Patent Publication Number: US-11389835-B2

Title: Sorter performance monitoring method and system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a divisional of U.S. patent application Ser. No. 16/040,860, filed Jul. 20, 2018, which claims priority benefit of U.S. provisional application Ser. No. 62/537,100, filed Jul. 26, 2017, the contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention pertains to a sorter apparatus and method and, in particular, to a technique for evaluating the sorter apparatus, including, but not limited to, determining defects in the sorter apparatus and predicting maintenance needs. The invention can be applied to positive displacement shoe and slat sorters, automated storage and retrieval systems, cross-belt sorters, and the like. 
     Sorter apparatuses tend to be very large systems. In the case of positive displacement shoe and slat sorters, by way of example, the conveying surface can extend for hundreds of feet or more. If the sorter apparatus goes out of specification, it may not be immediately apparent to a maintenance technician, and it may be difficult to determine with precision where a condition exists that, if uncorrected, may result in long-term downtime to the sorter apparatus. 
     SUMMARY OF THE INVENTION 
     The present invention provides a sorter apparatus having a unique diagnostic device that is useful for ongoing monitoring of sorter performance and method of diagnosing or providing long-term evaluation of the sorter apparatus. Embodiments of the invention are capable of predicting maintenance needs of the sorter apparatus with minimal downtime, as the sorter apparatus can be permanently equipped with the diagnostic device and operate continuously with it installed. 
     A method of sorting articles with a sorter apparatus and a sorter apparatus having a conveying surface that is adapted to transport articles in a direction of conveyance and a mechanism adapted to displace articles on the conveying surface, the sorter apparatus having an endless web of bodies travelling in an endless loop defining the conveying surface, according to an aspect of the invention, includes a distributed drive system having at least one drive that is adapted to produce to provide force with at least one of the bodies to propel the endless web. A diagnostic device travels with the web and is positioned at one of the bodies of the endless web. The diagnostic device is adapted to monitor operation of the sorter apparatus and includes at least one sensor that is adapted to detect at least one parameter of a proximate drive that is proximate to the at least one sensor, and a controller adapted to receive the at least one parameter from the at least one sensor. 
     The distributed drive system may includes a linear motor system and the at least one drive comprises at least one stationary linear motor primary that is adapted to produce a magnetic field to provide force in a linear motor secondary with one of the bodies to propel the endless web. The at least one parameter may include a distance between the at least one sensor and the proximate linear motor primary and/or a temperature of the proximate linear motor primary. The diagnostic device may further include an inductive pickup that is adapted to receive power through electromagnetic induction from the magnetic field produced by the proximate linear motor primary and to provide the received power to the diagnostic device. The diagnostic device may further include a wireless interface module that is adapted to receive data from the controller and wirelessly transmit the data to a remote receiver. 
     The at least one sensor may include an acceleration sensor that is adapted to detect the acceleration sensor travels with the endless web. The at least one sensor may include a magnetism sensor adapted to detect magnetic fields surrounding the magnetism sensor as the magnetism sensor travels with the endless web. The sorter apparatus may include at least one stationary surface that is adjacent a lateral edge portion of the endless web of bodies and wherein the at least one sensor further include a distance sensor adapted to measuring a distance between the distance sensor and the at least one stationary surface and positioned at an end of one of the bodies. The bodies may be slats. 
     A method of sorting articles with a sorter apparatus and sorter apparatus having a conveying surface adapted to transport articles in a direction of conveyance and a mechanism to displace articles on the conveying surface, the sorter apparatus having an endless web of bodies travelling in an endless loop defining the conveying surface, according to an aspect of the invention, includes a diagnostic device traveling with the web and positioned at one of the bodies of the endless web. The diagnostic device is adapted to monitor operation of the sorter apparatus and includes at least one sensor, a controller, and a wireless interface module. The sensor is adapted to detect diagnostic data of operation of the sorter apparatus. The controller is adapted to receive diagnostic data from the at least one sensor. The wireless interface module is adapted to receive diagnostic data from the controller and wirelessly transmit the diagnostic data to a remote receiver. An energy harvesting device at the endless web is adapted to wirelessly receive electrical power and supply electrical power to the diagnostic device. 
     The energy harvesting device may be adapted to convert movement of the endless web to electrical power. The endless web may be propelled by at least one linear motor primary that is adapted to produce a magnetic field to provide force to propel the endless web and wherein the energy harvesting device may include an inductive pickup adapted to receive power through electromagnetic induction from the magnetic field produced by the at least one linear motor primary. The diagnostic device may include an acceleration sensor, an inertial sensor, a temperature sensor, a distance sensor, and/or a magnetic field sensor. 
     At least one stationary surface may be adjacent a lateral edge portion of the endless web of bodies and wherein the at least one sensor may further include a distance sensor adapted to measuring a distance between the distance sensor and the at least one stationary surface and positioned at an end of one of the bodies. The at least one sensor may include at least one temperature sensor, wherein the at least one temperature sensor measures at least one of a temperature of the nearby linear motor primary or a temperature of the temperature sensor. The wireless interface module uses Wi-Fi to wirelessly transmit the diagnostic data to a remote receiver. 
     The remote receiver may be adapted to analyze received diagnostic data and identify a possible fault condition. The possible fault condition may be identified based at least in part on a comparison of the received diagnostic data to at least one of a corresponding threshold or to historical data. The diagnostic device may further include a data storage module, wherein the diagnostic data is stored with the data storage module until the wireless interface module wirelessly transmits the diagnostic data to the remote receiver. The bodies may be made from extruded metal and wherein the wireless interface module further includes an antenna positioned adjacent an end of one of the bodies to reduce the body becoming a Faraday shield to the antenna. 
     A method of sorting articles with a sorter apparatus and sorter apparatus having a conveying surface that is adapted to transport articles in a direction of conveyance and a mechanism adapted to displace articles on the conveying surface, the sorter apparatus having an endless web of bodies travelling in an endless loop defining the conveying surface, according to an aspect of the invention, includes a distributed drive system having at least one stationary drive that is adapted to produce to provide force with at least one of the bodies to propel the endless web. A thermal hotspot detection system includes a diagnostic device traveling with the web and a stationary thermal sensor. The diagnostic device is positioned at one of the bodies of the endless web and is adapted to monitoring operation of the sorter apparatus and having at least one sensor adapted to detect a temperature parameter of a proximate drive that is proximate to the at least one sensor, and a controller adapted to receive the at least one temperature parameter from the at least one sensor. The stationary thermal sensor monitors the endless loop and is operative with another controller that is adapted to receive thermal data from the stationary thermal sensor and correlate the thermal images with a portion of the endless loop. 
     The stationary thermal sensor may include a thermal imaging sensor and the other controller may determine which one or ones of the bodies correlate with any thermal image identifying a thermal hot spot. The endless loop may be supported at opposite lateral end portions and the stationary thermal sensor may be directed at the lateral end portions of the endless loop. 
     The distributed drive system may include at least one stationary linear motor primary that is adapted to produce a magnetic field to provide force in a linear motor secondary with one of the bodies to propel the endless web. The at least one sensor further may further sense a distance between the at least one sensor and the proximate linear motor primary. 
     These and other objects, advantages, and features of this invention will become apparent upon review of the following specification in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a sorter apparatus according to one embodiment; 
         FIG. 2  is a sectional view taken along the lines II-II in  FIG. 1  illustrating a linear motor primary and secondary within a slat; 
         FIG. 3  is a perspective view of a the endless web with a portion of a slat removed in order to reveal a diagnostic device; 
         FIG. 4  is a perspective view of a first sensor of the diagnostic device; 
         FIG. 5  is a perspective view of a second sensor of the diagnostic device; 
         FIG. 6  is a block diagram of an electronic circuit of a diagnostic device; 
         FIG. 7  is a three dimensional diagram illustrating sensing capability of an acceleration sensor; 
         FIG. 8  is a three dimensional diagram illustrating sensing capability of a gyroscope sensor; 
         FIG. 9  is a three dimensional diagram illustrating sensing capability of a magnetic field sensor; 
         FIG. 10  is a perspective view of a sorter apparatus according to another embodiment; 
         FIG. 11  is a perspective view of a stationary infrared sensor; 
         FIG. 12  is a perspective view of the stationary infrared sensor in  FIG. 11  taken from the direction XII-XII in  FIG. 11 ; 
         FIG. 13  is an illustration of thermal sensing pixels of bearings passing the infrared sensor in  FIGS. 11 and 12 ; and 
         FIGS. 14 a -14 c    are a logic flow diagram of a program according to an embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and the illustrative embodiments depicted therein, a sorter apparatus  10  includes a conveying surface  22  adapted to transport a plurality of articles  24  in a direction of conveyance  14 . In the embodiment shown in  FIG. 1 , sorter apparatus  10  is a positive displacement sorter, although it will be understood that other types of sorter apparatuses may be used in accordance with the present teachings, such as, but not limited to, carousel-type sorters such as tilt-tray sorters and cross-belt sorters, automated storage and retrieval systems, and other types of material handling systems. 
     As shown in  FIG. 1 , sorter apparatus  10  includes a frame  18  that is adapted to moveably support a plurality of material support members or bodies. The bodies are connected together to form an endless web  12  that defines conveying surface  11  on which articles travel. The web of bodies may comprise of slats  20 . A pusher shoe  26  is mounted around each slat  20  and is adapted to travel in a lateral direction. The lateral movement of pusher shoes  26  allows articles traveling on conveying surface  11  to be pushed off to one of sides and onto an adjacent takeaway conveyor or other structure (not shown) for further transportation to the article&#39;s final destination within a warehouse or other type of material handling facility. By selectively activating the shoes  26  at the appropriate times, the articles may be diverted onto the intended one of the plurality of takeaway conveyors. Sorter apparatus  10  thus functions as a sortation conveyor adapted to sort articles to their appropriate destination, and may be part of a larger material handling system that includes the takeaway conveyors, as well as additional conveyors feeding system  10  and other material handling structures. 
     The sorter apparatus  10  includes a charge end and a discharge end opposite charge end. The charge end receives articles from one or more feed conveyors (not shown). A conveying surface  11  moves the received articles towards the discharge end, and may deliver them to a recirculation conveyor if the pusher shoes  26  fail to divert the articles onto an adjacent takeaway conveyor or other structure. When slats  20  reach the discharge end, they are rotated downward to a lowered position where they then travel underneath the slats  20  that define conveying surface  11 . In the lowered position, slats  20  travel in a direction opposite to direction of conveyance and return to the charge end. At the charge end, the slats  20  are rotated back to their elevated position for further transportation of articles in direction of conveyance. The path of slats  20  thus defines an endless loop. 
     A distributed drive system such as a linear motor propulsion system powers sorter apparatus  10  and moves slats  20  along the endless loop. As shown in  FIG. 2 , the linear motor propulsion system includes one or more stationary drives such as linear motor primaries  28  and a plurality of linear motor secondaries  32  at the slats  20 . The linear motor secondaries  32  may include a magnet plate  30 . Using magnetic fields produced by the linear motor primaries  28 , linear motor secondaries  32  provide a thrust or propulsion tending to propel the endless web. As an example, further details of the construction and operation of linear motors in a sorter apparatus may be found in the commonly assigned U.S. Pat. No. 7,086,519 entitled POSITIVE DISPLACEMENT SHOE AND SLAT SORTER APPARATUS AND METHOD, the disclosure of which is hereby incorporated herein in its entirety by reference. Alternatively, the distributed drive system may include a plurality of distributed mechanical drives for propelling the slats such as disclosed in commonly assigned U.S. Pat. No. 8,813,943 entitled POSITIVE DISPLACEMENT SORTER, and in commonly assigned U.S. Pat. No. 9,499,346 entitled DISTRIBUTED SORTER DRIVE USING ELECTRO-ADHESION, the disclosures of which are hereby incorporated herein by reference. 
     Material handling systems such as sorter apparatus  10  are very large and complex systems that have a service life of many years. Over time, as parts wear and debris gathers in the system, maintenance is required in order to keep the system in proper working order. Such maintenance is most effective if provided to correct problems before failures occur. Such failures can lead to extended down-time for the system and compound the cost of repairs. However, determining when to conduct maintenance is difficult due to the limited accessibility of many components of the sorter apparatus  10 . For example, linear motor primaries  28  are commonly disposed immediately underneath the conveying surface  11 , and normally require a shutdown and partial disassembly of the sorter apparatus  10  in order to gain access to the primaries. In order to gather precise information for predictive maintenance during operation of the system and/or detect other latent faults, a modified slat assembly  50  is provided that includes a modified slat  51  and a diagnostic device  52 . The modified slat  51  is generally the same as any of the unmodified slats  20  and are fitted with a fully functional pusher shoe  26  with the exception that the modified slat  51  includes any mounting or openings necessary for the installation and functioning of one or more diagnostic devices  52 . While it is possible that one of the unmodified slats  20  may be removed and replaced with the modified slat assembly  50  ( FIG. 3 ), in the illustrated embodiment, the modified slat assembly  50  is a permanent fixture in the sorter apparatus  10  or it may be removed after the information is gathered and replaced with an unmodified slat. 
     The diagnostic device  52  includes at least one sensor  54  that travels with the web and may be adapted to detect at least one parameter of a linear motor primary  28  or other distributed drive. The sensor  54  may detect any manner of parameters of the linear motor primary  28  relevant to determining performance, predicting maintenance, or diagnosing faults. For example, the sensor  54  may detect the temperature of the linear motor primary  28  or sensor  54  may detect the distance of the primary from the sensor  54 , which is proportional to the air gap between the linear motor primary  28  and linear motor secondary  32 , or both parameters. In the illustrated embodiment, sensor  54  includes a first sensor assembly  70  ( FIG. 4 ) that includes a contactless distance sensor  72  and a contactless temperature sensor  74 . A contactless distance sensor  72  shown generating a beam  72   a  may, for example, use a laser known as a time-of-flight sensor to determine the distance to the linear motor primary  28 . Such a sensor may be able to determine distance with a resolution of less than 1 millimeter. The distance between a linear motor secondary  32  and a linear motor primary  28  is of critical importance. A distance greater than optimal will decrease the effectiveness of the linear motor by decreasing the torque provided by the motor while a distance less than optimal will risk contact between the primary  28  and the secondary  32 . A contactless temperature sensor  74  generates a beam  74   a  may, for example, use an infrared thermometer to detect the temperature of the linear motor primary  28 . Such information is a direct indicator of the health of the linear motor primary or other distributed drive. 
     As shown in  FIG. 6 , the diagnostic device  52  also includes a controller  92  that is adapted to receive the parameters from the at least one sensor  54 . The controller  92 , for example, may be a processor, a microprocessor, a Field Programmable Gate Array (FPGA), or the like. The controller  92  may conduct analysis, compression, or other manipulation of the parameters. The controller  92  may configure or adjust the sensors as necessary to acquire relevant data. The diagnostic device  52  may also include an energy harvesting system such as a field receiver coil such as an inductive pickup  60  that is adapted to receive power wirelessly through electromagnetic induction from the magnetic field produced by the linear motor primaries  28 . The energy harvesting system allows for the wireless reception of power. This provides power to enable the domestic device  52  to carry out its functions without needing to replace power storage device  61  with a pre-charged storage device. In this way, the diagnostic device  52  can be permanently placed within the sorter apparatus  10 . The conductive pickup  60  may be of any conductive material, such as copper. The conductive pickup  60  may include a coil of conductive material. The magnetic field produced by the linear motor primary  28  may pass through coil and induce a voltage, which in turn creates current in the coil. The conductive pickup  60  may be combined with an energy storage device  61 , such as a supercapacitor or a battery. The energy storage device  61  may provide power to the diagnostic device  52 , and allow for continued operation even when not receiving power directly from a linear motor primary  28  such as when sorter apparatus  10  is not in operation. The energy storage device may be pre-charged before installation into the sorter apparatus in order to provide initial power. 
     Other energy harvesting techniques that are powered through movement of endless web  12  include a dynamo driven from one of wheels  76  that moveably support endless web  12 . The main body of the dynamo can be mounted to slat  51  and drivenly connected with one of wheels  76  supporting that slat. Still other energy harvesting techniques do not need movement of endless web  12  for their operating. Examples of such other energy harvesting techniques include power-cast systems which wirelessly transmits power over radio frequency channels for far filed over-the-air charging. 
     The diagnostic device may include a wireless interface module  90  that is adapted to receive data from the controller  92  and wirelessly exchange data with a remote receiver  94 . The wireless interface module  90  may use any appropriate wireless technology to communicate with the remote receiver  94 , such as Wi-Fi or Bluetooth or the like. The wireless interface module  90  may connect directly with the remote receiver  94 , or alternatively the wireless interface module  90  may connect through an intermediary, such as a router, switch, or hub. Additionally, the diagnostic device  52  may include local data storage device, or memory, to store data locally until such a time the data is retrieved from the diagnostic device  52  or until the wireless interface module  90  is prepared to transmit the data. Such storage could be in any appropriate form, such as non-volatile memory or the like. An antenna  91  may be provided with the wireless interface module  90  to increase the effectiveness of the wireless communication. Because modified slat  51  may be made from an extruded metal and thereby act as a Faraday cage or shield, antenna  91  may be positioned at an open end of the slat  51  such as outside of any wheel assembly plate enclosing the slat ( FIG. 5 ). 
     The remote receiver  94  may be any appropriate device capable of communicating wirelessly, such as a computer, laptop, tablet, or mobile phone. The remote receiver may be capable of doing advanced statistical analysis of the diagnostic data to diagnose or predict faults or maintenance needs in the sorter apparatus  10 . Such statistical analysis may include using historical data from the sorter apparatus  10  or historical data from other sorter apparatuses. The remote receiver  94  may be capable of remote monitoring of the diagnostic data and alerting users when certain thresholds are reached or other anomalies are detected in the data. In this way, maintenance needs can be predicted and faults can be diagnosed with minimal downtime required of the sorter apparatus  10 . Remote receiver  94  may be a component in a warehouse or sortation system management system and may be able to take autonomous corrective action such as shutting down the sorter to avoid a fault damaging the sorter apparatus. 
     The diagnostic device  52  may include several other sensors  54 . For example, the diagnostic device  52  may include an acceleration sensor, such as an accelerometer  56  that is adapted to detect the acceleration of the sensor in three orthogonal axis X, Y, and Z as it travels with the endless web as illustrated in  FIG. 7 . The acceleration data can be passed through a digital signal processor to determine frequency of acceleration of the modified slat or can be used in longer term averages to determine inclination at the system level. The diagnostic device  52  may include a rotation sensor such as a gyroscope  57  that is adapted to detect the rotation of the sensor in three orthogonal axis X, Y, and Z as it travels with the endless web as illustrated in  FIG. 8 . A common form of such a rotation sensor is a digital gyroscope, but other types may be used. The rotation data may be combined with acceleration data produced by sensor  56  to provide robust and accurate direction and motion detection and rotational vibration. Furthermore, using well known mathematics, the rotation data can be used to determine average and relative speed as the rotation sensor passes through known points, such as the charge and discharge ends of the sorter apparatus  10 . 
     Further, the diagnostic device  52  may also include a magnetism sensor, such as a magnetometer  58  that is adapted to detect magnetic fields surrounding the magnetism sensor in three orthogonal north (N) south (S) planes as the magnetism sensor travels with the endless web as illustrated in  FIG. 9 . Magnetism data could be used to detect the orientation and heading of the sensor and thereby the location of modified slat  51  on the endless loop. In particular, the signals produced by a magnetism sensor could be used to determine if the modified slat  51  is on the top or bottom of the sorter apparatus  10  or shifts in heading due to mechanical errors. Magnetism data could also be used to measure the strength and direction of the magnetic fields produced by the linear motor primaries  28  or the presence of any local magnetic fields that are distorting earth&#39;s magnetic field. In the illustrated embodiment, as shown in  FIG. 3 , the diagnostic device  52  combines the acceleration sensor  56 , rotation sensor  57 , and magnetism sensor  58  into a single inertial measurement unit (IMU)  64 . The IMU  64  combines such sensors to provide highly accurate and sensitive position measurements. 
     The sorter apparatus  10  may include one or more stationary lateral surfaces adjacent to the endless web of bodies to prevent excessive lateral motion of the web. The diagnostic device  52  may include a second sensor  80  adapted to measuring a distance between the distance sensor and one of the plurality of stationary surfaces and positioned at one of the bodies of the endless web of bodies. This measurement can help alert a user if the modified slat  51  fails to maintain a uniform distance from the stationary surface as the modified slat  51  travels along the web. As shown in  FIG. 5 , second sensor assembly  80  that further includes a contactless distance sensor  82  and a contactless temperature sensor  84 . Similar to the first sensor assembly  70 , the second sensor assembly generates a thermal detection beam  40  detects the temperature and a time-of-flight beam  42  to detect the distance of the adjacent stationary surface. 
     The diagnostic device  52  disclosed herein has many uses. As noted, it may be a permanent auditing tool in order to monitor the sorter apparatus  10  over its service life. The data can be continuously collected, recorded, and compared as the system ages. The diagnostic device  52  may be used to gather data to compare to other systems. It may also be used as an installation tool. In such an application, the device is applied to the sorter apparatus after installation in order to verify that the system meets installation specifications as well as to diagnose the nature of any deviation from such specifications. Because sorter apparatuses are often relied upon to be operational with little down time, predicting maintenance and diagnosing faults or degradation in performance is highly beneficial. 
     Diagnostic device  52  and sensor  54  may be part of a thermal hotspot detection system  44  that includes device  52  and sensor that travel with web  12  and at least one stationary thermal sensor such as an infrared sensor  46   a ,  46   b  that senses thermal hotspots as the hotspot travels past the stationary sensor. Stationary thermal sensor  46   a  is an infrared camera mounted spaced from endless web  12  and monitoring the endless web as it travels. Sensor  46   a  is particularly focused at opposite lateral sides of the endless web as this is how the web is supported. For example, endless web  12  is supported by wheels or bearings  76  which are supported by a track. If a wheel or bearing becomes frozen it will generate heat which will be sensed by sensor  46   a . Sensor  46   a  is operative with another controller  86  which adapted to receive thermal data from the stationary thermal sensor. Controller  86  may coordinate with another controller which provides overall control for sorter apparatus  10  in order to correlate a sensed hotspot with a portion of the endless loop. Each slat  20  is uniquely numbered so that the hotspot can be correlated with that slat so the wheel or bearing can be identified and replaced. 
     Stationary infrared sensors  46   b  are mounted directly to frame  18  at the level of a tract  78  that supports wheels or bearings  76 . In that manner, wheels or bearings  76  pass directly past sensors  46   b  during operation of the sorter apparatus. An infrared temperature sensor  96  in the illustrative embodiment is a 4×16 sensor array that makes 500 samples per second thereby allowing high speed temperature evaluation of moving objects, namely wheels or bearings  76 . The output of temperature sensor  96  is supplied to an internal controller, such as a microprocessor for processing. An infrared sensor  46   b  is provided on each side of frame  18  in order to monitor the wheels or bearings supporting that lateral side of endless web  12 . Sampling of the temperature of wheels or bearings  76  as they pass temperature sensor  96  is illustrated in  FIG. 12 . Proximity sensors  98  on opposite sides of temperature sensor  96  provide triggering points along with relative speed calculations of wheels or bearings  76 . This allows for a reduction of excess data as the system can capture points of interest and ignore spaces between desired captures. A digital interface  88  supplies operating voltage as well as a digital output and digital input such as from external photo sensors or the like. An Ethernet interface  89  provides high speed transfer of thermal information both locally and remotely via cloud services which can be used by the warehouse of sorter apparatus controller to match hotspot readings with particular wheels or bearings or at least the slat  20  having the failed wheel or bearing. 
     A diagnostic program  200  residing on controller  92  is initiated at  202  by checking at  204  the power level of energy storage device  61  and, if determined at  206  to be adequate, begins an initiation and testing routine at  208 . If it is determined at  210  to be ready for operation then the program enters into an operational loop. If not, error flags and indicators are sent at  212 . 
     In the operational loop, an interrupt request (IRQ) is triggered periodically such as every millisecond. When it is determined at  214  that an IRQ is triggered, all sensors  54 ,  56 ,  57 , and  58  are polled at  216  and the data loaded into a memory array at  218 . Distance sensors  72  and  82  are polled at  220  and recorded at  222  and IR sensors  74  and  84  are polled at  224  and recorded at  226 . When it is determined at  228  that all data has been collected, a Fast Fourier Transform (FFT) is performed at  230  for the data from accelerometer  56  and at  232  for rotational sensor  57 . The quality of the FFT is indicated at  234  and the data is compressed at  236 . 
     It is determined at  238  if onboard RAM is available and, if so, the compressed data is transferred to the available RAM at  244 . If onboard RAM is not available, then it is determined at  240  if local RAM is available in remote received  94 . If so, the data is transferred at  242 . If not then a failure flag is set at  246  and oldest data deleted at  248  to make room for new data. 
     If it is determined at  214  that the program is in an idle interval between interrupt requests, a determination is made at  250  if the wireless interface  90  is awake. If so, power availability is checked at  252  and it is determined at  254  if a wireless connection is established. If not a wireless connection is attempted at  258 . If it is determined at  252  that sufficient power is not available, the wireless system is put to sleep at  256  in order to allow storage device  61  to become adequately charged and the system set to ultralow power operation mode at  260 . When it is determined at  262  that a wireless connection is made, local RAM and onboard RAM are transferred at  266 ,  270 , and  272 . The system then returns to  214  to again determine whether the system is generating an IRQ or staying in idle mode. 
     Changes and modifications in the specifically described embodiments can be carried out without departing from the principles of the invention. For example, the figures depict a combined acceleration, rotation, and magnetic sensor. However, these sensors could be separate or in different combinations to achieve the same result. The figures also depict a combined temperature and distance sensor into a time-of-flight sensor. Again, these sensors could be found in other arrangements in order to achieve the desired result. The invention may be a permanent fixture in the sorting apparatus, but it may also be removed when diagnosis is complete. The invention is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.