IMPROVEMENTS TO AN OPERATION CONTROL SYSTEM OF ONE OR MORE APPARATUSES

Abstract: The system allows to control the operation of one or more apparatus or plants, each one having at least a tele­ phone set coupled to the telephone system. The system comprises: one or more peripheral control units, each one coupled to a relevant apparatus or plant to be controlled, and coupled to one or more electrical sensors, in turn coupled to the con­ trolled apparatus or plant, each one of the sensors providing at its output electrical data signals indicative of controlled parameters, and which may be coupled to the telephone line connected to a the telephone set located in the same building where the apparatus or plant to be controlled is located; a central control unit, which may be coupled to the tele­ phone line, and apt to send signals to and receive signals from each peripheral control unit. Each peripheral control unit includes switching means coupled to the telephone set and to the telephone line and apt to: a) ascertain whether by means of said telephone line cal­ ling pulses are received at least during two subsequent time periods (T₁, T₂) starting from the start of the first calling pulse received; b) decouple for a predetermined period of time starting from the start of the first calling pulse the telephone set from the telephone line; c) in the case that during the second of said time periods T₂ no calling pulses are received, decouple said telephone set from the line and allow that the signals from the peripheral control unit are sent in the line, and d) restore the initial situation of wiring between said tele­ phone line, said telephone set and said peripheral unit when the transmission of information between peripheral and cen­ tral units by means of the telephone line is over.

Description: The present invention refers to a system to control the operation of one or more apparatus or plants, each one having at least a telephone set coupled to the telephone systemcontrol system for one or more apparatuses, each one coupled to at least a telephone set, connected to the telephone system. The control system includes: one or more peripheral control units, each one coupled to a relevant apparatus or plant to be controlled, and coupled to one or more electrical sensors, in turn coupled to the controlled apparatus or plant, each one of the sensors providing at its output electrical data signals indicative of controlled parameters, and which may be coupled to the telephone line connected to a the telephone set located in the same building where the apparatus or plant to be controlled is located; a central control unit, which may be coupled to the telephone line, and apt to send signals to and receive signals from each peripheral control unit. Each peripheral control unit includes switching means coupled to the the telephone set and to the telephone line and apt to decouple the telephone set from the telephone line and to allow that the signals from the peripheral control unit are sent in the telephone line. A control system of the above said type is e.g. described in the Italian Patent Application N. 67427-A/81 filed in the name of the same Applicant on march 27, 1981. The control system described in the above said Patent Application includes switching means connected to the telephone set and to the telephone system, apt to: a) decouple the said telephone set from the telephone system at the first calling pulse received on the said telephone line; b) decouple the said telephone set from the telephone system and permit to the peripheral control unit to send signals to the telephone line as soon as a further calling pulse is received via said telephone line, with a delay comprised within a minimum and a maximum predetermined value, and c) decouple the said peripheral control unit from said telephone line and connect again the telephone set to the line as soon as the transmission of information, via the telephone line, between the peripheral and the central unit is over. A control system of the described type, applied e.g. to central heating plants of buildings, allows the automatic remote control of the plant operation as well as a quick corrective action by the maintenance personnel, as soon as failures or malfunctionings happen, without the need of periodical visits to the plant, and without the need to arrange an ad hoc telephone line for each controlled apparatus. As described in the cited Patent Application, the service call from the central control unit to a peripheral control unit comprises two subsequent calls, each one consisting of one pulse only, the second one being sent a predetermined time, e.g. twenty seconds, after the first. The decoupling of the telephone set from the telephone line at the first calling pulse has the object not to disturb the telephone user in the case that the call is directed not to him but to the control unit. The system, as described in the cited Patent Application, proved to operate correctly every time the call pulses sent out by the telephone exchange did have the correct length and timings, as normally due. In fact normally a pulse lasts for a second and repeats every fourth second. In some cases, nevertheless, the initial pulse lasts less than one second and also the delay between the first and the second pulse is of variable length. As a consequence in some cases the peripheral control unit recognized a user call as a service call and viceversa, with obvious inconvenience. A system for accumulating data over non dedicated telephone lines is described in the US Patent No 4,126,762, wherein a telephone calling signal from a central station initiates the connection of a remote terminal, including a data accumulator, at a subscriber's station to a non dedicated telephone line for reading by a billing processor computer at the central station. The system, as described in the cited patent, if used for the purpose of the present application, will show the same inconveniences as the system disclosed in the above cited italian application and already discussed. In fact, the system described in US Patent No 4,126,762 would not work correctly in case of an abnormal user call; in fact let us suppose that an abnormal user call is received, having the following pattern: a first ringing call of 0.4 seconds; a pause of 3.5 seconds; a second ringing call of 1 second; a pause of 4 seconds; a third ringing call of 1 second. It has been experienced that such a pattern is quite common in Italy; it complies with the pattern shown in line 4 of the figure of the present Application. In such a call the second ringing pulse is received 3.9 seconds after the beginning of the first one and ends 4.9 seconds after said beginning; the third pulse is received 8.9 seconds after the said beginning. In other words the second pulse is received "before the normal five seconds delay", and the third one is received "after 8 seconds": it is therefore clear that such a call is considered a service call and that the answering apparatus will immediately seize the line and prevent telephone from responding (see lines 21-29, column 3). From Swiss Patent n. 395 202 a procedure is known to interrogate by telephone a plurality of metering apparatuses in order to ascertain the consumptions of electricity, water, etc. The procedure described is very similar and shows the same drawbacks. It is an object of the present invention to describe a controlling system of the specified type, apt to solve in a simple way the said problem, so avoiding the cited inconveniences. With this aim in view, the subject of the present invention is a system to control the operation of one or more apparatus or plants, each one having at least a telephone set coupled to the telephone system, said system comprising: one or more peripheral control units, each one coupled to a relevant apparatus or plant to be controlled, and coupled to one or more electrical sensors, in turn coupled to the controlled apparatus or plant, each one of the sensors providing at its output electrical data signals indicative of controlled parameters, and which may be coupled to the telephone line connected to a the telephone set located in the same building where the apparatus or plant to be controlled is located; a central control unit, which may be coupled to the telephone line, and apt to send signals to and receive signals from each peripheral control unit, wherein each peripheral control unit includes switching means coupled to the the telephone set and to the telephone line and apt to decouple the telephone set from the telephone line and to allow that the signals from the peripheral control unit are sent in the telephone line, characterized in that said switching means are arranged in particular to: a) ascertain whether by means of said telephone line calling pulses are received during three subsequent time periods starting from the start of the first calling pulse received, the first of said time periods being greater that the normal lenght of time corresponding to two calling pulses (9 seconds); b) decouple for a predetermined period of time, starting from the start of the first calling pulse received, the telephone set from the telephone line; c) in the case that during the second of said time periods at least one calling pulse is received, restore the initial situation of wiring between said telephone line, said telephone set and said peripheral unit; d) in the case that during the second of said time periods no calling pulses are received, and on the contrary at least one pulse is received during the third of said time periods, let said telephone set decoupled from the line and allow that the signals from the peripheral control unit are sent in the line, and e) restore the initial situation of wiring between said telephone line, said telephone set and said peripheral unit when the transmission of information between peripheral and central unit by means of the telephone line is over. Features and advantages of the control system according to the invention will be clear from the following description, which is made referring to the attached drawings, which are supplied only as a non limiting example, and where: the single figure shows schematically the temporal succession of the events, starting from the time point when a call is received by means of the telephone line in a control system according to the invention. In the figure four horizontal lines are drawn; the time increases from the left to the right. On the top line three subsequent time periods are represented, the first one (T1) of 9 seconds, the second one (T2) of 6 seconds and the third (T3) of 15 seconds; a time period (T4) of 5 seconds starting from the zero time point is also represented. The operation of peripheral control unit switching system is the following: as soon as the peripheral unit detects the first pulse of a telephone call (zero time point), it decouples the user telephone set so that, should the call be a service call, the set remains silent; after 5 seconds it connects the telephone set again; after a total of 9 seconds (first time interval T1) and during the subsequent 6 seconds (second time interval T2, from the 9th to the 15th second starting from the zero time point) the unit watches the line: if a calling pulse is detected, the unit decides that it is the case of a user call, restores the initial status and connects again the user set to the line; if during the second time interval no pulses have been detected , it watches the lines for a further 15 seconds (third time interval T3, from the 15th second to the 30th second starting from the zero time point); if at least one pulse is detected, it decides that it is the case of a service call, decouples once more the user set and sends to the central control unit the plant's data detected by the sensors; when the shake hand is over it connects the user set to the line again; if on the contrary during the third time interval T3 no pulses have been detected, the unit restores the initial status: i.e. if a pulse is received after a total of 30 seconds, it is considered as a starting pulse and the cycle starts again from the beginning. In the second line of the figure there are represented the two typical pulses of a service call from the central control unit; in the third line of the figure there are represented four typical pulses of a user call on the line; and in the fourth line of the figure there are represented four pulses of an anomalous user call, showing first pulse length of 0.4 seconds, the second pulse arriving after 3.5 seconds delay instead of 4 seconds. Please note that the length of the first pulse may be variable, according to the type of anomaly, ranging from a few milliseconds up to one second, and that the time delay between the first pulse and the second one may vary from less than one second to the four seconds of a regular call (in the figure such a variable delay has been indicated with "n"). As it can be understood immediately from the figure, the behaviour pattern of the control system according to the invention, which represents the result of the practical experiences made on many dozens of different cases, shows a much higher safety factor if compared to that described in the cited Patent Application 67427/A-81; it can correctly decide, even with calling patterns different from the regular ones, if the incoming call is a user or a service call. The behaviour of the peripheral control unit may be summarized as follows: it decouples the user set for the first 5 seconds starting from the zero time point (start of the first calling pulse); if and only if the listening during the first and the third time period are affirmative, it decouples the user set for the time necessary to perform the connection to the central control unit; in the contrary case (affirmative listening during the second period or negative listening during the third period) it restores to the initial status, waiting again for a starting pulse. General arrangement of the devices is the same as described in the above said Patent Application 67427-A/81; the switching means instead are substantially like those described in the Italian Patent Application N. 67395-A/82 filed on march 26, 1982 in the name of the same Applicant. As stated also in the cited Patent Application N. 67427-A/81, the peripheral control unit may also include a second unit apt to call the central control unit in case of emergency condition which require an immediate action without waiting for the periodic control call from the central control unit. Furthermore the case may happen where two peripheral control units are located in the same building and connected to the same telephone set; in this case, when one of them calls the central control unit in emergency condition, the second peripheral control unit may equivocate considering the call as directed to itself, with dangerous consequences. In order to avoid such an inconvenience, the calling peripheral control unit may be advantageously adapted to wait for a suitable time period (e.g. 20 seconds) between the last but one digit and the very last digit of the called telephone number. It has been verified that in this way no malfunctioning takes place. Of course many variations are possible to the circuitry described; as an example it is possible that in the data transmission procedure between peripheral control unit and central control unit, instead of waiting for a calling pulse during the third time period, wherein then the central control unit calls the peripheral one in order to receive the data, as soon as no pulse is detected during the second time period, the peripheral control unit calls the central one and sends the data. Of course in this case the peripheral control unit shall be able to dial telephone numbers and to recognize the free and busy tones received from the telephone system. Another variation may be to lengthen the described time periods, so that e.g. during the first and the third period more than one pulse may arrive, in order to improve the reliability of the connection between peripheral and central units, since during the initial part of a telephone call not always to a calling pulse detected by the calling device corresponds an equivalent arriving pulse detected by the receiving device.

Claims: System to control the operation of one or more apparatus or plants, each one having at least a telephone set coupled to the telephone system, said system comprising: one or more peripheral control units, each one coupled to a relevant apparatus or plant to be controlled, and coupled to one or more electrical sensors, in turn coupled to the controlled apparatus or plant, each one of the sensors providing at its output electrical data signals indicative of controlled parameters, and which may be coupled to the telephone line connected to the telephone set located in the same building where the apparatus or plant to be controlled is located; a central control unit, which may be coupled to the telephone line, and apt to send signals to and receive signals from each peripheral control unit, wherein each peripheral control unit includes switching means coupled to the the telephone set and to the telephone line and apt to decouple the telephone set from the telephone line and to allow that the signals from the peripheral control unit are sent on the telephone line, characterized in that said switching means are arranged in particulars : a) to ascertain whether by means of said telephone line calling pulses are received during three subsequent time periods starting from the start of the first calling pulse received, the first of said time periods being greater that the normal length of time corresponding to two calling pulses (9 seconds); b) to decouple for a predetermined period of time, starting from the start of the first calling pulse received, the telephone set from the telephone line; c) in the case that during the second of said time periods at least one calling pulse is received, to restore the initial situation of wiring between said telephone line, said telephone set and said peripheral unit; d) in the case that during the second of said time periods no calling pulses are received, and on the contrary at least one pulse is received during the third of said time periods, to decouple said telephone set from the line and allow that the signals from the peripheral control unit are sent on the line, and e) restore the initial situation of wiring between said telephone line, said telephone set and said peripheral unit when the transmission of information between peripheral and central unit by means of the telephone line is over. System to control the operation of one or more apparatus or plants, according to claim 1, characterized in that said second period of time is of about 6 seconds. System to control the operation of one or more apparatus or plants, according to any one of the preceding claims, characterized in that said third period of time is of about 15 seconds. System to control the operation of one or more apparatus or plants, according to claim 1, characterized in that said predetermined period of time is shorter than said first period of time. System to control the operation of one or more apparatus or plants, according to claim 4, characterized in that said predetermined period of time is of about 5 seconds. System to control the operation of one or more apparatus or plants, according to any one of the preceding claims, characterized in that if no pulses are detected during said third period of time, said peripheral control unit resets to the status existing before the arrival of the first calling pulse. System to control the operation of one or more apparatus or plants, each one having at least a telephone set coupled to the telephone system, said system comprising: one or more peripheral control units, each one coupled to a relevant apparatus or plant to be controlled, and coupled to one or more electrical sensors, in turn coupled to the controlled apparatus or plant, each one of the sensors providing at its output electrical data signals indicative of controlled parameters, and which may be coupled to the telephone line connected to a the telephone set located in the same building where the apparatus or plant to be controlled is located; a central control unit, which may be coupled to the telephone line, and apt to send signals to and receive signals from each peripheral control unit, wherein each peripheral control unit includes switching means coupled to the telephone set and to the telephone line and apt to decouple the telephone set from the telephone line and to allow that the signals from the peripheral control unit are sent in the telephone line, characterized in that said peripheral control unit includes a second peripheral unit arranged to call, in the case that predetermined conditions are verified, the central control unit, and in the case that two peripheral units are coupled to the same telephone line, in order to avoid that the call of one of them disturbs the operation of the other, the calling peripheral unit includes means arranged to wait for a predetermined period of time before dialling the last digit of the telephone number of the called unit. System to control the operation of one or more apparatus or plants, according to claim 7, characterized in that said predetermined period of time is of at least 20 seconds. System to control the operation of one or more apparatus or plants, according to claim 7, characterized in that said peripheral control unit is arranged a) in the case that during the second period of time no calling pulses are detected, to decouple said telephone set from the telephone line and to dial at least a telephone number corresponding to said central control unit and in the case that said central unit aknowledges the call, to allow that the signals from the peripheral unit are sent on the line, and b) to restore the initial situation of wiring between said telephone line, said telephone set and said peripheral unit when the transmission of information between peripheral and central unit by means of the telephone line is over.

Inventors: BO, GIORGIO, ING., MILANESE,ELIO
Applicants: TECNOENERGIA BY TEL S.R.L.
Application year: 1987
Main classification: H04M11
IPC codes: H04M11