DE4225042C2 - Method for transmitting consumption measurement data - Google Patents

Abstract

Described is a system for remotely reading out data from a multiplicity of measurement units (10), the system operating by radio transmission at a single frequency. The various measurement units (10) deliver their sets of data within stochastically selected time windows of short duration. In this way, the measurement units can have simply designed circuitry and can be operated over very long periods from long-life batteries.

Description

The invention relates to a method for transmitting Consumption measurement data according to the preamble of claim 1.

Such a method is described in EP 428 322 A1 ben. It carries out bidirectional data transmission between a mobile evaluation unit and in a room Units installed in the building. Each of these has a receiving unit with which they continuously a larger Number of predefined data transmission channels thereupon monitors whether the evaluation unit is on this channel an arming signal is transmitted through which the measuring unit from a standby state into a Working state should be switched. The evaluation unit in turn continuously checks on which of the total available radio channels the smallest interference and then select this channel for the data transfer with the measuring units. Is the data transfer channel determined in this way, the evaluation unit waits that signals from the measuring units are received on this will. The latter in turn continuously emit signal sequences from which they identify as a specific individual measuring unit. By the number of one in a considered instant Ver data transmission link assigned measuring unit smaller, the channel selection in the different measuring units based on a stochastic principle. The evaluation unit selects from the one considered Moment on the selected channel chose the one that gives the strongest signal and this unit of measurement is then made special by it assigned coded arming signal to deliver the causes consumption data to be transmitted. With this known methods thus find bidirectional data transmission between the measuring units and the evaluations unity instead.

DE 33 42 431 A1 is a building monitoring system with wireless data transfer between sensors and a central unit disclosed. To avoid that at the radio range beyond a property Central unit of a property on sensors of a be neighboring property appeals, are in the sup identification data strings built in, and the central units only consider such ones find signal sequences in which there are identification signs follow located, which are stored in the central unit are and for those on the property under consideration ten sensors are characteristic.

Method for transmitting consumption measurement data are often used in practice via data carrier cable unwound, which is between a zen central evaluation unit and several connected to it which measuring units extend. In the evaluation unit a multiplexer is then provided which is predetermined Times one of the measuring units with an I / O Interface of the evaluation unit connects.

Such a data transfer is for many applications not usable, either because the distances between the measuring units and the central evaluation unit are large, be it because the installation of the ver different data transmission cables from the cost or not acceptable from the associated annoyances is animal. An example of this is remote consumption reading in existing buildings. Here it would be very desirable, the different consumption measurement appliances for water, gas, oil, electricity, heat, etc., the in the different residential units of a house at ver installed at various points, without having access to the individual measuring points. Here are high personnel costs with the reading of the measuring devices most connected, especially because in most cases most one-person households during the day fen is.

One could think of it now in those cases where a subsequent installation of data transmission lines  tion, wireless data transmission is preferred see. Here, however, there is the problem that radio frequencies zen are only available to a very limited extent, and beyond that are for each transmission channel necessary receiver parts of the modems quite expensive. For the Remote reading of consumption meters is a matter of course term requirement that the cost of data transmission none if above that of the actual consumption measurement data acquisition may lie.

The task is therefore to be solved a large number of measuring units inexpensive and read out without errors.

It has now been recognized that a large number of such consumption measuring data transmission cases, especially for remote reading of consumption meters, only relatively small data quantities concern. The time span necessary for the transmission NEN for a measuring unit can range from a few 10 ms lie. In this case you can then all the interests measuring units on a common working area quenz send, the individual measuring units sto chastically distributed narrow transmission windows can be assigned. You can then use a single off for all measuring units provide a unit of value, the receiving part of which is based on the common same working frequency is matched. Since one of the above mentioned short individual transmission periods a very can realize a large number of time slices per day (a few million), the probability is two Measuring units (from a total of 100 to 1000 units, as they typically do for consumption reading at Wohnkom plexes are needed) at the same time, very much low. The small number of overlaps that occur in sent simultaneously by different measuring units Data sets are recognized by the evaluation unit and the corresponding signal sequences are rejected.

An inventive transfer specified in claim 1 The supply method can thus be operated with little circuit technology  niche effort and perform safely.

Assuming a constellation like that for the distance reading consumption data in apartment blocks is typical, so an RF transmit power of 20 mW is sufficient, which one Power supply for the operating circuit of approximately 200 mW corresponds. With the short transmission times mentioned of the order of magnitude This results in a total current of 10 ms consumption data when using long-life batteries a working of the measuring unit of typically 10 years enables. So that is the time of work ability Radio transmission comparable to the calibration periods of the Measuring units so that it is sufficient to measure them at intervals of typically replace about 10 years in total.

Advantageous developments of the invention are in Unter claims specified.

According to claim 2 consumption measurement data from a measuring point only then sent out if these ge to a significant extent changed compared to the last consumption measurement data sent. So z. B. for heat consumption measuring units in summer time when there is no heating, full for days and weeks transmission of consumption measurement data is constantly dispensed with. Here by means of an extended service life of the long-term battery Measurement unit reached.

As such, it is known from the transmission of data the data actually to be transferred additionally after a given algorithm a check number or a check bit calculate that along with the data on the transfer route is directed. At the receiving end can then from the actual data, the check number is calculated again and compared with the transmitted check number. Stim If both test numbers match, the data transmission was correct  rect. In the method according to claim 3, this is per se known test method used in a simple way To determine overlaps of data records, because at the time Lichen overlap between different measuring units data sets sent independently result in a total Signal sequence with a completely different bit pattern, which in the we Substantially an OR combination of the two individual patterns corresponds. Is the time shift between the two partial bit patterns, corresponds to that at the end of the Overall sequence of the check number recognized by the evaluation unit belongs to the later bit pattern, not the total previously obtained data. With only a small time delay shift is obtained either at the end of the overall sequence none at all recognizable as such a check number or else a check number that also does not match the previous Da sequence fits.

With the development of the invention according to claim 4 on the one hand it is possible to measure the temporal development of consumption to track data, on the other hand you can also from the fact thing that the last kor measurement data record received directly long ago, conclude that an error occurred in the measuring unit itself is kicking.

In a method according to claim 5 is also long Times guaranteed that the timing the incoming consumption measurement data is correct in time.

In a procedure according to claim 6, one receives an additional possibility of error detection. Test criteria can e.g. B. in consumption measuring units that the transmitted Consumption measurement data must grow monotonously. The transmission of Consumption measurement data that are smaller than the last correct over Average consumption measurement data indicate an error. One can  but not a data record received from a measuring point only compared to previously transmitted data records of the same Compare measuring point, but also with data records of others Measuring points, provided there is a factual connection. Results z. B. in a building complex from the trans gene records of other measuring units that the heat ver overall stagnated (e.g. due to heating switched off system) and increases with a single measuring unit according to the transmitted data records the heat consumption nevertheless significant, this indicates either one Measuring unit error or faulty installation location of the same.

According to claim 7, the errors occurring in the Save evaluation unit and for later evaluation ready for troubleshooting.

The development of the invention according to claim 8 is in With a view to increasing the security of data transfer wearing an advantage.

With the development of the invention according to claim 9 achieved that in a simple way using ident shear random generators the stochastic distribution of the Receive transmission window for the different measuring units will.

It is then ensured according to claim 10 that also by the identity of the random generators or in them Any algorithm-related residual-non-random times in the broadcasting time calculation are eliminated. As yourself uncontrolled changing physical variables can e.g. B. in the case of a high-resolution measuring device, the last or the last two decimal places of the measured value.

The invention will now be further elucidated with reference to the following play explained with reference to the drawing. In this show:

Fig. 1 is a block diagram of a system for measuring heat consumption in a building complex;

FIG. 2 is a flow chart which is used in a computer an evaluation unit of the system of Figure 1 a test program;. and

FIGS. 3 and 4: Figure 1 is similar block diagrams in which modified embodiments are shown dekomplex for a plant for heat consumption measurement in a buil..

In Fig. 1, 10 denotes a total heat consumption measuring unit, which radiates at irregular intervals a data record via an antenna 12 , which has the following structure: block start mark consumption measurement data (current status of heat counting), identification data (number and, if appropriate, type the measuring unit), block end mark. This data can be accommodated in a typical heat consumption measuring unit in an RF signal packet of approximately 10 ms duration.

The RF signal packet is collected by an antenna 14 which belongs to an evaluation unit 16 set up in the building complex for a reader. This demodulates the RF signal packet, checks it and stores the heat consumption data for the measuring unit in an assigned memory field (RAM and / or hard disk), as will be described in more detail later.

The measuring unit 10 is a self-sufficient, not dependent on electricity from the electrical network, which is attached to the heating body of a room of a residential unit of the building complex or a hot water meter for this living unit is assigned.

A larger number of further measuring units, one of which is symbolically represented at 10 -i, are installed in other locations in the building complex. Typically, the total number of measuring units 10 - i cooperating with the evaluation unit 16 can be between 20 and 1000.

The measuring unit 10 contains a temperature sensor 18 which is thermally coupled to the associated consumer. An identification signal for the measuring unit 10 is stored in a read-only memory 20 , e.g. B. in the form of a number assigned to this measuring unit.

A computing circuit 22 integrates the output signal of the sensor 18 , weights it, if necessary in a predetermined manner, and sets the consumption measurement data signal thus obtained with the identification signal transmitted from the read-only memory 20 and a block start mark and a block end mark to form a data record.

The data record provided by the computing circuit is forwarded to a memory 24 , which is activated for reading in at midnight in the exemplary embodiment under consideration here.

For this purpose, a clock module 26 of the measuring unit is connected to a timer circuit 28 programmed at midnight, the output terminal of which is connected to the control terminal of the memory 24 .

A random generator 30 is also triggered by the output signal of the time switch circuit 28 . This receives three input signals, namely the content of the read-only memory 20 , the output signal of the sensor 18 reduced by a cut-off circuit 32 to the last digit after the decimal point, as well as its own output signal. From these three signals, it calculates a set of transmission times distributed randomly over a full day according to a predefined algorithm. For the exemplary embodiment considered here, it is assumed that 6 broadcast times are desired per day, the mean interval of which is therefore 4 hours.

The six transmission times are provided at the output for a second time switch circuit 34 , which additionally receives the time of day provided by the clock module 26 .

If the current time of day coincides with a transmission time calculated by the random generator 30 , the time switch circuit 34 activates a transmission circuit 36 .

This is connected on the input side to the memory 24 and, when activated, takes over a complete data set with the structure already described above, "block start mark, consumption measurement data, identification data, block end mark", converts this data set into serial representation and modulates using the Serial bit pattern of the output signal of an RF generator belonging to the transmitter circuit 36 , not shown separately in the drawing, which has a transmitter power of approximately 20 mW and operates in the higher MHz or in the lower GHz range.

The power supply to the transmitter circuit 36 is from a long-term transmitter battery 38 , which can provide the power required to operate the transmitter circuit of approximately 200 mW for the abovementioned short transmission periods over a period of approximately 10 years.

The supply of the electronic logic timer circuits of the measuring unit 10 , on the other hand, takes place via a long-term measuring battery 40 , which is shown only schematically in FIG. 1, without specifying the connections to the individual timer circuits in detail.

A display unit 42 is also connected to the output of the memory 24 in order to provide the consumer with information about what data is being transmitted from the measuring unit 10 to the evaluation unit 16 .

The evaluation unit 16 has a receiving circuit 44 , which demodulates and forms the signals received at the antenna 14 . The signal stream then obtained is fed to an input of a computer 46 which operates according to the block diagram shown in FIG. 2 with regard to the evaluation and storage of incoming consumption measurement data.

The computer first checks the incoming signal stream on the occurrence of a block start mark. Will be one the following signals are read in, until a block end mark is determined.

The block marks are derived from the data record thus obtained split and the check bit separated. The consumption measurement data becomes then a control check number is calculated which then is compared with the transmitted check number. voices if the two check numbers do not match, there is a return to the starting point of the routine.

If the two test numbers match, the computer 46 fetches one or more of the previously transmitted consumption measurement data records stored according to the identification signal from a read / write memory 48 connected to it , which can be a sufficiently large RAM or a hard disk or a floppy disk drive Consumption measurement data set belonging measuring unit.

In a further block, the new consumption measurement data set is now saved subjected to a plausibility check for heat consumption measurement z. B. may simply consist of testing whether the new heat consumption value is greater than that last saved. For more complicated applications The plausibility check can also consist of checking whether the consumption data record just received is a constant and get plausible development of a majority beforehand represents records.

The plausibility check can also be carried out earlier keep the consumption data records for other measuring units, if their measurement signals are factually related hen.

If the consumption measurement data record just received also satisfies the plausibility check, the consumption measurement data record is combined with the time provided by a clock module 50 of the computer 46 and stored in a field of the read / write memory 48 provided for the measurement unit 10 under consideration.

In practice, this field can consist of only a single memory cell, but preferably the memory area comprises at least as many memory cells for data records as are sent by a measuring unit 10 per day.

The read / write memory 48 is generally read out once a day by a higher-level control center, not shown in the drawing, via a modem 52 . The modem 52 can, for example, be a TEMEX unit.

If an otherwise correct data record does not meet the plausibility check, this data record is also stored together with the time in an error memory 54 , which is also a read / write memory and is read out together with the read / write memory 48 via the modem 52 from the central control center which then draws conclusions from the errors that have occurred about possible repair measures to be taken or improvements to the installation. In practice, the read / write memory 48 and the error memory 54 can be subareas of a single large memory.

For local testing and maintenance of the computer 46 , a keypad 56 and a monitor 58 can be connected to it, e.g. B. in the form of a portable calculator.

From the above description of the system according to FIG. 1 it can be seen that this does completely without data transmission in the direction of the evaluation unit to the various measuring units. It is therefore only necessary to provide the receiving circuit 44, which is complex in practice, only once. A timely recording of the consumption measurement data is guaranteed, although the clock components contained in the individual measuring units drift away from real time over time due to small manufacturing errors. However, it is not necessary to readjust the local time in the individual measuring units in the above-described method of transmitting the consumption measurement data to the evaluation unit.

In the embodiment according to FIG. 3, the electronics of the measuring units 10 is further simplified. On the one hand, depending on the currently applicable broadcasting time, only a single next broadcasting time is calculated at random, that is, a next broadcasting time which, in the exemplary embodiment under consideration, lies at any time within four hours of the currently applicable broadcasting time. The transmission circuit 36 is also connected directly to the output of the computing circuit 22 .

In the further modified system according to FIG. 4, a further memory 60 is connected to the output of the memory 24 , which takes over the last consumption data record sent (C = clock terminal, I = data input, O = data output). The outputs of the memories 24 and 60 are connected to the inputs of a comparator 62 , which then provides an output signal when the two input signals differ by more than a predetermined value, which can be set, for example, on a potentiometer 64 . An AND gate 66 is inserted between the output of the time switch circuit 34 and the control terminal of the transmission circuit 36 , the second input of which is connected to the output of the comparator 62 . In this way, the transmission circuit 36 is not activated as long as the consumption measurement data have changed only slightly.

Claims (11)

1. Method for transmitting consumption measurement data from a number of measuring units ( 10 ) to a central evaluation unit ( 16 ), in which

• a) the measuring units ( 10 ) are connected to the evaluation unit ( 16 ) at different times via a radio data transmission link operating at a common operating frequency; and
• b) in the measuring unit ( 10 ) the consumption measurement data to be transmitted are compiled together with an identification signal characterizing the measuring unit ( 10 ) to form a data record;

characterized in that

• c) the measuring units ( 10 ) send their data sets in stochastically distributed narrow transmission windows and
• d) the evaluation unit ( 16 ) from the received on the Arbeitsfre frequency signal sequences on the basis of the bit pattern those that correspond to overlapping data sets and the signal sequences remaining after this selection, which correspond to a non-overlapping data set, for further evaluation.

2. The method according to claim 1, characterized in that the measuring units ( 10 ) store the measurement data last sent and the stochastic determination of a next transmission window is only carried out or activated when the current consumption measurement data is different from the last consumption measurement data sent differ by more than a predetermined value. 3. The method according to claim 1 or 2, characterized in that the measuring units ( 10 ) calculate a check number according to a predetermined algorithm from the consumption data to be transmitted and provide a corresponding test signal the consumption measurement data and thus an extended data record bil that the evaluation unit ( 16 ) splits off the test signal from the extended data, calculates a control test number from the consumption measurement data according to the same predetermined algorithm and only saves an adopted data set if the test number corresponding to the transmitted test signal and the Control check number match. 4. The method according to any one of claims 1-3, characterized in that the evaluation unit ( 16 ), together with a data record recognized as correct, stores the time at which this data record was received. 5. The method according to claim 4, characterized in that a clock module ( 50 ) of the evaluation unit ( 16 ) is set at intervals to normal time. 6. The method according to any one of claims 1-5, characterized in that the evaluation unit ( 16 ) compares a correctly transmitted data record with at least one of the previously received data records according to predetermined criteria and only saves if the new data record meets these criteria . 7. The method according to claim 6, characterized in that the evaluation unit ( 16 ) records records which do not meet the criteria, preferably stores these together with the time of their arrival and the type of non-fulfillment of the criteria. 8. The method according to any one of claims 1-7, characterized in that the measuring point units ( 10 ) save consumption measurement data sets at regular intervals and each specify a plurality of stochastically distributed transmission windows between the storage times. 9. The method according to any one of claims 1-8, characterized in that the stochastic transmission window is determined by a random generator ( 30 ) starting from a characteristic number for each measuring unit ( 10 ). 10. The method according to claim 9, characterized in that the determination of the stochastic transmission window additionally depending on an uncontrolled changing physical variables.