Abstract:
Provided is a method of monitoring conditions of a pneumatic tire comprising a central tread, one or more belt(s) disposed radially inwardly of the tread and an inner-liner disposed radially inwardly of the belt(s), the belt(s) having a side edge. An electronic tag and associated condition sensors are disposed within the tire. The method includes: sensing a first temperature which is temperature of the tire inner-liner adjacent to the bet edge with the electronic tag; sensing a second temperature which is the air temperature within the tire with the electronic tag; and sensing air pressure within the tire with the electronic tag.

Description:
TECHNICAL FIELD 
     The present invention is generally concerned with a process and apparatus for monitoring a condition of a tire, and more particularly with a process and apparatus for monitoring a condition of a pneumatic tire for diagnosing an impending failure thereof. 
     BACKGROUND OF THE INVENTION 
     In order to transport bulk materials, such as coal, iron ore and other minerals, the mining industry uses Off-The-Road (OTR) vehicles that typically weigh up to 250 tons when fully loaded, with the result that exceedingly high internal stresses are imposed on the tires of such vehicles in the course of their daily use. Such internal stresses, which are primarily attributable to a number of factors including driving at excessive speeds, are so destructive of such tires that it is not uncommon to have to replace the tires. On the other hand, in order to maximize the productivity of OTR vehicles, they are normally driven as fast as possible until a user perceives that the internal physical condition of any given tire is marginal. Whereupon, the operator either stops, in the case of a loss of tire pressure, or reduces the speed of the vehicle, in the case of an excessive temperature condition, to relieve the internal stresses giving rise to the marginal condition, thereby prolonging the life of the tires. Thus the speed of an OTR vehicle is controlled on the basis of the operator&#39;s perception of the condition of the tires at any given time. And, if the operator&#39;s perception is erroneous, the productivity of the vehicle is unnecessarily reduced. 
     Accordingly, a long-standing need of the mining industry has been to ensure that the operators of OTR vehicles are provided with accurate information concerning various conditions of the tires of such vehicles, with a view to maximizing the productivity of the vehicles. 
     Various attempts have been made in the prior art to meet the aforesaid need, most recently by mounting integrated circuits within each of the tires of an OTR vehicle, for detecting respective conditions related to an imminent failure of each tire and providing the OTR vehicle operators with timely information concerning such conditions. 
     For example, U.S. Pat. No. 5,562,787, issued to Koch et al., disclosed a method and apparatus for monitoring respective conditions in the tires of vehicles. The apparatus comprises a monitoring device that is connectable to the interior of a tire and includes an integrated circuit having a transmitter. In addition, the monitoring device includes a plurality of sensors connected to the integrated circuit. The sensors continuously detect respective conditions of the tire and provide corresponding signals to the integrated circuit. The integrated circuit is programmed to periodically sample the tire condition signals, to compare the respective samples to respective standards, to generate respective tire condition signals based on the comparisons, and to provide an information signal to the operator of the vehicle when any tire condition signal is indicative of a marginal condition of the tire. In addition, the integrated circuit is programmed to be normally dormant but to transmit information signals concerning the then current tire condition signal to the operator in response to receiving a wake-up signal from the operator. Moreover, the integrated circuit may also be programmed to store data corresponding to periodic tire condition signals for historical, record keeping, purposes, and to cause the transmitter to transmit such historical data in response to receiving another wake-up signal. 
     As discussed in European Patent No. EP 0 936 089 A2, published Aug. 18, 1999, in order to avoid the stress, strain, impact and cyclic fatigue that such monitoring devices are ordinarily exposed to when mounted within a tire, the prior art integrated circuits along with the attached transmitter and sensors have been encapsulated in rigid or semi-rigid materials, such as urethanes, epoxies, polystyrene resins, hard rubber compounds, or the like. The encapsulations have then been assembled with a battery connected thereto. The resulting assembly, know in the prior art as an electronic tire tag, has then been wrapped with a green rubber material forming a housing therefor, and the housing has thereafter been added to the structural green rubber material forming a tire assembly and been vulcanized therewith for forming a cured tire. The cured tire thus includes an electronic tire tag embedded in the tire and forming a part thereof, and is discarded when the tire is discarded. 
     To provide for repair and replacement of such electronic tire tags, the aforesaid European Patent, which is assigned to the assignee of the aforesaid U.S. Patent, discloses a method and apparatus for removably mounting such tags within a tire. The apparatus includes a rubber patch, which may be vulcanized with the tire but is preferably separately vulcanized and attached to a vulcanized tire. The rubber patch includes a housing having a cavity formed therein. The cavity has a sidewall and is dimensioned for removably receiving therein the electronic tire tag. The electronic tag of the European Patent includes the above discussed structure of the U.S. Patent, including a transmitter, sensors and a battery, it being noted that the aforesaid U.S. Patent is incorporated by reference into, and made a part of, the European Patent. In addition, the European Patent calls for the optional inclusion of an antenna extending from the encapsulation. Assuming the provision of the antenna, opposed slots are formed in the sidewall of the housing for receiving the antenna when the tag is removably connected to the housing of the rubber patch. For retaining the tag in the housing, the housing and tag are respectively provided with compatible connecting means, such as the structures discussed in the European Patent, wherein the tag is either removably pinned, splined, threadably connected or interlocked to the housing. 
     Notwithstanding the aforesaid advancements of the prior art, the data provided to the operators of OTR vehicles, concerning the temperature conditions of the tires of such vehicles, continues to inaccurately reflect marginal conditions of the tires, due to various factors. For example, the practice of the prior art is to mount electronic tire tags centrally of the innerliner of a tire, in order to minimize the effects of stress, strain, impact vibration and cyclic fatigue imposed on the electronic tags. As a result, the monitoring devices sample tire temperatures at a location that is removed a considerable distance from the area of the tire where the temperature is most closely indicative of a marginal condition signaling an impending breakdown of the tire, that is, the temperature at the side edges of the belts, and thus near the shoulder portions of tires, where delaminations of the ply, belts and surrounding rubber materials occur due to the build up of internal stresses. In order to compensate for the difference between the sensed temperature and the temperature at such side edges, the prior art integrated circuits have algorithms that apply a scaling constant to the sensed temperature to calculate the temperature from the center of the innerliner to the vicinity of the shoulder portions of the tire. Unfortunately, the tire temperature at the center of the innerliner of a given tire may be significantly less than the temperature at shoulder portions of the tire, and change with different tire designs. 
     Accordingly, in addition to the problem of tag location, it has been found that the prior art algorithms inaccurately calculate the temperatures at the side edges of the belt, due to such calculations being based on adding a constant temperature factor to the temperature measured at the centerline of the tire to compensate for the distance that the temperature sampling sensor is spaced from the side edges of a belt. Since the location of the temperature sensors and such calculations result in providing erroneous information to the operators of OTR vehicles, the operators may prematurely reduce the speed of such vehicles. The consequent adverse effect on the productivity of such vehicles is costly to the mining industry. 
     SUMMARY OF THE INVENTION 
     According to the invention, there is disclosed a method of monitoring conditions of a pneumatic tire. The pneumatic tire comprises a central tread, one or more belt(s) disposed radially inwardly of the tread and an innerliner disposed radially inwardly of the belt. The belt(s) having a side edge. An electronic tag and associated condition sensors are disposed within the tire. The method includes the steps of sensing a first temperature which is the temperature of the tire innerliner adjacent to the belt edge with the electronic tag. A second temperature is sensed which is the air temperature within the tire with the electronic tag. Also, the air pressure within the tire is sensed with the electronic tag. 
     The sensing of the conditions is performed by sensing at a sequence of discrete time intervals. A value of one or more of the conditions sensed at an immediately previous time interval is compared to a current value of the one or more conditions. At a current time interval, the process includes the step of determining whether select one or more of the conditions has changed by a threshold amount since an immediately previous time interval. 
     The select one or more conditions is either or both of the first and second temperatures and the threshold amount is plus or minus two degrees centigrade. Further, the select one or more conditions is the air pressure within the tire and the threshold amount is plus or minus two pounds per square inch. 
     Also according to the method, the electronic tag can be disposed adjacent a shoulder portion of the tire and/or at an area of the innerliner where the tire is thickest. The electronic tag can also be disposed at an area of the innerliner where the tire is least able to dissipate heat or at an area of the innerliner where the temperature samples are the most closely related to determining whether or not an internal breakdown of the tire is imminent. 
     Also according to the invention, there is disclosed a method of monitoring at least one condition of a pneumatic tire ( 10 ), the pneumatic tire by disposing an electronic tag within the tire adjacent a shoulder portion of the tire. The at least one condition is selected from the group consisting of a first temperature which is the temperature of the tire innerliner adjacent to the belt side edge, a second temperature which is the air temperature within the tire; and air pressure within the tire. The sensing the at least one condition is by performing sensing at a sequence of discrete time intervals. Also the method includes comparing a value of the at least one condition sensed at an immediately previous time interval to a current the value of the at least one condition. The steps include at a current time interval, determining whether the at least one condition has changed by a threshold amount since an immediately previous time interval. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     As shown in the drawings, wherein like reference numerals designate like or corresponding parts throughout the several views: 
     FIG. 1 is a partial, one-half, cross-sectional view of a pneumatic tire having mounted therein an electronic tire tag according to the invention; 
     FIG. 2 is an enlarged transverse cross-sectional view of the general details of the tag of FIG. 1, showing the encapsulating and mounting structures thereof; 
     FIG. 3 is a block diagram of a portion of an electronic control system according to the invention; 
     FIG. 4 is a block diagram of another portion of the electronic control system shown in FIG. 3; 
     FIG. 5 is a flow chart portraying a portion of a process according the invention; and 
     FIGS. 6A and 6B comprise a flow chart portraying another portion of the process shown in FIG.  4 . 
    
    
     DEFINITIONS 
     “Bead” generally means an annularly shaped, member located within either of the inner radial end portions of a tire; 
     “Bead Portion” generally means either of the opposed radial inner end portions of the carcass of a tire including a bead, the portion of a ply which is looped about the bead, and the rubber material surrounding the bead and ply portion. 
     “Carcass” generally means the tire structure including the beads and ply, but excluding the belt structure, undertread over the ply and the tread. 
     “Equatorial Plane” means the imaginary plane extending perpendicular to the axis of rotation of the tire and passing through the center of the tread; or the plane containing the circumferential centerline of the tread. 
     “Ply” generally means a cord-reinforced layer of rubber-coated, radially deployed material. 
     “Radial” mean directions extending radially toward or away from the axis of rotation of the tire. 
     “Sidewall” generally means the radially-extending portion of a tire. 
     “Tread width,” means the arc length of the outer circumference of the tread of a tire as viewed in transverse cross-section. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows half of a partial transverse cross-sectional view of a typical pneumatic tire  10 , for an OTR vehicle  11 , mounted on a wheel rim  12  thereof. Since the tire  10  is generally toroidally-shaped and symmetrically arranged with respect to an imaginary equatorial plane  14 , the transverse cross-section of the other partial half of the tire includes like or corresponding parts, and it should be understood that the explanation applies to the other half of the tire  10  as well. 
     The tire  10  which has a cavity  16  for receiving pressurized air when the tire is mounted on the wheel rim  12 , generally comprises a central tread  16  having opposite sides generally indicated by the numeral  18 . In addition, the tire  10  includes a plurality of radially-extending belts, exemplified by the belts  20  and  22 , that are centrally disposed radially-inwardly of the tread  16 . The belt  20  has opposite side edges  23 , and the belt  22  has opposite side edges  24 . Further, the tire  10  includes a carcass  25  having opposite sidewalls  27 . The respective sidewalls  27  merge with and radially-extend inwardly from opposite tread sides  18  and form therewith opposite shoulder portions generally indicated by the numeral  28 . The carcass  25  also includes opposite bead portions  29  at the radial inner ends thereof. Each of the bead portions  29  includes an annularly-shaped bead  29 A therein for urging the bead portions  29  into abutment with the wheel rim  12 . Moreover, the carcass  25  includes one or more plies  30 , radially disposed inwardly of the belts  20  and  22 . The ply  30  radially extends between and is looped about the opposed beads  29 A. And, the carcass  25  includes a radially extending innerliner  35  disposed radially inwardly of the ply  30 . 
     According to the invention, an electronic tire tag  40  (FIGS. 1 and 2) is preferably fixedly secured to the innerliner  35  of the tire  10  at an area thereof which is located substantially directly radially-inwardly of a side edge  23  of the belt  20  that is closest to the innerliner  35  of the tire  10  and thus adjacent to a shoulder portion  28  of the tire  10 . Since the tag  40  is thereby located adjacent at the an area of the innerliner  35  where the tire  10  is thickest and least able to dissipate heat, the temperature measurements taken at this location are the most closely related to determining whether or not an internal breakdown of the tire  10  is imminent. The breakdown is typically due to internal stresses causing delaminations of the belts  20  and  22 , ply  33  and surrounding vulcanized rubber material  36  at the shoulder portions  28  of the tire  10 . FIG. 1 also shows the relative dimensions of the width “w 1 ” of the tire tread  16  of a typical OTR vehicle  11 , that is, substantially 3 to 4 feet, and the width “w 2 ” of the tag  40  connected thereto, that is, substantially 3 inches. 
     The electronic tag  40  (FIGS. 1 and 2) generally comprises a microcontroller  42  and first temperature sensing structure  44  electrically connected thereto for sampling the temperature of the innerliner  35  of the tire  10 . In addition, the tag  40  includes second temperature sensing structure  46  electrically connected to the micro-controller  42  for sampling the air temperature within the tire  10 . Further, the tag  40  generally includes pressure sensing structure  48  electrically connected to the micro-controller  42  for sampling the air pressure within the tire  10 . Moreover, the tag  40  includes transmitter structure  50  electrically connected to the micro-controller  42  for transmitting relevant information concerning the respective samplings taken by the temperature and pressure sensing structures  44 ,  46  and  48 . Still further, the tag  40  preferably includes a battery  51  that is conventionally electrically connected to the microcontroller  42  for energization thereof. The pressure sensing structure  48  includes a tubular portion  52  thereof extending from the tag  40 . In addition, the transmitter structure  50  preferably includes an antenna  58 . The tag  40  also includes structure  60  for connecting the tag  40  to the tire  10 . The connecting structure  60  preferably includes a first internally threaded nut  62 , and an externally threaded bolt  64 . The bolt  64  is permanently threadably connected to the first nut  62  and has a threaded portion  64  thereof extending from the tag  40 . The tag  40  is preferably entirely encapsulated in a encapsulation material  65  such as a mixture of epoxy and glass beads coated with urethane. 
     The encapsulated tag  40  (FIG. 2) is preferably not directly connected to the innerliner  35  of the tire  10 . Rather, according to the invention, a vulcanized rubber patch  70 , having embedded therein a second internally threaded nut  71 , is affixed to the innerliner  35  of the tire  10 . Preferably, the patch  70 , has a lens-shaped transverse cross-section, defined by a substantially flat side  72  having a generally circular perimeter being connectable to the innerliner  35  of the tire  10  and an arcuately-shaped inner side  73  disposed on the opposite side of the patch. Side  72  of the patch  70  is dimensioned for disposition in abutment with the substantially arcuately shaped area of the innerliner  35  of the tire  10  at the shoulder portion  28  thereof. Side  73  of the patch  70  faces the interior of the tire  10 . The encapsulated tag  40  has a substantially rectangularly-shaped transverse cross-section and includes a substantially straight side  74 . The encapsulated tag  40  is connected to the patch  70  by threadably connecting the bolt portion  64 A, extending from the tag  40 , to the second nut  71 . Due to the arcuate shaped transverse surface  73  of the patch  70 , the side surface  74  of the attached tag  40  is separated from the patch  70  along substantially one-half of the arcuately shaped surface  73  of the patch  70 . A generally circular central portion  73 A of the surface  73  is substantially in abutment with surface  74  when the bolt portion  64 A of the tag  40  is threadably connected to the nut  71  of the patch  70 . Concurrently, the bolt portion  60  (FIG. 1) of the connected tag  40  is located substantially in abutment with an area of the innerliner  35  adjacent to a belt edges  21  at the shoulder portion  28  of the tire  10  for sensing the temperature thereat. While the connected tag  40  is preferably located at the shoulder portion  28  adjacent to the ends of the one or more belts  20 , 22 , it is also within the terms of the invention to locate the tag  40  near or on the center line  14  of the tire  10 . 
     Preferably, the first temperature sensing structure  44  (FIG. 2) is then conventionally thermally connected through the interconnection substrate  4 , such as a printed circuit board (PCB), to bolt  64  for sensing the temperature thereof and thus the temperature at the innerliner  35  where the patch  70  is attached. 
     The aforesaid arcuate transverse cross-section of the patch  70  (FIG. 2) is believed to prevent the patch  70  and attached tag  40 , or the tag  40  and attached nut  71 , from separating from the tire  10  in the course of rotation thereof. In this connection it is noted that as the tire tread  16  (FIG. 1) adjacent to the area of the innerliner  35  where the patch  70  and tag  40  tag are connected thereto rolls into contact with the ground, the tread  16 , and thus the innerliner  35  and the radially outwardly extending side  72  of the attached patch  70 , flatten. Thereafter, as the tire tread  16  (FIG. 1) adjacent to the area of the innerliner  35  where the patch  70  and tag  40  are connected thereto rolls out of contact with the ground, the tread  16  and thus the innerliner  35  and the radially outwardly extending side  72  of the attached patch, abruptly assume the arcuately-shape form thereof show in FIG.  1 . As a result of the abrupt conformation of the innerliner  35  and the radially outwardly extending substantially flat side  72  of the patch conforming to the arcuately-shaped form thereof shown in FIG. 1, the flexure stress imposed on the patch  70  and attached tag  40  may cause patch  70  and attached tag  40 , or the tag  40  and attached nut  71 , to eventually separate from the innerliner  35  of the tire  10  in the course of rotation thereof. It has been determined that when the inwardly extending side  73  of the patch  70  is arcuately shaped as shown in FIG. 2, the patch  70  is able to flex without imposing significant flexure stresses on the attached tag  40 . 
     As shown in greater detail in FIG. 3, the micro-controller  42  includes a first conventional microprocessor  80 , having ports p 1  through p 28  inclusive. The first microprocessor  80  internally includes a conventional analog to digital (AID) converter  82 . In addition, the first microprocessor  80  internally includes a conventional multiplexer  82 A that is conventionally electrically connected to a plurality of the ports, p 2 -p 5  and p 7 , of the microprocessor  80 . Moreover, the microprocessor  80  internally includes a conventional clock circuit  83  connected to ports p 9  and p 10  thereof. 
     Further, the transmitter structure  50  (FIG. 3) includes a second conventional microprocessor  84  having an internal counting circuit  85 , that is conventionally electrically connected to the first microprocessor  80 , at port p 11  thereof, for receiving and sending respective reset signals “Rs” and data signals “Ds” via respective data and reset leads “Ld ” and “Lr”. Preferably, the first and second temperature sensing structures  44  and  46  (FIG.  4 ), are directly electrically connected to the first microprocessor  80 , at ports p 2  and p 3  thereof, for providing respective first and second temperature sampling signals “Ts 1 ” and “Ts 2 ” thereto. Optionally, the micro-controller  42  may include first and second operational amplifiers,  90  and  92 , respectively connected between the first and second temperature sensing structures  44 ,  46 , and the first microprocessor  80  for providing amplified temperature sampling signals, Ts 1  and Ts 2 , thereto. In addition, the micro-controller  42  preferably includes an instrumentation amplifier  95 , conventionally electrically connected between the pressure sensing structure  48  and the first microprocessor  80 , at port  7 . Furthermore, the micro-controller  42  preferably includes conventional reference voltage generating structure  96  that is preferably directly connected to the pressure sensing structure  48 , for providing respective reference voltage signals “Vref” thereto. The reference voltage generating structure  96  is preferably additionally conventionally connected to the first microprocessor  80 , at port p 5  thereof, for providing thereto a reference voltage sample signal “Vref”. Optionally, the micro-controller  42  may also include of a third operational amplifier  98 , conventionally electrically connected between the reference voltage generating structure  96  and the pressure sensing structure  48  for providing an amplified reference voltage signal Vref thereto. The pressure sensing structure  48  (FIG. 1) samples the air pressure of the tire  10  via the tubular portion  52  (FIG. 2 thereof extending into the tire cavity  16 , and provides first and second analog pressure signals “Ps 1 ” and “Ps 2  “(FIGS. 4 and 5) corresponding thereto to the instrumentation amplifier  95 . And, the instrumentation amplifier  95  generates and provides to the first microprocessor  80 , at port p 7  thereof, an analog pressure difference sample signal “Pds” corresponding to the difference between the pressure signals Ps 1  and Ps 2 . The pressure difference sample Pds is generally at a maximum when the sensed pressure is at its full scale limit, and is at a minimum when the tire  10  is fully deflated. 
     The micro-controller  42  (FIG. 3) additionally includes a conventional oscillator  100  having clock input and clock output leads, “Cin” and “Cout, respectively electrically connected to the first microprocessor  80  at ports p 9  and p 10  thereof and thus to the clock circuit  83  thereof. 
     Moreover, the micro-controller  42  (FIG. 3) preferably includes conventional watchdog timing structure  105  that is conventionally electrically connected across the data and reset leads, Ld and Lr, of the transmitting structure  50  and to port p 13  of the first microprocessor  80 . The watchdog timing structure  105  includes a third conventional microprocessor  106  having a conventional, internal, low frequency counting oscillator  107 . Moreover, the watchdog timing structure  105  includes higher frequency oscillator  108  externally of the third microprocessor  106 . The internal counting oscillator  107  continuously counts successive seconds for a predetermined time interval, provides a count signal Cs to the reset-signal generating oscillator  108  upon counting for the predetermined time interval, and then recycles to commence a new count. If the watchdog timing structure  105  does not detect a voltage signal Vs 1  at port p 13  of the first microprocessor  80  and a transmitter data signal Ds, then, upon receiving the count signal Cs, the reset signal generating oscillator  108  provides a wake-up resetting signal “Wup” to both the transmitter microprocessor  84 , on the reset lead Lr, and the first microprocessor  80  via a conventional high impedance pull-up resistor  110  connected to port p 1  of the first microprocessor  80 . 
     The micro-controller  42  also includes a single pole, double throw, electronic switch  112 . The switch  112  preferably includes a input signal lead “Lin” electrically connected to the first microprocessor  80 , at port  15  thereof, for receiving input signals therefrom. In addition, the switch  112  has a common lead “Lc” electrically connected to the data lead Ld extending between the transmitting structure  50  and the first microprocessor  80 , at port  11  thereof. Furthermore, the switch  112  includes normally closed and normally open switch leads, “Lnc” and “Lno”, respectively electrically connected to the first microprocessor  80  at ports p 17  and p 18  thereof. When the switch  112  is in the normally open position thereof, data from port p 18  of the first microprocessor  80 , is applied to the data lead Ld of the transmitter structure  50  for use thereby. When the switch  112  is in the normally closed position thereof, data on the data lead Ld of the transmitter structure  50  is applied to port p 17  of the microprocessor  80  for use thereby. The switch  112  is usually in the normally open position thereof, for providing temperature, pressure, reference voltage level and transmitter voltage level data  114  to the transmitter structure  50 . After having provided such data  114 , the first microprocessor  80  applies a signal  116  from port p 15  to the switch  112 , resulting in the switch  112  being switched to the normally closed position. Whereupon the transmitter structure  50  provides an acknowledgement signal  118  to the first microprocessor  80  and returns the data  122  thereto. In the event that such data  122  is returned without an acknowledgement signal  118 , the first microprocessor  80  causes the switch  112  to be returned to the normally open position thereof and repeats the provision of the data  122 , and so on, until either an acknowledgement signal  124  is provided to the first microprocessor  80  or the data has been applied to the data lead Ld at least two times. 
     The battery  51  is conventionally electrically connected to the first microprocessor  80  by means of a first RC circuit  124 , having a first conventional storage capacitor  126  for providing a first stabilized input voltage “Vs 1 ” at port p 20  of the first microprocessor  80 , at the switch  112  and at the watchdog timing structure  105 , for respective energization thereof. Moreover, the battery  51  is conventionally electrically connected to the transmitting structure  50  by means of a second RC circuit  128 , having a second conventional storage capacitor  130  for providing a second stabilized input voltage “Vs 2 ” to the transmitter structure  50 . The micro-controller  42  (FIGS. 3 and 4) also preferably includes transmitter voltage sensing structure  136  that is conventionally electrically connected between the second storage capacitor  130  and at port p 4  of the first microprocessor  80 , for sensing the transmitter-structure input voltage Vs 2  and providing an input voltage sample signal “Vs 2 s” to port p 5  of first microprocessor  80 . The transmitter input voltage sensing structure  136  preferably includes a high impedance voltage dividing circuit  138  having a first high impedance resistor  140  connected in series with the first microprocessor  80  and a second high impedance resistor  142  connected across the first microprocessor  80  to ground “G 1 ”. Optionally, the transmitter input voltage sensing structure  136  may include a fourth operational amplifier  141  that is conventionally electrically connected between the first resistor  140  of the voltage dividing circuit  138  and the first microprocessor  80  for providing an amplified transmitter voltage input sample signal Vs 2 s to the first microprocessor  80 . The first microprocessor  80  additionally includes a voltage output lead “Vs 1 ” extending to the sensing structures  44 ,  46 , the reference voltage generating structure  96  and the instrumentation amplifier  95 , respectively for operation thereof. Moreover, assuming the provision of any of the first, second third or fourth operational amplifiers,  90 ,  92 ,  98 , or  140 , the voltage output lead Vs 1  would also extend thereto for operation thereof. 
     It is noted that the first, second and third microprocessors  80 ,  84 , and  106 , respectively, are conventionally programmed to execute each of the steps, if any, attributed thereto in the foregoing discussion and in following process. When the tag  40  (FIG. 1) is installed in a tire  10  that is inflated and mounted on the wheel rim  12  of a vehicle  11 , exemplified by an OTR vehicle, the process portrayed in FIGS. 5 and 6 is started (step  200 ). Thereafter, the first microprocessor  80  and transmitter structure  50 , and thus the second microprocessor  84  thereof, are concurrently energized (steps  202  and  204 ). The second microprocessor  84  of the transmitter structure  50  then generates a pulse  210  (step  206 ) at the end of a predetermined time interval, exemplified by the time interval of 1.4 seconds. The pulse  206  is applied by the second microprocessor  84  to the internal pulse counter  85  (step  208 ) followed by the second microprocessor  84  implementing the step  212  of inquiring whether a predetermined pulse count, exemplified by a pulse count of 152 pulses, has been attained. Assuming, the inquiry is answered negatively (step  210 ), processing is returned to step  206  and recycled therethrough and through steps  210 , and  212  until the inquiry of step  212  is answered affirmatively. Without departing from the spirit and scope of the invention, the pulse counter  85  may be conventionally loaded with a predetermined count, exemplified by the count of 152 pulses, and be programmed to sequentially count down to zero in response to the application thereto of sequential pulses  210 . In either case, when the inquiry of step  212  is answered affirmatively, the second microprocessor  84  causes the pulse counter  83  to be reset (step  214 ), return processing to step  206  to recommence the aforesaid pulse generation and counting process, and provide another count signal  216  to the first microprocessor  80 . 
     Upon detecting the count signal  216  (FIG.  5 ), the first microprocessor  80  applies the voltage Vs 1  to the first and second temperature sensing structures  44  and  46 , the reference voltage generating structure  96 , the transmitter voltage sensing structure  136  and the pressure sensing structure  48  (steps  220 ,  222 ,  224 ,  226  and  228 , respectively) for energization thereof. As a result, the first and second temperature sensing structures  44  and  46 , respectively, provide first and second temperature samples Ts 1  and Ts 2  (steps  230  and  232 ) to the first microprocessor  80 , which are representative of the respective temperatures of the tire innerliner  35  and the tire cavity  16 . In addition, the reference voltage generating structure  96  provides a reference voltage sample Vrefs to the first microprocessor  80  (step  234 ) that is representative of the reference voltage Vref. In addition, the transmitter voltage sensing structure  136  provides a transmitter voltage sample Vs 2 s to the first microprocessor  80  (step  236 ) that is representative of the transmitter voltage Vs 2 . And the tire pressure instrumentation amplifier provides a pressure difference sample Pds to the first microprocessor  80  (step  238 ) that is representative of the air pressure Ps 1  of the tire  10 . 
     The multiplexer  82 A of the first microprocessor  80  conventionally sequentially scans ports p 2 -p 5  and p 7  thereof and sequentially applies the temperature and pressure signals to the A/D converter thereof. The A/D converter  82  sequentially converts the respective first and second temperature samples, Ts 1 s and Ts 2 s (steps  242  and  244 ) to respective digital temperature signals Vt 1 s and Vt 2 s, each having a voltage level of 10 millivolts per degree C. (centigrade), and converts the pressure difference sample Pds (step  246 ) to a digital pressure difference signal Vpds having a voltage level of the 16 millivolts per pound per square inch. The first microprocessor  80  then sequentially inquires (steps  250  and  252 ), whether the respective digital temperature sample signals Vt 1 s and Vt 2 s are greater than a predetermined voltage level corresponding to a high temperature, exemplified by the temperature of 95 degrees C., and whether the digital pressure difference sample signal Vpds is less than a predetermined voltage level corresponding to low pressure, exemplified by the pressure of 80 pounds per square inch, or greater than a predetermined voltage level corresponding to high pressure, exemplified by the pressure of 120 pounds per square inch. Assuming each of the inquiries of steps  250  and  252  are negatively answered, the first microprocessor  80  inquires, steps  254  and  256 , whether the respective digital temperature sample signals, Vt 1 s and Vt 2 s, have changed by a predetermined voltage amount corresponding to a selected temperature change, exemplified by the temperature change of plus or minus 2 degrees C., since the last temperature sample was taken, and whether the digital pressure difference sample signal Vpds has changed a predetermined voltage amount corresponding to a selected pressure change, exemplified by the pressure change of plus or minus 2 pounds per square inch, since the last pressure difference sample was taken. Assuming each of  254  and  256  are answered negatively, then processing is returned to step  202 . 
     On the other hand, if any of the inquires of steps  250 ,  252 ,  254  or  256  (FIG. 6) is affirmatively answered, an unfavorable temperature sample, Vts 1  or Tts 2 , or an unfavorable pressure difference sample signal Vpds or both, has been taken. Whereupon, the first microprocessor  80  applies both of the temperature sample signals, Vt 1 s and Vt 2 s, to the data lead Ld of the transmitter microprocessor  84  (step  260 ), if either of such temperature samples signals, Vt 1 s or Vt 2 s, is unfavorable, or applies the pressure difference sample signal Vpds to the data lead Ld of the transmitter microprocessor  84  (step  260 ), if the pressure difference sample Vpds is unfavorable, or applies both of the temperature sample signals, Vt 1 s and Vt 2 s, and the pressure difference sample signal Vpds to the data lead of the transmitter microprocessor  84  (step  260 ), if either of the temperature sample signal, Vs 1 s or Vs 2 s and the pressure difference sample signal Vpds are unfavorable. In addition, if any of the temperature or pressure difference sampling signals, Vts 1 , Vts 2  or Vpds, is unfavorable, the first microprocessor  80  generates and applies an alarm signal “Alm” to the data lead Ld of the transmitter microprocessor  84  (step  260 ). Upon receiving the aforesaid alarm and sample signals, Alm, Vts 1  and Vts 2  and/or Vpds, the transmitter structure  84  preferably the transmits (step  262 ), such signals, Alm, Vtsl and Vts 2  and/or Vpds, a plurality of times, for example 12 times, to a remote receiver  150  followed by the step  263  of providing a transmission acknowledgement signal ACK to step  202  of the first microprocessor  80  and thereby returning processing thereto. The procedure of providing for multiple signal transmissions has been adopted to be sure that the transmitted signals, Alm, Vtsl and Vts 2  and/or Vpds, are received by the remote receiver  150 , which may be scanning for other input signals, outside of the scope of the present invention, at the time of the original transmission by the transmitter structure  50 . 
     In addition to providing the signals Alm, Vts 1  and Vts 2  and/or Vpds (step  260 ) to the transmitter structure  50 , the first microprocessor  80  inquires (step  264 ) whether the aforesaid acknowledgement signal ACK has been received. Assuming that the inquiry of step  264  is negatively answered, then, step  260  is repeated, step  266 , followed by the first microprocessor  80  again inquiring (step  268 ) whether the aforesaid acknowledgement signal has been received. Assuming that step  268  is negatively answered, then, step  260  is again repeated (step  270 ), followed by returning processing to the first microprocessor (step  202 ). Assuming that either of steps  264  or  266  is affirmatively answered, processing is also returned to step  202 . 
     As shown in FIG.  3  and in step  240  (FIG.  5 ), the multiplexer  82 A of the first microprocessor  80  also sequentially scans ports p 4  and p 5  for the transmitter input voltage sample signal Vs 2 s and reference voltage sample signal Vrefs. Upon detecting such signals Vs 2 s, the microprocessor  80  sequentially inquires whether the transmitter input voltage sample signal Vs 2 s is low (step  290 ). Assuming the answer to the inquiry of step  290  is negative, then processing is returned to step  202 , and, assuming the inquiry of step  292  is negative, processing is also returned to step  202 . Assuming however that the answer to either or both of the inquiries of steps  290  and  292  is or are negative, indicating that either or both of the sample signals Vs 2 s is unfavorable, then, the first microprocessor  80  (step  294 ) generates and applies an alarm signal Alm, for each unfavorable sample signal Vs 2 s or Vrefs, to the data lead Ld of the second microprocessor  84  of the transmitter structure  50 . Upon receiving the aforesaid alarm and sample signals Alm, Vs 2 s or Vrefs, or both, the transmitter structure  84  (step  296 ) preferably transmits such signals Alm and Vs 2 s, a plurality of times, for example  12  times for the reason hereinbefore discussed, to the remote receiver  150  followed by the step  298  of providing a transmission acknowledgement signal ACK to the first microprocessor  80  (step  202 ) thereby returning processing thereto. 
     In addition, to providing the signals Alm, and Vs 2 s or both to the transmitter structure  50 , the first microprocessor  80  inquires (step  300 ), whether the aforesaid acknowledgement signal ACK has been received. Assuming that the inquiry of step  300  is negatively answered, then, step  296  is repeated (step  302 ), followed by the first microprocessor  80  again inquiring (step  304 ) whether the aforesaid acknowledgement signal ACK has been received. Assuming that step  304  is also negatively answered, then, step  296  is again repeated (step  306 ), followed by returning processing to the first microprocessor  80  (step  202 ). Assuming that either or both of steps  302  or  306  is affirmatively answered, then processing is also returned to step  202  of the first microprocessor  80 . 
     The tag  40  (FIG. 1) according to the invention can be incorporated in a monitoring system  149  including the remote computer  150  (FIG. 6) and a display  160  which conventionally electrically connected the remote computer  150 . The remote receiver  150  can include a conventional microprocessor  152  that is conventionally programmed to calculate the sum of the respective temperature sample signals Vt 1 s and Vt 2  and divide the sum by the numeral  2 , to generate an average temperature sample signal Vtsavg. In addition, remote computer microprocessor  152  is conventionally programmed to cause the display  160  to display the respective alarm and sample signals Alm,Tt 1 s, Tt 2 s, Vs 2 s, Vrefs, and Vpds received from the transmitter structure  50  and to display the temperature sample signal average Vtsavg generated by the remote microprocessor  152 . 
     Although the inventions described herein have been shown in a few embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing teachings. Accordingly, the invention is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims.