DE2925116A1 - Electronic heat detector circuit for flat radiators - uses Wheatstone bridge with one branch formed by radiator heat sensor, while another branch contains room temp. sensor - Google Patents

Abstract

The circuit is intended for detaching heat emitted by flat radiators during a selectable time period. The radiators carry temperature sensors, firmly screwed at a specified height and connected in series. This series connection form a branch of Wheatstone bridge, whose other branch is formed by a room temperature sensor. The bridge supply voltage is provided by a pulse generator at discrete, equidistant time points only. The generator triggers a scanning and hold circuit, which supplies the bridge diagonal voltage during the time period between two voltage pulses. The output voltage of this circuit is converted into a pulse train by a voltage-frequency converter, the pulse train frequency being proportional to the voltage. The pulses are integrated by a counter. Pref. the series-connected temperature sensors are NTC resistors with practically linear temperature dependence.

Description

Shackling arrangement for the acquisition of the

Radiators of an apartment amount of heat given off The invention relates the preamble of claim 1.

when determining the heating costs for the individual apartments and hot water costs it is required that they be in a central location of one Apartment blocks can be read at any time, both by the meter and by the landlord can be queried or automatically via a dedicated telephone line and in an EDP can be processed. It must be ensured that no rieter is involved in this electronic determination of heating and hot water costs is disadvantaged.

r is known that to measure or determine the proportional heating costs, so-called evaporation tubes are used, in which the amount of evaporated Liquid is used as a measure of the amount of heat consumed per radiator.

Furthermore, there is an electronic heat cost allocator in DT-OS 27 34 406 describes the temperature difference between the radiator and the room via thermocouples detected, these thermal voltages summed up in relation to the apartment and this sum voltage integrated per apartment over the heating period.

Evaporation tubes for determining the heating costs have the disadvantage on that they can only be read individually per radiator and per apartment. On the other hand, the recording of heating costs via thermocouples requires a large one Circuitry and the summation of thermal voltages is very sensitive with regard to Influence by electromagnetic interference fields or with regard to manipulation of the Apartment owners, as very low level values are transmitted over long lines have to.

The invention is based on the object, on the one hand, of the evaporation tubes to be completely eliminated, otherwise it must be ensured that the apartment-related, used up Heat quantities can be easily and reliably determined by the respective tenant at any time and read manually, photographically or automatically by the tenant at any time or can be retrieved and viewed or processed anywhere. further must be ensured down to the level of the temperature sensors, that occurring errors and malfunctions (also due to manipulation) are recognized immediately and can be displayed optically or acoustically at any remote location, so that no tenant party in determining the proportionate heating box of a block of flats feels disadvantaged. The recording of the hot water consumed per apartment is another important parameter when allocating the costs per heating season to the meters of a block of flats.

This task is achieved by the characterizing features of the claim 1 solved.

Embodiments of the invention are shown in the drawings and are described in more detail below.

FIG. 1 explains some important terms. FIG. 2 shows a bridge circuit with the radiator and room temperature sensors Figure 3 represents the integration circuit FIG. 4 shows a monitoring circuit. FIG. 5 shows the apartment bus 6 shows the block of flats BUS Um the battery load with mains-independent power supply To keep to a minimum, the voltage source 1 delivers a square wave signal Amplitude A, the duration # and the period t, where t is relatively large compared to T. Electricity is only consumed significantly during pulse duration 2. An operational amplifier amplifies the tension% of the bridge diagonal, the amplification factor being by the feedback resistance Rw determined according to the housing factor can be influenced can.

At the output of the operational amplifier 2 there is thus a voltage which is essentially the sum of the mean apartment temperatures, multiplied with a flat constant, is proportional, in each case over the pulse duration % A sample and hold circuit 3 triggered by voltage source 1 (A / H circuit) now saves this output signal during the time t - #, in which there is no current in the sensor lines for reasons of the lowest possible battery load. Since the time constants of radiators, apartments and houses are generally right are large, the specified circuit can be used with pulse duty factors without loss of accuracy work from about 1: 1000 or even smaller.

The output voltage of the A / H circuit 3 is then via a voltage / frequency converter 4 converted into counting pulses, which are used in a mechanical or electronic counter 5 are added up, the counter reading of which is therefore the one in any period of time corresponds to the amount of heat consumed.

With tool 6, the tenant also has the option of monitor the heat energy he is currently consuming and can therefore control it intervene in its heat consumption in order to keep its heating costs to a minimum.

To interrupt the temperature sensors connected by a ring line To signal R1 ... Rn, according to Figure 4 at the beginning or end of the ring line Another resistor 8 is used, its resistance value compared to the sum the R1 ... Rn is small. If the ring line is intact, there is a at resistor 8 Voltage drop which is amplified by the operational amplifier 9 so that on Input of the AND gate 10 two approximately equal voltages are present. In the event of an interruption the ring line, however, the voltage drop across the resistor 8 is zero and thus switches the AND gate 10 through and allows an indicator lamp 11 or another signal to respond.

Figure 5 shows a complete home installation with a microprocessor (µP) and a BUS structure that includes all of the circuit functions described above perform digital basis, including the sensor linearization and thus a ensure flexible and modular structure. With this circuit arrangement you can not only the proportionate heating costs, but also the hot water consumption is recorded will. At the same time, it monitors the circuit arrangement with the aid of diagnostic programs itself, so that a failure or a tampering by the tenant is immediately recorded and would trigger an alarm message. The coupling with the central display panel of the block of flats takes place via the so-called central bus, which runs in a well-known way also how the apartment bus is implemented as a busbar.

Figure 6 shows the interconnection of the individual BUSSE apartment on the central bus, on which the central display unit, the alarm unit and a telemetry device is connected if necessary.

L e r s e i t e

Claims (17)

Claims 1. Circuit arrangement for electronic detection that emitted by radiators in an apartment during a freely selectable period Amount of heat at which the heat on the radiators is unchangeable at a defined level attached temperature sensors are connected in series, characterized in that that the series connection of these radiator temperature sensors (R1 ... Rn) the one Bridge branch, the room temperature sensor (Rw) the other bridge branch. a Wheatstone ash Bridge forms that a pulse generator (1) only increases the bridge supply voltage (Ue) discrete, equidistant points in time that a triggered by the pulse generator Sample and hold circuit (3) the bridge diagonal voltage (UD) during the between two voltage pulses lying time (t - T) that stores the output voltage this A / H circuit (3) via a voltage-frequency converter (4) into a pulse train is converted, the frequency of which is proportional to the voltage and that these pulses can be integrated via a counter (5). 2. Circuit arrangement according to claim 1, characterized in that the temperature-dependent resistors (R1 ... Rn) NTC resistors are practical with linear temperature dependence. 3. Circuit arrangement according to claim 2, characterized in that the NTC resistors (R1 ... Rn) have the same relative temperature dependence and that their absolute values at 0 ° C are determined by the size of the radiator will 4. Schaltungsa dilution according to claim 3, characterized in that that the room temperature sensor (Rw) is equal in its absolute value to the absolute value of the Resistance sum of the series connection R1 ... Rn is. 5. Circuit arrangement according to claim 4, characterized in that a measuring device (o) connected to the output of the operational amplifier (2) the current Heat output tends to. 6. Circuit arrangement according to claim 5, characterized in that the size of the feedback resistor (7) takes the specified apartment factor into account. 7. Circuit arrangement according to claim 6, characterized in that a @ End of the bridge branch R1. Rn a small resistor (8) is inserted, whose Connections at the same time to the input of an operational amplifier (9) go that the output of the operational amplifier (9) to one input of a UNT gate (10) goes that the other input of the AND gate (10) with the beginning of the bridge branch connected at R1 and that the output of the AND gate (10) with a signal lamp (11) is connected. 8. Circuit arrangement according to claim 7, characterized in that the individual heat meters of an apartment via a central apartment BUS are connected, the heat quantities being proportional to the individual exchanged Currents are added up via an operational amplifier, which is via its feedback resistor the structural properties of the apartment are taken into account and a V / F converter at its output is connected to control a counting circuit. 9. Circuit arrangement according to claim 8, characterized in that the central unit via an apartment block central bus (data, addresses, sterer signals) the FF storage of n apartments queries the functionality of the heat meter every apartment is monitored and in the event of a fault an optical or acoustic signal to a caretaker or to a collection center. 10. Circuit arrangement according to claim 9, characterized in that the most important functions of the central unit from a freely programmable computer perceived, which includes the possibility of self-diagnosis. 11. Circuit arrangement according to claim 10, characterized in that integration can be carried out using electromechanical counters or computers is, where either number wheels or LEDs are used to display the can be called up via a bell. 12. Circuit arrangement according to claim 11, characterized marked-eicbnet that all radiator temperature sensors are connected via a single-core ring line. 13. Circuit arrangement according to claim 12, characterized in that that the heating costs are determined depending on the outside temperature TA, whereby the proportional voltage value is queried by the µP in time division multiplex. 14. Circuit arrangement according to claim 13, characterized in that that the voltage pulse generator emits a sampled sinusoidal oscillation that is tamper-proof is. 15. Circuit arrangement according to claim 14, characterized in that that a transmission temperature sensor RT are placed in the bridge circuit can. 16. Circuit arrangement according to claim 15, characterized in that that a Cptocoupler is used for galvanic decoupling per residential unit. 17. Circuit arrangement according to claim 16, characterized in that that the ring line for the radiator temperature sensors represents the bridge branch A-B.