ES2531519B2 - DATA TRANSMISSION AND ENERGY SYSTEM FOR A SINGLE CABLE FOR POWERED TERMINALS WITH CONTINUOUS CURRENT. - Google Patents

Abstract

Data and energy transmission system by a single cable for terminals powered by direct current. It allows, through a single conductor, the communication of data between a plurality of terminals and jointly by said conductor the continuous electrical power necessary for the power supply of said terminals and the actuator elements that are associated therewith is transmitted.

Description

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DATA TRANSMISSION AND ENERGY SYSTEM FOR A SINGLE CABLE FOR POWERED TERMINALS WITH CONTINUOUS CURRENT.

DESCRIPTION

Data and energy transmission system by a single cable for terminals powered by direct current.

TECHNICAL FIELD OF THE INVENTION

The invention belongs to the communications sector between electronic devices and more specifically it is applicable in the communication of data between a plurality of terminals using the same conductor as a means of transmission and power.

OBJECT OF THE INVENTION

The object of the present invention is a system for transmitting and receiving data between computers using the same conductor for data and power, making the network capable of covering long distances without data loss due to the attenuation effect.

BACKGROUND OF THE INVENTION

The connection of terminals through a data bus is known in the state of the art, which may consist of one or more electrical conductors or optical fiber, under a certain communications protocol, for example CAN or LIN. In this type of interconnection, each device receives its electrical power through an independent conductor to the data bus, which can be made up of one or more conductors.

Document US007859397 discloses a system that uses the same DC power supply cable for data transport. The wiring of the energy wiring from the battery that supplies the electric current to automotive vehicles is used to communicate with each other the different electro-electronic devices that make up the electric architecture of the vehicle, the control of its actuators and sensors, and the interrelation between them.

To achieve this purpose, the system used is based on a technology disclosed in US 20030045970. This system provides a plurality of channels.

for communications based on technologies of superposition of high frequencies on the line of feeding of direct current, turning this into bus of data.

This system, due to the use of high frequencies to generate the communication channels, has the limitation of the network length and the number of connected terminals, due to the attenuations suffered by the signal that carries the data superimposed on the signal. feeding. The different charging devices connected to the line itself, and the number of terminals or nodes to be used also influence.

10 The use of the technology disclosed in the aforementioned patents is implemented through specific integrated circuits of high precision and very high integration value, using high frequencies for the generation of the different internal communication channels and having to adjust their performance in each type of installation where the wiring topology and the power elements connected to the power supply change. Using this technology with conventional electronic components implies a high cost of implementation.

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The invention to be protected offers numerous advantages over known data transmission systems through direct current networks:

- Better shielding to noise.

- Lower manufacturing cost due to the use of standard components.

- Shorter design times when using only switching techniques.

- Greater ease and less installation and commissioning time.

- System open to the use of custom protocols.

- Self-powered network of greater length.

- Greater number of user terminals.

- Simultaneous possibility of synchronous and asynchronous communications.

30 DESCRIPTION OF THE INVENTION

For a better understanding of the invention we will use the following codes: - DUP: single transmission driver (bus)

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- CODEC: intelligent terminals, nodes or peripherals that will be responsible for receiving and transmitting the DUP data and interacting with the different actuators and sensors to which they are connected.

- GCP: pulse current generator.

- TON: DC power supply time.

- tR: time that determines the moment of synchronization of the terminals.

- tD: duration of a data pulse.

Starting from a DC or battery power supply, the system features an electronic device for pulsating current generating (GPC) that produces a communication signal, as a pulsating current, which we can define as a direct current that undergoes changes in magnitude from a constant value. This pulsating current is transmitted by a single conductor (DUP) to the different terminals (CODEC). Said pulse current has the characteristic of alternating pulses of power current with a nominal voltage value of the power supply, with resting moments in which it presents a negative voltage value of desired magnitude in the line. That is, the GCP generates a square wave sweep as a sweep with two voltage values, that is, two communication channels in the same conductor, separating them by the polarity of the current, using one of the polarities to transmit data and the other for energy transport. Said negative pulse, used to transmit the data, is recessive and manageable for signaling and multiplexed communications. It is understood that all voltages and amplitudes refer to circuit ground or return cable.

The CODEC have implemented electronic circuits that are responsible for filtering and separating the data and energy by recomposing on the one hand the supply of direct current to the own voltage levels and on the other hand presenting the data and signals at the logic levels of the circuits. With the term CODEC we want to indicate the coding and decoding capacity that each element, device, peripheral or node that connects to the system must have implemented, regardless of whether their role in the data network is master or slave.

The CODECs are prepared to minimize the effects of the energy values, which may be deficient due to the intermittent power supply cuts in the pulse current signal generated by the GCP continuously, this is because they have the following elements :

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- Data dividing filters, clock synchronization and power.

- Capacitors and passive and active elements suitable for recomposing a linear curve of direct current supply without cutting noise.

- High performance switching power supplies (close to 95%) capable of processing a voltage range at their inputs, which in a preferred embodiment can be from 3.5 to 40 volts and provide a stabilized voltage of 12 volts, which is the nominal of the preferred embodiment represented in the figures.

The signal generated by the GCP can establish two forms of communication:

1.- Sfncrona Communication:

The electronic control of the GCP generates a signal consisting of pulse trains separated by rest periods so that a sweep is constituted. With the falling edge that occurs after the time that determines the time of synchronization of the terminals (tR) has elapsed, a square wave sweep starts between the nominal supply voltage levels and a determined negative voltage. Both the negative voltage value and the zero voltage value determine the logic states "0" or "1".

With each rising edge of the pulses at the supply voltage level, the CODEC terminals internally initiate a timer. This timer is reset every time a down edge occurs. That is, they measure the duration of the pulse at the nominal supply voltage value. The value of this time will be called tON. If tON is greater than a programmed time value that determines the time tR, the CODEC recognize that the transmission / reception time has ended and reset their counters and direct their data memories to the zero position. At this moment the synchronization of the CODEC terminals that constitute the system occurs.

When the pulse lowering edge starts, from the nominal voltage value, the CODEC microprocessor starts the clock count. That is, the clock uses the down front to increase the value of its counters and its memory positions. At the same time the DUP is enabled to write and read data.

The scanning frequency can vary without synchronization failures, provided that the time between bits does not exceed the time tR.

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2.- Asfnc communication:

It is established when in data time (tD), some device writes in the DUP line a sweep of square wave pulses between the ceo and negative voltage levels that we will call asynchronous data frame. This data frame is entered into the DUP at a frequency that is defined by programming in the system. When the rising edge of the positive supply voltage value does not occur during this time, the CODEC timers will not be initialized and the clock counters that are only sensitive to the downward front from the nominal voltage value will not be incremented. Therefore, asynchronous communication can be produced in the same line as required by the configuration of the equipment, coexisting both communication systems, synchronous and asynchronous.

During this period of asynchronous communication, the CODECs that are configured synchronously are not affected, since they recognize that the communication is not intended for them, due to the number of counter that they have accumulated in their clock counter, so that your program recognizes that this data does not correspond to your terminal.

In any of the aforementioned types of communications, the number of data to be transmitted by the DUP and the number of CODEC terminals to be connected does not have limits, you just have to take into account that for more data and number of CODEC terminals the communication would take longer . In synchronous communication, each data means an order position of an element of the system, to which a logical state “1” or “0” is sent so that the CODEC activates or deactivates the element associated with this data. It can also mean a specific order for a CODEC to execute an internal sequence. It can also be a shipment of a general instruction for a plurality of teams to perform some action. Each CODEC identifies, given the clock counter, the moment at which its communications time begins and when it ends depending on the order of the shift assigned to it in the internal program. The CODEC always read the line, so, in the event of an unexpected event, they can write a piece of information on it, outside the communications period assigned to their turn. You can also answer or order a specific maneuver that is requested by another CODEC.

This way of operating means that each CODEC has implemented extra functions that are not even assigned to the MASTER in a MASTER-SLAVE configuration, and

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It also means that more than one CODEC can be master of some functions and slave of others, which makes the installation very flexible and allows redundant equipment working in different positions of the installation, giving this more security to it.

As for the power supply or current, the system provides methods to regenerate at destination, that is, at the different terminals, nodes or peripherals. The pulsating current they receive is transformed into stabilized direct current and without electrical noises that interfere with its operation. For this purpose, filtering and stabilization elements of the current to the required voltage are used, using voltage boosting techniques (BOOST), voltage reducing (BUCK) and / or both in addition to switching power supplies.

As for the data, the peripherals have simple reading and writing systems since the data presented in the negative parts of the wave are recessive, as stated above and easily transformable at TTL or CMOS levels to be collected or issued by the logic of its circuits.

The interruption times of the power current will be determined by the communications needs of the system's paid equipment. Peripherals can have synchronous or asynchronous protocols and both features can coexist on the same DUP line.

The section of the DUP cable, is defined in function of the demands of current of intensity so that they guarantee the optimum operation of the elements that compose the system. The advantage offered by this system is that the working ranges and tolerance are greater due to the electronic controls that are used both for the data functions and for the treatment of the received power.

The GCP program foresees varying the continuous scanning condition if it is not necessary and minimizing consumption. For this, the signal generated by the GCP sends a negative impulse every certain interval of short duration, in a preferred embodiment it is 0.5 milliseconds for every one or two seconds. In this case, if any of the CODEC needs to request or enter data before the periodic bit occurs, it activates an output signal in the data line permanently. This output signal is emitted when the line voltage is in negative value. This can be used to initiate a sequence of data scanning of queries to the different terminals.

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The communications system allows analog data sequences to be implemented, which are established as discrete values in the negative voltage range. That is, at the same time established for the writing of a data, different corresponding voltage levels are established with analog values that are obtained directly, where the level of pulse amplitude corresponds to a different analog value, using for each value a single bit. If a greater resolution in the analog measurements were necessary, it would be sufficient to deliver in the negative part impulses of greater amplitude, that is to say greater value of negative voltage. These values are then processed and presented as well as the simple binary data of "1" and "0", to an analog input of the CODEC processor.

Throughout the description and the claims, the word "comprises" and its variants are not intended to exclude other technical characteristics, components or steps. For those skilled in the art, other objects, advantages and characteristics of the invention will be derived partly from the description and partly from the practice of the invention. The following examples and drawings provide by way of illustration, and are not intended to be limiting of the present invention. In addition, the present invention covers all possible combinations of particular and preferred embodiments indicated herein.

BRIEF DESCRIPTION OF THE FIGURES

Next, in order to facilitate a better understanding of this descriptive report and forming an integral part thereof, a series of figures are included in which the object of the invention has been shown with an illustrative and non-limiting nature.

FIG. 1 Shows a schematic view of a possible example of embodiment of the invention.

FIG. 2 Shows an example of the schematic configuration of the pulse current generator circuit (GCP)

FIG. 3 Shows another example of the schematic configuration of the pulse current generator circuit (GCP)

FIG. 4 Shows an example of the schematic configuration of the pulse current generator circuit (GCP) that incorporates CODEC functions

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FIG. 5 Shows a signal timing diagram for synchronous communication.

FIG. 6 Shows a signal timing diagram for asynchronous communication.

FIG. 7 Shows a signal timing diagram for analog signals.

FIG. 8 Shows a possible example of embodiment of the invention.

PREFERRED EMBODIMENT OF THE INVENTION

Next, a description of the invention is made based on the aforementioned figures.

Figure 1 shows in its most basic form of connection a pulse current generator GCP (1) with four terminals called “CODEC” (2) connected by a single conductor or DUP communications bus cable (3) which is also the energy and food carrier. With the term CODEC we want to indicate the coding and decoding capacity that each element, device, peripheral or node that connects to the system must have implemented, regardless of whether their role in the data network is master or slave. In the preferred embodiment, the power supply (4) corresponds to a 12-volt battery.

The system of the invention has a pulse current generator GCP (1), which in an embodiment as shown in Figure 2, generates a pulse sweep with positive voltage values of nominal voltage value of the power supply , which allows the CODEC terminals (2) and associated actuator elements to be fed, for the preferred embodiment the power supply is 12 volts and a negative voltage value which in this embodiment is -5 volts. In the GCP (1), the control logic (1.1), controlled by a microprocessor, generates the excitation of the electronic power switch (1.2) at the convenience of the need for the data bus and the elements associated therewith. It also controls the current converter (1.3) that supplies the negative system voltage and can activate it a moment before switching the switch (1.2) to the open state in order to avoid the consumption of the resistance (1.4) that occurs when it is in closed state. That is, the GCP (1) generates two voltage signals, that is, two communication channels in the same conductor, separating them by the polarity of the current,

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using in this embodiment the negative polarity of - 5 volts to transmit data and the positive polarity of 12 volts for power supply.

Figure 3 shows another example of a schematic embodiment of a pulse current generator GCP (1), where the following elements can be defined:

- microprocessor (1.5)

- Power current treatment unit (1.6)

- Negative power generating unit (1.7)

- Signal filter unit and converters (1.8)

Figure 4 shows an example of a schematic embodiment of a GCP pulse current generator (12) having an integrated CODEC element, where the output input signal connections (1.9) are connected directly to external actuator elements.

In Figure 5 we see a time diagram of the signal when the communication is synchronous. For this embodiment, the control electronics of the GCP generate a signal consisting of pulse trains separated by rest periods (5) so that a sweep is constituted. After a pulse (5) of duration greater than the time determined by the timing of synchronization of the terminals tR (11), an 8-bit square wave sweep is initiated between the nominal supply voltage levels of 12 volts and a voltage negative of - 5 volts. Both the negative voltage value of - 5 volts and the zero voltage value determine the logic states "1" and "0" respectively.

With each rising edge of the pulses (8), the CODEC terminals internally initiate a counter of the duration of the energy pulse, a timer that is set to zero each time a falling edge (9) occurs, if the time is less than tR (11). That is, they measure the duration of the pulse at the nominal supply voltage value (7). When the duration of the pulse (5) is greater than a programmed time value that determines the synchronization of the tR system (11), the CODEC recognize that the transmission / reception time has ended and reset their counters and direct their data memories to zero position.

Being in a waiting situation or zero position, which occurs when the time (tR) has expired, the new down edge that occurs (9), determines the start of the CODEC clock count again and indicating the situation of “DUP ready for data” that is read or written by the CODEC immediately after each clock lowering edge.

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Each pulse lowering edge (9), from the positive voltage value, determines the presence of a new data and another clock pulse.

In Figure 6 we see a time diagram of the signal when the communication is asynchronous. For this embodiment, the GCP control electronics enable the state of -5 volts on the line for an agreed time (10) so that the corresponding terminal can write on it. Defining that the situation of -5 volts is recessive and means “1” logical, therefore if you have to write two “1” in a row it keeps it as it is and in the next bit that is a logical “0”, the terminal activates its Line closing transistor to write a logical "0". In the event that the same processor of the GCP is the one that has to write, it would act in the same way. When the positive voltage rising edge does not occur during this time, the CODEC timers will not be initialized and the clock counters will not increase, as there will be no lowering edge (9), so they keep their position on hold until the next clock flank that makes them follow.

During this period of time (10), the CODECs that are configured synchronously are not affected by the transitions of “1” and “0”, since they recognize that the communication is not intended for them, due to the number of counter that have accumulated in your clock counter, so your program recognizes that this data does not correspond to your terminal.

Figure 7 shows a seven-bit sequence that simulates measurements of certain analog sensors that have different amplitudes on the negative side. Seven different levels corresponding to seven different analog measures have been represented to mean that at the same time (6), different levels corresponding to analog measures can be sent directly since the amplitude level corresponds to a different analog value and using to Each value a single bit. If the installation needs a greater resolution in the analog measurements, it would be enough to deliver in the negative part impulses of greater amplitude, for example -10 volts, or another convenient value. These values are then processed and presented as well as the simple binary data of "1" and "0", to an analog input of the CODEC processor.

Figure 8 shows a preferred example of system installation where there is a GCP (1) and a GCP with integrated CODEC (12), which signals from external industrial elements arrive. Two DUP bus lines (3, 13) leave each GCP. It looks like

There is a communication between the two DUPs through lines that inject data (14) from one DUP (1) to the other DUP (13) and lines that read (15) data. In this embodiment, several CODECs have connection to the two DUPs, which allows the information to be unified in a supervisory position application.

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Claims (9)

5 10 fifteen twenty 25 30 35 1. Data and energy transmission system by a single cable for terminals powered by direct current characterized in that it comprises a pulse current generator (GCP) that produces a square wave communication signal composed of positive pulses of the nominal voltage value of the associated power supply and current pulses with a negative voltage value, said signal being sent to at least one intelligent terminal (CODEC) that will be responsible for receiving and transmitting the data and interacting with the different actuators and sensors to which they are located connected. 2. Data and energy transmission system by a single cable for terminals fed with direct current according to claim 1 characterized in that the positive pulses have a nominal voltage value that allow the direct current supply of the CODEC terminals and the elements actuators associated with these. 3. Data and energy transmission system by a single cable for terminals fed with direct current according to claim 1 characterized in that the current pulses with a negative voltage value are used to transmit data, said pulse being recessive and manageable for signaling and multiplexed communications. 4. Data and energy transmission system by a single cable for terminals powered by direct current according to claim 1 characterized in that the intelligent terminals CODEC have implemented electronic circuits that are responsible for filtering and separating the data and energy by recomposing a On the other hand, the DC power signal at its own voltage levels and on the other hand the data signal at the logic levels of the circuits. 5. Data and energy transmission system by a single cable for terminals powered by direct current according to the preceding claims, characterized in that the CODECs are prepared to minimize the effects of the energy values, which may be deficient due to intermittent power outages. GCP power supply of its pulse current continuously, this is because they have data splitting filters, synchronization and power clock, capacitors and passive and active elements suitable to recompose a linear current supply curve 5 10 fifteen twenty 25 30 35 It continues without cutting noise and high-performance switching power supplies capable of processing a voltage range at its inputs and providing a stabilized voltage at its output. 6. Data and energy transmission system by a single cable for terminals supplied with direct current according to the preceding claims characterized in that the interruption times of the power current will be determined by the communication needs of the equipment connected to the system. Peripherals can have synchronous or asynchronous protocols and both features can coexist on the same DUP line. 7. Data and energy transmission system by a single cable for terminals supplied with direct current according to the preceding claims characterized in that for the communication signal it is synchronous, for which the control electronics of the GCP generates a signal consisting of pulse trains separated by rest periods so that a sweep is constituted. With the falling edge that occurs after the time that determines the time of synchronization of the terminals (tR) has elapsed, a square wave sweep starts between the nominal supply voltage levels and a determined negative voltage. Both the negative voltage value and the zero voltage value determine the logic states "0" or "1". With each rising edge of the pulses at the supply voltage level, the CODEC terminals internally initiate a timer. This timer is reset every time a down edge occurs. That is, they measure the duration of the pulse at the nominal supply voltage value. The value of this time will be called tON. If tON is greater than a programmed time value that determines the time tR, the CODEC recognize that the transmission / reception time has ended and reset their counters and direct their data memories to the zero position. At this moment the synchronization of the CODEC terminals that constitute the system occurs. When the pulse lowering edge starts, from the nominal voltage value, the CODEC microprocessor starts the clock count. The clock uses the down front to increase the value of its counters and its memory positions, while the DUP is enabled to write and read data. 8. Digital data transmission system by means of an electric network of direct current supply according to the preceding claims characterized in that the communication signal is asynchronous, for which it is established in data time (tD), where a terminal writes in the DUP line an asynchronous data frame, at a frequency established. When the rising edge of the positive supply voltage value does not occur during this time, the CODEC timers will not be initialized and the clock counters that are only sensitive to the downward front from the nominal voltage value will not be incremented. 5 9. Digital data transmission system by means of an electric network for direct current supply according to the preceding claims, characterized in that the GCP envisages varying the continuous scanning condition if it is not necessary and minimizing consumption. For this, the signal generated by the GCP sends a negative impulse each 10 short time interval. In this case, if any of the CODEC has Need to request or give data before the periodic bit occurs, activates an output signal in the data line permanently. This output signal is emitted when the line voltage is in negative value. 15 10. Data and energy transmission system by a single terminal cable supplied with direct current according to the preceding claims characterized in that the signal generated by the GCP allows to implement analog data sequences, which are established as discrete values in the negative voltage range. The same time established for the writing of a data establishes different levels of 20 corresponding voltage with analog values that are obtained directly, where the level of pulse amplitude corresponds to a different analog value, using for each value a single bit.