Radio frequency controlled system for testing emergency lighting units

An system is provided for testing emergency lighting units using a receiver connected to the emergency lighting unit and a portable transmitter operable remotely with respect to the emergency lighting unit. The emergency lighting comprises a transfer relay for switching a battery between a primary power source and a lamp. A TEST button and the receiver each include a normally closed contact switch connected in series with each other, as well as with a primary power source input and transfer control circuitry. The transmitter generates encoded signals for wireless transmission to the receiver as long as a control switch on the transmitter is being activated by a user. The receiver receives and decodes the encoded signals and opens its normally closed relay as long as encoded signals are being received, causing the transfer control circuitry to activate the transfer relay to switch the battery from the primary power source to the lamp. The transmitter terminates transmission of encoded signals when the user deactivates the control switch. The receiver then closes its normally closed relay when encoded signals are no longer received, and the transfer control circuitry via the transfer relay switches the battery from the lamp to the primary power source for charging.

FIELD OF THE INVENTION 
The invention relates to a system for remotely controlling the switching of 
a battery in an emergency lighting unit between a primary power source and 
a lamp. 
BACKGROUND OF THE INVENTION 
Emergency lighting units (ELUS) are used to illuminate residential and 
commercial facilities in the event of a power outage. Most ELUs are 
connected to an alternating current (AC) line power source during normal 
operation, and charge a battery to power the lighting unit when AC line 
power is interrupted for a significant period of time. These units are 
typically tested on a periodic basis to ensure that the battery is being 
sufficiently charged and that the ELU will operate during AC power 
failure. Testing generally entails activating a test instrument on the 
housing containing the emergency lighting fixture. This presents 
difficulties for human operators because the ELUs are generally located in 
inaccessible areas such as on the walls and ceilings of residential and 
commercial buildings. Thus, testing can be an arduous, time-consuming task 
for human operators, particularly when a large number of ELUs is present 
in an installation such as a warehouse. 
A number of systems have been developed to facilitate testing of ELUs. For 
example, U.S. Pat. No. 5,148,158 discloses an ELU having a remote testing 
capability. The lighting fixture is provided in a housing which is mounted 
on a ceiling, for example, and which encloses circuitry for receiving 
radio frequency control signals from a hand-held transmitter. The remote 
test function commences when a button on the transmitter unit is depressed 
by an operator. The transmitter unit generates first and second radio 
frequency (RF) signals which, when received by the receiver circuitry, 
cause a bi-stable relay in the housing to interrupt and continue, 
respectively, the supply of line power to the lighting fixture. In another 
embodiment, the generation of a momentary RF signal initiates the test 
function, that is, disconnects the lighting fixture from the line power 
source for a predetermined period of time, and operates the lighting unit 
from a battery, before connecting the line power source once again. 
U.S. Pat. No. 5,154,504 discloses an emergency lighting system comprising a 
portable control unit which communicates with each of several lighting 
units via a two-way, infrared communications link. The portable control 
unit comprises Start Test and Stop Test buttons to start and stop a test 
function, respectively, whereby the lighting unit is disconnected from a 
primary power source and operated from an alternate source. 
SUMMARY OF THE INVENTION 
The present invention provides an ELU that is advantageous because it does 
not require two transmitted signals to commence and interrupt an ELU test 
function, nor does it limit the test function to a predetermined period of 
operation. In addition, it uses a minimal number of test instruments or 
control buttons, among other advantages. 
The present invention also provides an ELU that is advantageous because it 
is capable of operating a lighting fixture from an auxiliary power supply 
for a continuous and variable amount of time. The variable amount of time 
depends on the amount of time an operator activates a push button switch 
on a portable transmitter unit which is designed to communicate with a 
remote lamp control receiver unit. 
In accordance with an embodiment of the present invention, an emergency 
lighting system for testing emergency lighting units is provided 
comprising a lamp, a primary power source, a battery for supplying power 
to the lamp during primary power source interruption, a lamp control 
circuit connected to the lamp and battery, and a transmitter comprising a 
control switch that is operable remotely from the lamp control circuit to 
generate and transmit a control signal thereto The duration of the control 
signal corresponds to the amount of time the transmitter control switch is 
activated The lamp control circuit comprises a receiver operable to 
receive the control signal and transfer circuitry to switch the lamp to 
the battery. The lamp control circuit switches the battery from the 
primary power source to the lamp in response to receipt of the control 
signal, and switches the battery from the lamp to the primary power source 
for charging after a period of time has elapsed. The period of time 
corresponds to the duration of the control signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 is a front view of an emergency lighting unit (ELU) 10 having the 
front cover (not shown) removed to reveal the contents of the unit housing 
12. An incandescent or halogen lamp, such as those depicted at 14 and 14' 
in FIGS. 2 and 3, is mounted in a conventional manner on the top, front or 
sides of the housing 12 and the wires 16 are placed through an aperture 18 
in the housing 12 in order to be connected to a charger board 20. With 
reference to FIG. 4, the housing 12 encloses a battery 22 which is 
connected to a charger board 20 via battery wires 24. The battery 22 is an 
alternate power source when current from an AC power source is not 
available on the AC line 26, or AC power has been interrupted 
intentionally to test the ELU, as will be described below. 
With continued reference to FIG. 1, the charger board 20 carries light 
emitting diodes (LEDs) 28 which extend outside the housing 12 to indicate 
that the AC supply is present for the ELU, whether the ELU is in the 
battery backup mode (i.e., emergency operation mode) and to indicate the 
status of the battery (i.e., high or low charge). The housing 12 allows 
for mounting of an optional voltmeter 30 and an ammeter 32 that can be 
connected to the charger board 20. To test the operation of the ELU 10 on 
battery power, a TEST push button 34 is provided on the housing. When an 
operator depresses the button 34, the charger board 20 switches the lamp 
14 from AC line to battery power. In accordance with an embodiment of the 
present invention, the ELU 10 can also be tested using a receiver 36, 
which is mounted in the ELU fixture housing 12, in conjunction with a 
hand-held transmitter depicted in FIGS. 6 and 7. 
With reference to FIG. 4, the charger board 20 is connected to a primary 
power source via a transformer 44 and AC lines 26, to an alternate or 
auxiliary power source such as a battery 22, to a TEST button 34 and to a 
receiver 36. The charger board 20 can also be connected to an optional 
voltmeter 30, an ammeter 32 and to a time delay device 40. The charger 
board 20 is preferably a low voltage, low wattage Economy #703069 charger 
printed circuit board (PCB) manufactured by Hubbell Lighting Incorporated, 
Christiansburg, Va., which switches the lamp output on the negative lead 
of the battery, as shown in FIG. 5. The ELU 10 is preferably in a model 
PE612 or HE625 ELU, also manufactured by Hubbell Lighting Incorporated. It 
is to be understood that other ELUs can be used in accordance with the 
present invention. Further, other battery and charging assemblies can be 
used in accordance with the present invention such as the Hubbell low 
voltage, high wattage, #703067 emergency charger manufactured by Hubbell 
Lighting Incorporated, which switches the lamp output on the positive lead 
of the battery. 
As shown in FIG. 5, the charger board 20 is of a conventional type and 
includes DC rectifying and voltage regulating and transfer control 
circuitry 21 for maintaining the battery 22 in a fully charged condition. 
The charger board 20 has four output terminals designated B+, B-, L+ and 
L-. The B+ and B- terminals are the battery terminals of the charger board 
and are connected to the positive and negative terminals of the battery 
22, respectively. The L+ and L- terminals are the lamp output terminals of 
the charger board 20 and are connected to the lamp 14 or 14'. The B- 
terminal is also electrically connected to the lamp 14 or 14' via the PCB 
20. 
To switch between standby and emergency or test modes, the charger board 20 
comprises transfer control circuitry 21 and a transfer relay and 
transistor (indicated generally at 42). The transfer control circuitry 21 
operates the transfer relay and transistor 42 to selectively switch the 
lamp(s) to the battery power source in response to open circuit conditions 
due to activation of normally closed relays 35 and 80 by the TEST push 
button 34 and the receiver 36, respectively, or the condition of the loss 
of the primary AC power source. The transfer relay 43 has a coil 45 which 
is coupled to the transfer control circuitry 21. When AC power is 
available, the relay contacts of relay 43 are in an unswitched position to 
prevent the lamp polarities from being electrically connected to the 
battery output terminals B+ and B-. This condition allows for the charging 
and transfer circuit 21 to maintain the battery in a fully charged 
condition during the standby mode. When the AC power is interrupted or 
falls below a predetermined level, the transfer control circuitry 21 
energizes the coil 45 and allows the relay 43 to go to a switched 
position. The lamp terminals are therefore electrically connected to the 
battery terminals. The isolation between the lamp terminals and the 
battery terminals can also be accomplished using a power transistor. Thus, 
the relay 43 or a power transistor operates as a transfer switch for 
automatically initiating emergency or test mode operation in the event of 
a power supply interruption, and for automatically returning the ELU 10 to 
standby operation once power has been restored. 
With continued reference to FIG. 4, the ELU 10 also comprises a transformer 
44 for stepping down the voltage from the primary power source (e.g., a 
120 VAC power supply) to a reduced input voltage (e.g., an input voltage 
range of 10 VAC minimum and 35 VAC maximum). The input voltage is used to 
power the receiver 36, as indicated by lines 46, and is used to charge the 
battery when the ELU is not in an emergency or test mode. 
In accordance with an embodiment of the invention, the TEST button 34 and 
the receiver 36 each include a normally closed contact switch and are 
connected in series with each other, as well as with the power supply 
input transfer control circuitry 21 of charger board 20. When either the 
TEST button 34 (e.g., a momentary push button) or the receiver 36 is 
activated and opens its normally closed switch, the supply of input 
current from the primary power source is interrupted The transfer control 
circuitry of the charger board 20 detects an open circuit condition on the 
serial line 48 and, accordingly, switches the transfer relay transistor to 
operate the lamp from the battery. 
The receiver 36 is activated by a transmitted radio frequency (RF) signal 
generated by the hand-held transmitter 50 depicted in FIGS. 6 and 7. The 
transmitter preferably comprises a plastic-molded housing 52 having a belt 
clip 54 and a key ring 56. The transmitter housing 52 encloses a battery 
and a transmitter control circuit as described below in connection with 
FIGS. 8 and 10. A momentary push button switch 58 is provided such that 
when it is activated by a user, the transmitter generates a RF control 
signal via an antenna 60 (FIG. 8) for transmission to the receiver 36 for 
essentially as long as the user activates the switch 58. An LED 62 or 
other indicator is provided to indicate when the transmitter 50 is 
generating and transmitting a control signal to the receiver 36. 
With reference to FIG. 8, the transmitter 50 comprises an encoder 64 for 
generating an encoded signal for as long as the button 58 is depressed by 
a user. The encoder 64 is connected to a RF signal generating circuit 66 
for combining the encoded signal with a RF carrier signal. The encoded RF 
signal is amplified by an amplifier 68 and broadcast to the lamp control 
circuit via the antenna 60. The RF signal generating circuit 66, amplifier 
68, and antenna 60 can be an LC oscillator 92 as described in connection 
with FIG. 10. It is to be understood that other wireless for communicating 
with the lamp control unit can be used. For example, the transmitter can 
be provided with circuitry for modulating the encoded output signal from 
the encoder into an infrared signal or ultrasonic signal. The receiver in 
the lamp control unit can be provided with corresponding circuitry for 
receiving encoded infrared or ultrasonic signals. 
With reference to FIG. 9, the receiver 36 comprises an antenna 70 for 
receiving encoded RF signals from the transmitter 50. The RF signals are 
processed by an amplifier 72 and then demodulated into digital signals by 
a RF regenerative detector 74, which is tuned to the transmitter 
frequency, and digitizing operational amplifiers 76. The digital signals 
are decoded by a decoder 78, which opens the normally closed relay 80 to 
interrupt the primary power supply if the decoded signals are recognized 
as valid control signals from the transmitter 50. The charger board 20 in 
turn energizes the transfer relay and transistor 42, thus connecting the 
lamp 14 or 14' to the battery An advantage of placing the receiver relay 
80 in series with the manual TEST button 34 and of using normally closed 
contacts on the relay 80 is that the ELU 10 remains operational and 
continues to have a manual test function via TEST button 34 even if the 
transmitter 50 or receiver 36 malfunction. 
The encoding and decoding processes will now be described with reference to 
FIGS. 10 and 11, which are schematic diagrams of the transmitter 50 and 
receiver 36, respectively As shown in FIG. 10, the transmitter 50 
comprises a battery 82 which supplies a voltage Vcc to the encoder 64 as 
long as the switch 58 is closed. The switch BT1 58 can be a push 
button-type switch that must be pressed and held to remain closed. Enable 
pin 14 on the encoder 64 is tied to ground such that the encoder is 
enabled as long as it is receiving a supply voltage. The encoder 64 
comprises nine pins (i.e., A1 through A9) and is configured to generate 
one of three different output signals on pin 15 depending on which the 
nine pins are tied to Vcc, to ground, or are left floating, respectively. 
For example, the encoder 64 can be configured to generate two wide pulses 
for each pin connected to Vcc, one wide pulse and one narrow pulse for 
each pin connected to ground, and two narrow pulses for each pin left 
floating to create an encoded output signal of eighteen, serial pulses. A 
three-position switch or jumper 84 can be used to set each pin to a Vcc, 
ground or floating state. The switch settings can be varied among several 
transmitters and, correspondingly, among receivers configured to recognize 
a particular pattern of eighteen, wide and narrow pulses in a received 
signal. Varying the switch settings reduces the likelihood of unintended 
reception of transmitted signals by the wrong ELU or other wireless device 
(e.g., a security device or automatic door in the vicinity of the ELU 10). 
With continued reference to FIG. 10, the resistors 86 and 88 and the 
capacitor 90 connected to the encoder 64 are selected to establish a 
predetermined rate of pulses output on pin 15. When a pulse appears on pin 
15, an LC oscillator 92 begins oscillating at a tuned frequency (e.g., 318 
MHz) for the duration of the wide or narrow pulse. The tuned frequency is 
preferably selected from a range of frequencies between 286 and 370 MHz 
and tuning is performed by varactor 94. Thus, one of the RF pulses in an 
encoded signal is generated by the oscillator 92 for transmission to the 
receiver 36. When no pulse appears on pin 15 of the encoder 64, the 
transistor 96 turns the coil 98 off until the next wide or narrow pulse 
appears at the pin 15. After eighteen pulses appear on the pin 15, the 
encoder 64 generates six synchronization pulses before generating the next 
sequence of eighteen pulses. The LED 62 is illuminated each time a RF 
pulse is transmitted. The LED 62 becomes dim as battery charge decreases 
and therefore functions as an indicator to replace the transmitter battery 
82. 
With reference to FIG. 11, a conventional power supply is provided within 
the receiver 36 for converting the voltage from the secondary of the 
transformer 44. The receiver 36 comprises an antenna 70 and an amplifier 
(i.e., transistor 102) for amplifying a received RF pulse in an encoded 
signal. When a RF pulse is received that is tuned to the same frequency as 
the RF regenerative detector 74 (i.e., a tuner comprising capacitors 104 
and 106, inductor 108, varactor 110 and transistor 112), the regenerative 
detector 74 changes the amplitude of its oscillating output signal such 
that the signal can be converted to a square wave, digital signal by the 
operational amplifiers 114 and 116. The digital signal at the output of 
the operational amplifier 116 is provided to the decoder 78. 
With continued reference to FIG. 11, the decoder 78 compares the input 
digital signal at pin 9 with switch data at pins A1 through A9, which are 
configured in a manner identical to the transmitter using three-position 
switches or jumpers 118, as described above. When the decoder 78 detects 
two identical encoded signals of eighteen pulses, which are separated by a 
synchronization signal of six pulses, the decoder generates a high output 
signal at pin 11. The pin 11 remains high, as long as valid encoded 
signals are detected by the decoder 78. The decoder output signal is 
provided to the relay 80 via gates 120 and 122 and transistor 124. A high 
output signal causes the transistor 124 to conduct and operate the relay 
coil 126 to open a normally closed contact. Accordingly, the charger board 
20 switches the lamp 14 or 14' to the battery 22 to operate the ELU 10 in 
a test mode. When the output signal at pin 11 then goes low, the 
transistor 124 turns off, and the relay closes. The charger board 20 
disconnects the lamp 14 or 14' from the battery 22. 
When valid encoded data is being received, the relay 80 remains open until 
encoded pulse signals are no longer detected by the decoder 78, even if 
there is a momentary loss of data (e.g., the transmitter user 
unintentionally breaks contact of switch S1 for an instant). Protection 
against momentary, unintentional loss of encoded data is provided by the 
second gate 122. Since the output signal from the second gate 122 is 
required at one input of the first gate 120, gate 122 establishes a 
minimum time for providing an output signal from the decoder 78 to the 
first gate 120 that has not changed state (i.e., changed from high to low, 
or low to high). Capacitor 128 and resistor 130 are selected to set the 
predetermined minimum time for providing a signal to the first gate 
without changing state to a desired value (e.g., two seconds). Conversely, 
if the button 58 on the transmitter 50 is depressed for only a brief 
period of time (e.g., one second), the test feature is engaged (i.e., a 
high decoder output signal is generated to open the relay 80) for the 
minimum time of two seconds. 
The present invention is advantageous because, among other reasons, it does 
not require two transmitted signals to commence and interrupt, 
respectively, an ELU 10 test function. An emergency lighting system is 
provided, in accordance with an embodiment of the present invention, with 
a receiver 36 connected to an ELU 10 and a portable transmitter 50 
operable remotely with respect to the ELU. The transmitter 50 is 
configured to generate and transmit a single encoded signal to the 
receiver 36 as long as a switch 58 on the transmitter is activated by the 
user. The switch 58 can be of the type which must be depressed and held to 
continue generation of the encoded signal, or of the type which is 
depressed once to commence encoded signal generation and depressed once 
more to terminate encoded signal generation. The receiver 36 receives and 
decodes the transmitted signal and opens a normally closed relay 80 as 
long as the signals are being received. The battery 22 in turn is 
disconnected from the primary power source and connected to the lamp 14 or 
14'. When the transmitter 50 discontinues generation and transmission of 
encoded signal to the receiver 36 (i.e., the switch 58 is no longer 
activated), the receiver closes the normally closed switch 80. The battery 
22 in turn is reconnected to the primary power source for recharging. The 
emergency lighting control system therefore can remotely control the 
normally closed switch 80 and, therefore, the switching of the battery 
between the primary power source and the lamp 14 or 14' using only one 
transmitted signal and one switch 58 on the transmitter, thereby reducing 
the complexity of the transmitter and the receiver. Further, the time 
during which the lamp is operating from an auxiliary power source (e.g., 
battery 22) can be continuous and variable depending on how a user 
operates the switch 58 on the transmitter 50. The test mode, therefore, is 
not limited to a predetermined period of time, as in some systems for 
testing ELUs wherein a momentary RF signal initiates a test function using 
an auxiliary power source such as a battery to power a lamp for a 
predetermined period of time before reconnecting the battery to the 
primary power source. 
While certain advantageous embodiments have been chosen to illustrate the 
invention, it will be understood by those skilled in the art that various 
changes and modifications can be made herein without departing from the 
scope of the invention as defined in the appended claims. For example, the 
charging board 20, test button 34 and receiver 36 can be designed such 
that the lamp is switched from a primary power source to an auxiliary 
power source such as the battery 22 when a normally open switch is closed 
in response to the test button being activated or a transmitter signal is 
received.