DE2348461A1 - Electronic ticket usage counter - using field effect transistors uses inductive loop as sensor and has integrators - Google Patents

Abstract

An electronic ticket usage counter may be made using an inductive loop or a transfermer as a sensor. Rectified current from the transformer secondary coil is the turn connected to the sources of two field effect transistors. These transistors represent the active sensing elements. The gates to the transistors are controlled by an integration circuit, which is used to fix the voltage reference. The inductive loop senses an electromagnetic field and cuases the transistors to switch, during normal usage. This action causes a counter to be tripped, every time a ticket is passed through the machine.

Description

SIEMENS AKTIENGESELLSCHAFT Erlangen, 2 pp. U6p. iii / 3

Berlin and Munich Werner-von-Siemens-Str. 5Q

VPA 73/3246 Hs / Nit

Electronic bill consumption meter

For measuring the apparent consumption of an alternating or three-phase current, measuring devices with Hall generators are known (OT-PS 1 010 156, 1 048 997, 1 209 653), where one size is a field magnet and the other size is the control electrodes of a Hall generator are fed. A counter is then connected to the hall electrodes. This counter can be either a Direct current meter or an induction meter, whereby the voltage coil of the induction meter is connected to the phase voltage and the current coil is connected to the output of the Hall generator.

Furthermore, a bill consumption meter has been proposed (DT-OS 2 032 781), in which the phase currents proportional Voltages are formed which are converted into a corresponding pulse frequency in a voltage-frequency converter are, which preferably via a frequency divider directly to a stepping motor driving a counter drives. However, the prerequisite for the accuracy of the measurement is that the mains voltage is constant. Is this not the case, an intervention in the circuit must be made in such a way that the changes in the mains voltage be taken into account, for example by changing the gain of an amplifier stage accordingly.

The disadvantage of the known circuit arrangements, however, is that these devices usually do not have the required • Accuracy work. Furthermore, they only work reasonably accurately in a limited power factor range.

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The invention is based on the object of a simple electronic To create bill consumption meters that also cover a larger power factor range with sufficient accuracy is working. The electronic bill consumption meter according to the invention is characterized in that a current proportional Size is rectified and fed via a changeover switch to an integration stage, which is a limit value stage is connected downstream, the two response values of which are inversely proportional to the mean value of the voltage and which then switches the switch when the integrator voltage reaches one of the two limit values. A simplification increasing the accuracy can still be achieved by using an electronically compensated current transformer is used.

The invention is explained in more detail with reference to the drawing, in which an exemplary embodiment is shown in principle.

With 1 the Hetzzuleitungen are referred to, in which a current transformer 2 is switched on. In the drawing is a conventional current transformer with a primary winding 3 and a Secondary winding 4 shown. Preferably one will, however use an electronically compensated current transformer instead of such a current transformer 2. The one in the secondary winding 4 induced current-proportional variable is rectified with the aid of the rectifier arrangement 5, in which case Output terminals 6 two equal resistors 7 are connected. The connection points 6 are also via resistors 8 and the source-drain line of field effect transistors 9 is connected to an input terminal 10 of an integration stage 11. Of the Integration stage 11 is followed by a limit value stage 12, whose upper and lower response values can be set inversely proportional to the mean value of the phase voltage U. The limit value stage 12 is connected to the gates via a line 13 the field effect transistors 9 j, once directly and once via an inverting circuit 14 in connection. Further the center point 15 of the two resistors 7 is connected to the reference potential via a line 16, which is also via

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a resistor 17 is connected to the second input of the integration stage 11. As soon as the upper or lower The limit value of the limit value stage 12 is reached in each case Connection point 6 connected via the associated electronic switch 9 to the input of the integrator 11, whereby a Reloading of a capacitor 18 of the integration stage is carried out. A capacitor 19 is used to smooth the current proportional Size at the output of the rectifier 5.

The response value, which is inversely proportional to the mean value of the voltage, can be obtained in various ways. Preferably this is obtained with the help of a module that forms the value (x. y): ζ from the three variables x, y and ζ and in which the quantities χ and y are kept constant and the quantity ζ is derived from the rectified voltage.

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Claims (5)

- 4 - YPA 7373246 £ 34.8461 Claims / Ί.) Electronic bill consumption meter, thus marked-Wnet, that a quantity proportional to the current is rectified and via a switch (9) of an integration stage (11) is supplied, which is followed by a limit value stage (12) whose upper and lower response values are inversely proportional to the mean value of the phase voltage U are and each then switches the switch (9) when the integrator voltage is one of the two limit values achieved. 2. Electronic bill consumption meter according to claim 1, characterized characterized in that an electronically compensated current transformer is used to obtain a variable proportional to the current is used. 3. Electronic bill consumption meter according to claim 1 or 2, characterized in that the output is one for rectification of the current used rectifier (5) is terminated with two equal resistors (7) whose Center (15) is placed on reference potential (0) and its connection points (6) each via an electronic Switch (9) can be switched to the input (10) of the operational amplifier of the integration stage (11). 4. Electronic bill consumption meter according to claim 3, characterized in that field effect transistors as electronic switches, in particular complementary field effect transistors are used. 5. Electronic bill consumption meter according to one of claims 1 to 4, characterized in that the mean value The response value inversely proportional to the voltage (U) is obtained with the help of a module that forms the value (x. y): ζ from the three quantities x, y., ζ and in which the quantities χ and y are kept constant and the Quantity ζ is derived from the rectified voltage. 509816/0439