DE1272441B - Device for the transmission of telecontrol signals via a supply network carrying AC voltage - Google Patents

Description

Device for the transmission of telecontrol signals via an alternating voltage leading supply network The subject of the main application is a device for Transmission of telecontrol signals via a supply network carrying AC voltage for electrical energy in which the signals are superimposed on the AC mains voltage are, with at least one signal transmitter and one signal receiver as well as with one arranged at each signal transmitter, in series with a pulse contact to the supply network connected electrical oscillating circuit for the duration of the signal transmission is connected to the supply network in the manner of a series of pulses, the Time interval between the individual, consecutive switch-on pulses in a series of pulses unequal to the single or multiple integer value of half the period duration is the AC mains voltage superimposed with the signals.

The invention relates to an advantageous further development of the object of the main registration.

It has now been found that the transmission security of such devices or the amount of information that can be transferred with these without the use of significant significant means further increased significantly and the transmission level at most can be further reduced if the facility defined in the main application additionally has the features characteristic of the present invention, that the electrical resonant circuit has at least two selectable natural frequencies has, the first of which is a first and the second of which is a second of at least two differently modulated pulse series is assigned as a carrier frequency, and that further in the signal receiver for each of the carrier frequencies selective evaluation members are arranged for the respective carrier frequency and its modulation frequency.

Details can be found in the following on the basis of the drawing figures described embodiment. It shows F i g. 1 is a voltage diagram and F i g. 2 shows a diagram of a telecontrol device.

In a supply network for electrical energy, usually in the further abbreviated to "network", the frequency of the network alternating voltage is z. B. 50 Hz, theirs Period duration thus 20 milliseconds (abbreviated: ms). When turning one off an inductive and a capacitive element existing electrical oscillating circuit An alternating current with a natural frequency of the resonant circuit is formed in the network prescribed frequency, the initial amplitude of which corresponds to that at the time of connection applied instantaneous value of the mains voltage proportional and its logarithmic Decrement depends on the damping of the resonant circuit.

When the oscillating circuit is switched off, the capacitive element has this The resonant circuit has a charge, its polarity and size at the time of switch-off corresponding instantaneous value of the mains voltage. In order to be as large as possible To achieve inrush current, the resonant circuit is switched on again advantageous in a half-wave of the mains voltage with opposite polarity, according to the invention, however, at a different amount of the instantaneous value of the mains voltage than the previous connection. In FIG. 1 this is illustrated.

For example, the time t l- coincides with the first connection the peak value of a positive half-wave (-I-) of the mains voltage U, the point in time the shutdown t2 with the peak value of the next positive half-wave together; the switch-on period A of the resonant circuit is then one period the mains voltage, i.e. 20 ms. The second connection following a pulse pause P now only sets a small amount of time Z, e.g. B. 2 ms, after the occurrence of the peak value which is on the positive half-wave (-I-) when switched off became, following negative half-wave (-) of the mains voltage; the period T one Connection, that is the time interval between the individual connection impulses, is at selected example therefore 32 ms; Switch-on duration A and pulse pause P are therefore different measured.

In the example given, the time of connection falls behind five switch-on periods each, corresponding to a period of 160 ms, with homologs Instantaneous values of the mains voltage together. The amount changes during this period the initial amplitude of the inrush current between a maximum value and a value equal to or close to zero, depending on the magnitude of the instantaneous value of the mains voltage at the time of the first connection within a series of connection pulses. The inrush current of the resonant circuit is thus in the example discussed with (160 ms) -1 = 6.25 Hz modulated practically 100%. By choosing any switch-on periods T within the scope of this dimensioning rule, other amplitude modulation frequencies can also be used achieve the inrush current, e.g. B. 4 Hz.

An example of the practice and use of the invention FIG. 2.

A low-voltage network 1, for example, serves as the telecontrol channel a district network of public electricity supplied by a distribution transformer 2 is fed. The remote control task consists in the transmission of the electrical State of signal contacts of a large number of signal transmitters to a central one Receiving center. Volume meters serve as signal transmitters to measure the consumption of public consumer goods such as gas, water, electricity.

In FIG. 2 an electricity meter is indicated as a signal generator 3, a signal contact 4 switches from a contact element 5 to a contact element 6 and vice versa. Of the Electricity meter measures the electrical work converted in a consumer 7.

The signal transmitter 3 is a transmission device consisting of a capacitor 8 and from a coil 10 having a tap 9 electrical Reihenschßingkreis and a pulse generator 11 assigned. The pulse generator 11 has z. B. three via gear pairs l.2,13,14 coupled shafts 15,16,17 with different Speeds that are in a fixed ratio to the speed of one of a clockwork or, as shown, drive shaft 19 moved by a synchronous motor 18.

A cam disk 20 , which acts on a first pulse contact 21, is fastened on the shaft 15, while the shaft 16 carries a cam disk 22 for actuating a second pulse contact 23. Finally, two cam disks 24 and 25 are arranged on the shaft 17, the first of which controls a motor contact 26 and the second of which controls a main contact 27. The cam disk 25 can be rotated by hand with respect to the cam disk 24 by means of a slip clutch 28 or by means of an adjusting screw.

The parts just described are included in an electrical circuit as follows: A branch line 29 is connected to the low-voltage network 1 in one phase. From a phase conductor of the branch line 29, a connecting line 30 leads via the main contact 27 to the capacitor 8 of the series resonant circuit 8, 10, and from a coil end 31 of the coil 10 via the first pulse contact 21 to the contact element 5 of the signal contact 4, while the tap 9 of the coil 10 is connected to the contact element 6 of the signal contact 4 via the second pulse contact 23, the switching arm of which is connected to the neutral conductor 0 of the branch line 29 via a line 32.

The signal generator 3 is also connected to the branch line 29, which also provides the operating voltage for the synchronous motor 18 on the one hand via the connecting line 30, a control contact 33, a line 34 and on the other hand via a connecting line 35 supplies. The motor contact 26 is electrically parallel to the control contact 33, which from a time switch or from one connected to the low-voltage network 1 Ripple control receiver 36 is operated. If a timer is arranged, can these also serve as a drive for the pulse generator 11, timer or remote control receiver 36 are usually only used by the telecontrol device described, thus also fulfill other tasks, e.g. B. tariff switching, switching on and off from consumers, etc., which is not shown in the drawing.

The parts of the figure described above are in place of each Signal transmitter 3 arranged; a timer or a ripple control receiver 36 can, however operate several signal generators 3 with pulse generators 11 and then assign accordingly many Control contacts 33 open.

The part of the telecontrol device described so far works as follows: The information to be transmitted is contained in the electrical state of the signal contact = 1, it can have the form a or b , then the signal contact 4 is a switch with two contact elements 5, 6 Signal contact 4 more than two contact elements; the information can then have at least as many different forms as there are contact elements. In the simplest case, the information has a content a or 0, the signal contact 4 would then have only one contact element and an “off” position and thus correspond to a simple on-off contact.

Each contact element, e.g. B. 5, 6, of the signal contact 4 is connected to an associated pulse contact 21 or 23, "occupied"; the pulse generator 11 thus has as many pulse contacts and cam disks controlling them as there are occupied contact elements on the signal contact 4.

As can be seen from the drawing, the resonant circuit 8, 10 is located with the signal contact 4 and each one of the pulse contacts 21 and 23 electrically in series and is connected to the mains voltage each time the relevant pulse contact is closed switched on, provided that the main contact 27 is closed. This creates As mentioned, electrical compensation oscillations S (F i g. 1), which the network as Superimpose signal currents and are thus forwarded via the network. The frequency this compensating oscillation, which serves as a carrier, depends on which of the two Pulse contacts 21 and 23 for signaling is just effective, since the resonant circuit 8, 10 has a different setting for each of the pulse contacts. Of the time interval T between the individual switch-on pulses and thus the duration of a switching cycle of a pulse contact is equal to the reciprocal product of the number of cams the cam disc controlling the pulse contact and the speed of this cam disc. For each cam disc controlling a pulse contact is the reciprocal of the product from speed and number of cams, i.e. the duration of a switch-on period T, different and unequal to the simple or integral multiple value of half the period duration the mains AC voltage selected. A value of z. B. called 32 ms; it could e.g. B. but also 11 ms or 31.25 ms or any other values, preferably those close to an odd multiple half the period of the AC mains voltage and those in the already described Wise amplitude modulation frequencies result from interference frequencies and network harmonics have a sufficient distance.

When the control contact 33 is closed, the drive shaft 19 of the set in motion as a revolving cam switch pulse generator 11, be it by switching on the synchronous motor 18 or by z. B. electromagnetic Coupling of the drive shaft 19 in a continuously running clockwork drive, which the drive shaft 19 has a constant speed of z. B. 50 U / see granted.

Shortly after the pulse generator 11 starts, the motor contact closes 26 and holds the drive, e.g. B. the synchronous motor 18, for a full revolution of the Cam 24 energized.

A set period of time after the start of the pulse generator 11 closes the main contact 27 is determined by the design of the cam disk 25 Duration, e.g. B. for 1.5 seconds. During this period of time, the oscillating circuit 8, 10 by the respective pulse contact 21 or 23 according to the switching status of the signal contact 4 in a characteristic for the pulse contact in question connected to the network at a certain time. This creates the signals of the already described type, in the form of a series of pulses, the length of which is the Corresponds to the duration in which the main contact 27 is closed.

The information contained in the electrical state of the signal contact 4 now appears in the telecontrol channel as a series of switch-on pulses one for the position of the signal contact 4 characteristic carrier frequency. The for the Transmission especially the initial amplitude of the switch-on pulses is with a also for the respective state of the signal contact 4 characteristic frequency modulated to practically 1001 / o, for example with 6.25 Hz or with 4 Hz or the like, as described.

With the help of the ripple control receiver 36 (or a timer) can the series of pulses, i.e. the information, is called up at a desired point in time will. It is possible - many signal generators 3 by a single ripple control command at the same time. At the moment of the call, that is when the control contact is closed 33, all pulse generators start 11. By setting the cam disk accordingly 25 is achieved that the main contacts 27 of all started pulse generator 11 to different Times are closed, so that one signal generator after the other sends its information delivers without the information overlapping.

The chronological order in which the individual signal generators their Submit information is fixed and serves to identify the individual Signal transmitter 3. A central receiving point 37 knows the time of the call from everyone included in the telecontrol device signal transmitter 3 and can so each in the receiving point Assign incoming pulse series to a specific signal transmitter 3.

For decoupling the signals from the superimposed low-voltage network 1 is a transmitter in the receiving station 37, for. B. a current transformer 38, with a Arranged working resistor 39, at the terminals of which, among other things, the signal alternating voltages appear. These pass through band filters 40 and 41, in which the outside of the voltages lying in the desired frequency bands are filtered out, and via amplifiers 42 and 43 to demodulators 44 and 45. The demodulated voltage is now correlation systems, z. B. ring modulators 46 and 47 known per se are supplied.

Each of the band filters is permeable to one of the possible carrier frequencies or their sidebands generated by the modulation, while the switching frequency of one of the ring modulators 46, 47 is identical to one of the amplitude modulation frequencies generated by the pulse generator 11. so that a DC voltage is produced at the output of the ring modulator when a signal corresponding to the switching frequency of the ring modulator is present in the telecontrol channel. This direct voltage is smoothed in an integration element 48 or 49 and fed via an amplifier 50 or 51 to a relay 52 or 53, each with a working contact 54 or 55.

Each of the mentioned operating modes as a highly selective filter acting ring modulators 46 and 47 advantageously consists of two working in parallel Correlation systems, the contact cycle of the first system compared to that of the second is phase shifted by 90 °, so that between the signal voltage and the Contact cycles of the ring modulators without any disadvantage any phase shift can occur.

In the receiving station 37, a band filter must be used for each carrier frequency and for each occupied contact element (z. B. 5; 6) of the signal contact 4 a pair of correlation systems and a relay connected downstream of them (e.g. 52; 53) be arranged.

Based on the previous explanations it can be seen that the switch position all working contacts 54 located in the receiving point; 55 in a defined Moment of time an image of the electrical state of the signal contact 4 of a whole represents certain signal generator 3 of the telecontrol device. This switch position the working contacts 54; 55 is now evaluated accordingly in the receiving station 37.

Instead of the pulse generator 11 shown in the figure are of course also other types of mechanical control devices for the pulse contacts 21, 23 conceivable; The activation pulses can also be generated by purely electronic switching elements take place, likewise with the help of vibrating tongue contacts or by tuning forks controlled impulse contacts. Finally, it is also possible to connect the signal contact 4 even by tuning fork or Vibratory tongue control properties a pulse contact that is mechanically detuned in every switch position the oscillating system generates different pulse repetition frequencies.

In the above it was shown that it is now based on the invention is possible with very simple low-power transmitting and receiving devices Information about an already existing and widely ramified, but numerous Telecontrol channel exposed to interference, such as a distribution network for electrical Represents energy, reliably in any direction, so in particular also in the opposite direction the direction of flow of the network energy. Interference voltages that are within the of the band filters 40 and 41 of the receiving station 37 of the frequency band passed can only impair the transmission of information if they are too modulated with one of the amplitude modulation frequencies selected for the signals and last a long enough time, e.g. B. a second what the probability of is extremely low.

Could by a changeover switch not shown in the drawing For example, for control purposes, the pulse contact 21 with the tap 9 and the Pulse contact 23 connected to the end 31 of the coil 10 of the series resonant circuit will. This measure can of course also be used to increase the amount of information that can be transmitted use.

By means of simple circuit measures, the in itself can be used in any Number of available carrier and modulation frequencies a variety of combinations are formed, of course, when choosing the evaluation elements of the signal receiver 37 are to be taken into account, so that with this simple device at most Multi-digit even without the aid of a coding of the transmitted pulse series Have numerical values transferred.

To change the natural frequency of the resonant circuit 8, 10, apart from tapping the coil, of course, all known measures can be used, e.g. B. a change in the capacitance of the capacitor 8 or a change in an air gap in an iron core of the coil 10. In particular, the last-mentioned measure results in the additional possibility of giving the carrier frequency a frequency modulation. This can also be done by at least one cam disk which actuates a modulation element according to the rules given here for achieving amplitude modulation and thus generates a periodic detuning of the resonant circuit 8, 10 in a purely mechanical way by changing the air gap or by connecting and disconnecting electrical elements. The reference frequency of the correlation systems 46, 47 of the signal receiver 37 must then be adapted to the type of modulation used.

Claims (5)

Claims: 1. Device for the transmission of remote control signals via an alternating voltage leading supply network for electrical energy on which the signals of the AC mains voltage are superimposed, with at least one signal transmitter and a signal receiver as well as one arranged at each signal transmitter, in Series with a pulse contact connected to the electrical supply network Resonant circuit for the duration of the signal transmission to the supply network is switched on in the manner of a series of pulses, the time interval being the individual successive switch-on impulses of a series of impulses unequal to the simple one or integer multiple value of half the period duration of the signals superimposed mains AC voltage is, according to patent application E 24670 VIII b / 21d =, German Auslegeschrift 1264599, characterized in that the electrical oscillating circuit (8, 10) has at least two selectable natural oscillation numbers, the first of which is one first and second of a second of at least two differently modulated Pulse series is assigned as a carrier frequency, and that also in the signal receiver (37) for each of the carrier frequencies selective evaluation members (40, 46; 41; 47) for the respective carrier frequency and its modulation frequency are arranged. 2. Device according to claim 1, characterized in that one winding end (31) of a coil (10) of the resonant circuit (8, 10) with a first pulse contact (21) and a tap (9) of the coil (10) with a second pulse contact (23) is electrically connected. 3. Device according to claim 1 or 2, characterized in that to choose the carrier frequency and its modulation frequency a signal contact (4) of the signal generator (3) is used. 4. Device according to claim 2, characterized in that the assignment of the two pulse contacts (21, 23) to the End (31) and for tapping (9) of the coil (10) can be exchanged by means of a changeover switch is. 5. Device according to one of claims 1 to 4, characterized in that at least one modulation element is arranged for frequency modulation of the carrier frequency is.