RU2474958C1 - Method to couple devices of information transceiving along combined double-wire communication line and dc supply and device for its realisation - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: in the method to couple devices of information transceiving along a combined double-wire communication and DC supply line based on realisation of information transceiving by the method of analogue modulation, a low-frequency carrier is modulated in a device transmitter by an information digital signal, the produced radio signal is summed with supply voltage and sent along a combined communication and DC supply line, an information radio signal is identified in a receiver from total voltage on the line, the initial digital information signal is recovered in the device receiver, with the help of the device controller, the signal is decoded from the receiver, and the responsive information signal is generated for the transmitter. At the same time, an uncoupler between a transceiver of each device and a line is a rejection filter, providing for matching of impedances of device receiver and transmitter and wave resistance of the combined communication and DC supply line and made on the basis of the oscillating circuit with partial inclusion into the combined communication and DC supply line, where the received radio signal is identified from the total voltage of the line during reception, a permanent component of device supply voltage is identified, and the transmission radio signals are summed up with the voltage on the line.

EFFECT: reduced level of electromagnetic noise developed by devices, lower sensitivity to external noise, increased speed of transmitted information, makes it possible to increase the number of devices simultaneously connected to a line, increased length of a line permitted for operation, simplified circuit realisation of an information transceiving device and considerable reduction of economic inputs for its production.

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Description

The invention relates to the field of information exchange over wire lines and can be used for lines up to 1000 m or more in length and is intended primarily for constructing systems for collecting and processing information, monitoring, remote control, telemetry, security systems and information protection systems.

A known method of the system for duplex transmission of information on a combined power line, in which the information is transmitted in the form of pulses, in which the transmitted signals are encoded by the encoder, the amplitude and shape of the signals distorted by the communication line, restore the amplitude-frequency correction device. Power from the central device is supplied to the remote device via the communication line (Patent No. 2381627, IPC H04L 5/14, Н04В 1/56, publ. 02/10/2010).

The known method of transmission requires precise coordination of the parameters of the line and the receiving and transmitting devices to prevent distortion of the information signal. These conditions are difficult to achieve in power circuits with a variable number of connected devices and dynamic current consumption.

A known method of transmitting information on a power line by transmitting and receiving data through modulation and demodulation of higher frequency oscillations (carrier) superimposed on the supply voltage in the line. In accordance with the known method, the frequency band is divided into N subbands, where N is an integer greater than two or equal to two; apply the OFDM (orthogonal frequency division multiplexing) technique on each of these subbands; and performing calculation operations on each of the subbands. The known method is characterized in that the calculations based on each of the subbands are independent of the calculations based on other subbands, and these subbands are activated and assigned in a dynamic manner (RF Patent No. 2398351, IPC Н04В 3/54, published on 08.27.2010 .).

The disadvantage of this method is the difficulty of implementing the device at the software and hardware level, the relatively low transmission speed.

A device is known for receiving and transmitting information on a DC power line, containing bi-directional blocks for decoupling digital signals and a supply voltage in a combined power line and for exchanging information installed in controllers — in components of an on-board monitoring, protection and / or machine control system. Each of the isolation blocks contains a power switch and a diode-capacitor circuit or inductor, connected in series to the DC power line. Digital signals are transmitted in the device by modulating the voltage in a combined power line and exchanging information (RF Patent No. 2276094, IPC В66С 13/18, published on 05/10/2006).

Closest to the proposed one is a device for receiving and transmitting information through a DC power line, which contains bi-directional blocks for decoupling digital signals and supply voltage, containing transformers, the first windings of which are connected in series to the DC power line, and the second are connected to the receiving devices and transmission of digital signals, configured to interlock their operation. A digital signal receiving device comprises, in particular, an amplifier, a rectifier or a demodulator, a filter and a threshold device connected in series, and a transmission device — a controlled pulse generator (RF Patent No. 2404509, IPC Н04В 3/54, publ. November 20, 2010).

A disadvantage of the known devices is the significant loss of the information radio signal, and therefore, high energy costs for transmitting information, high levels of electromagnetic interference emitted by the line and the influence of external interference on the useful signal in the line, technical complexity and high economic costs in implementation.

The technical problem to which the claimed invention is directed is to reduce the level of electromagnetic interference generated by devices, reduce sensitivity to external interference, increase the speed of transmitted information.

The stated technical problem is solved by the fact that, according to the proposed invention, in a method for pairing information transmission and reception devices via a combined two-wire communication line and DC power, based on the implementation of information reception and transmission by the method of analog modulation, the low-frequency carrier is modulated in the transmitter of the device by an information digital signal summarize the received radio signal with a supply voltage and transmit along a combined communication line and DC power, isolated in the receiver the radio frequency information signal from the total voltage on the line, the original digital information signal is restored in the device receiver, the signal from the receiver is decoded using the device controller and a response information signal is generated for the transmitter, and a blocking filter is used as a decoupling between the transceiver of each device and the line the impedances of the receiver and transmitter of the device and the wave impedance of the combined communication line and DC power and space filled on the basis of the oscillation circuit with partial inclusion in a combined link and a DC power supply which was isolated from the total received radio signal on the line voltage when the reception device emit a DC component voltage and sum voltage of a radio transmission line.

The stated technical problem is also solved by the fact that, according to the proposed invention, a device for receiving and transmitting information on a combined two-wire communication line and DC power supply includes a receiver including an input amplifier, a detector and a digital sequence regenerator, a transmitter including a modulator and an output amplifier-shaper , a device controller that performs decoding of the incoming information and the formation of a response information signal, a blocking filter made on ba e oscillating circuit with partial inclusion in the combined two-wire link and the DC supply for interfacing the receiver unit and transmitter line and filtering a DC voltage from the power line to all parts of the device.

The inventive device is characterized by additional significant features:

- the blocking filter is made using a transformer with a given coupling coefficient, the secondary winding of which with a parallel connected capacitance form a resonant oscillatory circuit;

- the inductive part of the oscillating circuit in the blocking filter is made in the form of a coil with a tap or as an inductive divider;

- the receiver of the device contains an input amplifier and a detector, combined by a negative feedback circuit, which provides a decrease in the gain of the input amplifier with increasing voltage at the detector to ensure a constant amplitude of the signal from the detector when the level of the radio signal coming from the trap filter to the input of the receiver changes over a wide range;

- the digital sequence regenerator contains a comparator covered by a positive feedback loop, the inverting input of which is galvanically connected to the detector, and the non-inverting input is connected to the detector through a time delay circuit, while the comparator operating and releasing thresholds are determined in accordance with the dynamics of changes in the amplitude of the signal coming from the detector and the depth of positive feedback spanning the comparator;

- the device includes a power source for the combined two-wire communication line and power, connected to the input of the barrage filter connecting the device with the combined two-wire communication line and DC power.

The technical result, the achievement of which is ensured by the implementation of the claimed combination of essential features, consists in reducing the level of electromagnetic interference generated by devices, reducing sensitivity to external interference, reducing the loss of information signal on the line, increasing the speed of transmitted information.

By achieving the specified technical result, it becomes possible to increase the number of devices simultaneously connected to the line, to increase the length of the line that is acceptable for operation. In addition, the proposed invention allows to simplify the circuitry implementation of a device for receiving and transmitting information and significantly reduce the economic costs of its production.

The invention is illustrated by drawings, where figure 1 shows an example of a functional diagram of a system that implements the inventive method of pairing, including at least two proposed device for receiving and transmitting information and a power source for the line;

figure 2 shows an example of a functional diagram of a device that implements the proposed method of pairing and provides high-speed information exchange through a combined two-wire communication line and DC power;

on figa), b) and c) presents examples of circuits for the blocking filter, where

on figa) presents an example of a blocking filter based on a transformer, the secondary winding of which with a capacitor form an oscillating circuit,

on figb) presents an example of a blocking filter, the composition of the oscillatory circuit of which includes an inductive divider;

on figv) presents an example of a blocking filter circuit with an oscillatory circuit, in the inductive part of which is used a coil with a tap (autotransformer circuit);

figure 4 presents the functional diagram of the transmitter of the device;

figure 5 presents the functional diagram of the receiver of the device;

figure 6 presents a diagram of a digital sequence regenerator (RPC) that implements the function of restoring the parameters of the original modulating information signal.

Presented on the drawings, figures 1-6 contain the following positions:

1 - two-wire combined communication line and DC power

2 - power supply line with a barrier filter between its output and the line

3, 4 ... N - information transmitting and receiving devices connected in parallel to the line

5 - blocking filter based on the oscillatory circuit of the device for receiving and transmitting information

6 - receiver device information transmission

7 - transmitter of a device for transmitting information

8 - controller device transmitting information

9 - power supply source or stabilizer information reception and transmission device

10 - capacitor of the oscillatory circuit (CK)

11 - shunt filter capacitor (SF)

12 - inductor of an oscillatory circuit (Lк)

13 - communication transformer (Tr)

14 - modulator

15 - output amplifier

16 - the blocking filter between the line and the device of reception and transmission

17 - input amplifier

18 - detector / demodulator of the input modulated signal

19 - digital sequence regenerator

20 - time delay circuit

21 - comparator

Elin - total voltage on the line

Epit - supply voltage of the device nodes

Fmod - information signal transmitted by analog modulation method (a radio signal containing transmitted information)

Fnes - carrier frequency signal

Rx - received digital information signal

Tx - transmitted digital information signal

The invention is based on the physical property of a two-wire line to transmit a low-frequency radio signal into hundreds of kilohertz with low energy losses on the active resistance of the conductors, on radiation and dielectric absorption in isolation, while the line is proposed to be used simultaneously for transmitting information signals by analog modulation and powering two and more devices.

Figure 1 shows an example of a functional diagram of a system that implements the inventive method of pairing, including at least two proposed device for receiving and transmitting information 3, 4 and a power source 2 of a two-wire communication line 1 and DC power.

The inventive method of pairing devices for transmitting / receiving information using the combined method of analog modulation is that a low-frequency carrier of hundreds of kilohertz is modulated by an information digital signal in the device’s transmitter, the received radio signal is summed with the supply voltage and transmitted over the combined communication line and direct current power, allocated to the input of the receiver information radio signal from the total voltage on the line, restore the original digital information signal in the receiver of the device, decode using the device controller the signal from the receiver and generate a response information signal for the transmitter. In this case, as a decoupling between the transceiver of each device and the line, a blocking filter is used, which each device connected to the line is equipped with. Using the trap filter, the transmitted radio signal is added with a constant component of the supply voltage on the line during data transmission, the received radio signal is extracted when receiving for further processing and decoding of digital information, the device’s supply voltage is filtered, and the impedances of the receiver and transmitter of the device and the impedance matching are matched communication lines and DC power, which provides a significant reduction in the mutual influence of chennyh devices to the line distortion of the transmitted radio signal information, signal external electromagnetic interference and line noise arising from the operation of the devices, reducing the energy costs and the loss of useful transmission of the information signal on the line.

The proposed method of pairing the transmit-receive devices to the line allows implementing any topological configuration of the system, for example, a ring, a star or a tree.

As a power source 2 can be used any source of constant voltage with the required load capacity, supplemented by the output of a blocking filter. Also, the power source can be included in any device for receiving and transmitting information (in Fig.2, the ability to provide power to the line is indicated by a dotted arrow). At the same time, there is no need to use a separate power supply for the line.

A device for transmitting information on a DC power line (Fig. 2), in which the proposed method is implemented, comprises a blocking filter 5 connected to a combined two-wire communication and power line 1, receiver 6, transmitter 7, device controller 8, voltage stabilizer 9, coming from the line, or your own power source.

The blocking filter 5 is implemented on the basis of a resonant oscillatory circuit. To optimally match the line and the devices connected to the line, reduce the distortion of the transmitted information radio signal and the mutual influence of the filters connected to the device line, achieve the necessary selectivity and bandwidth, a partial inclusion of the oscillatory circuit in the line is used, which ensures the matching of the impedance of the transceiver of the device and the wave resistance of the combined line communication and DC power.

The blocking filter 5 prevents the closure of the current carrier frequency of the information radio signal through the low resistance of the line power source or the internal stabilizer of the device connected to the line, when receiving, it isolates the radio frequency information signal and the device voltage from the total line voltage, and when it is transmitted to it, the modulated information radio signal with supply voltage on the line.

On figa), b) and c) are examples of a simple execution of the blocking filter. The connection of the receiver and transmitter in the general case can be carried out at various points of the oscillating circuit to ensure optimal coordination with the communication and power lines.

The filter freely passes the constant voltage component Epit supply and out-of-band signals, which are suppressed by the shunt capacitor Cf in the filter. At the same time, the shunt capacitor serves as a storage capacitor to ensure the stability of the device by reducing the level of ripple of the supply voltage.

The constant component of the supply voltage from the trap filter is supplied to the device power stabilizer 9, and the selected informational radio signal is sent to the input of the device receiver 6.

Power nodes transceiver device is provided by the stabilizer 9 linear or pulse type.

The controller 8 of the device receives and decodes the digital information signal from the receiver 6 of the device, generates a carrier frequency and a modulation signal for transmitter 7. When using popular microcontrollers, for example, MICROCHIP, ATMEL, a latency unit built into the used microcircuit is used as a carrier frequency generator -pulse modulation, the outgoing modulating signal can be removed from the output Tx, and the incoming signal from the receiver of the device is fed to the input Rx. In parallel with the reception and transmission of information via a combined two-wire communication and power line, the controller can process data and signals from various sensors, as well as monitor and control actuators.

The transmitter 7 of the device (figure 4) consists of a modulator 14, an output amplifier 15 and a blocking filter 16 at the input of the device. The output amplifier 15 can be implemented on the basis of an amplifier having a high output impedance in the pauses between cycles of information transfer, which reduces the loss of information radio signal. For example, a class C transistor cascade can be applied, and its load is the input blocking filter 16, which suppresses the by-products of the frequency conversion resulting from modulation.

The receiver 6 of the device (Fig. 5) consists of a blocking filter 16 at the input of the device, an input amplifier 17, a detector or demodulator 18, and a digital sequence regenerator 19. The amplitude of the information radio signal coming from the line to the input of the device depends on the distance to the transmission source and the number connected to the line of loads, therefore, the input amplifier and detector are combined by a negative feedback circuit (OOS), which reduces the gain of the input amplifier in accordance with the growth of the signal level at the output e detector. This ensures the stability of the amplitude of the signal from the output of the detector when changing over a wide range of the level of the radio signal from the trap filter to the input of the receiver.

As the detector / demodulator 18, for example, a transistor amplitude detector can be used.

The digital sequence regenerator 19 implements the function of restoring the parameters of the original information signal.

The main disadvantage of regenerators of known devices implemented on the basis of a comparator with fixed thresholds for operation / release are significant fluctuations in the time parameters of the recovered digital information pulses. For example, when transmitting information modulated by the NRZ code, the noted instability of the pulse duration is a limitation for increasing the speed of information exchange.

In the inventive device, the digital sequence regenerator (RCP) (Fig. 6) contains a comparator 21 covered by a positive feedback loop, the inverting input of which is galvanically connected to the output of the detector, and the non-inverting one is connected through a time delay circuit 20. The thresholds of operation and release of the comparator 21 are determined by the dynamics of change (rise / fall times of the pulse fronts) and the amplitude of the signal coming from the detector 18, which allows you to restore the information signal at high speeds exchange with deviations from the shape and duration of the original digital signal that are acceptable for reliable decoding.

The advantage of the proposed circuit implementation of a digital sequence regenerator is the high accuracy of reconstructing the time parameters of the original digital signal in the presence of distortions of the fronts of information pulses that occur during the detection of a radio signal. It is possible to use such a digital sequence regenerator circuit to restore a digital signal when transmitting information over two-wire lines by digital coding.

The output signal of the regenerator is inverted with respect to the output signal of the detector of the receiver and allows you to directly connect the information input Rx of the controller to the output of the regenerator when transmitting information in the UART protocol.

The minimum threshold of the amplitude of the input signal, from which the guaranteed stable reception of modulated information begins, is determined by the gain of the input amplifier, the depth of feedback covering the input amplifier and detector, and the width of the hysteresis loop of the comparator in the digital sequence regenerator.

When a modulated radio signal propagates along the line at the receiver input of the information transmission receiving device, distortions arise due to incomplete matching of the line and devices connected to it with a finite duration of rise and fall of oscillatory processes in the line of such a system.

The optimal selection of the parameters of the blocking filter, the gain of the input amplifier of the receiver, the depth of the negative feedback covering the input amplifier and the detector / demodulator, the parameters of the delay line and the depth of the positive feedback in the RCs minimize the influence of distortions in the transmission and detection of signals and obtain high rates of exchange rate between devices on a combined two-wire communication line and power. For example, when transmitting information over a combined two-wire line with a length of 650 m of amplitude-modulated digital signals using the UART protocol at a carrier frequency of 385 kHz, an exchange speed of 57,600 bps was reached for 60 transmit-receive devices connected to the line. To increase the speed of information exchange, it is necessary to increase the value of the carrier frequency and / or apply another type of modulation, for example, phase-modulation.

The following protocol is proposed as one of the possible options for exchanging data between devices.

1. Each of the devices continuously monitors the occupancy of the information channel.

2. After making sure that the channel is free, the transmitter device issues an information message (packet), addressed either to all or to a particular message receiver device. Each packet must contain the receiver address, message source address, command field, and checksum fields. Broadcast and multicast addresses are allowed.

3. If the address of the message receiver coincides with its own, as well as when the calculated and received checksums match, the addressed device performs the actions prescribed by the command code. If necessary, displays a response message with information about the result of the execution of the command.

The described physical level of data transmission allows exchange using various channel, network, transport, and application layers of information transfer protocols, for example, LIN, TCP / IP, etc.

The proposed method of pairing and a device for transmitting information make it possible to provide two- or multilateral communication between devices in half-duplex mode.

The advantages of the proposed method and device for transmitting information on a direct current power line are:

1. Low costs, ease of laying the line and connecting devices to it. For the communication line and the power of the connected devices, any mounting power two-wire wire with a wave resistance of tens to hundreds of Ohms can be used, and docking of sections of a two-wire line with different values of wave resistance is permissible.

2. High speed multilateral exchange between devices up to 100,000 bps or more at a low carrier frequency of hundreds of kilohertz, which allows real-time monitoring of the status of actuators and sensors.

3. High noise immunity of the information transmission channel, provided at the hardware and software level.

4. The high length of the communication line (hundreds of meters) due to the low attenuation of the low-frequency radio signal containing the transmitted information.

5. The possibility of backup control line controllers or computers.

6. The ability to connect to the line a large number (over 100) of actuators and line controllers.

7. The ability to "hot" connect additional devices or power supplies to anywhere in the line.

8. The simplicity of the refinement of any power device for use as a line power source. The ability to connect several individual power sources to the line or as part of the transmit-receive devices to provide compensation for the voltage drop in the long line.

9. No restrictions on the applicable line topology.

10. Low production costs of the device, high repeatability of its parameters.

Claims (7)

1. A method for interfacing information transmitting and receiving devices over a combined two-wire communication line and DC power, based on the implementation of information reception / transmission by analog modulation, which modulates a low-frequency carrier with an informational digital signal in the device’s transmitter, summarizes the received radio signal with voltage power and transmit on a combined communication line and DC power, select the information radio signal in the receiver from the total voltage on the line, the initial digital information signal is installed in the device’s receiver, the signal from the receiver is decoded using the device’s controller and a response information signal is generated for the transmitter, and a blocking filter is used as a decoupling between each device’s transceiver and the line, which ensures matching of the device’s receiver and transmitter impedances and wave impedance combined communication line and DC power and based on an oscillatory circuit with partial inclusion into a combined communication line and direct current power, on which the received radio signal is isolated from the total voltage on the line when receiving, the constant component of the device supply voltage is isolated and the transmission radio signal is summed with the voltage on the line. 2. A device for receiving and transmitting information over a combined two-wire communication line and DC power supply, comprising a receiver including an input amplifier, a detector and a digital sequence regenerator, a transmitter including a modulator and an output driver, a device controller that decodes the incoming information and generates response information signal, a blocking filter made on the basis of an oscillatory circuit with partial inclusion in a combined two-wire communication line and DC power, which provides the pairing of the receiver and transmitter of the device with the line and filtering the DC voltage from the line to power all parts of the device. 3. The device according to claim 2, characterized in that the blocking filter is made using a transformer with a given coupling coefficient, the secondary winding of which with a parallel connected capacitance form a resonant oscillatory circuit. 4. The device according to any one of paragraphs.2 and 3, characterized in that the inductive part of the oscillating circuit in the blocking filter is made in the form of a coil with a tap or an inductive divider. 5. The device according to claim 2, characterized in that the receiver of the device contains an input amplifier and a detector, combined by a negative feedback circuit, which provides a decrease in the gain of the input amplifier with increasing voltage at the detector to ensure constant amplitude of the signal from the detector when changing over a wide level radio signal coming from the blocking filter to the input of the receiver. 6. The device according to claim 2, characterized in that the digital sequence regenerator comprises a comparator enclosed in a positive feedback loop, the inverting input of which is galvanically connected to the detector, and the non-inverting input is connected to the detector through a time delay circuit, while the thresholds for operation and release of the comparator are determined in accordance with the dynamics of changes in the amplitude of the signal coming from the detector, and the depth of the positive feedback covering the comparator. 7. The device according to claim 2, characterized in that it includes a power source for the combined two-wire communication line and power supply, connected to the input of the barrage filter connecting the device with the combined two-wire communication line and DC power.

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