TRANSPORT REFRIGERATION SECURITY SYSTEM
CROSS-REFXRENCE TO RELATED APPLICATION
[OOOl] This is an international patent application filed pursuant to the Patent
Cooperation Treaty claiming priority under 35 U.S.C. $1 19(e) to 1J.S. Provisional Patcnt
Application Serial No. 611373,507 filed on August 13, 2010.
FIELD OF THE DISCLOSURE
[0002] The present disclosure generally relatcs to transport units, and morc particularly,
to security systems and mctliods for monitoring transport refrigeration units.
BACKGROUND OF "I'HE DlSCLOSURE
[0003] Security systems are well known in the art and comtnonly used to monitor
various parameters of transpoll: refrigeration units and the cargo carrie,d therein. Such
security systenis provide security sensors that are configured to, for instance, detertiline
the status of one or more doors of the transport unit and monitor the level of fucl in ilic
transport unit. Using these sensors, it is possible to dctcct unauthorized access to tlie
cargo andlor detect critical levels of f~lels o as to provide the appropriate alerts and inform
those responsible orthe transport unit or cargo. More specifically, the data provided by
the security sensors can be, transniitled to a remote monitoring facility, stored at a local
data rccorder for later retrieval, or used hy tlie control system to trigger an alarm iftlic
data indicates atypical andlor unP~volahlce vents. Although thcse co~itrols ystelils offcr
sollie level of security, there are still some significant deficiencies.
[0004] In order to efrectively monitor thc transport refrigeration unit and its rcspectivc
cargo, existing security systems require a continuous supply of dirccl current (DC) powcr
that is generally supplied by the battery ofthe transporl vehicle or unit. As with common
vehicle accessories, these control systclns arc typically switched to the ignition systeni of
the transport unit such that DC power is only supplied while the engine, alternator and/or
the battery of the transport unit is powered on. When tlie ignition is switched off,
however, the power supplied to the control system as well as most other vehicle
accessories is disabled. Furthermore, when the control systetii is disabled, its security
sensors are unable to detect a fault condition in which, for example, a door lias been
opened without authorization. In such a way, even with such security measures, transport
units are still vulnerable to theft, vandalism, and the lilte, when they are powered off
and/or left unattended.
[0005] 'To co~npensatefo r such vulnerabilities, some existing control systems provide
periodic monitoring while the transport nnit is powered o f f . These control systems are
configured to enter a sleep mode when tlie transport unit is turned off, during which tlie
sccurit:y sensor data are monitored and/or recorded at predetermined walte up intervals
rather than being continuously on. I-iowever, tlie walte up intervals are generally long,
lasting anywhere between 15 niinutes to an hour, so as to conserve battery power and
memory space. Any fault co~iditionw hich occurs during these intervals can only be
detected at the next wake up instance rcsulting in a dclayed rather than an itnmctliatc
response. Furtlier~iiore,d uring these long intervals, a person can easily disconnect the
battery, disable power to tlie sccurity sensors and access the cargo witliont triggering any
alarm. Accordingly, whilc wake up circuits provitlc some added sccurity, transport
refrigeration units are still vulnerable to theft when they are powered of'andlor
unattended.
[0006] It is therefore an object of the present disclosure to provide a security device
and system that overcomes such deficiencies and provides more comprehensive
lnonitoring of a transport unit. Specifically, thcrc is a nccd for a sccurity dcvicc that is
capable of continuously monitoring the key parameters of a transport refrigeration unit for
extended periods of time regardless ofthe operational status thereof. Moreover, there is a
need for a security system that can operate on reduced power and provide immediate
response to a fault cotidition.
SUMMARY OF THE DISCLOSURE
[0007] In accordance with onc aspect of the disclosure, an energy conserving security
monitor system for a transport unit is provided. The security monitor system may include
at least one input device configured to receive an input signal for selectively performing a
function on the transport unit, and a controller having a plurality of inputs, a plurality of
outputs, and a low power control circuit. The low power circuit may provide electrical
communication between a battery ofthe transport unit, the input dcvicc, and at least one
ofthe inputs of the controller. 'I'hc colitrol circuit may hc configured to maintain thc
controllcr in low power mode whcn the input signal is not indicative of performing a
function on the transport unit. The control circuit may be configured to enable power to
the controller when the input signal is indicative of performing a [unction on the transport
~lnit.
[0008] In accordance with another aspect ofthe disclosure, a security monitor system
for a transport unit is provided. Thc sccurity monitor system may include at least one
security sensor configured to detect a fk1i111 condition, and a controller having a plurality
of inputs, a plurality of outputs, and a low power control circuit. The low power circuit
may provide electrical communication between a battery of the transport unit, the security
sensor, and at least one of the inputs of the controller. The control circuit may be
configured to maintain the controller in low power mode when there are no detected fault
conditions. The control circuit tiiay bc configured to enable powcr to the controller wlieli
lherc is a detected fault condition.
[0009] In accordance with another aspect of the disclosure, another security monitor
system for a transport refiigeration unit is provided. The security monitor systetii may
include at least otie door switch configured to detect utiauthorized access to the transport
refrigeration unit, and a cotitroller having a plurality of inputs, a plurality of outputs, and
a low power control circuit. The low power control circuit lnay provide electrical
co~ii~nunicatiobnet ween a battery of tlie transport refiigeration unit, the door switch, atid
at least one of the inputs of thc controller. 'l'lre control circuit may be configul.ed to
maintain the controller in low power Inode when there are no detected fault conditions.
Tlie control circuit lnay be cotifigured to enable power to the controller when there is a
detcctcd fault condition.
[0010] 111 accorda~icew ith yet another aspect of the disclosure, a method for
conserving energy in a transport unit is provided. The method tnay provide an input
device callfigured to receive an input signal and selectively perform a fi~nctiono n the
transporl utiit based oti tlie input signal, provide a low power cotltrol circuit in
communication between a battcry oftl~ctr atlsporl unil, the input device and at least onc of
the inputs ofthe cot~trollevm, aintain the controller in low power rnodc wlie~tih e input
sigtlal is trot indicative of performing a f~~nctiootni the transport nnit, and a~ltotiiatically
cnablc power to tlic co~~trollwerh cn the input signal is i~~dicdlivocfp erfortning a f~~nclion
on the transport unit. Tlie low power control circuit may be configured to bias a
controller into a low power ~iiodeo f operation.
[0011] Thcsc and othcr aspccts ofthis disclosu~cw ill become lnorc readily apparent
upon reading the followi~lgd ctailed dcscription when take11 ill co~~junctiowni th the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic diagram of an exemplary security monitor systc~lal s
applied to a transport refrigeration unil;
[0013] FIG. 2 is a schematic diagram of another exemplary security monitor systc~u;
and
[0014] FIG. 3 is flow diagram of an exemplary method for monitoring a transport
reftigeration unit,
[0015] While the prcscnt disclosurc is susccptiblc to various modiiicatio~lsa nd
altcl.nafive conrlrnclions, ccrtain illustrative embodimcnls thereof have bccn shown in the
drawings and will be dcscribcd below in detail. I1 should hc undcrst.ood, however, that
tlierc is no intention to be limited to the specific forms disclosed, but on the contrary, the
intention is to cover all modifications, alternative co~istructionsa, nd cquivalenls failing
with the spirit and scope of the present disclosu~.e.
DETAILED DESCRIPTION
[0016] Rcfcrring to the drawings and wit11 particular rcfere~lcelo ];I(;. 1, an exemplary
qecurity monitor systctn for a transport rcfsigcration unit is p~ovideda nd vcfcrred to as
reference number 10. It is understood that the teachings of the disclosure may bc used to
construct security inonitor systems for transport units above and beyond those specifically
disclosed below. One of ordinary skill in the art will readily understand that the
following are only exemplary embodiments.
[0017] 'Turning to FIGS. 1-2, schematics of exemplary low power security monitor
systems 10 that may be installed in a transport refrigeration unit are provided. In addition
to transport refrigeration units, the security monitor systems 10 disclosed herein may also
be integrated into other types of transport units, sucli as trailers, +eight containers, trucks,
rail cars, and thc like. Moreover, the security illonitor systems 10 lnay be provided to any
transport unit which requires continuous monitoring of one or more parameters thereof
but is limited to a poltable energy source, sucli as a battery or a fuel tank with a capacity
that is restricted to what the transport unit call carry or support.
[0018] As shown in FIGS. 1-2, an exemplary security monitor system I0 may
essentially include one or more input devices 1 1, such as security sensors 12, a controller
14, notification devices 16, and a low power control circuit 18 for electrically coupling
these colnponents to a power source ofthe transport unit, such as a battery 20, or the like.
The input devices 11 mily be associated with an auxiliary or accessory device of the
transport unit and configured to receive an input signal Gom an operator andlor owner of
the transport unit. The auxilia~yo r accessory devices associated with the illput devices 1 1
[nay include, for example, a refrigeration unit, a heating, ventilation and air-conditioning
(IIVAC) system, a lighting unit, or ally other acccssory that lnay rcccive powcr rrom thc
battcry 20 andlor file1 combustion. Rased on the itipl~st ignal rcccivcd by the input dcvicc
I I, the controller 14 may he seleclively pe~l'orm an auxiliary or acccssory function on ihe
iransporl unit, such as operating a 1)ort~blere kigeration unit, operating (he lLIVACs ystem,
providing light, and the like.
100191 The input devices 11 may also include security sensors 12 that are configured to
observe various security parameters of the transport unit while the controller 14 monitors
the observed parameters for fault conditions. If a fault condition is determined by the
controller 14, the appropriate notification devices 16 may alcrt and notify tlic users andlor
owners of the transport unit of the fault condition. Furthermore, the low power
configuration of tlie control circuit 18 may ensure tliat the controller 14 is only engaged
when it is needed, for example, when a potential fault is detected at tlie security sensors
12. Such a low power configuration essentially eliminates tlie aniount oftime the
controller 14 is needlessly online, and thus, greatly reduces tlie power consunled by the
controller 14. By reducing the atnount of energy needed to operate the controller 14, the
charge in the battery 20 is greatly conserved, and among otlier things, fuel consumption
may he significantly reduced.
[0020] The security sensors 12 of FIGS. 1-2 may include one or Inore sensors that are
configured to detect fault conditions, or critical changes to the transport unit that niay he
indicative of unauthorized access, tlieft, vandalism, malrunction of the transport onit, or
any other a\xior~i>aolr undesired activity. For example, the security sensors 12 niay
include a discrete sensor, suclr as a door switch 12a tliat is capable of determining when a
cargo door of the transport unit is opened or closed. As shown in FIG. 1, tlic door switch
12a may be a normally closcd switch wliicli allows ilow of current theretlirougli when all
of the doors of the transport unil are closcd. When at least onc cargo door is opcncd, thc
normally closed door switch 12a may open to break the flow of current. Alternatively,
the door switch 12a may also be a normally opened swilc,li, as shown in FIG. 2, wliicli
prohibits flow of current ihcrcllirougl~ wlien all oftlle doors arc closcd. When a1 least one
cargo door is opened, tlie nonnally opened switch 12a may close to enable ilow of current
therethrough.
[0021] The security sensors 12 may also i~?cludean aanalog sensor, such as a fuel level
sensor 12b which outputs a continuous analog signal that is indicative of the level of fucl
in the transport unit. Rased on such feedback, a concsponding controller 14 niay be able
to monitor for a critically low level of fuel andlor for a critically high rate of reduction in
fuel. In alternative embodiments, the security sensors 12 may include a banery voltage
sensor andlor battery connection sensor that is configured to detect whcn the battery
voltage level drops to a critical minimum andlor detect when the battery 20 is
disconnected. In still further alternatives, the security sensors 12 may additionally
include one or more of a temperature sensor, pressure sensor, a humidity sensor, a
movement sensor, an impact sensor, a tilt sensor, and the like.
[00221 Still referring to FIGS. 1-2, the controller 14 of the security monitor system 10
may be implernellted using one or more of a processor, a microprocessor, a
tnicrocontroller, an electronic control lnodule (ECM), an electronic control unit (l3ClJ), or
any other suitable means for clectroliically controlling functionality of the security
~iionitors ystc~ii1 0. Tlie controller 14 may include a plurality of inputs 22 for receiving
discrete andlor analog ~leclronicsi gnals as well as a plurality of outputs 24 for
transmitting discrete andlor analog electronic signals to othcr auxiliary, accessory or
periphery devices, such as the notitication devices 16 shown.
[0023] Anlong the inputs 22 provided, the controller 14 may include at least a powcr
enabling input 22a and a reference voltagc input 22b. Based on the input voltage rcceived
at thc power enabling input 22a, the controller 14 nlay be powered off, powcrcd on,
placed in low po\vcr mode, placed in slccp nlodc, or the likc. 1:or cxaniple, the controller
14 may be configured to auto~naticallyp ower on if the electrical signal provided to the
power enabling input 22a correspolids to approximately 5 VDC, 10 VDC, 15 VDC, or
any other direct current (DC) reference voltage corresponding to a logical high value.
The appropriate reference voltage may be determined in accordance with the vollage
value provided to thc rcfcrencc voltage input 22b of the controller 14. The rererence
voltage may also be deterniined based on the respective specifications of the battery 20 of
the transport unit, tlie resistance values R1-R5 provided by tlic low power control circuit
18, and the like.
[0024] The controller 14 may also be powered off if the voltage at the power enabling
input 22a is less than a predetermined lnini~nuni voltage to conserve energy. For instance,
if tlie voltage supplicd to tlie power enabling input 22a is approximately 0 VDC or
corresponding to a logical low value, the controller 14 may auto~naticallyp ower ofrand
remain powered off until tlie next logical high value is received. 111 alternative
embodiments, the controller 14 may provide a power enabling input 2221 that is inverted,
in which case voltage supplied to the power enabling input 22a corresponding a logical
low value liiay be used to powcr on the controller 14 while a voltage corresponding to a
logical high value may be used to power off the controller 14.
10025) The controller 14 inay additionally operate in a low power niode or operation or
a sleep mode so as to conserve battery power or fuel. Low power or sleep niodes may
enable the controller I4 to operate on minimal battery powcr while still allowing sonic
f~~nctionalirthye reol; such as the monitoring of security sensors 12. During low power
niode or sleep mode, tlic vollagc provided at the powcr enabling input 22a rniiy be within
a prcdctcrniined range of relatively low voltages. For instance, tlic range ol'voltagcc
corresponding to low powcr niode eiay be higlic~in niag~iitudeth an 0 VDC but Iowcr in
magnitude than the reference voltage provided, for example, 5 VIIC, 10 VDC, 15 VIIC,
or tlie like. 'The controller 14 may 11e configured to enter a low power mode or sleep
mode by its ow11 determination based on different criteria preprogramtned therein. 1,ow
powcr niode or sleep mode may also bc induced on the controller 14 by adjusting tlie
voltage supplied thereto. The controller 14 may Turtlier include a status input 22c by
which the controller 14 may determine the desired or current mode of operation based on,
for example, the magnitude ofthe voltage detected at the status input 22c.
[(I0261 In response to the input signals and any fault conditions, tlie controller 14 !nay
generate one or more signals at its outputs 24 to be transmitted to one or more auxiliary,
accessory or periphery devices of the transport unit, such as the notification devices 16
shown. The notification devices 16 may include one or more of an audible device 16a, a
visual device 16b, and the like. The audible device 16a tnay include a ringer, a buzzer, or
any other device that can produce an audible alert and call attention to the transport unit.
The visual device 16b may include blinking light emitting diodes (LEDs), screen activity
on a liquid crystal display (LCD), or any other form of visual alert that may call attention
to tlie transport unit. Each of the audible dcvicc 16a and the visual device 16b may be
provided in tlie vicinity of the transport unit andlor at a reniote monitoring location.
[On271 The notification device I6 may also employ a teleniatic device 16c that is
configured to generate an alert to the appropriate users andlor owners ofthe transport unit
via cellular networks, satellite communications, and tlie like. More specifically, the
controller 14 and the tclcmatic device 16c ]nay generate a fault codc, a tcxt message,
electronic niail message, or the like, and further, transmit the code or niessage to the
pager, cellular device or coniputcr of'the respective users and/or owners. 'Tlic codc or
mcssagc may sini~lyin dicate that a fault condition has been detected, or provide further
details of the detected hult, such as tlie type of fault, the frequency or duration of the
fault, possible solutions for correcting the fault, and the like.
[0028] As shown in FIGS. 1-2, thc low power control circuit 18 may be configured to
interconnect each ofthe security sensors 12, controller 14, notification devices 16 and the
battery 20 so as to enable the security monitor system 10 to fully operate on minimal
power from the battery 20 and on minimal fuel. More specifically, the control circuit 18
may be configured such that the discrete security sensors 12, such as door switches 1211,
enable or disable an electrical connection between the power enabling input 22a ofthe
controller I4 and the battery 20 based on the slate of the security sensors 12. In
e~iibodilnentsi n which analog sensors, such as fitel level sensors 12b, are employed, the
low power control circuit 18 and co~ltroller 14 may be configured to enable monitoring of
the analog sensor while in a low power mode of operation.
[0029] In association with the discrete and normally closed door switch 12a of FIG. 1 ,
for example, the low power control circuit 18 may be configured to electrically couple the
power enabling input 22a of the controller 14 to ground while the door switch 12a is
closed. As such, the controller 14 )nay be provided with a logical low voltagc valuc so as
leave the controller 14 powered off or in a low power mode when there are no fatilts
present. When one or more doors are opened and when the door switch 12a is opcned,
the power cnabling input 22a of thc controller 14 niay he disconnecied from grou~ld and
provided with a logically high voltage value from the positive tenninal ofthe battery 20.
Similarly, in association with ilie discrete and normally opened door switch 12a ofFlG. 2,
thc low power control circuit I8 may be configured to electrically coi~pleth e power
enabling input 22a of the co~ltroller1 4 to ground while the door switch 12a is opened. As
such, the controller 14 niay be provided with a logical low voltage value so as leave the
controller 14 powered off or in a low power mode when there are no faults present.
When one or more doors are opened and when the door switch 12a is closed, the power
enabling input 22a of the controller 14 may bc provided with a logically high voltage
value from tlie positive ter~ninalo f the battery 20.
[0030] Once supplied with an enabling voltage, the controller 14 {nay auto~natically
wake up from the low power mode and power on. The controller 14 liiay then determine
whether tlie detected fault condition, or tlie opening of cargo doors, was an authorized or
ail tunauthorized event. If the fault condition is confirmed to be an authorized event, the
controller 14 may si~iiplyig nore the fault, return lo low power or sleep ~riodea nd continue
monitoring the security sensors 12. If the fault condition is co~ifir~iietod be an undesired
or uiiauthorized event, the controller 14 may generate the approprialc signals to be
transmitted to the notificatiori devices 16. Based on the signals received fi.0111 the
controller 14, for example, one or Inore of the audible device 1 6a, visual device 16b and
telenlatic device 16c niay be engaged Lo alert llie users andlor owners oflhe transport u~lil.
'Thc controllcr 14 niay Clirther be conligured to aulomalically record my or all data
pertaining to thc trarlspot.1 u~iiiln response to tlie detected hult. The recorded data 11iily
be stored in a memory 26,28 for later retrieval and review. The inanncr in which the
controller 14 responds to a detectcd fault condition may be configurahle by the user
andlor owncr oTthe transport unit. For exaniple, a user or owner may enable or disablc
one or Illore of the notification devices 16 that are set to engage for a particular fault type.
A user or owncr m.ay also adjust the types of data to rccord, duraiioii of the recording,
interval of tlic recording or tlisahle tlic data recordirig reaturc.
[0031] Still referring to FIGS. 1-2, the low power control circuit 18 may also provide
electrical co~n~nunicatiowni th a backup battery 30. For instance, a scco~idaryb attery 30
may be couplcd to the security sensors 12, the controller 14 and the notification devices
16 through an auxiliary andlor a parallel connection therewith. The auxiliary connection
!nay further be auto~iiaticallys witched such that tlic backup battery 30 is only coupled to
the security monitor system 10 if the primary battery 20 is disconnected. Accordingly,
the security sensors 12 may e~iiploya battery connection sensor for motiitoring the
connection to the primaly battery 20.
[0032] Turtling now to FIG. 3, an exemplary method by which the controller 14 {nay
conserve energy while monitoring a transport unit is provided. In particular, tlie
controller 14 may be preprogratnmed with an algorithm or a set of program codcs to
perform accorditig to the method shown. The algorithm may be stored within an onboard
or internal memory 26 of the controller 14 andlor on an external memory 28 that is
in communication with the controller 14. The external memory 28 tiiay take the fonn of,
for example, a floppy disk, a hard disk, optical medium, random access Inenlory (RAM),
read-only liiemory (ROM), or any other suitable computer-readable storage liiediu~ii
cotn~iiotilyu sed in the art.
[0033] in accordance with the embodiments ofI~IGS1. -2, the method of FIG. 3 may
include a step of providing at least one security sensor I2 that is configured to detect a
fault condition within a transport unit. 'Slie method may also enable electrical
communication hctwcctl the battery 20 ol'llic transporl unit, tlie securily sensor I2 and thc
inputs 22 oftlie controller I4 using a low powcr control circuit 18. 'l'lie low power
cotilrol circuit 18 tnay be confgurcd to bias tlie controller 14 into a low power modc of
operation so as to conscrvc battery power. 'I'hc nlctliod tiiay furtl~erti ionitor fbr any bolts
detected by the security sensor 12. If 110 faults are detected, the tilethod may continue to
~iiaintainth e controller 14 in low power mode, If one or more Saults are detected, tlie
method may autotnatieally direct power frotii the battery 20 to a power etiabli~igin put 22a
of the controller 14 so as to wake the controller 14 up fiom the low power mode and to
allow the controller 14 to respond to tlie detcctcd fault accordingly. Optionally, the
method may further generate an alert, for example, using one of the notification devices
16 of FIGS. 1-2, so as to notify a user and/or owner of the transport unit of the detected
fault condition. Additionally or alternatively, tlie ~netliod rnay record various data fro111
the transport unit for a predefined period of time in response to the detected fault
condition.
(00341 Rased on the foregoing, it can be seen that the present disclosure provides niore
comprehensive monitoring of a transport reftigeration unit with several advantages over
currently existing security configurations built for transport units. Moreover, the present
disclosure provides continuous monitoring of various parameters of a transport unit for
extended periods of time without being limited to the operation state or the transport unit.
I:urthermore, the present disclosure provides such continuous monitoring schemes while,
anlong other things, significantly conserving battery charge and fuel.
[0035] While only cerlain enibodi~nentsh ave been set forth, alternatives and
modifications will be apparent fro111 the above description to those sltilled in the art.
These and other alternatives are considered cqnivalents and within thc spirit and scope of
this disclosure.
WHAT IS CLAIMED IS:
I. A security monitor systeni (10) for a transport unit, tlie security nionitor
systeln (10) comprising:
at least one security sensor (I 2) configured to detect a fault condition; and
a controller (14) having a plurality of inputs (22), a plurality of outputs (24), and a
low power control circuit (I 8) providing electrical com~nunicationb etween a battery (20)
of the transport unit, the security sensor (12), and at least one of the inputs (22) of tlie
controller (I 4), tlie control circuit (I 8) being configured to maintain the controller (I 4) in
low power mode when there are no detected fault conditions, tlie control circuit (18)
being configured to enable power to tlie controller (14) when there is a detected fault
condition.
2. 'Uie security liioliitor systeni (10) of clairil 1, wherein the security scnsor
(1 2) includcs one or more of a door switch (I 2a), a fuel level sensor (1 2b), a battery
voltage scnsor, a battery connection sensor, a ternperalure sensor, a pressure sensor, a
huniidity sensor, a movement sensor, an itlipact sensor, and a tilt sensor.
3. 'She security tiionitor systetii (10) of clai~ii1 , wherein tlie control circuit
(18) further provitles electrical coniniunication between at lcast one notificatio~id evicc
(16) and at least one of the outputs (24) of tlie controller (14), tlie controller (14) being
configured to enable tlic notification devicc (1 6) in response to a fault condition detected
at tlie security scnsor (12).
4. The security monitor systeln (1 0) of claim 3, whcrcin tlie notification
device (16) includes one or tilore of an audible dcvice (16a), a visual device (16b), and a
telelnatic device (I 6c).
5 . Thc security monitor system (10) of claim 1, wherein tlre controller (14) is
further configured to retrievably record any data pertaining to fault conditiot>s detected by
the security sensor (12) in a lrrelnory (26, 28).
6. The security tnonitor systelri (10) of claim 1, wherein the control circuit
(18) further provides electrical communication with a backup battery (30).
7. The security monitor system (10) of claim 1, wherein the security sensor
(12) includes a nortnally closed switch disposed between the battery (20) and a power
enabling input (22a) of the controller (14).
8. The security monitor system (10) of claim 1, wherein the security sensor
(12) includes a tlor~nallyo pened switch disposed between the battery (20) and a power
enabling input (22a) of the controllel. (14).
9. The security monitor system (10) of clai~n1 , wherein tlre security sensor
(12) i ~ ~ ~ l uadnc asn alog sensor, the coti~roller( 14) being configuretl to continuously
monitor rcadi~igso fthe analog se.1isor while operating itr the lower power mode.
10. A security monitor system (10) for a trallsport refrigeration unit, the
security monitor systelrr (1 0) comprising:
at least one door switch (1 23) colifigured to detect unauthorized access to the
traasport refrigeration unit; and
a controllet (14) having a plurality of inputs (22), a plurality of outputs (24), and a
low power control circuit ( I 8) providing electrical com~rionicatio~bcr twcen a battcry (20)
ofthe transport refrigeration unit, the door switch (1 2a), and at least one of the inputs (22)
ofthe controller (14), the control circuit (18) being configured to maintain the controller
(14) in low 11ower mode when there are no detected fault conditions, the control circuit
(18) being configured to enable power to the controllcr (14) when there is a detected fault
condition.
11. The security tnonitor system (10) of claim 10, wherein the door switch
(12a) is electrically coupled between the battery (20) and at least a power enabling input
(22a) of the controller (14).
12. The security tnonitor systeni (10) of claim 10 further comprising a fuel
lcvel sensor (12b) configured to detect at least one of a level of fuel and a rate of
reduction in fuel in the transport unit.
13. The security monitor systetn (I 0) d c l a i ~ n1 0 further comprising one or
more of a battery voltage sensor, a battery connection sensor, a temperature sensor, a
pressure sensor, a humidity sensor, a lnovetnent sensor, an i~npacst ensor, and a tilt sensor.
14. The security monitor systetn (10) ofclai~n1 0, wherein the control circnit
(1 8) Surthcr providcs electrical cornli~unicatio~bcl twcen at least onc notification devicc
(16) and at least one of thc outputs (24) ofthc controllcr (14), the cnnlroller (14) bcing
configured to enable the notification device (16) in response to a fault condition detected
at the security sensor (I 2).
15. The security monitor system (10) of claim 14, wherein the notificat:ion
device (I 6) includes one or Inore ofan audiblc devicc (lba), 21 visual device (l6b), and a
telematic device (16c).
16. The security illonitor system (1 0) of claim 10, whcrcin the nolilication
dcvice (I 6) to be used in response to a detected fault is configurable by a user.
17. The security monitor system (10) of claim 10, wherein the controller (14)
is configured to retricvably record any data pertaining to fault conditions detected by the
security sensor (I 2) in a mcmory (26, 28).
18. Tlie security monitor system (10) of claim 10, wherein the control circuit
(1 8) further provides electrical communication to a bacltup battery (30).
19. A method for conserving energy in a transport refrigeration unit, the
tilethod coniprising the steps of:
providing an input device ( I I) configured to receive an input signal and
selectively perform a function on tlie transport refrigeration unit based on the input signal;
providing a low power control circuit (18) in co~nrnunication between a battery
(20) orthe transport unit, tlie input device (1 1) and at least one ofthe inputs (22) of a
controller (l4), the low power control circuit (18) being configured to bias thc contt.oller
(14) into a low power mode OF operation;
maintaining the controller (14) in low power niode when the input signal received
by the input dcvice (1 1) is not irtdicalive of petforli~inga fui~ctiona; nd
automatically enabling power to the controller (14) when the input signal rcccived
by the input dcvice (1 I) is indicative of performing a function.
20. The neth hod of claim 19, wherein the input device (1 1) includes a security
sensor (1 2) configured to dctcct a fault condition, thc controllc~(.1 4) being ~naintaincdi n
low powcr mode if there arc no Pd.nult conditions dctecled by the security sensor (I 2) and
being autoniatically cnabled when a fault condition is received.
21. The method ofclaim 20 further comprising the stcp of generating an alert
in rcsponsc to the detected fault contlition.