KR19980071249A - Data and power transmission method and system - Google Patents

Abstract

It is proposed to supply a 2-pole AC voltage to the line for transmitting power and data on the very same line to which multiple stations are connected, where one polarity is used for power supply only and the amplitude correction of pulses of the other polarity is avoided. Only data transmission is achieved. High power can be supplied to the station if the pulses with different polarities are supplied with very low resistance values, and very low power can be supplied for data transmission when pulses with different polarities are supplied with high resistance values. Required for modification As a result, only two leads are needed, where one lead can be replaced by the system ground in the simplest case. If three conductors are used, it is possible to improve the tolerance of defects in the conductors in a very simple way. Another possibility of retaining at least parts of the system in operation in the event of a short circuit is when the conductors are disconnected by a disconnect circuit that automatically disconnects at least one conductor in the event of a short circuit and automatically reconnects after the short circuit is removed. exist.

Description

Data and power transmission method and system

The present invention relates to transmitting data and power through one common transmission line to which one power source and several stations are connected, and each station can basically receive power and data through the common transmission line. In addition, data can be transmitted through this transmission line.

When a very identical transmission line is used for the transmission of power and data, this transmission line, which is necessary, has only a few individual conductors or wires or in extreme cases only two conductors. This greatly reduces the cost of the transmission line, especially in systems with a wide spatial distribution. Thus, this principle has been used in many forms in the past.

DE 39 07 652 A1 discloses a circuit arrangement in which one current supply unit carries a DC voltage to the side of a two wire bus line to which several stations are connected. An energy storage device in the form of a capacitor is provided in each separate station, charged by the DC voltage on the two wire bus line via a rectifier and a resistor, and serves as a current source for the electronic circuit of the station. For data transmission, the bus line is shorted according to the data to be transmitted. However, this means that the current supply unit must deliver the DC voltage to the bus line side in a relatively high resistance manner so that only a limited number of stations can be supplied through the bus line, in particular any high load is supplied to the station. It can't be.

DE 41 38 065 A1 discloses an apparatus for transmitting data and power via a transmission line having two wires and a screening in which these wires are housed. Each station is connected to the two wires and the screening, and thus can receive half of the operating current through each wire, and the total operating current is returned through the screening. The data is transmitted on both transmission lines by a voltage signal that is out of phase. The power is derived from the two leads by the current sink of the station to load the voltage signal as little as possible with the power transfer. Thus, relatively expensive means are needed to obtain a substantially constant DC voltage for supplying the circuits of the station, in which case the power that can be transmitted to the station is limited.

It is an object of the present invention to provide a data and power transmission system and method in which data can be supplied in a high resistance manner in a highly reliable transmission mode of a transmission line without fundamentally limiting the power that can be transmitted.

1 shows the principle of construction of a system having one power source and several stations interconnected by two transmission lines.

2 shows a first embodiment of the configuration of a station;

3 shows an example of a voltage gradient on two transmission lines due to data modulation.

4 shows a first embodiment of the construction principle of a power supply;

5 is a diagram showing the configuration of a power supply having a transformer;

Fig. 6 is a diagram showing the configuration of a power supply having a transformer having a center tap on the secondary side for a three-line system.

7 shows another embodiment of the configuration of a station particularly suitable for a three line system.

Fig. 8 is a diagram showing the configuration of a power supply for a three-line system in which a third transmission line is used only when there is a defect.

9 shows a configuration of a system having three lines independent of the ground connection.

FIG. 10 shows a configuration of a system having only a single line and a ground connection used as the return line. FIG.

11 is a block diagram illustrating the use of a separation unit.

12 is a block diagram of a separation unit on the line with high potential.

13 is a detailed circuit diagram of a separation unit.

14 is a detailed circuit diagram of a separation unit having transistors of opposite conductivity types.

Fig. 15 is a circuit diagram of a separation unit in which an element for recognizing a short circuit in two half waves is added.

FIG. 16 is a circuit diagram of a separation unit with the addition of a device for generating hysteresis for a trigger threshold. FIG.

* Explanation of symbols for the main parts of the drawings

10: generator 11, 12, 13: transmission line

14,15,16: Station

According to the invention, this object is achieved by the AC voltage being transmitted via two transmission lines, one polarity of voltage being used for the electrical supply of the station, and the other polarity of voltage being used for data transmission. do. As such, two wires are used for time multiplexing for the transmission of power and data, wherein the stations are powered from a local energy storage device during data transmission, and the local energy storage device is recharged during the power transmission process. . The inversion of the polarity allows the power supply and data transfer to be performed independently of each other. The static and dynamic characteristics of the data transmission method and power supply and the static and dynamic characteristics of the applied loads of the station are separated from each other by time sequence and also by polarity change. Thus, reliable data transmission can also be achieved in the simplest form of modulation.

It is important to the reliable operation of such a system that the separation relationship is provided using an AC voltage previously and thus can occur without active synchronization of the station itself and without causing an operation such as switching operations, for example. Do. The separation at these stations is easily realized by passive elements if the current is derived from the conductor in one direction only for power supply, for example by a diode, and this current is modulated in the other direction only for data transmission. Can be. By preventing active mode switching or synchronization at these stations, a very simple and reliable system can be obtained.

A power source in the form of a generator supplying an AC voltage to the two leads can generate the voltage irrespective of the ground potential, so that a short between the system ground or some other supply line and the leads can be accommodated and this short Does not require any operation.

Also, given the proper arrangement of the system, blocking faults may be accommodated by using a third lead as an alternative lead for the blocked lead. The system ground may also be used as an alternative lead for the disconnected lead, in which case the system function is maintained in such backup mode, but the differential function no longer effectively contributes to the electromagnetic compatibility (EMC) of the system. Will not. If the system ground is used as the replacement conductor, shorts in the conductor can no longer be accepted simultaneously in accordance with the arrangement.

In the case of the short circuit, in order to protect the generator supplying power to the transmission line, one of the defective conductors or one of the defective conductors may be separated by a fuse of the generator. However, this means that power supply and data transfer are not possible for any connected station in some embodiments of the system according to the invention. In the case of a short circuit, at least one separation unit can be inserted into the at least one conductor in order to operate at least some systems, which in the case of a short circuit automatically disconnect the associated conductor. As such, the system may operate with at least some stations in this case. In particular, when the lead system is configured as a ring track and several distributed separation units are used, the main parts of the system can remain operational in the event of a short circuit.

The separation units are each equipped with at least one monitoring unit and one switch, wherein the monitoring unit controls the switch so that the switch of the corresponding line can be opened in the event of a short circuit or overload. The switch is to form a shunt by the current limiting element. Thus, the voltage is transmitted to the lead portion side after the separation unit in a high resistance manner. The monitoring unit controls the switch of the separation unit based on the voltage. In the event of a short or overload, the switch is automatically closed by the monitoring unit.

The switch is preferably provided with two power field effect transistors of the same conductivity type having sources connected to each other. The gates are also connected to each other and to the control transistor of the monitoring unit. The control transistor is also a field effect transistor having a conductivity type opposite to the power transistor of the switch, and wherein the control transistor has a potential different from that of the conductor in which the switch with the power transistor is included during normal operation. It shows the connection to two conductors. The monitoring unit monitors the potential of the connected conductor portions. When this potential rises above the first trigger threshold present at a value above the threshold voltage of the field effect transistors of the supervisory units, the control transistor becomes conductive and connects an uninterrupted lead to the gates of the power transistors in the switch. Let's do it. This causes the power transistors in the switch to conduct, thus closing the switch. In the event of a short or overload, the potential at the connected lead portions falls below the second trigger threshold, which may coincide with the first trigger threshold, such that the control transistor of the supervisory unit and thus the power transistor of the switch to be controlled are not. The conduction state is established, whereby the lead is cut off and the shorted lead portion is effectively separated from the remaining operating portion of the lead system.

Since the control transistor can drive the power transistor of the switch only at half a wave of the AC voltage, a power storage element is added to the switch. This power storage element is preferably a capacitor which is charged, for example during a positive half wave and stores the power required to close the switch during a negative half wave. The capacitor is connected between the connection point of the two sources of the power transistors and the connection points of the interconnected gates of the power transistors. However, a short circuit occurring during the half wave in which the switch is closed by the stored charge of the capacitor is not recognized. However, by further configuration the separation unit may also recognize a short circuit during the second half wave.

The conduction type of the power transistor of the switch determines in which half wave the short is recognized.

The current limiting element shunting the switch is preferably a high resistance resistor or a controllable resistor combination, and hereinafter referred to as a test resistor. The voltage is transferred to the output side of the separation unit through the test resistor when the switch is opened. When the short is removed, the voltage necessary to trigger the monitoring unit is generated across the test resistor, and the switch is automatically closed.

The test resistor is advantageously operated in stages. For this purpose, the current limiting device has resistors with several resistance values connected in series. Thus, test resistors of high and low resistance values can be realized. First, the voltage is transferred from the input side of the separation unit to the output side of the separation unit through a test resistor having a high resistance value. Now, if the monitoring unit detects a short, the switch of the disconnecting unit remains open, ie the transistor of the switch is in a non-conducting state. The test resistor switches to a low resistance value only when a potential that is above the first trigger threshold is detected and the switch is closed.

The increase in reliability for the detection of a short is achieved by the hysteresis of the trigger threshold of the control transistor of the monitoring unit. During normal operation in which the switch is closed, the trigger threshold has a high value to quickly indicate the voltage drop in the event of a short circuit and to open the switch quickly. The trigger threshold has a low value for the purpose of achieving a defect free test for a short through a test resistor with a high resistance value when the switches are opened.

For example, it is ensured by using the separation unit that the short circuit in the station's supply line does not interfere with the communication between the other stations.

An advantage of the present invention is that the fault tolerance is independent of operation such as mode switching, for example, so that high reliability and consistency of the system is achieved. Another advantage is that the differential transmission remains unchanged in the case of a fault and thus the advantages of low emission level, high immunity to incoming interference, and high tolerance of ground level shift between stations are obtained. Another advantage is that the time criteria for the implementation of the data transfer protocol may not be very accurate or may be completely absent, which means that the starting point of the AC voltage is already at the time at which a reliable scanning of the bits of the data telegram is obtained. Because it provides a distinction.

Hereinafter, with reference to the drawings will be described in detail an embodiment of the present invention.

1 shows a data transfer system in which an AC voltage is generated by the generator 10 and provided to two lines 11, 12. The connected stations 13, 14 and 15 are electrically supplied by the positive half wave of the AC voltage and transmit data during the negative half wave of the AC voltage.

FIG. 2 shows the configuration of one of the stations, for example station 14, where capacitor 23 is charged via diode 21 during positive half wave from which various components of the station are controlled by the voltage controller. (25) is provided to the circuit which executes the data transfer protocol 26, the dedicated control circuit 27, and the dedicated load 28. As shown in FIG. The negative half wave can simply be amplitude modulated by the switch 24 and other diodes 22 under the control of the protocol. The amplitude of the negative half wave is obtained by comparator 29 and its differential threshold voltage is negative and is also shown in FIG.

3 shows the principle of a voltage gradient over time. Positive half wave 31 serves to power the station, and negative half wave 32 may have an amplitude modulated by switches 24 of the station. The comparator 29 of each station has a negative differential reception threshold 34, so that amplitude modulation can be obtained in a simple manner. For example, the phase of the negative half wave may represent a bit, the overall amplitude, ie half wave 32 may represent a dormant or idle state, and the reduced amplitude, ie half wave 33 may represent an active state. The active state is achieved by closing the switch 24 of one or several stations, so that simultaneous transmissions from multiple stations are made without interference, and data link layers such as Ethernet, CAN, and J1850, for example. In addition, in principle, any carrier sense multiple access (CSMA) protocol can be used. At this time, the active state represents logic bit 0 and the idle state represents logic bit 1, and vice versa.

Since individual bits are clearly distinguished at the station by the associated positive half-waves inserted, a simple protocol can be used that satisfactorily handles complete telegrams without any mechanism for synchronization and for secure scanning of a single bit, but typically Complicated and expensive An inaccurate time reference may be used for the implementation of the protocol because the circuit 26 for implementing the data transfer protocol can scan each single bit in a reliable manner, which is responsible for the phase between the two positive half-waves. Interpret one bit each time. Depending on the protocol used, the time reference may be entirely absent at the station since the cycle duration of the AC voltage may already serve as the time reference.

The AC voltage may also be square wave voltage or other, depending on the characteristics of the generator. It is also possible to make the positive half wave longer than the negative half wave for high power transmission.

4 shows the construction principle of the generator. This generator includes an AC power supply 41. Since the negative half wave is provided with a higher resistance value than the positive half wave, the switch 24 of the station 24 can be realized as a low power semiconductor switch. This is realized by series resistors 42 and 43 connected in parallel to diodes 44 and 45, so that the positive half-wave maintains a low resistance state. In this embodiment, one of the resistors having a parallel diode can be omitted, i.e. replaced by a short, so that one terminal of the generator 41 is directly connected to the leads 11 or 12. Can be connected. The generator may be, in the simplest case, an H bridge switched alternately of a semiconductor switch.

5 shows a generator using an additional transformer 46. This transformer is optional. The principle of power and the data transmission over both lines are done without a transformer. However, the transformer offers four other advantages. Firstly, two half waves are provided symmetrically, thus the interference wave is minimized. Secondly, the main voltage amplitude can be converted to the voltage required for conversion to the second voltage amplitude. Third, the AC voltage can be generated in a very simple manner from a single polarity power supply. Fourth, the AC voltage can be supplied without a ground potential, so that a short circuit of a conductor having some other potential, such as ground potential or some other supply voltage, can be accommodated.

In another embodiment of the system, the generator and the station are somewhat expanded to accommodate the blocking fault. An extended generator is shown in FIG. 6, in which a transformer 47 with a central tap is used which is connected, for example, to system ground 48. The expanded station of FIG. 7 is provided with another diode. If there is a blocking fault in the line 11, the station is routed through a current path from the system ground through the diode 51, the capacitor 23 and the paralleled load, the diode 53, and the lead 12. Half of the second voltage can still be provided from the positive half wave. Similarly, the amplitude of the negative half wave can be modified by the switch 24, i.e., through the current path of the lead 12, the diode 56, the switch 54, and the system ground to transmit data. The principle is the same for interference in the lead 12. At this time, the current path for supplying from the positive half wave passes through the diodes 21 and 52. The current path for data transmission passes through diodes 55 and 22.

This backup mode of operation occurs automatically without active switching at the station or at the generator. Typically, the desired effect of the minimized interference wave is no longer achieved due to the different characteristics of the leads and the system ground and asymmetry of the voltage gradient over time on the two lines, but the transmission is one different for the two half waves in the backup mode. Keep it. In addition, the tolerance for short faults in lines 11 and 12 is limited in systems with the extended configuration to allow for blocking faults, where other current paths through the system constitute ground, and This is because, for example, a short circuit of one of the lines 11 and 12 having ground shorts the secondary winding.

The latter disadvantage can be eliminated if the generator's short circuit protection to be realized is configured as, for example, precision fuses 49a and 49b, so that a short fault activates the fuse and thus acts as a blocking fault, It is already allowed by the provided array. In this way short-circuit defects or one or several blocking defects in one conductor may be tolerated.

In other embodiments of the system, blocking defects may be accommodated in some other way. The station is configured in the same way as in FIG. 7, but the generator is configured without a central tap in the transformer as shown in FIG. 8 and has additional switches 57 and 58 controlled through the control circuit 59. have. The control circuit 59 may alternately close the two switches when a blocking fault is detected, for example when there is a communication fault at the station until communication is reopened. This embodiment, unlike the above-mentioned embodiment, requires a positive operation to overcome the defect. However, these operations are centrally controlled once once, although the station does not need to take any action on its own. This is still an advantage over other known fault-tolerant systems, for example in this known system the operation must be carried out at all stations until the lines have been identified in a series of communication attempts that are still available and also in synchronization with others in accordance with ISO11992. do.

Another advantage of this embodiment is that the minimum short circuit fault to ground can be overcome without any measurement, since no ground connection is provided when switches 57 and 58 are open. Therefore, no precision fuse is provided in this embodiment. Short or blocking faults can be accommodated and the control circuit 59 confirms that short circuits are unlikely to occur at the same time before the switch 57 or 58 is closed, for example by voltage scanning.

Another advantage of this embodiment is that a complete voltage sweep is available at the station in the case of a blocking fault after a ground potential is applied to each correct conductor on the generator side, the above mentioned embodiment having a center tap on the transformer. Only half of the peak value is useful. Thus, it is not necessary to increase the dimensions of the power supply to anticipate certain defect conditions and to enable more effective conversion operation.

The disadvantage of increased interference in the case of a defect remains in both embodiments allowing for blocking defects. This can be eliminated through additional provision when the third lead 13 is located in parallel to the leads 11, 12 instead of the system ground, as shown in FIG. The desired effect of minimized interference radiation in the operation of the backup mode also occurs again because the operation remains very different. The use of other conductors 13 instead of system ground in one embodiment of the system can provide simultaneous tolerance of breaking faults and shorts in the conductors, since the conductors 13 also operate free from ground potential. . Short circuits between the conductors are also overcome, ie the generator provided between the conductors 11 and 13 and between the conductors 12 and 13 is protected against short circuits. The benefits of tolerances for shorts in conductors with ground or other supply potentials and tolerances for shorts between one or several blocking faults in one conductor are also obtained in other embodiments of the system. Short circuits between the conducting wires 11 and 13 or between the conducting wires 12 and 13 are similarly permitted in this embodiment.

The minimum cost embodiment of the invention shown in FIG. 10 is provided in contrast to the embodiment of the invention mentioned above which allows for defects. The transmission of power and data is done with only one conductor and only one conductor, e.g. conductor 11, is installed since no additional connection to the system ground and fault tolerance are required in a system that can accommodate increased interference. This is very cheap. Another lead, such as lead 12, is replaced by system ground. In this embodiment also resistors and diodes may be provided for the generator.

Thus, the present invention can be optimally used for certain applications in terms of cost reductions achievable and the tolerances required for defects. If at least several stations are maintained to be able to operate in these embodiments, for example in a simple circuit configuration according to Figs. 1 to 5 and 10, then the separation units can be inserted into at least one conductor as seen in the generator. The shorted part at the back of the separation unit can be automatically disconnected and can be automatically connected after the short is removed.

In FIG. 11, the separation units for disconnecting the entire system block (separation unit 17) block only the lines 11, 12 for the stations 14, 15, 16 and this station (separation unit 18). The system provided on the supply line to the station is shown. Reference numeral 11a denotes a lead portion disconnected with all stations connected to the lead portion from behind the separation unit and from the rest of the system in case of a short circuit or overload as can be seen on the generator 10 side. Indicates. In FIG. 11 the lines 11 and 12 are connected in a ring arrangement and are returned back to the generator 10. Another separation unit (not shown) is provided in this ring so that at least one station is provided between two separation units each time. If a short circuit occurs in the lead section between two separate units, only the stations in the lead section are disconnected and the rest of the system remains fully operational.

12 is a block diagram showing a separation unit 17 connected to the line 11. This separation unit 17 comprises a switch 60, a test resistor 63, and monitoring units 61, 68, which are connected in series with the monitoring unit 68 and control. The input 65 and the uninterrupted line 12 are connected. The potential of the lead portion 11a of the switch 60 is tested at the output side by the test line 62 of the monitoring unit 61, and the potential of the lead portion 11 is switched by the test line of the monitoring unit 68. Tested at the input of 60. The test resistor 63 is controlled via the control input 64 of the monitoring units 61, 68.

FIG. 13 shows a circuit arrangement for realizing the separation unit according to FIG. 12. The device comprises p-channel power transistors 71, 72 and resistors 73, 74, as well as capacitor 70 and diode 75 of switch 60, and n-channel control transistor 80 of supervisory unit 61. And a resistor (81). The capacitor 70 is arranged between the connection point of the two sources of the power transistors 71 and 72 of the switch 60 and the connection point of the interconnected gate of the power transistors 71 and 72. The test resistor 63 serving as a current limiting element for shunting the switch 60 is not controlled in this example and thus has only a simple resistor 90.

At this time, only the scanning of the line 11a on the output side of the switch 60 is performed by one monitoring unit 61. The test line 62 of the monitoring unit 61 for triggering the control transistor 80 scans the potential of the line 11a on the output side of the switch 60 via a resistor 81. The switch 60 is included in the line 11 and the gates of the two power transistors 71 and 72 are connected to the control input 65 via a voltage divider including resistors 73 and 74. The capacitor 70 is charged through the resistor 74 and the diode 75 only when a potential lower than that of the line 11 is applied to the control input 65, in which case the power transistor 71, 72 is in a conductive state. During the negative half wave of the AC voltage, when the potential of the line 11 is lower than the potential of the line 12, the diode 75 prevents reverse charging of the capacitor 70, and consequently the power transistor 71, The voltage necessary to close 72 is maintained. The discharge of the capacitor 70 through the resistor 73 must be adjusted so that no excessive change occurs in the state of charge of the capacitor 70 during the negative half wave.

The potential of the line 11 on the input side of the switch 60 is at the output side of the switch 60 and on the line portion 11a via the test resistor 63 when the power transistors 71, 72 are opened. Delivered. This potential is scanned by the test line 62 and provided to the gate of the control transistor 80 through the control input of the monitoring unit 61 and the resistor 81. When the potential of the test line 62 exceeds the first trigger threshold, the control transistor 80 of the monitoring unit 61 is closed. The monitoring unit provides the potential of the line 12 to the control input 65 of the switch 60, so that the power transistors 71, 72 are closed by the voltage drop across the resistor 73. . Unblocked normal operation of the separation unit is performed in this manner.

If there is a short circuit or overload between the lines 11a and 12 on the output side of the separation unit, the potential delivered to the line portion 11a via the test resistor 63 is the test input 62 of the monitoring unit 61. It becomes smaller than the trigger threshold required to close the control transistor 80 on the side), and the control transistor 80 of the monitoring unit 61 is in a non-conductive state. As a result, the control input 65 cannot be connected to the potential of the line 12, and the voltage required to close the power transistors 71 and 72 cannot be set, so that the power transistors 71 and 72 can be set. Is in a non-conducting state and the switch 60 is in an open state. Thus, the supply generator 10 (FIG. 1) and all stations which are not connected to the line portion 11a are separated from the short circuit.

A test state is created through the connection of the test resistor 63. Once the short or overload is eliminated, the potential can re-form across the test resistor to exceed the trigger threshold, so that the control transistors 80, 80a reconnect the potential of the line 12 throughout The power transistors 71 and 72 are in a conductive state and the switch 60 is closed, so that normal operation is automatically restored.

The circuit arrangement of FIG. 13 recognizes a direct short, a short through the resistor, and a short of the diode being activated in the positive half wave, but a short of the diode being activated in the negative half wave, i. The short circuit of the diode connected to the transmission line 11 cannot be recognized. An embodiment for this case will be described.

14 shows one embodiment of a separation unit in which a switch 60 is included in a transmission line 12 having a low potential during a positive half wave. In this embodiment, only one scanning of the transmission line 12a on the output side of the switch 20 is shown. The test resistor 23 is also not controllable in this embodiment and includes only a single resistor 50.

The n-channel power transistors 71 and 72 of the switch 60 are in a conductive state only when a potential higher than that of the transmission line 12 is applied to the control input 65 side. The monitoring unit 21 is provided with a p-channel control transistor 80, by which the potential of the transmission line 11 is transferred to the control input 65 side. This direct connection is achieved in accordance with the potential of the line portion 12a scanned by the test line 62 on the output side of the switch 60. During switching on, the potential of the transmission line 12 on the input side of the switch 60 is transferred to the output side of the switch 60 through the test resistor 63 when the power transistors 71, 72 are in a non-conductive state. This potential is scanned into the test line 62 and transferred to the control input side of the control transistor 80 of the monitoring unit 61. The control transistor 80 is closed when the potential exceeds the trigger threshold. Therefore, the control input 65 side of the switch 60 is connected to the potential of the transmission line 11, which causes the power transistors 71 and 72 to be in a conductive state, thereby starting the normal operation of the separation unit. . If a short circuit or overload occurs between the transmission lines 11 and 12, the potential on the line portion 12a side does not reach the value of the trigger threshold required to close the control transistor 80, and the control transistor 80 It remains nonconductive. Therefore, the control input 65 is no longer connected to the potential of the transmission line 11, and the voltage necessary to close the power transistors 71 and 72 cannot be set. The generator 10 (FIG. 1) is separated from the short in this manner. The test state is performed through the test resistor 63. If a short circuit occurs during operation, the potential on the line portion 12a side is lowered below the trigger threshold, the control transistor 80 is in a non-conductive state, and the switch 60 blocks the line 12. When the short between the lines 11 and 12a is eliminated again, the line portion 12a at the output of the switch 60 and at the test line 62 of the monitoring unit 61 is controlled by the control transistor of the monitoring unit 61. The value above the threshold for closing 80 can be taken again and the normal operation can be automatically restored.

The arrangement of FIG. 14 also does not recognize shorts with diodes that are active in the negative halfwaves of the AC voltage.

The separation unit shown in FIGS. 13 and 14 may be used to allow a short circuit occurring in the negative half wave of the AC voltage in a similar manner. In this case, the separation unit of FIG. 13 must be included in the line 12 because the latter has a higher potential during the negative half wave, and the separation unit of FIG. 14 must be included in the line 11 This is because it has a lower potential during negative halfwaves. Short circuits with diodes active in positive half-waves are not allowed in these embodiments.

13 and 14 provide only one scanning at the output of switch 60, respectively. However, the circuit may be supplemented with a monitoring unit 68 for scanning also at the input of the switch 60 of FIG. 12. The monitoring unit must in this case be connected in series.

15 shows an embodiment in which the potential of the line 11 is higher than the potential of the line 12 during the positive half wave and the potential of the line 11 is lower than the potential of the line 12 during the negative half wave. The circuit of FIG. 14 is the starting point of the circuit of FIG. 15 where n-channel transistors 71 and 72 are also used for switch 60. This switch 60 includes a capacitor 70 and a diode 75 for storing the electric charges necessary for the conduction state of the power transistors 71 and 72 during the positive half wave. The control transistor 80 of the monitoring unit 61 is a p-channel transistor as shown in FIG. 14.

If there are no elements 801-808 in the monitoring unit 61, only a short in negative half wave is recognized because the control transistor 80 must be triggered with a negative gate-source voltage for conduction. In order to provide the monitoring unit 61 which is also suitable for short circuits operating only in the positive half wave, the monitoring unit 61 is provided with the switches 801, 803, 804, transistors () during the positive half wave to control the switch 60. 802, 806, 807, a capacitor 805, and a diode having a diode 808 connected to the transmission line 11 and a cathode connected to the transmission line 12 for recognizing a short circuit condition through the diode. Extended with circuitry. When the power transistors 71 and 72 are conductive, the capacitor 805 is positive during the positive half wave through the current path, i.e., resistor 807 → diode 808 → resistor 806 → switch 804. Is filled with a value. Discharge during the negative half wave is prevented by the diode 808. Thus, the capacitor 805 holds the voltage at which the switches 803 and 804 are closed. If a discharge is made through the resistor 806 during the negative half wave, dimensioning is made such that the capacitor 805 can discharge only a small amount during a single cycle period, and charging through the resistor 807 may be done during the positive half wave. . When switches 803 and 804 are closed in succession, the switch 801 is always in the open state, so the control transistor 80 typically operates during negative half wave in a manner similar to that of the circuit of FIG.

When the voltage of the line 11 is lower than the voltage of the transmission line 12 during the negative half wave, the p-channel transistor 80 receives the negative gate-source voltage and thus becomes conductive. In this state, the capacitor 70 of the switch 60 passes through a current path, i.e., a switch 80 → a diode 75 → a resistor 74 → a resistor 73 → a diode of the power transistors 72, 71. Can be charged. Thus, a positive gate-source voltage rises for the power transistors 71 and 72, which cause them to conduct and the switch 60 is closed. When the capacitor 70 is discharged through the resistor 73, dimensioning is performed such that the voltage across the capacitor 70 can only change slightly over a cycle period. The capacitor 70 is charged through the resistor 74 in a period of negative half wave.

Short circuits that provide the same result during two half-waves are direct (low resistance) short circuits and short circuits through the resistor between the transmission line 11 and the transmission line 12, the resistance being dependent on the dimensions of the separation circuit. do. If a direct short or a short through the resistor is made at the output side of the separation circuit between the transmission line 11 and the transmission line 12, the control transistor 80 which is normally closed during the negative half wave is opened. The control transistor 80 is always open during positive half wave. As a result, the control input 65 is no longer connected to the voltage of the transmission line 12, and the capacitor 70 is discharged through the resistor 73. Accordingly, the positive gate-source voltage of the power transistors 71 and 72 is not formed, which causes the power transistors 71 and 72 to be in a non-conductive state. As such, the generator 10 is disconnected from a short and the test state is established with a connection through the test resistor 63. The part of the circuit having the switches 803, 804 and 801 leads to this situation in a direct short.

A diode having an anode connected to the line 12 having a high potential during the negative half wave, that is, a cathode connected to the line portion 11a having a low potential during the negative half wave. Short circuits through only have the same situation as in the case described above, in which the control transistor 80 remains inactive during the negative half wave because of the short circuit and the control transistor 80 is always inactive during the positive half wave. This is because it is in a conductive state. The capacitor 805 has an anode connected to the line 11 having a high potential only in the positive half wave, i.e., during the positive half wave, and to the line 12 having a low potential during the positive half wave. It is not charged when done via a diode having a cathode connected to it. The capacitor 805 is discharged through the resistor 806, and the switches 803 and 804 remain open at all times. During the positive half wave, the control transistor 80 and the switch 801 remain open or non-conductive at all times. Upon transition to a negative half wave, the switch 801 is EKE, so that the control transistor 80 is provided with a gate-source voltage below a switching on threshold, which causes the transistor 80 to transmit the negative half wave. Maintain non-conduction state while Thus, the control input 65 is no longer connected to the potential of the line 12 and the capacitor 70 is discharged through the resistor 73. The power transistors 71 and 72 are non-conducting and the switch 60 is open. As such, the generator 10 (FIG. 1) is separated from the short circuit and the test state is obtained by a single connection through the test resistor 63. If a short is made during operation, the monitoring unit 61 detects a short between the line 11 and the line 12 in the manner described above, and the power transistors 71 and 72 of the switch 60 Closed at high speed When the short circuit between the lines 11a and 12 is removed again, the potential at the output side of the switch 60 may again take value in the test line 62 of the monitoring unit 61 through the test resistor 63, The control transistor 80 is inverted here, and normal operation is automatically returned.

The arrangement of the switch 60 on the line 11, which has a lower potential than the line 12 only during the negative half wave, ensures that any short circuit occurring during the negative half wave is detected by the control transistor 80 of the monitoring unit 61. It means. Additional circuitry with switches 804 and 803 in the monitoring unit 61 also detects the short circuit occurring in the positive half wave.

In contrast to the arrangement shown in Fig. 15, when the switch 60 with n-channel transistors is arranged on the line 12 having low potential only during the positive half wave, the monitoring unit 61 is p-channel. While indicating the connection with the line 11 through the control transistor 80, the control transistor 80 of the monitoring unit 61 detects all short circuits occurring during the positive half wave. Additional circuitry with switches 804, 803, and 801 of the monitoring unit 61 recognizes other shorts that may occur in negative half-waves.

Another similar embodiment may be provided based on the principle of the circuit arrangement of FIG. The switch 60 includes a p-channel transistor on the line 11, and the control transistor 80 is an n-channel transistor. The switch 60 of the line 11 has a high potential only during the positive half wave, and any short circuit occurring during the positive half wave is connected to the control transistor 80 of the monitoring unit 61 which forms a connection with the line 12. Is detected immediately. Additional circuitry with switches 804, 803, and 801 in the monitoring unit 61 detects other shorts that may occur in negative half-waves. The switches 71, 72, 704 and 803 are configured as p-channel transistors, and the switches 80 and 801 are configured as n-channel transistors.

If a switch 60 having two p-channel transistors is included in the line 12 having a high potential only during the negative half wave, then any short circuit occurring during the negative half wave will form a connection with the line 11. It is detected by the control transistor 80 of the unit 61. Additional circuitry with switches 804, 803 and 801 in the monitoring unit 61 detects other short circuits that may occur in the positive half wave. The switches 71, 72, 804 and 803 are configured as n-channel transistors, and the switches 80 and 801 are configured as p-channel transistors.

The embodiment just described recognizes all three of these types of shorts without error, and the resistance value, which is regarded as a short circuit in the case of a short circuit through the resistor, depends on the value of the test resistor 90 and the current flowing during normal operation. .

Another possibility of detecting a short at the AC voltage and controlling the power transistor is to provide one separation unit for the negative half wave and one separation unit for the positive half wave. For the positive half wave, when the potential of the lead 11 is higher than the potential of the lead 12, the switch 60 according to FIG. 13 is provided to the lead 11 or to the lead 12 according to FIG. . When the potential of the conducting wire 11 is lower than the potential of the conducting wire 12 during the negative half wave, the switch 60 according to FIG. 13 is provided to the conducting wire 12 or the switch 60 according to FIG. 14 is connected to the conducting wire 12. Or on the conductor 11 according to FIG. Since each separation unit must be functionally connected in series, the data and power of the generator 1 can only be connected until each separation unit detects no short circuit. This arrangement requires a fairly large number of power transistors and is significantly different from the arrangement of FIG.

FIG. 16 shows an embodiment in which the switch 20 is included in the line 12 according to the basic arrangement of FIG. 14. The monitoring unit 61 directly detects all short circuits occurring during the positive half wave with the control transistor 80 and detects further short circuits occurring during the negative half wave with the switches 801, 803, and 804. Hysteresis is provided for the trigger threshold of the control transistor 80 to improve detection reliability for shorts during positive half-waves. A high trigger threshold is obtained during normal operation of the disconnect unit in the closed switch 60 to open the switch 60 at high speed for the purpose of preventing overload of the generator 10 (FIG. 10), and at the output of the disconnect unit When this falls, the voltage is scanned into the test line 62 through the resistor 81 during the positive half wave. However, when the switch 60 is opened, a low trigger threshold is obtained so that an error test for shorts during positive half-waves can be made through a high resistance test resistor 63, in which the station's normal load at other stations simulates a short. Can't rate

This hysteresis is obtained by the switches 813 and 814 and the control diode 811. When the control transistor 80 is conducting for a positive half wave, the switch 60 is also closed. This information is used to hold the switch 814, that is, the capacitor 817 charges itself through the control transistor 80, the diode 819 and the resistor 818 during the positive half wave. This charging condition is maintained for the negative half wave since it is set so low that the change of the charging condition is difficult. The switch 813 remains open by the closed switch 814, so the zener diode 811 determines the trigger threshold for switching of the control transistor 80. The adjustment of the trigger threshold must protect the switch 60 and the closing of the capacitors 70 and 817 for a positive half wave that can be sufficiently charged in the hysteresis definition circuit of the supervisory circuit 61. If the control transistor 80 is in a non-conducting state during the positive half wave, the switch 60 is also opened and there is only a connection between the input / output of the switch 60 via the test resistor 63. This information is used to adjust the trigger threshold for the control transistor 80 to a low voltage value during low voltage, that is, capacitor 817 is discharged through resistor 816 and opened through switch 814. This causes the zener diode to form a shunt because the switch 813 is closed during the positive half wave.

In order to improve isolation characteristics in the transmission of power and / or data by the switch 60, the test resistor 63 should not have very small resistance values. A conflicting requirement is that there must be a minimum voltage level at the output side of the switch to ensure that it is normal, i.e. no short circuit. In the case of a large load, ie a low load resistance after the switch, the test resistor should be chosen with the corresponding low resistance. In the above-described system, which transfers power during the positive half wave, and therefore has a low resistive load, and transmits data during the negative half wave, and thus a high resistive load is provided, the test resistor 63 according to the situation. There is a possibility to adjust the value of). For this purpose, the state of the line 12a on the output side of the switch is scanned into the switch 82 of the monitoring unit 61 through the resistor 43 and the test line 62 during the negative half wave. If the negative half wave can be formed normally, the switch 82 is closed and the shunt capacitor 904 in the control unit 91 of the test resistor 63 is charged via the control line 64. The state of charge is maintained during the positive half wave, and the switches with transistors 906 and 907 in the control unit 91 are kept in a continuously closed state, so that the parallel resistor 903 of the resistor unit 90 forms a shunt. Thus, a portion of the low resistance value of the test resistor 63 is provided with partial resistors 901 and 902 that are active between the input and the output of the separation unit. In the case where a negative wave cannot be formed, that is, when the lead 11 and the lead 12a are shorted, the switch 82 is not closed, and then to the control unit 91 of the test resistor 63. The switch with transistors 906 and 907 cannot also be closed, so that the partial resistor 903 is not shunted. Accordingly, the sum of the partial resistance values 901, 902, 903 of the test resistor 63 that is active between the input and the output of the switch is provided.

The two-stage switching on of the separation unit is achieved by the arrangement, that is, a short circuit test can be done first with a high resistance test resistor 63 during the negative half wave. Direct shorts, shorts through low resistance resistors, and shorts through diodes where the anode is connected to line 12 and the cathode is connected to line 11 are recognized. Only in the absence of such a short circuit, the switch is made of a low resistance test resistor, which detects a short circuit via a diode whose anode is connected to the conductor 11 and the cathode is connected to the conductor 12 during a positive half wave. Can be. When the switch 60 is opened, there is a high resistance connection between the input and output of the switch 60 during the positive half wave through the test resistor 63, i.e. satisfactory separation of the system in operation from the shorted part of the system. do. The sum of the partial resistance values 901, 902, 903 of the test resistor 63 is dimensioned such that a sufficiently strong signal can occur at the output side of the switch 60 during the negative half wave of the high resistance, thus normal operation and any that may be present. Short circuits can also be clearly distinguished. Similarly, the sum of the resistance values 901,902 should have a value that allows the short circuit to be clearly distinguished from normal operation during the positive half wave.

In these embodiments, n-channel transistors and p-channel transistors have been used in the monitoring unit 61 to detect short circuits and switch the control input of the switch 60. The use of such transistors constitutes one possible embodiment, in which a short circuit can be recognized in a simple and reliable manner. Another possibility is formed, for example, by the use of components similar to voltage comparators. The switch may also consist of a bipolar transistor.

Claims (28)

A method for transmitting data and power over at least two stations for data transmission and at least two conductors to which one power source for powering the station is connected, the method comprising: A two-pole AC voltage is transmitted on the wire, a pulse having one polarity of the AC voltage is used for power transmission only, and a pulse having a different polarity is used for data transmission only. The method of claim 1, wherein the pulse having one polarity of the AC voltage is supplied in a low resistance manner, and the pulse having the other polarity is supplied to the lead in a high resistance manner. 3. The method of claim 2, wherein for transmitting data by the station, the pulses of the AC voltage having the different polarity are modified at the station in accordance with the data to be transmitted. A system having at least two stations interconnected by at least two conductors for data and power transmission, and having a power source connected to the conductor, The power supply is designed to transmit a two-pole AC voltage having pulses of the first and second polarities to the lead wires, and means for absorbing and storing power only from the pulses having the first polarity, respectively, without power supply A correction means connected to the lead of each of the stations provided for transmission of data, the correction means having the second polarity according to the data to be transmitted. A detector for modifying only the pulses of the AC voltage and finding only the amplitudes of the pulses having different polarities is connected to the leads of each of the stations provided for the reception of data. 5. The system of claim 4, wherein the power source is designed to transmit a pulse of an AC voltage having the first polarity to the lead with a lower resistance value than a pulse having the other polarity. 6. The system of claim 5, wherein the power source is connected to the lead via at least one resistor in which rectifiers are connected in parallel. 7. The power supply according to any of claims 4 to 6, wherein the power supply comprises an AC voltage generator and a transformer having a main winding and an auxiliary winding, wherein the main winding is connected to the generator and the auxiliary winding is The system is connected to the said lead wire. 8. A system according to any one of claims 4 to 7, wherein a third lead is provided to the power source and to the station. The system according to claim 7 or 8, wherein the auxiliary winding has a central connection portion connected to the third lead. 9. A switch according to claim 7 and 8, wherein two switches and a control unit are preferably provided to the power source, wherein the switch is between the first lead and the third lead and between the second lead and the third lead. And arranged respectively between the conductors, wherein the control unit closes the associated switch when the first conductor or the second conductor is interrupted. The system according to any one of claims 5 to 10, wherein one of the conductors is formed by a ground connection. 5. A switch according to claim 4, wherein a separation unit is included in at least one conductor, each separation unit separating the associated conductor into first and second lead portions and connected to the lead portion, and at least one And a monitoring unit connected to the lead portion and configured to operate the switch when the voltage of at least one lead portion of the connected lead portion rises above the first trigger threshold or falls below the second trigger threshold. The switch is shorted by a current limiting element. 13. A station for a system as claimed in any of claims 4 to 12, having a connection terminal for receiving power and for receiving and / or transmitting data for operating a circuit of the station, Voltage supply means for deriving power from a pulse having only a first polarity from the lead and storing this power, Correction means for correcting only pulses having a second polarity on the lead according to the data to be transmitted; And a detector for obtaining only the amplitude of the second polarity is connected to the conducting wire. The energy storage device of claim 13, wherein the means comprises a rectification arrangement and an energy storage device, wherein the rectification arrangement supplies power to the energy storage device only during a pulse of a first polarity, the energy storage device having an electron at the station. And a station connected to the voltage supply terminal of the circuit. 14. A station as claimed in claim 13 for the system as claimed in claim 8, wherein the voltage supply means has a series arrangement of a first rectifier, an energy storage device and a second rectifier, the arrangement being the first arrangement. A station connected between the lead and the second lead, wherein the two connecting terminals of the energy storage device are connected to the third lead via another rectifier. 14. A station as claimed in claim 13 for the system claimed in claim 8, wherein the modifying means comprises a series arrangement of a first rectifier, a switchable impedance, and a second rectifier, the impedance and the first and A connection point between the second rectifiers is respectively connected to the third lead via each other rectifier. In the separation unit for the system claimed in claim 12, The switch controlled by the monitoring unit connects the lead separated by the switch when the voltage exceeds the first trigger threshold and disconnects the lead when the voltage falls below the second trigger threshold. Separation unit characterized by. 18. The separation unit according to claim 17, wherein the monitoring unit is connected to two conductive wire portions. 19. The separation unit of claim 17 or 18, wherein the switch is configured for current flow in both directions. 20. The switch according to any one of claims 17 to 19, wherein the switch has first and second field effect transistors of the same conduction type connected in series between the two conductor portions, the gates of which are interconnected. And is connected to the monitoring unit. 21. The device of claim 20, wherein the gates of the first and second field effect transistors are connected to junctions of the first and second field effect transistors through capacitors and discharge elements connected in parallel thereto, and through the diodes. The separation unit is connected to the third field effect transistor. 22. The isolation unit of claim 21, wherein the capacitor of the switch stores the charge required to close the first and second field effect transistors at half a wave of the AC voltage opposite the trigger threshold. 23. The device according to any one of claims 20 to 22, wherein the monitoring unit includes a third field effect transistor for each of the connected conductor portions, which transistor comprises the non-divided conductor and the first and second field effects. Connected between the gates of the transistors, the gates of which are connected to the connected lead portions, so that the connection of the monitoring unit to the two lead portions creates a series connection of the connected third field effect transistors. Separation unit, characterized in that. 24. The method of claim 22 or 23, wherein the conductivity type of the first and second field effect transistors is opposite to the conductivity type of the third field effect transistor, and the conductivity type of the field effect transistors is the trigger threshold of the monitoring unit. Separating unit according to which half of the AC voltage is placed. 25. The circuit according to any one of claims 22 to 24, wherein the monitoring unit is provided with an additional circuit portion for bringing the third field effect transistor into a non-conducting state when the half wave overload is not monitored by the trigger threshold. Separation unit, characterized in that. 18. The separation unit of claim 17, wherein the trigger threshold of the monitoring unit has hysteresis, the trigger threshold being high when the switch is closed and the trigger threshold being low when the switch is open. 18. The isolation unit of claim 17, wherein the current limiting element includes a test resistor that can be switched between a high resistance state and a low resistance state. 28. The separation unit of claim 27, wherein the high resistance test resistor is active when the switch of the lead is opened and the test resistor has a low resistance value due to a short circuit of the partial resistor when the switch is closed.