GB2311398A - Monitoring system - Google Patents

Abstract

A monitoring system for occupied and unoccupied sites comprises a plurality of sensors associated with each site and adapted to provide analogue, digital or dichotomous electrical signals each relating to a sensed parameter to first computer means. Signalling means transmits data from the first computer means to a second computer means located at a central control station e.g. by radio. The first or the second computer means provide control and alarm signals from the central control station when data from the sensors deviates from predetermined criteria, the second computer means providing control and alerting signals for transmission by the central control station to an operator when deviation occurs. The sensors comprise sensors providing a dichotomous signal indicating when a certain limit has been passed or an event has taken place or they provide an analogue signal relating to the value of a sensed parameter. The sensors may comprise sensors which provide a digital output in which pulse frequency or encoding provides a signal which relates to the value of a sensed parameter. Transmissions are acknowledged, and repeated via neighbours if acknowledgement is not received, though the neighbour declines if the signal is too weak or the neighbour does not have a direct route to the target. Successful routes are stored for future use.

Description

MONITORING SYSTEM.

This invention relates to a monitoring system.

particularly for remote locations. which displays the status of a plurality of parameters in each location and provides a warning in the event that one or more parameters deviates from its preset limits.

There is frequently a need to save labour and eliminate the need for continuous monitoring of sites. For 24 hour surveillance or monitoring at least three people must be available working in shifts. For the protection of sites. such as warehouses. monitoring systems are in use which can detect the presence of smoke or intruders.

However such primitive monitoring is inadequate when the lives of human beings or livestock need protection.

The present invention provides a particularly useful and secure system for the care of elderly. infirm or otherwise vulnerable people allowing them to remain in their own homes. A situation requiring human intervention is detectable without action on the part of the person protected by the system.

According to the present invention there is provided a monitoring system for occupied or unoccupied sites comprising a plurality of sensors associated with the site and adapted to provide analogue. digital or dichotomous electrical signals each relating to a sensed parameter. a first computer means arranged to accept the outputs of all the sensors. signalling means to transmit data to a central control station from the first computer. a second computer means located in the central control station and arranged to accept the data from the first computer means. the first or the second computer means providing control and alarm signals from the central control station when the data from the sensors deviates from predetermined criteria. the second computer means providing control and alerting signals for transmission by the central control station to an operator when the deviation occurs.

The sensors associated with the sites may comprise simple sensors providing a dichotomous signal indicating when a certain limit has been passed or an event has taken place. such as smoke detectors. gas detectors. intruder detectors. mains failure detectors. temperature detectors.

etc. Other sensors may provide an analogue signal relating to the value of a sensed parameter or a digital output in which pulse frequency or encoding provides a signal which relates to the amplitude of the sensed parameter.

Sensors which may provide analogue or digitally encoded signals include water use monitors. temperature measuring devices. movement detectors. airflow detectors. electrical power consumption meters. illumination measuring devices.

etc.

Ihe first computer means is arranged to accept the outputs of all the sensors and to store. transmit to the central control station and/or process the received signals. In the case of signals relating to the value of a measured parameter the first computer means may compare the value of the input signal from the sensor with a preset value and send an alarm signal to the second computer means if the sensed value deviates from the preset value.

Alternatively the comparison process may be carried out by the second computer means using information transmitted to it by the first computer means. The first computer means may send routine signals to the second computer means indicating the status and/or the measured value of each item from which a measured parameter is obtained.

In the case of alarm or similar signals indicating an excessive deviation from a preset value, the signal from the first computer means to the second computer means will take place rapidly with priority coding. Routine signals may be sent at infrequent intervals determined by the first computer means or, more preferably, as a result of polling by the second computer means The signalling means used to transmit data to the central control station from the first computer may be carried by wire, optic fibre or radio link; the latter means is preferred. The link is preferably two-way so that control signals may be sent from the second computer means to the first computer means. Such communication links are frequently referred to as between transceivers.

The data from the first computer means is preferably recorded and reproduced in the form of a visible record.

The control and alarm signals from the central control station may be sent by signalling means to human operators so that action can be taken in response to the signals such as making a visit to the relevant site.

The system is particularly useful for maintaining a caring watch on people living on their own. In a particular embodiment involving the home care of vulnerable people it is possible to monitor a series of homes within a wide radius from the central control station dependent on the permitted power of the radio link and the geographical surroundings. A radius of 10 km is easily achieved and for individual sites a relay link may be used to extend this distance.

The data received at the central control station is continuously logged for each site enabling the station to be unattended for long periods. The alarm signals are sent by radio link to an operator who carries a pager or a telephone adapted to receive the signals. On receipt of an alarm signal the operator can activate a mobile carer who can be instructed to proceed to the relevant site.

During the journey time the carer and/or the operator can communicate via the radio link with the site occupant with instructions. if necessary. or a confirmation message that the carer is on his/her way.

Control procedures. recorded and logged by at least the second computer means. ensures that the call to the carer. the response from the carer and any ancilliary messages may be confirmed subsequent to an emergency situation.

Access to the site may be provided by the occupant however as the occupant may be incapacitated or not mobile direct access must always be available to the carer. A preferred method of carer access is a coded radio link lock mechanism. Operation of the radio control led lock can be recorded automatically by the first computer means and logged via the second computer means to provide a complete audit of the response to the emergency.

In one example the central control station was fitted with a VHF transceiver capable of communication by means of digital signals. The effective range of the transmitter was 10 km providing a service area of over 300 km2.

Each house unit was fitted with a low power UHF transceiver associated with the microcontroller that communicated with a plurality of sensors and alarms deployed around the house and a VHF transceiver to enable the microcontoller to communicate with the central control station. All sensor and alarm devices included a radio transmitter and microcontroller interface operating in the allocated frequency band for radio telemetry and telecontrol. The sensor units were battery powered providing about three weeks of service before battery replacement was necessary. Imminent battery failure is automatically transmitted via the house unit microcontroller to the central control station to warn the carer that the relevant battery should be replaced during the next visit. The use of batteries ensured independence from mains supplies and continued operation in times of mains failure. The first computer means comprised the microcontroller for receiving and processing the outputs of the sensors.

The microcontroller in the house unit is programmed to recognise when the parameter monitored by any sensor deviates to an extent that an alarm signal should be generated. When such deviation occurs an emergency status signal is sent to the central control station using the VHF link. The status signal identifies the sensor or sensors initiating the alarm. The status signal also identifies the house unit. the measured parameter and the sensor location within the house unit enabling the computer in the central control station to alert an approriate carer and/or other service. e.g. the fire brigade in the event was initiated by a smoke detector. The house unit microcontroller was mains operated with battery back-up.

All signals between the microcontroller in the house unit and the computer in the central control station sent in the VHF band are encoded to provide source identification. security and to avoid cross-talk.

In the preferred embodiment of the system data is transmitted using the 'Manchester' dual frequency FM format which is inherently self-clocking. has no DC component and is relatively noise immune. Each data packet is retransmitted, in known manner, to the sender to ensure that no corruption has taken place. In the event that the received signal is not identical with the transmitted signal the data packet is retransmitted.

The described command and control system, particularly adapted for community care for elderly and diabled people, allows them to remain living in their own homes. Each home is provided with sensors detecting a variety of alarm conditions and an intelligent radio transceiver which communicates those alarm systems to a control centre enables nursing and practical assistance to be deployed. A single control; centre can monitor several hundred homes within its operational radius. Reliability of the communication system is paramount. To ensure continuous reliable communication an alternative routing system is used as hereinafter described..

When a transceiver calls it is heard by all other tranceivers on that frequency within range. Its communication is typically a signal lasting a fraction of a second, digitally encoded to identify itself and the target site to which it calls, plus a few bytes of message.

The communications are duplex and any signal is acknowledged by the target receiver echoing back with a check-sum digit to ensure that no bit of information has been lost. Where a transceiver calls but is not heard due to radio shadow there will be no acknowledgement. The tranceivers used are 'intelligent' however and if a signal is not acknowledged the originating transceiver will then repeat its call to sequential technical neighbours'. Each transceiver has an ID number and its 'neighbours' are transceivers with adjacent ID numbers. The repeat message will be rebuilt as a request to the neighbour to pass it on, relay it, to the target site. This repeat message is then transmitted to the neighbour. The neighbour carries out a status check on the strength of received the received signal and also on whether it has direct communication with the target. If either the signal is too weak or there is no direct communication to the target then the call is declined. If both status checks provide a satisfactory outcome the neighbour attaches its route to the message string and transmits the message to the target.

Acknowledgement of the received message is returned to the originator by the same route.

Once a successful route is established it is stored for future use without the need for further trial transmissions. Should a route fail on some future occasion then a new route will be established through re-trial and stored in the manner described above.

By use of this system regardless of adverse topography affecting the transmission of radio signals, all transceivers will either communicate direct to the centre or will store an indirect route threaded through one or more of the population of participating transceivers so that there will always be some communication route between a transceiver and the centre.

A secondary benefit of this system is the facility for installing supernumerary transceivers at strategic positions, such as on high ground or on tall buildings, to provide additional or more efficient routing across difficult topography.

Claims (12)

1. A monitoring system for occupied and unoccupied sites comprising a plurality of sensors associated with each site and adapted to provide analogue, digital or dichotomous electrical signals each relating to a sensed parameter, a first computer means arranged to accept the outputs of all the sensors, signalling means to transmit data to a central control station from the first computer means, a second computer means located at the central control station and arranged to accept the data from the first computer means, the first or the second computer means providing control and alarm signals from the central control station when data from the sensors deviates from predetermined criteria, the second computer means providing control and alerting signals for transmission by the central control station to an operator when deviation occurs.

2. A monitoring system as claimed in claim 1, in which the sensors associated with the sites comprise sensors providing a dichotomous signal indicating when a certain limit has been passed or an event has taken place.

3. A monitoring system as claimed in claim 1, in which the sensors associated with the sites comprise sensors provide an analogue signal relating to the value of a sensed parameter.

4. A monitoring system as claimed in claim 1, in which the sensors associated with the sites comprise sensors provide a digital output in which pulse frequency or encoding provides a signal which relates to the value of a sensed parameter.

5. A monitoring system as claimed in claim 1, in which the first computer means is arranged to accept the outputs of all the sensors and to store, transmit to the central control station and/or process the received outputs.

6. A monitoring system as claimed in claim 1, in which electrical signals from each site are transmitted to the first computer means by a radio link.

7. A monitoring system as claimed in claim 1, in which the signalling means to transmit data to the central control station from the first computer means is a radio link.

8. A monitoring system as claimed in claims 6 or claim 7, in which the radio link is a two-way system.

9. A monitoring system as claimed in claim 8, in which the radio link communications are duplex and any signal is acknowledged by its target receiver by echoing back a check-sum digit to ensure that no bit of information is lost.

10. A monitoring system as claimed in claim 9, in which any unacknowledged signal is sent to a sequential technical neighbour transceiver.

11. A monitoring system as claimed in claim 10, in which the unacknowledged signal is routed through a neighbour transceiver to its target receiver.

12. Monitoring systems as claimed in claim 1 and as herein described.