of devices includes at least a first device that collects data from the patient and communicates with the transponder. The patient identification system is preferably designed to identify a patient, and more specifically to identify a patient to be associated with the data collected by the device. The patient identification system, however, may be alternatively used in any suitable environment and for any suitable reason.

Abstract: One or more secondary data channels are added to existing RFID protocols within the existing bandwidth, data clock rate and message frame times of the protocols. An RFID system is described having at least one reader and at least one tag includes communication between the reader and the tag using a radio frequency carrier signal modulated by a modulation signal to provide a modulated carrier signal conveying digital data in either direction. The modulation signal includes a first encoded modulation signal perturbed by encoded perturbations, the first encoded modulation signal being produced from a first data string. The encoded perturbations are produced from a second data string. The modulation signal modulates the radio frequency signals to transfer data representative of the first and second data strings simultaneously between the reader and the tag. The modulation signal modulates the amplitude, phase, frequency or any combination of the radio frequency carrier signals.

Abstract: There is provided a physical token for use in a defined venue with a server having communication with the physical token. The physical token may comprise an identification data and a transmitter configured to transmit the identification data. The physical token is configured to transmit the identification data to the server to cause the server to initiate a sensory interaction with a user possessing the physical token. The sensory interaction may comprise a character in the defined venue interacting with the user possessing the physical token. The sensory interaction may also comprise a display screen in the defined venue displaying information to the user possessing the physical token. The sensory interaction may further comprise an audio speaker in the defined venue announcing information to the user possessing the physical token. The physical token may represent an affinity comprising an experience, entitlement, or characteristic of the user possessing the physical token.

Abstract: The current invention is a method and system for tracking an RFID tag within a defined 3D space and can be used to identify objects within a live performance and create hotspots with respect to the objects, which allows viewers the ability to select objects that are associated with one of the hotspots, and transmits their interest in the selected object to one or more users. Preferably, the system operates such that hotspots can be created for previously created video, newly created video media, as well as live broadcasts.

Abstract: Disclosed is a tire pressure monitoring system for motor vehicles, including a central unit (2, 7) with at least one trigger module (4), which is integrated into the central unit or connects through control lines (3) to the central unit, and with at least one tire module (6) arranged in a vehicle wheel (5), with the tire module being in communication with the central unit and the trigger module by means of wireless transmission technology, and with the tire pressure monitoring system including fewer trigger modules than tire modules.

Abstract: In a circuit for a data carrier, which data carrier comprise a sensor that is designed for providing a sensor signal that represents an environment parameter and a communication element that is designed for the contact-less communication with an interrogator station, first connection elements for connecting the circuit to the communication element and second connection elements for establishing an electronic connection of the circuit to the sensor are provided, wherein the second connection elements are realized by the first connection elements and wherein the circuit comprises a sensor signal processing stage designed for receiving said sensor signal via the first connection element and for processing said received sensor signal.

Abstract: Methods of determining patch cord connectivity information include receiving, at each of a plurality of RFID readers, a signal from an RFID tag that is associated with a first patch cord and then, identifying the one of a plurality of connector ports that the first patch cord is connected to based at least in part on respective strengths of the signals received at each of the plurality of RFID readers. RFID triangulation systems and methods of calibrating such systems are also provided.

Abstract: A portable consumer device includes a base, and a computer readable medium on the base. The computer readable medium comprises code for an issuer verification value and a supplemental verification value. The issuer verification value is used by an issuer to verify that the portable consumer device is authentic in an on-line transaction and the supplemental verification value is used to verify that the portable consumer device is authentic in an off-line transaction.

Abstract: Enhanced security is provided in an RFID system comprising a plurality of RFID devices and at least one reader which communicates with one or more of the devices. In one aspect of the invention, a first command is transmitted from the reader to write a first data unit to a memory of given one of the RFID devices. A reply is received in the reader from the given RFID device indicating that a second data unit determined based on contents of the first data unit is available in the memory to be accessed by the reader. A second command is transmitted from the reader to the given RFID device to allow the reader to read the memory to thereby obtain the second data unit. The first and second data units comprise information exchanged as part of a cryptographic protocol carried out between the reader and the given RFID device. In an illustrative embodiment, the cryptographic protocol may comprise a challenge-response authentication protocol.

Abstract: In embodiments of the present invention improved capabilities are described for a method of memory mapping disparate memories on a composite radio frequency identification (RFID) tag, where the RFID tag includes a plurality of individual RFID devices each having a memory store with a physical memory address range and mounted to a common substrate, where at least one of the individual RFID devices comprises memory configuration information, and where a memory addressing facility maps the physical memory address ranges of each of the individual RFID devices to a single logical addressing space and presents the address space as a single memory, where the memory addressing facility is included on a computing facility separate from the composite RFID tag.

Abstract: An RFID tag is capable of storing data, receiving a signal from a reader, determining a response taking into account the tag mode and the data, and transmitting a response to the reader. The data includes a first plurality of bits and a second plurality of bits. The tag mode may be set by a current or a prior command by the reader. Depending on the tag mode, the response may be complete, or the second plurality of bits may be truncated, compressed, or encrypted. In an aspect of the invention, the response includes an implicit indication of whether the response is complete, truncated, encrypted, or compressed. In another aspect of the invention, a command from the reader indicates how many bits should be truncated, compressed, or encrypted.

Abstract: A system includes an ordering module, an asset tagging module, a database, and a manufacturer server. The ordering module is configured to receive an order for a component from a web browser. The asset tagging module is configured to receive information for an asset tag from the web browser, and to receive a selection of a location on the component to place the asset tag. The database is configured to store the order for the component, the information for the asset tag, and the location of the asset tag on the component. The manufacturer server is configured to retrieve the order for the component, the information for the asset tag, and the location of the asset tag on the component, and to direct printing of the information on the asset tag and placement of the asset tag at the location on the component prior to placing the component in packaging for the component.

Abstract: A manner of creating an electronic device directory containing the identity of electronic devices that registered in an area associated with a plurality of events, which events are similar in certain respects. The directory is useful, for example, investigating criminal cases. When such an event occurs, an application server is notified and generates one or more device registration capture requests to determine which electronic devices are registered in the area and at approximately the same time at which the event occurs. The device registration capture associated with this event is compared with other device registration captures associated with other, similar events to create the electronic device directory. The electronic device directory entries are preferable filtered to select the devices most likely to be associated with the actual events in question.

Abstract: The present disclosure provides a power rectifier for a Radio Frequency Identification tag circuit. The rectifier is constructed from a pair of complementary MOS transistors. Gates of the transistors have predetermined voltages applied to them. The applied voltages bias the transistors to near their active operating region. During the same time additional control signals are applied to the gates of the transistors, the control signals are synchronous, but out of phase, with each other.

Abstract: A system and method remotely monitor a plurality of meters in a non-wireless service network using a wireless system transmitting short message service messages separate from the non-wireless service network. The system includes a query computer for generating a query message including a command to a selected meter of the plurality of meters, for processing a reply message from the selected meter, with the reply message including a response to the command from the selected meter, and for storing the response in a memory; and a wireless telecommunications network for transmitting completely wirelessly the query message and for transmitting the reply message completely wirelessly from the selected meter to the query computer, for remotely and wirelessly monitoring at least the selected meter in the non-wireless service network. The response in the reply message includes data in a SMS message in a Global System for Mobile Communications format.

Abstract: Transaction processing involves receiving data from an access transaction application of a portable consumer device, wherein the received data comprises data from an access transaction data string that includes a transit verification value wherein, with the exception of the transit verification value, the access transaction data string is substantially similar to a retail data string comprising retail data, wherein the access application data string is adapted for use with an access transaction processing system and the retail data string is adapted for use with a retail processing system. The transaction processing involves processing access transaction application data for selective authorization of the transaction.

Abstract: The invention concerns a medical instrument disinfecting system (1) comprising a disinfecting chamber (4) adapted to implement a cycle for disinfecting the instruments. The invention is characterized in that each instrument (1) comprises identification data (5) and in that the chamber (4) is associated with means (6) for acquiring the identification data of the or each instrument (1) when it is introduced into or withdrawn from the chamber (4) at the start and at the end of a disinfecting cycle, with means (7, 8) for acquiring characterization data of the disinfecting cycle and with means (9, 10, 11, 12, 13) for associating the identification data of the or each instrument and the characterization data of the disinfecting cycle to generate traceability data of the disinfection of the or each instrument.

Abstract: In embodiments of the present invention improved capabilities are described for a Radio Frequency ID (RFID) tag that contains multiple Radio Frequency (RF) network nodes that provide enhanced memory capabilities, redundant functionality, and multiple frequency capabilities to the RFID tag using an inter-RF network node communication connection. The inter-RF network node communication may allow the coordination of RFID tag memory and functionality.

Abstract: A method for improving RFID readers includes transmitting an outgoing RF signal to an antenna through a directional device, and generating a demodulated vector signal from an RF signal related to the RF signal received from the receiver. The method also includes setting the impedance of a controllable-variable-reflectance element with control-parameters from a memory circuit. The memory circuit includes a look up table having therein a corresponding relationship between the control-parameters and an error vector related to the demodulated vector signal.

Abstract: A method, apparatus and system for radio frequency identification provides an on-off keyed amplitude-modulated illumination signal containing a sequence of bits configured to illuminate a radio frequency identification (RFID) tag, The illumination signal is received at the RFID tag, rectified to generate a wake signal for waking a processor which is subsequently powered by a battery. The received illumination signal is sampled and subjected to a thresholding process. Mobile telephone band interference is countered by correlating the sampled illumination signal to determine its bit sequence and then correlating the bit sequence against a predetermined key. An identification signal from the RFID tag is sent in response to a match.

Abstract: A dual-mode RFID reader is capable of automatically switching from a far-field interrogation mode to a near-field interrogation mode upon the detection of certain operating or handling conditions. The RFID reader includes an RFID radio module configured to support a far-field interrogation mode and a near-field interrogation mode, an antenna arrangement coupled to the RFID radio module, and a mode-switch sensor architecture coupled to the RFID radio module. The mode-switch sensor architecture is configured to detect conditions indicative of near-field interrogation, and the RFID radio module automatically configures itself for operation in the near-field interrogation mode upon detection of such conditions.

Abstract: A system is provided for identifying implanted medical devices, leads and systems, as well as objects in close proximity to a patient having an implanted medical device (IMD), using a radio frequency identification (RFID) tag having retrievable information relating to the IMD, lead system and/or patient. An RFID tag communicator includes a circuit for limiting the total continuous transmit time of an interrogation signal, and a time-out circuit for delaying a second and any subsequent interrogation of the RFID tag. An external IMD programmer incorporating a multi-functional RFID reader is capable of identifying and communicating with various types of implanted medical devices, even if such devices are made by different manufacturers.

Abstract: A wireless network communications unit is operable to transmit and receive data for a host device. The wireless network communications unit includes a wireless network communications interface configured to transmit and receive data using a wireless network protocol when a host device having the wireless network communications unit is turned on. The wireless communications unit also includes a tag component detecting when the host device is turned off. In response to detecting the host device being turned off, the unit enters a tag operational mode wherein the tag component is configured to transmit data identifying the host device via the wireless network interface.

Abstract: A method of manufacturing an identifiable roof covering incl. the product thereof, comprising the steps of providing a first layer of material, providing a second layer of material onto said first layer of material and arranging a RFID tag onto the first layer of material prior to providing the second layer of material.

Abstract: Methods and apparatuses for identifying devices, such as RF tags, are described. In one exemplary embodiment, a reader identifies tags without requiring or determining whether a response to an interrogation was a single response from a single tag or multiple responses from multiple tags. In another exemplary embodiment, a method is performed by a tag in an identification system, and the method includes receiving a first data from a reader, and correlating the first data with a first corresponding portion of the tag's identification code, and specifying a match if the first data matches the first corresponding portion, and receiving second data which, combined with the first data, is correlated with a second corresponding portion of the tag's identification code.

Abstract: A method for recognizing time-variable functional states, e.g., in the course of a programming process, in RFID systems is disclosed, which includes at least one transponder or remote sensor and at least one base station, which transmits data and/or power to the transponder or sensor by a carrier signal. According to the invention, after a specified process state is attained at least one confirmation symbol is transmitted by the transponder or sensor to the base station. As a result, no unfavorable “worst case” scenario has to be provided for chronologically controlling time-variable processes because the base station is able to clearly recognize the beginning and end of the process, as well as the state thereof. RFID systems or remote sensor systems can thus be controlled more quickly and more reliably, resulting especially in reduced costs.

Abstract: A method for determining a maintenance interval for a consumable part and/or for equipment containing a consumable part obtains a plurality of measurements of temperature of the consumable part, receives each of the measurements at a totalizing unit, correlates each of the measurements to one of a plurality of temperature subranges, accumulates for each of the subranges an amount of time the measurements of temperature were correlated to each of the subranges, determines a total time by aggregating the accumulated time for each subrange with a weighting function, and generates a signal to prompt a maintenance event when the total time equals or passes a runtime setpoint. In supplement to or in alternative to the above, the method also correlates a subrange of two sequential measurements, indexes a breakpoint register if the correlated subranges are different, and generates a signal to prompt a maintenance event when a value of the breakpoint register equals or passes a breakpoint setpoint.