Note: Descriptions are shown in the official language in which they were submitted.
CA 02315500 2003-08-20
FIELD OF THE INVENTION
This invention relates to a photocontroller diagnostic system which, inter
alia,
detects whether the photocell and the relay of the photocontroller are faulty
and which
also provides an indication of a faulty relay or photocell condition by
transmitting
information about that condition to a remote base station and/or illuminating
a signal light
on the photocontroller.
BACKGROUND OF THE INVENTION
Photocontrollers are typically mounted on street lights and operate to turn
the light
off during the day and on at night. Since the cost of servicing a single
street light can cost
$100 or more on busy roads and in busy areas, and since there are 60,000,000
street lights
in the United States alone, the problem of servicing faulty photocontrollers
is severe. For
example, when the relay of the photocontroller fails, or when the photocell
fails, the street
light will remain on during periods of daylight thereby wasting electricity.
Alternatively,
a faulty relay or a faulty photocell could cause the lamp to remain off during
the night
causing a safety hazard. Since repair typically occurs during daylight hours,
it is often
difficult to detect the latter condition.
The problem of high pressure sodium (HPS) street lights cycling at the end of
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their useful life is also severe. The phenomena of cycling of HPS lamps as
they age from
use is caused by some of the electrode material being plated off the
electrodes and then
being deposited on the inside of the arc tube. This makes the tube darken and
traps more
heat inside the arc tube. As a result, an increased voltage is required to
keep the lamp
ignited or ionized. When the voltage limit of the ballast is reached, the lamp
extinguishes
by ceasing to ionize. Then, the lamp must cool down for several minutes before
an
attempt at re-ignition can be made. The result is "cycling" wherein the worn
out lamp
keeps trying to stay lighted. The voltage limit is reached, the lamp
extinguishes, and
then after an approximately one-two minute cool down period, the arc tube re-
ignites and
the light output increases again and until the voltage limit is reached
whereupon the lamp
again extinguishes.
Cycling may waste electricity, cause RFI (radio frequency interference) which
adversely effects communication circuits, radios, and televisions in the area,
and may
adversely effect and prematurely wear out the ballast, starter, and
photocontroller.
l 5 For example, if an HPS lamp undergoes cycling for a many nights before it
is
finally serviced and replaced, the ballast or starter can be damaged or
degraded. But,
when the HPS lamp is replaced, this damage or degradation might not be
detected. Later
service. calls then must be made to service these problems. The ballast and
starter
components are more expensive than the lamp or the photocontroller.
The cycling problem is well documented but so far the only solutions offered
are
to replace the 1-IPS lamps with less efficient mercury lamps or to reconfigure
existing
photocontrollers with a special fiber optic sensor which senses light from the
lamp and
sends a signal to a microprocessor to indicate whether the lamp is on or off.
After three
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on/off cycles, the microprocessor turns the lamp off and turns on a red strobe
light which
can he seen from the street. Unfortunately, this prior art solution requires
modifications
to the existing light fixture (e.g. a hole must be drilled in the fixture
housing) and the use
of an expensive fiber optic sensor. See, e.g., U.S. Patent No. 5,235,252
Another problem with all luminaries including HPS or other types of lamps is
the
cost involved in correcting the cycling problem and other faults such as a
lamp out
condition. For example, a resident may report a lamp out or a cycling
condition but
when the repair personnel arrives several hours Inter, the lamp may have
cycled back on.
Considering the fact that the lamp pole may be 2S-35 ft. high, repair
personnel can waste
a considerable amount of time checking each tamp in the area. Also, repair and
maintenance personnel may not be able to service a givers residential area
until daylight
hours when all of the street lights are off by design.
SUMMARY OF INVENTION
It is therefore an object of this invention to provide a photocontroller
diagnostic
system and method.
It is a further object of this invention to provide such a photocontroller
diagnostic system which detects and reports a faulty photocell and/or relay of
the
photocontroller to aid repair personnel in repairing failed photocontrollers.
2 C IL is a further object of this invention to provide such a photocontroller
diagnostic system which conveniently resides on a microprocessor Which itself
is a
component of the photocontroller.
It is a further object of this invention to provide a luminaire diagnostic
system
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which, inter alia, detects and reports cycling street lights.
It is a further object of this invention to provide a method of monitoring
luminaries such as street lights.
It is a further object of this invention to provide such a system and method
which, because of its ability to detect cycling, saves electricity, reduces
RFI, and
prevents the premature failure of baltasts and starters associated with
luminaries.
It is a further object of this invention to provide such a system and method
which significantly reduces the cost of servicing and repairing luminaries
such as street
lights.
It is a further object of this invention to provide such a system and method
which can be implemented in a cost effective way without the need for making
complicated modifications to existing luminaries and/or the use of expensive
fiber optic
sensors.
It is a further object of this invention to ptovide such a system and such a
1 S method which provides a positive indication of a cycling or lamp off
condition in real
time.
It is a further object of this invention to provide a combined photocontroller
and
Iuminaire diagnostic system which is a part of the photocontroller and which
detects a
failed photocontroller relay, a failed photocontroller photocell, a failed
lamp, and a
2 0 cycling lamp Condition.
This invention results from the realization that the proper operation of a
photocontroller for a street lamp or other luminaire can be diagnosed by a
microprocessor resident on the photocontroller and programmed to detect a
faulty relay
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by reading whether current is drawn by the lamp during daylight hours and also
programmed to detect a faulty photocell by determining whether the lamp
remains
continuously on or off for a present period of time such as twenty four hours.
This invention results from the further realization that cycling of a street
light
and other faulty iuminaire conditions such as a lamp out condition can be
detected by
monitoring the load drawn by the lamp at different times and then comparing
the load
differences to pre-determined thresholds, that such detection can be
accomplished by an
inexpensive transformer added to the photocontroller circuitry and coupled to
a
specially programmed microprocessor, and that a transmitter can be linked to
the
microprocessor to transmit lamp out, lamp cycling, and other fault conditions
to a
location remote from the street lamp to initiate repair/maintenance services
in real time.
Alternatively, the microprocessor can illuminate one or a series of LEDs
resident on
the photocontroller to provide repair personnel with a positive indication
regarding the
condition of the photocontroller and/or lamp even in the daylight hours when
the lamp
is purposefully turned off. Further, the controller can shut the lamp off
after a
predetermined number of cycles. This feature eliminates ballast and starter
degradation.
. This invention features a photoeontroller diagnostic system comprising a
photocontroller including a sensor for determining the presence of daylight,
and relay
2 0 means, responsive to the sensor, for de-energizing a lamp during periods
of daylight.
A diagnostic subsystem is responsive to the photocontroller and includes:
means for
verifying the operability of at least one of the relay means and the sensor,
and means,
responsive to the means for verifying, for transmitting a signal
representative of the
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operability of the relay means or the sensor.
The relay means typically includes a switch which when activated energizes a
relay to present a voltage to the lamp- The means for verifying may include
programming steps operable on a microprocessor which detect whether current is
being
drawn by the lamp during daylight hours to detect a faulty relay. The means
for
transmitting then preferably includes additional programming steps which send
a relay
fault signal when current is being drawn during daylight hours.
Alternatively, or in addition, the means for verifying includes programming
steps, operable on a microprocessor, which detect whether the lamp is on or
off for a
period of time greater than a preset threshold to detect a faulty sensor. The
rneans for
transmitting then includes additional programming steps which send a sensor
fault
signal when the lamp is on or off for a period of time greater than the preset
threshold
(e.g., twenty four hours).
The diagnostic subsystem preferably includes a microprocessor which is a
component of and integral with the photocontroller and programmed to detect a
faulty
relay and/or a faulty sensor (e.g., a photocell).
Further included are indicator means, responsive to the signal representative
of
the operability of the relay means or the sensor, for providing an indication
of the
operability of the relay means or the sensor means. Such as indicator means
includes
?0 one or more visual alarms such as LED's on the photocontroller.
Alternatively, the
indicator means may include a transmitter for transmitting the fault signals
to a remote
location.
The photocontroller diagnostic system of this invention may be combined with a
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luminaire diagnostic system which includes means for determining the
operability of
one or more components of the Iuminaire; and means, responsive to the means
for
determining, for transmitting a signal representative of the inoperability of
the
components of the luminaire, typically a failed lamp condition, and/or a
cycling lamp
S condition. Such a combined luminaire and photocontroller diagnostic system
comprises: a photocontroller circuit for automatically turning a lamp on
during periods
of darkness and off during periods of daylight; means for detecting a load
drawn by the
lamp; a microprocessor, responsive to the means for detecting,
programmed to detect a condition of the lamp based on the load drawn by the
lamp,
l0 and programmed to detect a condition of the photocontroller based on the
load drawn
by the lamp; and means, responsive to the microprocessor, for indicating the
occurrence of a detected condition.
The programming which predicts a condition of the lamp based on the load
drawn by the lamp and includes processing steps which reads the load shortly
after the
15 lamp is turned on then again after predetermined time, calculates the load
difference,
and determines whether the load difference exceeds a predetermined threshold
to detect
a failed lamp condition.
The programming which predicts a condition of the lamp based on the load
drawn by the lamp may also include processing steps which calculates whether
the load
2 0 difference at predetermined times exceeds a predetermined threshold, and
counts the
number of times the load difference exceeds said predetermined threshold to
detect a
cycling lamp condition.
The programming which predicts a condition of the photocontroller based on
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the load drawn by lamp includes processing steps which detect whether current
is
drawn by the lamp during daylight hours to detect a relay fault condition.
The ptogramming which predicts a condition of the photocontroller based on
the load drawn by lamp may also include processing steps which detect whether
the
lamp is on or off for a period of time greater than a preset threshold to
detect a
photocell fault condition,
Usually, the load drawn by the Jamp is used as the input to determine whether
the lamp has failed or is cycling and also to determine whether the
photocontroller
relay and/or photocell components are faulty. Such a photocontroller
diagnostic system
comprises a photocontroller for automatically turning a lamp on during periods
of
darkness and off during periods of daylight; means for detecting a load drawn
by the
lamp; a microprocessor, responsive to the means for detecting, programmed to
determine a condition of the photocontroller based on the load drawn by the
lamp; and
means, responsive to the microprocessor, for indicating the presence of a
failed
photocontroller. The microprocessor further includes programming which
determines
a condition of the lamp based on the load drawn by the lamp. The programming
which determines a condition of the lamp based on the load drawn by the lamp
and
includes processing steps which read the load shortly after the lamp is turned
on then
again after predetermined time, calculate the load difference, and
2 a determine whether the load difference exceeds a predetermined threshold to
detect a
failed lamp condition. The programming which determines a condition of the
lamp
based on the load drawn by the lamp may also or alternatively include
processing steps
which calculate whether the load difference at predetermined times exceeds a
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predetermined threshold, and counts the number of times the load difference
exceeds
the predetermined threshold to detect a cycling lamp condition.
The programming which determines a condition of the photocontroller based on
the load drawn by lamp includes processing steps which determine whether
current is
S drawn by the lamp during daylight hours to detect a relay fault condition.
The
programming which determines a condition of the photocontroller based on the
load
drawn by lamp may also or alternatively include processing steps which
determine
whether the lamp is on or off for a period of time greater than a preset
threshold Eo
detect a photocell fault condition.
This invention also features a method of diagnosing the operability of
photocontroller components such as the relay and/or the photocell sensor. The
method
includes detecting whether a load is drawn by a lamp; determining whether it
is
daylight; determining whether the load is continuously drawn by the lamp for a
period
of time greater than a preset threshold; and sending a fault signal if a load
is drawn by
the Tamp during daylight or if a load is drawn by the lamp for a period of
time greater
than the preset threshold. The method of this invention also includes
diagnosing
whether the lamp is properly operating. The method includes reading the load
shortly
after the lamp is turned on then again after predetermined time, calculating
the load
difference, and determining whether the load difference exceeds a
predetermined
2 0 threshold to detect a failed lamp condition. In addition, a cycling lamp
condition may
be detected by calculating whether the load difference at predetermined times
exceeds a
predetermined threshold, and counting the number of times the load difference
exceeds
the predetermined threshold to detect a cycling lamp condition.
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BRIEF DESCRIPTION OF TI-IE ARAWINCS
Other objects, features and advantages will occur to those skilled in the art
from
S the following description of a preferred embodiment and the accompanying
drawings,
in which:
Fig. 1 is a schematic view of a photoeontroller including both the
photocontroller diagnostic and the luminaire diagnostic systems of this
invention;
Fig. 2 is a block diagram of the primary components of the photocontroller and
luminaire diagnostic systems of this invention;
Fig. 3 is a wiring diagram showing the primary components of the
photocontroiler and luminaire diagnostic systems of this invention;
Fig. 4 is a flow chart depicting the program steps for detecting a faulty
photocell and a faulty relay in accordance with the subject Invention;
~ 5 Fig. S is a flow chart depicting the routine for detecting a lamp out
condition in
accordance with this invention;
Fig. 6 is a flow chart depicting the routine for detecting cycling in
accordance
with this invention;
Fig. 7 is a schematic view showing one method of externally transmitting
2 0 photocontroller and luminaire fault conditions diagnosed in accordance
with this
invention; and
Fig. 8 is a schematic view showing another method of externally transmitting
photocontroller and luminaire fault conditions in accordance with the subject
invention.
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DISCLOSURE OF TI-1F PREFERRED EMBODIMENT
Photocontrol device 10, Fig. 1, includes thermoplastic, high impact resistant,
ultraviolet stabilized polypropylene cover 12 and clear window 14 made front
UV
stabilized, UV absorbing, acrylic for the light sensor which resides on a
circuit board
within cover I2. Photocontrol device IO is typically configured to fit an ANSI
C136.10 receptacle but may be mounted in an ANSI C136.24 "button" package or
other enclosure. Photocontroller 10 is typically mounted on a street light at
the top of
a Iight pole. Photocontroller 10 may also be used, however, in conjunction
with other
types of luminaries and other devices such as golf course water fountains.
The circuit board within cover 12 is configured to operate in accordance with
the block diagram shown in Fig. 2 and the specific circuit diagram shown in
Fig. 3.
Microcontroller 54 shown in the circuit diagram of Fig. 3 is programmed in
accordance
with the flow charts shown in Figs. 4, 5, and 6 in accordance with this
invention, and
transmitter 80 shown in the circuit diagram of Fig. 3 can be linked to a
l. 5 communications network or networks as shown in Figs. 7 and 8 in
accordance with this
invention.
A standard street light type luminaire 20, Fig. 2, typically includes a
controller
such as controller I0, Fig. 1, ballast 22, starter or igniter 24, and a HPS or
ocher type
of lamp 26. Lamp 26 is generally referred to as an electrical device.
2 0 Photocontroller diagnostic subsystem circuitry 27 and luminaire condition
sensing Circuitry 28 in accordance with this invention may be integral with
photocontroller 10, Fig. 1. Photocontroller diagnostic subsystem circuitry 27
includes
faulty photocell detector 29 and faulty relay detector 31. Lumiriaire
condition sensing
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circuitry 28 includes lamp out sensor circuitry 30 and cycling detector
circuitry 32. In
the preferred embodiment, faulty photocell detector 29, faulty relay detector
31, lamp
out sensor circuitry 30, and cycling detector circuitry 32 all uniquely share
the same
electronic components discussed with reference to Fig. 3. Faulty photocell
detector 29
and faulty relay detector 31 operate, in the preferred embodiment, as means
for
verifying the operability of the relay of the photocontroller and also the
operability of
the light sensor, typically a photocell, of the photocontroller. There are
also means for
sensing a condition of luminaire 20 such as a lamp out condition or a cycling
condition,
namely lurninaire condition sensing circuitry 28. Also a part of the present
invention
are transmitter means such as communication circuitry 34 which may include off-
site
remote communications subsystem 36 and/or on-site communications subsystem 38
which may simply be visual indicator means such as LED 13, Fig_ 1 of one color
for
indicating the occurrence of a cycling condition or a faulty photocell
condition and
LED 1~ of another color for indicating the occurrence of a lamp out condition
or a
faulty relay condition. The LED's may also be made to flash to indicate a
faulty
photocontroller and be steady on to indicate a cycling or lamp out condition.
Off site
communication circuitry 36 may also be implemented to transmit these and other
conditions to remote location for real time diagnostics.
Thus, luminaire diagnostic system 40 which includes condition sensing
circuitry
2 0 28, diagnostic circuitry 27, and communication circuitry 34 eliminates the
guess work
involved, especially in the day time, when repair personnel attempt to
determine which
street light and/or a photocontroller has a faulty component. The cost of
servicing
street lights is severely reduced in part because the guess work of on-site
diagnosing of
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problems with the street light systems is eliminated.
Photoeontroller diagnostic subsystem circuitry and luminaire condition sensing
circuitry 28, Fig. 3, includes means for detecting the load drawn by the lamp
such as
transformer 50 coupled to load line S1 and connected to microprocessor 54 via
line 56.
A hall effect sensor could also be used as it is functionally equivalent to
transformer
S0. Microprocessor 54 predicts a faulty photocontroller relay and/or a faulty
photocontroller photocell in accordance with programming described with
reference to
Fig. 4. Microprocessor S4 also predicts a lamp out and/or lamp cycling
condition in
accordance with programming described with reference to Figs. 5 and 6. Diode
58 is
located on line 56 to rectify the current from transformer 50. Resistor 60,
capacitor
62, and Zener diode 64 are connected across line 56 and neutral line 66 to
filter and
stabilize the current. Capacitor 62 filters the rectified AC current present
on line 56
and typically has a value of 10 pF. Resistor 60 has a typical value of 100
k~'~ and acts
as a bleeder for capacitor 62. Zener diode 64 acts to limit the voltage to
microprocessor 54 and has a typical value of 4.7 volts at one watt.
Microprocessor 54
then transmits signals over lines 70 and 72 through resistors 74 and 76 which
limit the
current output current (typical values are 4.7 k~) to LEDS 13 and 15,
respectively.
. Alternatively, or in addition, transmitter 80 may be connected to
microprocessor 54 and used to transmit signals indicative of photocontroller
and/or
2 0 lamp conditions sensed by photocontroller diagnostic circuitry and sensing
circuitry 28
to a remote Location as discussed infra via RF communications. Alternatively,
such
communication signals may be placed back on the power line to which the Jamp
is
connected via power line carrier electronics package 82. Microprocessor 54 is
CA 02315500 2003-08-20
preferably at 18 pin microprocessor part no. PIC 16C710 or an eight pin PIC 1
X671 with
an analog to digital converter capability available from Microchip. Much of
the
remainder of the circuitry shown in Fig. 3 is described in general in U.S.
Patent
5,195,016. Specifically, 120 volt AC line 100 is fed to resistor 102 ( 1 kS~ )
which is used
to limit the current to bridge rectifier 104. Bridge rectifier 104 rectifies
the AC current to
a rippled 100 VDC presented to relay 106 and resistor/capacitor filter network
108.
Resistor 110 has a typical value of 10 kS2 and capacitor 112 has a typical
value of 10 ~F.
RC filter network 108 filters the rippled DC signal to a smooth DC signal and
Zener
diode 116 clamps the voltage at 8 volts DC. Regulator 118 receives this 8 volt
VDC
signal and maintains a constant 5 volt DC signal to microprocessor 54. When
light is
sensed by the sensor, e.g., photocell 120, the voltage level on pin 1, 122 of
microprocessor 54 will vary inversely with the light level. When the light
level is high
(daylight) the voltage is low and when the light level is low (night time) the
voltage is
high. Program variables in the programming of microprocessor 54 make it
possible to
select what light level will turn on switch 126 which in turn energizes relay
106 and also
the light level which will turn off switch 126 which in turn de-energizes
relay 106.
In accordance with this invention, microprocessor 54, Fig. 3, is also
programmed
in accordance with the flow charts shown in Figs. 4, 5 and 6.
Photocontroller dia ng ostics
In general, the photocontroller diagnostic section of the program is written
to
allow detection of photocontroller component failures. The operability of two
components that the program can detect are typically photocell 120, Fig. 3 and
relay
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106. A faulty relay condition is defined as the current being drawn by the
lamp during
a certain ambient tight condition, typically daylight or a day. In ocher
cases, such as
for golf course water fountains, the ambient light condition is night. A
faulty photocell
condition is defined by twenty-four hours of continuous daytime and nighttime
lamp
operation.
When power is first applied to the photocontroller, initialization step 130,
Fig.
4 sets alt counters. The light level is then read every 0.5 seconds in step
131. The
light level read is compared to a predetermined level and a decision is made
whether it
is Iight or dark, step 132. If it is light, the next question is whether a
fault has already
been detected, step 133. If so, the program will go back and check light level
again.
If no fault has previously been detected, then the program will wait
two~seconds, stop
134, and then read the current, step 135. The program will then check to see
if there
is a current draw, step 136. If no current is drawn, then the relay is
properly operating
since there should be no current drawn during daylight hours. Next, the
program will
call the hour counter, step 137. If current is drawn, then there is a problem
and one
second is subtracted from the counter, step 138 and a check is made to see if
hour
counter i5 at zero, step 139. If the hour count is not zero, then the program
proceeds
to step i37 to call the hour counter. if the hour count is zero, then the
relay is faulty,
a condition which is communicated via a reiay fault signal, step 140 to
1..ED's 13
2 C and/or 15, Fig. t . In addition, or alternatively, the relay fault signal
could be
transmitted to a remote location as discussed with reference to Figs. 7-8.
If, in step i32 it was determined chat it was night, the program would next
determine if it was a new night, step 141. if it is a new night, then all
faults and
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counter and timers are reset, step 142. The program then goes on to check the
light
level again step 131.
If it is not a new night, then the hour counter is called, step 137. This hour
counter is used to count the length of the night or day. If in step 143 it is
determined
that the hour counter is equal to a preset threshold, e.g., twenty-four hours,
then the
photocell is faulty. The program then communicates this fault, step 140 and
causes
LEDs 13 and/or 15, Fig. I, to energize. Again, this faulty photocell signal
could also
or alternatively be communicated to a remote location as discussed below with
reference to Figs. 7-8. If the hour counter in step 143 is not equal to twenty-
four
hours, then the light level is checked again, step 131.
Luminaire diagnostics
Another routine, called a lamp out detection routine, begins by reading the
voltage level on line 56, Fig. 3 at some time t, after the lamp is first
turned on, step
I50, Fig. 5. t, is typically about 2 seconds which is sufficient tirne to
eliminate any
transients in the circuitry. AL some time later, t=, typically 3 minutes, the
voltage is
again read, step 152, and these two voltages are compared lo determine whether
they
are lower than a preset threshold, step 1~4, typically about 12.5 percent. if
the
difference between the two different voltage level readings is greater than
this
threshold, processing transfers to the cycle detection mode discussed with
reference to
? 0 Fig. 6. If, however, on the other hand, the difference between the two
different
voltage readings is less than this threshold, this is indicative of a lamp out
condition,
step 156.
1n other words, a properly working lamp consistently draws more and more of a
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load during the start up mode while a failed lamp or ballast does nor. The
threshold
level for the comparison at step 1S4 could be Zero but the 12.5 percent level
is
preferably used because the power correction capacitor used in the luminaire
often
draws a load even when the lamp is out but it always draws a constant load
over time.
Once microprocessor S4, Fig. 3, determines a lamp out condition, step 156,
Fig. S, it
can take any number of lamp out condition actions, step 158, such as
energizing 1_.El~
15, Figs. 1 and 3, step 160, Fig. S, provide a signal to transmitter 80, Fig.
3 to
communicate to a remote base station, step 162, Fig. 5, andlor turning the
power off to
the lamp, step 164, to save energy and the Life of the starting aid and
ballast. Receiver
81 may be used as a means to activate certain routines programmed in
microprocessor
54, Fig. 3 including a routine to power the lamp in daylight hours for daytime
testing.
Microprocessor S4, Fig. 3, also includes the cycling detection routine shown
in
Fig. 6 wherein the count representing the number of cycles is set to a number
such as
five upon initialization, step 180, and then the voltage on line S6, Fig. 3,
is read
periodically at a time t such as every second, step 182. If a subsequent
voltage reading
is greater than a previous voltage readinS, step 184, the subsequent voltage
reading is
stored and used as the base line, step 186. This voltage level is stored in a
buffer as a
bench mark so that any transients and any voltage levels read during the warm
up
period will be accounted for. Processing then continues until a subsequent
voltage
reading is lower than a previous voltage reading, step 188, by some
predetermined
threshold, for example, 25 % , which indicates the presence of a cycling
event. The
2S% threshold could be as low as 12%, but a 12% variation could also be
indicative of
a power surge and so the 2S % threshold is preferred. The count is then
decremented,
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step 190, and once the count reaches some predetermined minimum, step 192, for
example, 0, the fact that a cycling event has occurred is communicated, step
194, in a
fashion similar to the actions taken after step 158, Fig. S. The lamp can be
turned off
permanently or the microprocessor can be programmed to turn the lamp off only
for
one night and then re-set to again detect cycling the next night to prevent
erroneous
cycling detection events. In addition, or alternatively, LEDs 13 or 1S, Fig. 1
can be
made to flash, and/or a signal can be sent via transmitter 80 to a remote
location to
indicate the occurrence of a cycling event. An available alarm could also be
used_
External communications may occur via RF transmission or via powerline
1 o carrier technology as shown in Fig. 7 from street light 200 to street
light 202 to street
light whereupon the condition information is sent to final or intermediate
base station
204 and, if required, to other base stations or other locations as shown at
20ti in any
number of ways including satellite transmission, RF transmissions, land line
transmissions, and the like. Alternatively, as shown in Fig. 8, a
comrrtunication
network utilizing I2F transmitters and/or transmitter receivers can be used
wherein one
set of transmitters resident on the photocontrollers described above transmit
to
communication control unit 2i0 which in turn communicates to network control
node
212 which also receives communications from communication control unit 214.
Network control node 212 then communicates with central base station 216 as is
known in the art of remote meter reading technology. In this way, information
regarding the operability of the photocontroller (faulty relay, faulty
photocell) and/or
the luminaire (a cycling condition, faulty lamp) can be transmitted to remote
locations
for real time diagnostics.
CA 02315500 2000-08-11
Note, however, that in one embodiment, such remote communication
capabilities are not required and LEDs 13 and 15, Figs. 1 and 3, can be the
only
indicators in an less expensive, less campiex photocontroller in accordance
with the
subject invention. Note also that other types of visual and even non-visual
alarm
indicators could be used instead of LEDs 13 and 1S. Also, additional L)rDs
could be
used such that one signals the occurrence of a faulty relay, one signals the
presence of
a faulty photocell, one signals the presence of a cycling condition, and one
signals a
faulty lamp condition.
Thus, photocontroller 10, Flg. 1, includes sensor 120, Fig. 3 which, in
7.0 combination with microprocessor 54 and the circuitry shown in Fig. 3
determines the
presence of daylight. Relay means, such as relay 106 is responsive to sensor
120 via
microprocessor 54, de-energizes luminaire ?0, Fig. 2 during periods of
daylight and
energizes lamp 20 during periods of darkness. In other embodiments, such as
golf
course water fountains, the reverse is true and thus microprocessor 54 is
programmed
to turn the fountain on during the day and off at night. The relay means could
also be
a TRlAC, FFT or other sold state device.
The diagnostic subsystem of this invention includes two primary components: a
photocontroher diagnostic routine and a luminaire diagnostic route.
Microprocessor
~4, Fig. 3 is programmed in accordance with steps 130-143, Fig. 4 to verify
the
2 0 operability of relay 106, Fig. 3 and sensor 120, typically a photocell and
to then
transmit a signal representing a failure of either component. A faulty relay
is usually
detected by determining whether current is drawn by the lamp during daylight
hours.
A faulty photocell is usually detected by determining whether the lamp remains
on or
21
CA 02315500 2003-08-20
off for a pre-established time period, e.g. 24 hours.
The luminaire diagnostic routine operates in accordance with the processing
steps
shown in Figs. 5 and 6. Transformer 50, Fig. 3 is used, in combination with
microprocessor 54 to detect the load drawn by the lamp. This information is
used both by
the photocontroller diagnostic routine and the luminaire diagnostic routine.
Although specific features of this invention are shown in some drawings and
not
others, however, this is for convenience only as each feature may be combined
with any
or all of the other features in accordance with the invention. And, other
embodiments
will occur to those skilled in the art and are within the following claims.
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