DK170790B1 - Telemetry terminal and telemetry terminal system - Google Patents

Description

in DK 170790 B1

The invention relates to a telemetry terminal as set forth in the preamble of claim 1, as well as a telemetry terminal system as set forth in the preamble of claim 11.

The invention relates to remote monitoring or control of loads and will be described in terms of control or monitoring of an electricity company's users, but may also be used in connection with other applications such as gas and water.

10 In an electrical supply network, it is known that discount tariffs connect hot water systems with "tone" signals transmitted by the company over the supply lines. This requires the introduction of large currents into the power grid at 15 frequencies of about 400 Hz. In a known electronic meter reading system, meters store electronic readings at the consumer's property and the meter reader connects a transportable meter reading apparatus to the electronic meter and the reading is transferred to the transportable apparatus.

In addition, from US Patent No. 4,232,195, an apparatus which can be coupled to the property of a telephone user with a user circuit containing a telephone set is known, the apparatus being adapted to permit the transmission of status report of the apartment in response to receiving telephone calls from a remove location where the apparatus comprises: 30 - means for detecting ring signals received on the user's circuit through an incoming telephone call; means coupled to the ring signal detecting means for counting the number of incoming signals received on the user's circuit, said counting means corresponding to receiving a predetermined number n of incoming ring signals, where n> 1, to establish a connection state to user circuit; status reporting means in response to establishing the connection state of the user circuit by said counting means for generating and transmitting reporting signal over the user circuit through the connected state, said reporting status signal being recognizable by a calling subscriber displaying the states of the property; - means in response to the transmission of the status reporting signal by said status reporting means for returning the user circuit to an unconnected state; and - means for enabling the property control function in response to receiving a second telephone call from a distant location, subsequently the aforementioned first telephone call, said control means including electrical switching means operative in response to receiving said counting means with a predetermined number n of incoming ring signals through the second telephone call.

Furthermore, from US Patent No. 4,388,690, a useful system is known in which transponders on the user's property are connected to a central computer via the telephone network. The transponder includes microprocessors and is capable of reading and storing times during the day and executing instructions in response to command from the central computer. However, the publication does not show transponders which enable load balancing operations to be implemented in the absence of instructions from the central computer which may occur if there is a fault in the telephone line. Since the load balancing operations are vital to the stability of generators in many electrical supplies, it is an object of the invention to provide a user terminal which enables load balancing operations to be performed in the event of failure of communication between the terminal and the central computer.

The object is met by an apparatus of the type specified in the preamble of claim 1, characterized in that the means include electronic clock means and are adapted to execute at certain times of the day a program for checking the user control devices in response to detecting errors on the telephone line or where the terminal is not connected to a telephone line.

In this way, as previously mentioned, a greater certainty is obtained that faults on the telephone line do not result in the control functions of e.g. load balancing operations become inoperative.

Another embodiment permits load distribution at an individual user's property where the user's load 20 exceeds a maximum allowable. This system can allow short-term loads beyond the maximum. A maximum permissible load per the consumer can be stored in a memory and distributed by load when this load is exceeded for a specified period of time.

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A further embodiment which can be used, e.g. where the tariff changes when use over a period exceeds a predetermined total, e.g. excessive water consumption will allow the system to compare 30 cumulative uses with the average allowable use and give the user an indication of when actual consumption exceeds the allowable average. During water restriction periods, external taps that are passed through a remote controlled valve can be switched off for 35 specified periods.

DK 170790 B1 4

Therefore, Intelligent Units, termed as Corporate Management Terminal (UMT), are installed at the user's property and these are capable of reading meters and connecting loads.

5

As mentioned, the invention also relates to a telemetry terminal system. This system is characterized in that the central processor means is programmed to transmit load decoupling commands over the telephone line to a 10 or more telemetry terminals when the load exceeds a first threshold, and to transmit a load recovery command to one or more of the telemetry terminals which have been switched off when the load is below another threshold and where the load is switched off cyclically between groups of users.

The advantage of such a system is that it allows selective remote reading and load smoothing operations.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the drawing, in which: 1 is a block diagram of a system according to the invention; FIG. 2 is a block diagram of a telemetry terminal (UMT); FIG. 3 shows a more detailed embodiment of the embodiment of FIG. 2 shows the UMT.

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Best way to practice the invention

FIG. 1 shows the main elements of the system. In the first area 1, the equipment is located at the company's central control, while area 2 shows the equipment installed at the telephone exchange and area 3 shows the equipment at the user's property.

DK 170790 B1 5

At each user's property, there may be Installed Measurement Reading Equipment 4 or Load Control Equipment 5 or both. There may be more than one appliance for each consumer.

5

The subscriber is assigned a corporate management terminal (UMT) 6 which is connected to the telephone line 7 in parallel with the telephone.

At the telephone exchange, line 7 is connected to a scanner 8 capable of monitoring about 2000 of such lines. This connection is made on the subscriber line and no central switching equipment need be involved. The scanners serve to concentrate the information and pass it to the host computer 9. The UMTs are connected through the host computer to the central control 10. This computer 9 serves as a special purpose message switch that sends messages to the UMT and examines recognition. If a UMT does not recognize a message or there is an error affecting the system, a report is sent to the central control 10.

Some of the features that can be provided with the system are listed below.

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The status of the UMT becomes available at the central control unit by a question / answer sequence and there may be a status indicator on site. If the power is removed from the UMT for up to 60 seconds, when the power supply is restored, the UMT will return the load to the state it was in before the shutdown. A capacitor or battery can be used to maintain status. If the power is removed from the UMT * for more than 60 seconds, then the UMT can be programmed to ensure that the load 35 is interrupted when the power is restored. Restoration of the previous state will first be ordered from the central control equipment. If a UMT is installed in a 6 DK 170790 B1 area where the Telecommunications is not yet available, then it will be possible to set the time of day on the UMT. The UMT will then act as a time clock and connect and disconnect the load at predetermined 5 times. If a UMT loses its connection to the scanner to which it is connected, that UMT may be programmed to act as a time clock. An UMT is individually addressable and is capable of being connected or disconnected at any time from the central control equipment. An UMT can be assigned to any operating group from the central control site. On-site access will not be required to change a UMT group. The group to which a UMT has been assigned is known at the central control station. Communication loss with a UMT is reported to the central control site.

The central control equipment 10 has some or all of the following characteristics.

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Control of user loads connected to the network. Load management to manage UMT groups in a special order of priority. System load data from the SCADA system is used as control input. The purpose here is to approximate the integral of the load over a 15 minute period to a straight line from 0 to maximum load during that period. The control equipment can connect or disconnect an individual UMT load at a single command. The control equipment can connect or disconnect all 30 UMT loads in a particular group with a single command and connect or disconnect all UMT loads with a different command. The control equipment can execute an introduced program to periodically connect or disconnect.

There may be different programs for holidays and 35 working days. It is possible to manually override the program. Password protection can be used to prevent access to sensitive parts of the central control equipment's pro- gram 170790 B1 7 gram. It can read accumulated meter pulses from the UMT. All system error messages can be entered on a printer with a time and date stamp. These messages will include reports of any UMT errors as well as any communication problems.

If there is a loss of communication to the UMT or if a telephone circuit is not available to a particular user when a UMT is Installed, then the UMT will turn -10 back to an automatic fold-down mode. This is referred to as the Preset Automatic Operating Facility (PADF) and now allows load control to be maintained through any temporary interruption to the network.

15 PADF functions come into operation if communications are interrupted for more than a predetermined period of time, e.g. 1 hour. The features available are described below: 20 The UMT will switch the connected load on and off at predetermined times. These times can be set in any of the following ways: at the factory before delivery, 25 by the authority before installation, by the authority at the time of installation, or by the authority after installation.

The UMT can be provided with one preset on-time and one 30 preset off-time. These times can be programmed to meet authority requirements, and are included in the UMT EPROM.

The Authority will be able to generate UMT 35 EPROMs with alternate switching times, using a master EPROM and can set the required switching times using EPROM programs. These EPROMs can be inserted into UMTs prior to installation or they can be installed in place at any time if necessary. The program can be changed with a message sent over the telephone line.

5

In addition, it is possible to change the non-appearance time at which the UMT switches, by making on-site adjustments without changes to the EPROM.

10 The time of day is programmed into an internal clock in each UMT when installed. This is done using switches that are available when a cover on the UMT is removed or by instruction over the telephone line.

15

The clock can be set, in 30 minutes, at any time between 8 in the morning and 4 in the afternoon. This time is maintained with a high-precision crystal.

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The optional PAOF features provide significant increases to the PAOF mode of operation of the UMT. The switching times can be programmed in a UMT from the central control station, provided both power and communications for a working UMT are available. The UMT can store previous on and off switching times. This enables a UMT to operate continuously, as it did in the past. The UMT can maintain a time reference during long-term power failure, so that the operation will resume at the correct time of day after a long-term power supply failure. This ability can be extended to cover power loss for several days.

The system can be designed to operate in either a digital 35 or analog network. 1 FIG. 2 and 3, embodiments of a UMT are shown in block form.

When a message is received with the UMT, it is entered into the computer 43, which recognizes the message as a request for meter reading, instruction for switching loads, routine examinations, etc. and is programmed to respond 5 appropriately.

Wiring modem 41 may serve the purpose of connecting the signals to the telephone line, while isolating the UMT power supply from the line. It may include e.g. an opto-coupler or a line transformer.

The receiver circuit 42 detects the presence of a company's management system UMS message on the telephone line and transmits the message to the microcomputer 43. The receiver 42 15 is able to recognize a UMS code and prepare the signal for the computer. If the signal is digital, the receiver can perform pulse shaping functions, but if the signal is analog, the receiver can convert it into an appropriate digital format. In a present embodiment, the signal is an FSK signal which the receiver converts into a digital signal.

The message is stored in a command buffer in the computer 43, checked for validity, and executed.

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The message may be one which causes the microcomputer 43 to affect a relay, e.g. 48 or 49 or a lock 48a in FIG. 3 or can send a meter reading from meters 46 and 47 stored in the computer memory or in NOVRAM 122 of FIG. 3 via the transmission circuit 45 over the telephone line to the scanner 8 at the telephone exchange 2 (see Fig. 1), where the information is processed with the host computer 9 and sent to the user's central control. Transmitter 45 may be digital or analog dependent on the network. In one embodiment containing an analog network, the microcomputer 43 may produce a digital signal which converts the transmitter to a suitable analog format, e.g. FSK. In a further embodiment, the computer 43 can produce the analog signal which the transmitter 45 amplifies for transmission. Transmitter 45 and receiver 42 may be contained in a single IC modem. A supervisory tone can be applied to the line via the tone generator circuit 100a, 100b.

To a digital network, the computer produces a digital signal and the transmitter then becomes a digital conduit modem and can perform such functions as smoothing.

10

A recognition message system (handshake) can be used to confirm receipt of messages at one end or the other. This can be especially important when the phone is used by the subscriber at times when a variety of messages are exchanged. The system can work by sending bursts during conversation, leaving the messages open to destruction with the voice signals. Therefore, at this event it is necessary to send signals confirming the successful receipt of a message. In the absence of such confirmation, the transmitter repeats the message. When the central control equipment does not receive a confirmation, it will repeat the message a predetermined number of times or until a previous confirmation, and report a failure if it fails.

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In addition, a clock 44 and a series of switches 51. are connected to the microcomputer. The switches can be used to set the time of day to operate the local clock.

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Pill protection in the form of one or more switches, which are operated e.g. when the cover is opened is positioned at 50.

A large capacitor 52 may also be included to preserve the contents of the computer's memory should the power to the UMT fail. Using this condenser, the UMT can store the meter reading or impulse signal from the meter so that data is not lost. In another embodiment, meter readers 1 are stored in non-volatile RAM to obtain a permanent record of reading 5 at the time of failure.

The UMT contains a clock oscillator 44 which maintains the logic of the microcomputer at a time of day 1 so that functions such as discount rate switching 10 can be maintained in the event of a disconnect to the telephone line.

The system allows the authority to manage discount-rate conditions more precisely than was previously possible and the greater predictability of peak loads is of great value to the electricity companies. Where the company has installed an automatic data acquisition monitoring device (SCADA), it has the information showing the load trend. Thus, it is possible to predict with reasonable accuracy when the load will approach 20 a permissible maximum. Using this information, it is possible to begin a load distribution program to avoid exceeding the allowable value. With a program containing a suitable hysteresis factor, the load can be kept below this value.

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FIG. 3 is a more detailed functional diagram of one embodiment. The telephone line is connected to modem 41 and shunted with a protection circuit 200. Incoming messages from the telephone line are detected with 42a, which is a 30 FSK input filter in the case of a FSK signaling system. The filter 42a enters a demodulator 42b which sends the demodulated signals to P16.

The incoming message may be: 35 a) a switch command, b) a meter request, c) a reprogramming command, d) a routine check.

In following 3, an address lock 120 and memories 121 and 5 122 are used to save space in the microcomputer 43.

In the case of a switch command, the microcomputer 43 commands a data bus 110 to an output page 123, which starts the switch operation, and then causes a confirmation signal to be sent via terminal P10 to the line. In the case of a | -5K system, this signal will be transmitted via FSK-Buffer-Filter 45a, controlled with output energy level switch 45c to FSK output switch 45b and for wiring through modem 41.

In 1 case with a meter request, either an absolute readout meter or a pulse generating meter can be used. Where the pulse meter is used, an accumulative count is stored in the microcomputer or an associated memory. In the event of an absolute meter reading, the reading can be taken directly from the meter.

The meter query command causes the meter reading or cumulative count to be fed back to line 25 via P10.

A read / write decode circuit 140 can be used to modify microcomputer data by modifying NOVRAM 122. This can be used for e.g. to update the load switching time or change other program properties.

Routine studies can be used to investigate the operation of the subscriber terminal unit. Such investigations may include a memory test, transmitter and receiver circuitry or function data examination, such as a brief activation of load relays and receipt of a confirmation signal. Other features can also be monitored.

DK 170790 B1 13

Other commands that can be embedded include: enable load estimation; this causes the UMT to send data from one or more meters to the central control equipment at fixed intervals of e.g. 15 minutes to make a load assessment. An assessment delete command causes the assessment to be interrupted.

"Maximum Requirement" query; the UMT stores the maximum energy consumed for a fixed period (15 minutes) in a register and the time of day when this occurs, and this is sent with the UMT on request. command resets the register Setting load groups; defines which group commands affect the UMT loads.

15 The UMT also allows meter readings to be settled at different rates during the day. This is achieved by having a plurality of registers for each of the impulses stored during specified hours during the day. In this way, peak load periods are stored in a register and low load periods are stored in a further register and there may be one or more intermediate registers. The clock time of the day in the UMT is used to switch the meter pulses to a series of registers depending on the time at which the pulses are generated. When the meters are read, the register readings of the transmitter 45 are read out in sequence and the correct tariff values are added to the many readings of the central control equipment when bills are issued.

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Additional records can be provided to allow differentiation between weekday and weekend or holiday consumption.

35 where there are a number of meters attached, they can be read in sequence so that their readings are fed to the correct registers with the microcomputer 43. The meter outputs can be sampled at a higher frequency than the maximum frequency at which the pulses are produced in the meter. obtain redundant verification, ie. an Impulse Not recognized unless it is present in two successive samples.

5 The UMT can be reprogrammed from the central control equipment by sending a reprogramming message over the telephone line. The message is decoded stored in the microcomputer's command buffer, verified and then fed to e.g. NOVRAM 10 122 over line 111 to rewrite the parts of the program that it is desirable to change. It can for example. it may be desirable to change the daily tariff scales when daylight swings are introduced or removed or otherwise allow for seasonal spikes.

15

Industrial applicability

The invention provides equipment for remote reading of meters and for controlling loads connected to 20 utility supplies such as electricity, water and gas. The information and instructions are transmitted between the subscriber's property and a central control via the telephone circuit.

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Claims (11)

A telemetry terminal containing processor means (43), 5 transmitter means (45) connected to a user's telephone line for transmitting information over the telephone line, wherein the terminal contains one or more measuring means (46, 47) each adapted to produce a measurement signal which expression of consumption measured by the responsive meter, storage means (43) for storing the measurement signals, transponder means responding to a first command signal received over the telephone line to cause one or more of the measurement signals stored in the storage means transmitted over the telephone line, one or more user control devices (48, 48a, 49, 50) controlled by user control logic means which are part of the processor means (43) for performing load balancing routines, by switching at least one of the user control devices either in response to another command signal received over the telephone line or under the control of one predetermined control program stored in the processor means, characterized in that these means (43) contain electronic clock means (44) and are adapted to execute at predetermined times of 25 days the predetermined program for checking the user control devices in response to detecting an error of the telephone line or when the terminal is not connected to the telephone line. Telemetry terminal according to claim 1, characterized in that the transponder means include confirmatory signal means for transmitting confirmation signals over the telephone line when a signal is received over it. Telemetry terminal according to claim 1 or 2, characterized in that the terminal is connected to the telephone line in parallel with the user's telephone. DK 170790 B1 Telemetry terminal according to one or more of claims 1-3, characterized in that the transponder means include receiver means (42) connected to a user's telephone line for receiving control signals transmitted over the telephone line, the user control means responding to the output of the receiving means, for controlling the user devices of one or more user supplies or parts thereof of the user. The telemetry terminal according to one or more of claims 1-4 and comprising an independent power supply or storage (52) for maintaining clock functions in the event of a failure of the telephone line. The telemetry terminal of one or more of claims 1 to 5, wherein the processor means (43) comprise a microprocessor and wherein the storage means or portions thereof are controlled by the microprocessor, the microprocessor being programmable to execute instructions received via the receiving means (42). The telemetry terminal of claim 6, wherein microprocessor programs are stored in the microprocessor and / or in auxiliary storage means and wherein means (140) are equipped to change the program in response to signals received through the receiving means (42). Telemetry terminal according to one or more of claims 1-7, characterized in that storage means comprise two or more storage registers, for storing reading of the measuring means, and wherein the logic means are arranged to send the measurement signals to any of the storage registers which are selected by means of a register selector signal generated by a register selector signal generator. DK 170790 B1 Telemetry signal according to claim 8, characterized in that the register selector signal generator comprises a programmable time clock which generates the register selector signals in accordance with a preselected program. 5 Telemetry terminal according to one or more of claims 1-9, characterized in that the means responding to a fault on the telephone line, and wherein the user control means respond to the detector means which have responded to the line fault, to initiate the load equalization routine under the control of the time clock. . A telemetry terminal system comprising central processor means (10) arranged to transmit control signals 15 to and to receive information from multiple telemetry terminals (6) according to one or more of claims 1-10, and further comprising concentrator means (8, 9) which are interposed between the central processor means and the telemetry terminals, and containing user metering equipment for transmitting information on request from the user to the central processor means, characterized in that the central processor means (15) is programmed to transmit the load decoupling commands across the telephone line to the telephone line or to the telephone line. exceeding a first threshold, and for transmitting a load recovery command to one or more of the telemetry terminals which have been disconnected when the load is below a second threshold and where the load is cyclically decoupled between 30 groups of users. 35