U.S. patent application number 10/277560 was filed with the patent office on 2003-09-25 for battery change apparatus and method for a locomotive remote control system.
Invention is credited to Kornick, David F., Kraeling, Mark B., Peltz, David.
Application Number | 20030178533 10/277560 |
Document ID | / |
Family ID | 28044669 |
Filed Date | 2003-09-25 |
United States Patent
Application |
20030178533 |
Kind Code |
A1 |
Kornick, David F. ; et
al. |
September 25, 2003 |
Battery change apparatus and method for a locomotive remote control
system
Abstract
A remote control system (10) for a locomotive (14) having a
auxiliary power source (42) in the operator control unit (OCU) (16)
so that the unique communications link identifier stored in the
volatile memory (40) of the OCU is not lost during change-out of
the OCU main battery (22). A method (20) for changing the OCU main
battery (22) may include the step of entering a power saving mode
(54) while operating on the auxiliary power source. The locomotive
is maintained in a safe condition without unlinking from the OCU
for a predetermined time interval (66) until full power is
re-established using the refreshed battery in the OCU. In one
embodiment, auxiliary power may be provided by one of two batteries
(72, 74) in the OCU while the other of the two batteries is being
changed. A sliding panel (78) may be used to allow only one battery
to be removed from the OCU at a time.
Inventors: |
Kornick, David F.;
(Melbourne, FL) ; Kraeling, Mark B.; (Melbourne,
FL) ; Peltz, David; (Melbourne, FL) |
Correspondence
Address: |
BEUSSE, BROWNLEE, BOWDOIN & WOLTER, P. A.
390 NORTH ORANGE AVENUE
SUITE 2500
ORLANDO
FL
32801
US
|
Family ID: |
28044669 |
Appl. No.: |
10/277560 |
Filed: |
October 22, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60365634 |
Mar 19, 2002 |
|
|
|
Current U.S.
Class: |
246/187A |
Current CPC
Class: |
B61L 3/127 20130101;
B61L 17/00 20130101 |
Class at
Publication: |
246/187.00A |
International
Class: |
B61L 003/00 |
Claims
We claim as our invention:
1. A method for refreshing a power source in a portable operator
control unit (OCU) used for remotely controlling the operation of a
locomotive, the method comprising: operating an OCU with a first
power source to control a locomotive over a communication link
characterized by a unique identifier; and switching the operation
of the OCU from the first power source to a second power source
without losing the unique identifier so as to maintain the
communication link with the locomotive.
2. The method of claim 1, wherein the step of switching comprises
providing power from the second power source to a volatile memory
storing the unique identifier so that the volatile memory is not
erased while the first power source is being refreshed.
3. The method of claim 1, further comprising providing power from
the second power source to a transmitter portion of the OCU while
the first power source is being refreshed to allow the transmitter
portion to maintain the communication link.
4. The method of claim 1, further comprising sending a signal to
the locomotive to put the locomotive in a safe mode prior to the
step of switching.
5. The method of claim 1, further comprising providing one of a
capacitor, a long-term storage battery, and a solar panel as the
second power source.
6. The method of claim 1, wherein the OCU comprises two batteries
each capable of powering the OCU, the method further comprising:
switching the source of power for the OCU from a first of the
batteries to a second of the batteries in response to movement of a
mechanism that limits access to only one of the two batteries at a
time.
7. The method of claim 1, further comprising: monitoring a
condition of the first power sources; and switching operation of
the OCU from the first power source to the second power source when
the condition reaches a predetermined level.
8. The method of claim 1, further comprising allowing transmission
from the OCU to the locomotive to be suspended for a predetermined
time period during the step of switching without interrupting the
communication link.
9. A system for hot-swapping power sources in a locomotive remote
control system, wherein a portable operator control unit (OCU) is
in communication with a receiver on a locomotive being remotely
controlled over a communication link comprising a unique identifier
stored in a volatile memory of the OCU, the system comprising: a
first power source; a second power source; and a circuit for
providing power to the OCU from the second power source so that the
communication link with the locomotive is maintained while the
first power source is being refreshed.
10. The system of claim 9, further comprising a circuit for
providing power to a transmitter portion of the OCU from the second
power source while the first power source is being refreshed.
11. The system of claim 9, further comprising a circuit for
providing power from the second power source to a volatile memory
portion of the OCU storing the unique identifier while the first
power source is being refreshed.
12. The system of claim 9, wherein the second power source
comprises one of a capacitor, a long-term storage battery and a
solar panel.
13. The system of claim 9, further comprising: two batteries each
capable of powering the OCU; and a mechanism limiting physical
access to only one of the two batteries at a time.
14. The system of claim 13, further comprising a switch responsive
to a position of the mechanism for switching the source of power
for the OCU from a first of the two batteries to a second of the
two batteries.
15. The system of claim 13, wherein the mechanism comprises a
sliding panel in a battery compartment of the OCU.
16. The system of claim 9, further comprising a timer circuit for
unlinking the communications link if the first power source is not
refreshed within a predetermined time period.
17. The system of claim 9, further comprising a failsafe mode
preventing inadvertent loss of power to the OCU.
18. A remote control system for controlling a locomotive
comprising: a controller onboard a locomotive for controlling the
locomotive in response to a remote control signal comprising a
unique identifier; an operator control unit (OCU) remote from the
locomotive for generating the remote control signal, wherein the
OCU further comprises: a first power source; a second power source;
and a circuit for providing power to a volatile memory portion of
the OCU from the second power source to maintain the unique
identifier in the volatile memory while the first power source is
being refreshed.
19. The system of claim 18, wherein the second power source
comprises one of a capacitor, a long-term storage battery and a
solar panel.
20. The system of claim 18, further comprising: a first battery; a
second battery; a mechanism providing access to only one of the
first battery and the second battery at a time; and a switch
responsive to a position of the mechanism for switching power for
the OCU from the first battery to the second battery.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/365,634 filed Mar. 19, 2002.
FIELD OF THE INVENTION
[0002] This invention relates generally to the field of rail
transportation, and more particularly to a remote-control system
for a locomotive.
BACKGROUND OF THE INVENTION
[0003] It is known to remotely control a locomotive using a
handheld operator control unit (OCU) that is in radio communication
with associated slave equipment onboard the locomotive. Such units
are often used in a switching yard where assemblies of railcars and
locomotives are coupled together to form trains. Such units may
also be used in an industrial application where a locomotive is
used to deliver railcars filled with various materials to multiple
locations within a plant site. One such system is available from
Canac Inc. and is described in Canac's U.S. Pat. Nos. 5, 511,749
and 5,685,507. Another remote control system is offered by
Cattron-Thiemeg, Inc.
[0004] Remote-control systems for locomotives rely on a two-way
radio communications link between the operator control unit and the
onboard equipment. Command signals are input to the OCU by the
operator in the form of the movement of a switch, lever, dial, etc.
The command signal is converted to an electromagnetic signal that
is transmitted from the OCU to an onboard receiver. The received
electromagnetic command signal is then converted into an
appropriate control action by an onboard servomechanism. Signals
may also be initiated by onboard equipment and transmitted back to
the OCU for display to the operator to report the status of onboard
systems. The signals transmitted to control a locomotive typically
comprise a binary locomotive status word that represents the
requested operative state of the locomotive being controlled. One
such locomotive radio control system incorporating transmission of
binary locomotive status words to remotely communicate with a
locomotive is sold under the trademark Beltpack.TM. by Canac, Inc.
of Montreal, Canada.
[0005] The quality and security of the radio communication link
between the OCU and the onboard equipment are critical for safe,
reliable remote control of the locomotive. Importantly, the
locomotive must respond only to signals initiated by the locomotive
operator's OCU and not to spurious radio signals generated by other
sources, including other OCU's operating in the same area. To
ensure the integrity of the radio communication link, it is known
for the OCU and the onboard equipment to communicate by using a
unique link identifier. The link identifier is an electronic code,
stored in volatile memory in the OCU that uniquely represents the
transmitter designated to control the locomotive. Whenever a
command is transmitted to a designated locomotive, the link
identifier is retrieved from volatile memory and appended to the
locomotive status word that is then transmitted to the onboard
receiver. In addition, the transmitter can be programmed to
repetitively transmit the locomotive status word at a fixed rate.
By providing the transmitter with a unique repetition rate, the
likelihood of transmission errors is reduced when several portable
transmitters in close proximity broadcast control signals to
individual locomotives.
[0006] To initialize the OCU link identifier to communicate with a
designated locomotive, the operator boards the locomotive with the
OCU to execute a linking procedure that enters the unique
locomotive identifier into the OCU volatile memory. Once the
identifier has been downloaded to the OCU volatile memory, the
onboard remote control equipment will then respond to radio control
signals that are encoded with the correct link identifier. For each
transmitted locomotive status word received by the locomotive, the
onboard receiver extracts the identifier code embedded in the
status word and verifies that the received identifier code matches
the code of a remote transmitter designated to control the
receiving locomotive. This ensures that only the intended OCU will
have control over the locomotive. As a safety measure, the onboard
equipment is programmed to place the locomotive in a safe condition
(stopped and brakes applied) if no properly linked communication is
received from the OCU within a predetermined time period.
[0007] Because they are intended to be portable devices, the
operator control units are powered by batteries. The batteries have
a useful charge life and they must be recharged or replaced with
fresh batteries periodically. Most locomotive remote control
systems include a sophisticated microprocessor-based power level
sensor that accurately predicts the remaining battery life for the
OCU. This information allows the operator to avoid a situation
where the remote control system fails unexpectedly due to a low
battery charge condition. When the remaining charge life of the
batteries drops below a predetermined limit, the batteries are
changed in an orderly manner at the convenience of the operator.
However, the change-out of batteries causes a break in the radio
communication link between the OCU and the locomotive, and it
deletes the link identifier from the OCU volatile memory.
[0008] Once the new batteries are installed, the secured
communication link must be reestablished. This necessitates the
operator boarding the locomotive to execute the linking procedure
to re-enter the unique locomotive identifier into the OCU volatile
memory. This may result in an extended delay, since the locomotive
may be located as far as 1/2 mile away from the operator's
location.
[0009] It is known in the art to "hot-swap" batteries in electronic
devices. Systems such as laptop computers typically incorporate hot
swapping features to allow refreshing batteries without requiring
system shut down. One such system is described in U.S. Pat. No.
5,832,282. However, prior art hot-swapping solutions do not address
the problem of maintaining a communication link when a battery
changeover is required.
BRIEF SUMMARY OF THE INVENTION
[0010] A method for refreshing a power source in a portable
operator control unit (OCU) used for remotely controlling the
operation of a locomotive is described herein as including:
operating an OCU with a first power source to control a locomotive
over a communication link characterized by a unique identifier; and
switching the operation of the OCU from the first power source to a
second power source without losing the unique identifier so as to
maintain the communication link with the locomotive. The step of
switching may include providing power from the second power source
to a volatile memory storing the unique identifier so that the
volatile memory is not erased while the first power source is being
refreshed.
[0011] A system is described for hot-swapping power sources in a
locomotive remote control system, wherein a portable operator
control unit (OCU) is in communication with a receiver on a
locomotive being remotely controlled over a communication link
comprising a unique identifier stored in a volatile memory of the
OCU, the system including: a first power source; a second power
source; and a circuit for providing power to the OCU from the
second power source so that the communication link with the
locomotive is maintained while the first power source is being
refreshed. The system may further include a circuit for providing
power from the second power source to a volatile memory portion of
the OCU storing the unique identifier while the first power source
is being refreshed. The second power source may be one of a
capacitor, a long-term storage battery and a solar panel. The
system may further include: two batteries each capable of powering
the OCU; and a mechanism limiting physical access to only one of
the two batteries at a time. The system may further a switch
responsive to a position of the mechanism for switching the source
of power for the OCU from a first of the two batteries to a second
of the two batteries. The mechanism may be a sliding panel in a
battery compartment of the OCU.
[0012] A remote control system for controlling a locomotive is
described herein as including comprising: a controller onboard a
locomotive for controlling the locomotive in response to a remote
control signal comprising a unique identifier; an operator control
unit (OCU) remote from the locomotive for generating the remote
control signal, wherein the OCU further comprises: a first power
source; a second power source; and a circuit for providing power to
a volatile memory portion of the OCU from the second power source
to maintain the unique identifier in the volatile memory while the
first power source is being refreshed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The features and advantages of the present invention will
become apparent from the following detailed description of the
invention when read with the accompanying drawings wherein:
[0014] FIG. 1 illustrates a locomotive being remotely controlled by
a handheld operator control unit.
[0015] FIG. 2A is a functional block diagram of component parts of
the operator control unit of FIG. 1.
[0016] FIG. 2B is a functional block diagram of the locomotive
onboard controller of FIG. 1.
[0017] FIG. 3 illustrates a method of changing the battery of the
operator control unit of FIG. 2A without losing the communication
link between the OCU and the locomotive onboard equipment.
[0018] FIG. 4 illustrates the battery compartment of an operator
control unit having a device that allows the change-out of only one
of two batteries at a time.
[0019] In certain situations for reasons of computational
efficiency or ease of maintenance, the ordering of the blocks of
the illustrated flow charts could be rearranged or moved inside or
outside of the illustrated loops by one skilled in the art. While
the present invention will be described with reference to the
details of the embodiments of the invention shown in the drawing,
these details are not intended to limit the scope of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The present invention allows the operator of a remotely
controlled locomotive to replace discharged batteries in a handheld
operator control unit (OCU) without losing the communication link
with the locomotive, so that the operator does not have to board
the locomotive to re-perform the linking operation of reloading the
volatile memory of the OCU unit with the unique locomotive
identifier. The present invention retains the safety feature that
when the communication link between the OCU and the locomotive is
lost for reasons other than a battery change-out or recharging, the
locomotive will automatically come to a safe stop and will unlink.
For the case where an operator intentionally changes out the OCU
batteries, the communication link is maintained during the battery
change-out process until normal operating conditions are
reestablished.
[0021] FIG. 1 illustrates a remote control system 10 being used by
an operator 12 to remotely control a locomotive 14. The remote
control system 10 includes a handheld battery-powered operator
control unit (OCU) 16 in radio communication with communication and
control equipment 18 located onboard the locomotive 14. To initiate
remote control operation, the operator 12 must board the locomotive
designated to be controlled and perform a linking operation between
the OCU 16 and the control equipment 18 mounted on the locomotive
14. During the onboard linking process, the operator downloads the
unique locomotive identifier into the volatile memory of the OCU
16.
[0022] The downloaded unique identifier is thereafter included in
commands transmitted to the designated locomotive 14 so that the
locomotive control equipment 18 can identify the source of the
command by the associated unique identifier and respond
appropriately. Once the unique identifier is downloaded, radio
communication with the locomotive is established. The radio link
thus established will be maintained provided the unique identifier
code remains in volatile memory and the communication link is not
broken.
[0023] FIG. 2A is a functional diagram of component parts of the
operator control unit 16 of FIG. 1. OCU 16 includes a main computer
processing unit (CPU) 24 that is normally powered by battery 22.
CPU 24 receives control input signals 26 from various
operator-actuated control input devices 28. The CPU 24 controls the
function of radio transmitter 30 to broadcast electromagnetic
signals 32 to the onboard equipment 18. In an embodiment, the
electromagnetic signals 32 comprise a locomotive status word
encoded to provide control information. CPU 24 is programmed to
intelligently assemble the locomotive status word by continuously
scanning the electric contacts of the control input devices 28 and
recording their settings. Based on the scanned input device 28
settings, the CPU 28 constructs a locomotive status word that is a
string of bits uniquely representing the functions to be performed
by the controlled locomotive 14.
[0024] Receiver 34 receives electromagnetic signals 36 from the
onboard equipment 18 for processing by the CPU 24 and display of
status information on operator display 38. A volatile memory 40 is
associated with CPU 24 and is used to store a unique link
identifier for establishing exclusively linked communication with
onboard equipment 18. For example, the unique identifier may be the
identification number of the locomotive, the serial number of the
locomotive, or any identifier that is uniquely assigned to and
associated with a specific locomotive 14. In an aspect of the
invention, the unique identifier may be an encoded identifier to
provide a secure link between the locomotive onboard equipment 18
and the OCU 16. In an embodiment, the unique link identifier is
retrieved from volatile memory and appended to each locomotive
status word transmitted to a target locomotive 14 to uniquely
identify the transmitter designated to control the locomotive 14.
The purpose of this feature is to ensure that the locomotive will
only accept the commands issued by the transmitter generating the
proper identifier. Loss of electrical power to the CPU 24, however,
results in the loss of the link identifier from the volatile memory
40. The CPU 24 will be unable to retrieve a valid unique identifier
from volatile memory, and subsequent transmissions will lack the
required unique identifier. Consequently, in the absence of a
unique identifier, the target locomotive 14 will not recognize a
received remote control command.
[0025] To prevent the loss of information stored in volatile and
memory and the resulting loss of the communication link, OCU 16 is
also provided with a supply of auxiliary power 42. This auxiliary
power supply 42 may be a small long-term storage battery, such as a
lithium cell, a charged capacitor, or a solar panel, etc.
Optimally, the power storage capacity of the supply of auxiliary
power 42 need only be a small fraction of the power storage
capacity of battery 22 since power is drawn from the supply of
auxiliary power 42 during only a short period when battery 22 is
being changed.
[0026] The CPU 24 and other components of the OCU 16 may be powered
by either the battery 22 or the auxiliary power 42 depending upon
the state of a switching device, such as switch 44. In addition, a
battery power monitor 23 monitors the condition of the battery 22
and provides an available power indication to the CPU 24. When the
available power from the battery reaches a predetermined level, an
indication is provided to an operator, such as activating a light
emitting diode (LED) 39 on the OCU 16 or providing an indication in
the display 38. Optionally, an auxiliary power monitor 43 monitors
the condition of the auxiliary power 42 and provides an available
auxiliary power 42 indication to the CPU 24. When the available
power from the auxiliary power 42 reaches a predetermined level, an
indication is provided to an operator, such as activating the LED
39 on the OCU 16 or providing an indication in the display 38.
[0027] When the CPU 24 indicates a low power condition, a switch 44
is provided to allow an operator to select the source of power
supplied to the OCU 16. When an operator recognizes a low power
indication, the operator sets the switch 44 to an auxiliary power
position to provide power from the auxiliary power source 42 before
changing or refreshing the battery 22. After installing a new
battery 22 or recharging the battery 22, the operator can set the
switch 44 to a primary power position to select providing power to
the OCU 16 from the battery 22. In an alternative embodiment, the
switching device detects impending removal of the battery 22, such
as a switch operably connected to a battery access cover. When an
operator opens the battery access cover, the switching device is
activated and switches the power supplied to the OCU 16 from the
battery 22 to the auxiliary source 42. When the battery is
reinstalled 22 and the access cover replaced, the switching device
detects the replacement of the access cover and switches the power
supplied to the OCU 16 from the auxiliary source 42 back to the
refreshed battery 22. In yet another embodiment, the processor is
programmed to automatically switch power when the battery's 22
power output declines below a predetermined minimum power output
level. The processor, receiving inputs from the battery power
monitor 23, detects a low power condition in the battery and
automatically commands the switch 44 to switch power supplied to
the OCU 16 from the battery 22' to the auxiliary source 42, until
the battery 22 is refreshed.
[0028] In addition to the above described switch embodiments, the
CPU 24 can be programmed to provide failsafe modes to prevent
accidental loss of power, such as an operator-ignored low battery
condition or accidental removal of the battery 22 or auxiliary
power source 42. For example, if an operator has set the manual
switch to auxiliary power, removes the battery 22, and accidentally
sets the switch to primary power while the battery 22 is removed,
the CPU 24 can be programmed to override the switch 44 setting if
the battery 22 is not present. The CPU 24 detects the absence of
the battery by receiving a "no power" indication from the battery
power monitor 23 when the battery is removed 22.
[0029] FIG. 2B is a functional block diagram of the locomotive
onboard controller of FIG. 1. The control equipment 18 located
onboard the locomotive 14 includes a receiver 19, a CPU 20, and a
timer circuit 21. In an embodiment, the timer circuit 21 times the
duration that the locomotive is instructed to remain in a safe
condition, such as when the OCU 16 battery 22 is being refreshed.
The CPU 20 instructs the timer circuit 21 to start timing when a
safe mode command is received. The timer circuit 21 provides time
information to the CPU 20, stops timing when a predetermined time
period is exceeded, and provides the CPU 20 with an indication that
the predetermined time period has been exceeded. The CPU 20
processes the timer circuit 21 information according to programmed
timeouts. For example, if the time duration in the safe mode
exceeds a preset time, the CPU 20 commands the locomotive onboard
equipment 18 to unlink communications with the OCU 16.
Alternatively, if the time in the safe mode exceeds a preset time,
the CPU 20 commands the locomotive onboard equipment 18 to ignore
transmission from the OCU 16, even if the link remains active. In
both cases, when the predetermined safe mode time period is
exceeded as determined by the timer circuit 21, the operator of the
OCU 16 must re-board the locomotive to re-link the OCU 16 to the
onboard equipment.
[0030] FIG. 3 illustrates a method 45 for changing the battery 22
of the OCU 16 without losing the communication link between the OCU
16 and the onboard equipment 18. Upon an indication of a low charge
level in battery 22, or at any time selected by the operator, the
remote control system 10 may be placed in a battery change mode at
step 46. This may be accomplished by energizing a special switch 44
on OCU 16, by activating a routine of programmed instructions
stored in CPU 24, or automatically, according to programmed
instructions stored in CPU 24. Upon entering the battery change
mode at step 46, a safe mode signal is sent from the OCU 16 to the
onboard equipment 18 in step 47 to place the locomotive 14 in a
safe condition. The onboard equipment 18 receives the signal in
step 48 and places the locomotive the in a safe condition, or safe
mode, at step 50. In this condition the onboard equipment 18 will
not unlink even if the radio signal 32 from the OCU 16 is
temporarily lost, as described below.
[0031] After the onboard equipment 18 locomotive has been
instructed to place the locomotive in safe mode, the power source
for the OCU 16 is changed from the battery 22 to the auxiliary
power source 42 at step 52. To reduce the necessary capacity of the
auxiliary power source 42, the OCU 16 may be placed in a power save
mode at step 54 either before or after being connected to the
auxiliary power supply 42. Even in the power saving mode, power is
maintained to at least the volatile memory 40 so that the stored
link identifier is not lost. Alternatively, in the power saving
mode, power is provided to the entire transmitter portion of the
OCU 16 to maintain the communication link with the locomotive
control equipment 18, with other power requirements dropped
temporarily to reduce the power draw during the battery change-out
period.
[0032] Battery 22 is then changed out to install a fully charged
battery 22' at step 56. Battery power is restored as the power
source for the OCU 16 at step 58, and power save mode is exited at
step 60. Once full power is restored to the OCU 16, battery change
mode is exited at step 62 and if the communication link is
operative in step 63, full control of the locomotive 14 is regained
by the OCU 16 at step 64. If the communication link has been
unlinked in step 63, then the link must be reestablished 65 by the
operator by boarding the locomotive to perform the re-linking
procedure, a step that is to be avoided by the system and method of
the present invention.
[0033] During the battery change mode procedure (steps 52 to 62),
the onboard equipment 18 will instruct the locomotive 14 to remain
in the safe condition without unlinking from the OCU 16, provided a
predetermined time period, indicated by "X," is not exceeded at
step 66. A safe mode timer circuit 21 is provided as part of the
battery change mode onboard equipment 18 to time the period the
locomotive is in safe mode. If control of the locomotive 14 has
been regained (in step 64) before the time period is exceeded at
step 68, then the onboard equipment 18 will recognize and respond
to OCU 16 commands in step 69. If control of the locomotive 14 has
not been regained at step 68 prior to the end of the predetermined
time period, the onboard equipment 18 will unlink at step 70 and
the operator will have to re-board the locomotive to re-establish
remote control operation. This option is provided as a safeguard in
the event that battery refreshing can not be completed
satisfactorily for any reason.
[0034] FIG. 4 illustrates an alternative method and system for
providing an auxiliary power supply 42. The OCU 16 may be provided
with two batteries 72, 74. Batteries 72, 74 are installed in a
battery compartment 76 of an OCU. Battery 74 is illustrated in
phantom in FIG. 4 because it is hidden from view behind a sliding
panel 78. Sliding panel 78 is one embodiment of a device that
permits only one of a plurality of batteries to be changed at a
time. A regulated power supply in the OCU 16 may permit the remote
control system 10 to be operated with an OCU battery voltage
varying over a wide range, such as from 3-14 volts. In one
embodiment, two 6 volt batteries 72, 74 are provided and the power
output of each battery 72, 74 is monitored. Once the charge level
in the batteries 72, 74 drops to a predetermined level as indicated
by the power monitor, the battery change procedure 45 of FIG. 3 is
implemented. In this embodiment, the auxiliary power is provided by
operating the OCU 16 with just one of the two batteries 72, 74. The
amount of power supplied is sufficient to at least maintain
electrical power to volatile memory 40 so that the stored link
identifier is not lost. Alternatively, the amount of power supplied
is sufficient to at least maintain electrical power to transmitter
34 to maintain the communication link. Battery 72 is changed out
with sliding panel 78 moved to a position directly over battery 74.
Once battery 72 is refreshed, sliding panel 78 is moved directly
over battery 72 and battery 74 is changed out. After both batteries
72, 74 are changed, full power and normal operation are restored
using both refreshed batteries 72, 74. This procedure allows the
communication link to be maintained and prevents loss of the unique
identifier from volatile memory 40.
[0035] In another embodiment, OCU 16 is operated on one battery 72
of a two battery 72, 74 pair until battery 72 is nearly depleted as
indicated by the power monitor. Power draw is then switched to a
second battery 74 of the two battery 72, 74 pair. This power source
change may be accomplished by the actuation of a switch moved in
conjunction with the movement of sliding panel 78. Battery 72 may
then be changed out at the convenience of the operator at any time
before the charge in battery 74 is depleted. In this manner,
battery power to OCU 16 may be refreshed during operation of remote
control system 10 without the loss of the stored unique link
identifier, without loss of the communication link, and without the
need for the operator 12 to re-board the locomotive 14.
[0036] While the preferred embodiments of the present invention
have been shown and described herein, it will be obvious that such
embodiments are provided by way of example only. Numerous
variations, changes and substitutions will occur to those of skill
in the art without departing from the invention herein.
Accordingly, it is intended that the invention be limited only by
the spirit and scope of the appended claims.
* * * * *