Electric lamp and discharge devices: systems – With signal – indicator – or alarm – Electrically operated switch controlling the signal circuit
Patent
1995-12-05
1997-04-29
Pascal, Robert
Electric lamp and discharge devices: systems
With signal, indicator, or alarm
Electrically operated switch controlling the signal circuit
315130, 315131, 315256, 315291, H01J 160
Patent
active
056252609
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to systems and methods for forming pulse signals by operation of switch mechanisms causing impedance variations in a circuit containing a transformer.
In accordance with a first embodiment of the invention a method and a system are provided for communicating from the secondary side of an isolation transformer to a processor via operation of a circuit containing an appropriate switch mechanism providing impedance variations forming pulsed voltage signals which are transmitted through the primary of said transformer onto a power transmission line or cable.
According to a further embodiment of the invention a monitoring system is provided for airfield lighting lamps powered in series from an ac current supply via a transmission or supply cable. In the system, each of the lamps is associated with an isolation transformer having a secondary side containing the lamp, each lamp having assigned thereto a unique address and an associated lamp monitoring unit which is able to communicate with a communicating unit by means of a communicating signal transmitted over said transmission cable.
DESCRIPTION OF RELATED ART
At airports, lighting systems are used for directing all phases of airplane operations including take offs, landings, taxiing and related aircraft movement. These lighting systems often have a large number of lamps and it is important for failed lamps to be detected and replaced as quickly as possible, especially during times of low visibility. Otherwise, the consequences of planes missing taxiways or warning signals such as a stop signal can be catastrophic. Since visual lamp inspection increases the risk for an accident and is costly to perform, automatic lamp monitoring systems have been developed.
Heretofore, the lamps in lighting systems usually have been fed by a constant current power supply over a transmission or supply cable. In such systems, the lamps are connected in series via isolation transformers with the supply cable. The most common type of automatic lamp monitoring system monitors the current and/or the voltage supplied to the cable. If a lamp fails, the impedance in the loop changes, and this is reflected in the current and/or voltage detected by a sensing unit. The disadvantage with this system is that there is no information which is fed to the sensing unit for identifying the failed lamp. It is, therefore, difficult to determine the necessity or urgency for replacing the lamp. Also, if a large number of lamps are connected to the circuit, the change in the impedance caused by lamp failure can be so small that it becomes difficult to detect.
Another type of monitoring system is based upon assigning a unique address along with a monitoring unit to each lamp. When the lamp fails, the unit short-circuits the lamp and periodically breaks the short-circuit in a timed sequence determined by the address of the lamp.
Identification of the failed lamp is made by determining the time (with regard to some reference) at which the change of impedance occurs in the loop. The disadvantage with this system is that the change of impedance due to lamp failure can again be so small that it is difficult to detect.
Yet another type of monitoring system includes a monitoring unit for each lamp, which communicates with a central unit by transmitting a high frequency signal over the transmission cable. Systems of this type, which are available today, are all relatively expensive. They use transformers along with signal amplification equipment or relatively large choke coils. It is, therefore, difficult to automate the production of the monitoring units, and the electronics cannot be integrated into a single integrated circuit solution, a so-called ASIC (Application Specific Integrated Circuit).
SUMMARY OF THE INVENTION
It is an object of the present invention to provide communication methods for monitoring systems which do not require signal amplification equipment or associated components, and therefore makes possible
REFERENCES:
patent: 4398178 (1983-08-01), Russ et al.
patent: 5034659 (1991-07-01), Taniguchi
patent: 5099177 (1992-03-01), Taniguchi et al.
patent: 5168198 (1992-12-01), Watanabe
patent: 5243340 (1993-09-01), Norman et al.
patent: 5359325 (1994-10-01), Ford et al.
Airport Technology in Scandinavia AB
Pascal Robert
Philogene Haissa
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