JP4890004B2 - Information transmission method between transmitter and receiving unit and apparatus therefor - Google Patents

Description

  The present invention relates to a method for the transmission of information between a transmitter and a receiving unit, a receiving unit for receiving a signal of the transmitter, and a transmitter for transmitting a transmitter signal to the receiving unit.

  There is already known a sensor that sends an analog output signal to an engine control device through an analog interface. In the engine control device, an analog / digital converter is disposed after the normal protection circuit and the low-pass filtering device. Through the analog interface, the signal is transmitted in only one direction, i.e. the sensor's analog output signal is generated in the sensor and routed through the analog interface's analog signal line to the analog / digital converter of the engine controller. The analog / digital converter performs analog / digital conversion of the analog output signal of the sensor.

  Provided are a method for transmitting information between a transmitter and a receiving unit, and an associated device, enabling bidirectional communication between the transmitter (1) and the receiving unit (5) with minimal power consumption.

  According to the present invention, in a method for transmitting information between a transmitter and a receiving unit for receiving a signal of the transmitter, the signal of the transmitter is changed by the receiving unit, and the output of the transmitter is changed by the transmitter. A change in the transmitter signal at the output of the transmitter is detected by the transmitter.

  In this way, information transmission is possible not only from the transmitter to the receiving unit, but also from the receiving unit to the transmitter. This makes the analog interface between the transmitter and the receiving unit a bi-directional interface, thereby enhancing the function of the interface between the transmitter and the receiving unit.

The invention further allows for advantageous extensions and improvements.
Changes in the signal of the transmitter are detected as information communicated from the receiving unit by a suitable evaluation device in the transmitter.

  This is because the transmitter output current or output voltage is monitored in the transmitter using a predetermined current region and / or voltage region, and the transmitter output voltage is a predetermined voltage region. When the output current of the transmitter is outside the predetermined current region, the transmitter transmits the information transmitted from the receiving unit, and this is realized by a simple method.

For this purpose, for example, the output current is measured in a simple manner using a current measuring resistor in the transmitter.
The transmitter determines the time length of the change in the transmitter signal at the output of the transmitter, and detects information communicated from the receiving unit to the transmitter according to the time length. Another advantage is born. In this way, for example, the stability of transmission with respect to disturbing pulses due to electromagnetic coupling or capacitive coupling during transmission of information from the receiving unit to the transmitter is enhanced. Furthermore, by evaluating the time length of the change of the transmitter signal at the output of the transmitter, various information transmitted from the receiving unit to the transmitter, for example information in the form of individual pulses or multiple pulses Digital information consisting of

  Another advantage arises when a function is performed by the transmitter in response to the information received at the receiving unit. In this way, the transmitter can be controlled from the receiving unit side.

  Another advantage arises when the transmitter signal is applied with at least one pulse from the receiving unit and at least one pulse is detected by the transmitter on the output of the transmitter. In this way, the information of the receiving unit can be detected very easily and reliably at the transmitter.

In this case, at least one pulse can be applied to the transmitter signal as a current pulse or a voltage pulse in a particularly simple manner.
A particularly simple technique for generating such a current pulse or voltage pulse on an analog signal line between a transmitter and a receiving unit is to use a predetermined current source or a predetermined current signal. This can be made possible by a short-time activation of the switch for connecting to the potential being applied.

One embodiment of the invention is illustrated in the drawing and is explained in detail in the following description.
In FIG. 1, reference symbol 1 indicates a transmitter, for example a sensor in a car. The reference symbol 5 indicates a receiving unit for receiving the signal of the transmitter 1, and this unit is incorporated in, for example, the above-described automobile control device. However, the transmitter 1 and the receiving unit 5 are not limited to applications in vehicles, but are suitable for any application. FIG. 1 shows only the components of the transmitter 1 and the receiving unit 5 that are important to the present invention as well as some other components that are useful for understanding the present invention. The transmitter 1 includes an output stage 50, shown in FIG. 1 in the form of an operational amplifier, which has a first output terminal 10 and a second output terminal 15, and so on. A transmitter signal (hereinafter also referred to as a transmitter signal) is applied to the output terminal. The second output terminal 15 of the output stage 50 is a reference potential, for example, ground. The first output terminal 10 of the output stage 50 is simultaneously the first output terminal of the transmitter 1, and the second output terminal 15 of the output stage 50 is simultaneously the second output terminal of the transmitter 1. Yes. The transmitter signals at the two output terminals 10, 15 can be, for example, a signal indicating the measured pressure, a signal indicating the measured temperature, a signal indicating the measured number of revolutions, and the like. The transmitter 1 is provided for measuring an arbitrary numerical value and outputting a measurement signal or a transmitter signal corresponding to the numerical value to the first output terminal 10 and the second output terminal 15 of the transmitter. ing. Further, a supply voltage input terminal 95 is provided in the transmitter 1, and the supply voltage VVS is supplied to the transmitter 1 through the input terminal. This supply voltage VVS is sent to the output stage 50 through the current measuring resistor 40, and a first, for example, positive (positive) operating potential is applied to the operational amplifier 50 as the output stage of the transmitter 1 through this supply voltage VVS. Supplied. A reference potential is supplied as a second operating potential to the output stage 50 through the second output terminal 15. The generation of the transmitter signal through the non-inverting input terminal and the inverting input terminal of the output stage 50 is not shown in further detail in FIG. 1 for the sake of clarity. The supply voltage input terminal 95 is further coupled to the inverting input terminal of the second operational amplifier 45 of the transmitter 1, whereas the potential between the current measuring resistor 40 and the output stage 50 is second. To the non-inverting input terminal of the operational amplifier 45. The two operating potentials of the second operational amplifier 45 are only shown schematically in FIG. 1 for the sake of clarity. At this time, the second operational amplifier 45 is used as a comparator that generates an output signal in accordance with the potential difference between the inverting input terminal and the non-inverting input terminal of the amplifier. The use of this output signal is arbitrary and can be sent to the timer 55 as shown in FIG. The output of the timer 55 is sent to a further evaluation device in the transmitter 1, as suggested by the timer 55 output arrow. Thus, the second operational amplifier 45 sends out a corresponding output signal in response to the voltage drop across the current measuring resistor 40. The receiving unit 5 is coupled to the transmitter 1 through an analog interface 60. At that time, the first analog signal line 20 of the analog interface 60 couples the first output terminal 10 of the transmitter 1 with the first input terminal 85 of the receiving unit 5, and the second analog signal of the analog interface 60. Line 25 couples the second output terminal 15 of transmitter 1 to the second input terminal 90 of receiving unit 5. At that time, the second input terminal 90 of the receiving unit 5 is further connected to the reference potential 35, which is ground in this example. The first input terminal 85 and the second input terminal 90 of the receiving unit 5 are coupled to each other through a protective capacitor 65 that filters high frequency interference and electrostatic discharge of the received signal by guiding them to the ground 35 (ESD protection). . The reception signal pre-filtered in this way at the reception unit 5 is then further filtered by the low-pass filter 70 of the reception unit 5. The low-pass filtered received signal is then fed in a manner known to the person skilled in the art to an analog-to-digital converter not shown in FIG. The first input terminal 85 of the receiving unit 5 is further coupled through a pull-up resistor 75 to a previously applied potential of the receiving unit 5, for example + 5V. Furthermore, the first input terminal 85 of the receiving unit 5 can be coupled through the controllable switch 30 to the reference potential 35 and hence in this case to ground. The controllable switch 30 is controlled by a control signal 80 of the receiving unit 5.

  According to the present invention, the signal of the transmitter 1 received by the first analog signal line 20 and the second analog signal line 25 is changed by the receiving unit 5, that the transmitter 1 is on the output side. It has been proposed that on the output side of the transmitter 1 and to be monitored, a change in the signal of the transmitter 1 made by the receiving unit 5 is detected by the transmitter 1. At that time, the change of the transmitter signal is performed using the control signal 80 for coupling the first analog signal line 20 or the first input terminal 85 of the receiving unit 5 to the reference potential 35 from the receiving unit 5 side. In particular, the switch 30 is activated for a short time. At this time, the switch 30 is closed to couple the first analog signal line 20 to the reference potential 35. As a result, during the length of time that the switch 30 is closed, the voltage between the first output terminal 10 and the second output terminal 15 of the transmitter 1 is changed between the first analog signal line 20 and the second output terminal 15. A voltage pulse is applied according to the conduction resistance of the analog signal line 25, and as a result, the voltage pulse further generates a current pulse that flows through the current measurement resistor 40. The voltage pulse between the first output terminal 10 and the second output terminal 15 of the transmitter 1 is then added or superimposed on the transmitter signal transmitted from the output stage 50 and transmitted to the receiving unit 5. Is done. As described above, the current pulse or voltage pulse has a time length corresponding to the length of time that the switch 30 is closed. In doing so, it is particularly advantageous to close the switch 30 with the control signal 80 for a short time in order to limit the time influencing the signal of the transmitter as short as possible. On the other hand, a current or voltage pulse generated by closing the switch 30 may cause the pulse to be generated on the first analog signal line 20 and the second analog signal line 25 by, for example, electromagnetic coupling or capacitive coupling. It needs to last long enough to be distinguishable from the pulse. Therefore, the control signal 80 shall be appropriately adjusted, for example, on the test bench, so that the length of time for closing the switch 30 meets the above requirements. At that time, the switch 30 is arranged so that a plurality of pulses and thus a pulse train are superimposed on the signal of the transmitter 1 or the voltage between the first output terminal 10 and the second output terminal 15 of the transmitter 1. By means of a control signal 80, the switch can be controlled so that it is closed and reopened several times in succession.

  The transmitter 1 typically corresponds to the physical value measured by the transmitter 1 between the first output terminal 10 and the second output terminal 15 through its output stage 50 or this measured physical value. Generate a defined voltage that is representative of the value. At that time, the output stage 50 drives the voltage between the first output terminal 10 and the second output terminal 15 within a predetermined voltage operation region during normal operation, An output current is caused to flow through the first output terminal 10 and the second output terminal 15 at a current intensity within a predetermined electric field operation region. At that time, the sum of the output currents flowing through the first output terminal 10 and the second output terminal 15 also flows through the current measuring resistor 40. At this time, the predetermined voltage operation region or current operation region is, for example, a voltage pulse or current pulse to the output terminals 10 and 15 of the transmitter 1 when the switch 30 is closed on the test stand. The predetermined voltage operation region or current operation region is over-adjusted by the superimposition of. Monitoring of the output current or output voltage at the output terminals 10, 15 of the transmitter 1 using a current threshold or voltage threshold corresponding to the limit of the current operating region or voltage operating region is thus performed within the transmitter 1. Allows detection of transmitter signal changes caused by closing switch 30. In this way, information is transmitted from the receiving unit 5 to the transmitter 1 by means of current pulses or voltage pulses at the output terminals 10, 15 of the transmitter 1, which are generated through the operation of the switch 30, and the transmitter. Therefore, effective communication from the receiving unit 5 toward the transmitter 1 is possible. As described above, when the communication is performed using a plurality of current pulses or voltage pulses, digital information can be transmitted from the receiving unit 5 to the transmitter 1.

  The functional mode of the circuit device based on FIG. 1 is as follows. Via a control signal 80, which can be generated by suitable software, when the switch 30 is closed for a predetermined length of time on the test bench as previously determined and described, this allows During the time length, the analog signal at the first output terminal 10 of the transmitter 1 flows in the direction of the reference potential 35. The transmitter 1 tries to keep the output signals of the first output terminal 10 and the second output terminal 15 constant through its output stage 50, and as a result, in response to the switch 30 being closed, the first The output currents of the output terminal 10 and the second output terminal 15 are increased. This raised output current also flows through the current measuring resistor 40. As a result, the voltage applied to the current measuring resistor 40 is also increased. Pulled up by closing switch 30 by a switching threshold given in advance for the second operational amplifier 45, which threshold determines a predetermined current operating region for the output current of the transmitter 1 Whether the output current flowing through the current measuring resistor 40 is outside the predetermined current operating region of the transmitter 1 is confirmed. If the output current is outside the operating region, a change in the output signal of the second operational amplifier 45 is brought about. The timer 55 measures the time length of this changed output signal of the second operational amplifier 45 and thereby the time length of the raised output current of the transmitter 1. If this time length matches a predetermined time length for closing the switch 30, the current pulse or voltage pulse generated by closing the switch 30 is included in the information signal of the receiving unit 5. It corresponds. The length of time previously given to close the switch 30 for this purpose can also be stored in the transmitter 1. The comparison between the predetermined time length and the time length obtained by the timer 55 is performed by a comparator following the subsequent stage of the timer 55. This comparator is illustrated in order to simplify the drawing. 1 is no longer shown. As already mentioned, if the time length measured by the timer 55 matches the predetermined time length, the transmitter 1 closes the switch 30 from the receiving unit 5 to the transmitter 1. It detects the information signal conveyed to it and reacts to this by, for example, activating a specific function. The function can be, for example, a switch-off or calibration function of the transmitter 1 or any other function that can be performed by the transmitter 1. In so doing, various functions can be performed by the transmitter 1 depending on the information detected and received by the receiving unit 5. As already mentioned, a pulse train is also transmitted to the transmitter 1, for example by means of the receiving unit 5, and thereby also a digital signal. Thus, for example, various digital signals are transmitted from the receiving unit 5 to the transmitter 1 according to the generated pulse train. The transmitter 1 evaluates such various pulse trains in an evaluation unit following the comparison unit, in a manner already known to those skilled in the art, and in this case the detection of the various pulse trains transmitted from the receiving unit 5. The transmitter 1 can activate various functions. In this way, the transmitter 1 is also controlled by the receiving unit 5. In this case, various pulse trains are understood as different trains of pulses having the same predetermined pulse time length in this example.

  However, according to another embodiment, it has also been proposed that the switch 30 can be closed for different lengths of time to generate different pulses. Also by doing this, if this different time length is also stored in the transmitter 1 and compared with the time length measured by the timer 55 in the comparison unit, the different information in the receiving unit 5 is transmitted to the transmitter. 1 is distinguished. However, in this case, as already described, the minimum time length of the pulse is such that at least the pulse is not mistaken for an interference pulse caused by, for example, electromagnetic coupling or capacitive coupling at the analog interface 60. Would have to be long.

  Different pulse trains can also be generated and evaluated as a train of pulses of the same or different arrangement of at least two pulses, each of a different duration. Different pulse trains can also be distinguished from each other by their number of pulses.

  Thus, by the control of the switch 30 according to different pulse time lengths and / or to generate different pulse trains, different information is generated at the receiving unit 5 and conveyed to the transmitter 1 through the analog interface 60 and already described there. Detected.

  When the drive output of the receiving unit 5 is lower than that of the transmitter 1, the communication signal in the analog transmitter signal generated by the receiving unit 5 by closing the switch 30 is almost undetectable. . The output stage 50 of the transmitter 1 ideally fully compensates the communication signal according to the adjustment speed of the output stage 50. The transmitter signal is thereby disturbed only for a short time and to an almost undetectable extent. However, if the drive output of the receiving unit 5 is higher than that of the transmitter 1, the analog transmitter signal is disturbed to the extent that it can be detected by the communication signal generated by the receiving unit 5 by closing the switch 30. In this case, the output stage 50 of the transmitter 1 can no longer fully compensate for this communication signal. Thus, the transmitter signal is disturbed to a detectable extent for the length of time of the communication signal, and thus for the length of time that the switch 30 is closed.

  FIG. 2 shows a flow chart for generating a communication signal in the receiving unit 5. After the start of the program, the software of the receiving unit 5 determines a control signal 80 for generating a desired pulse train or pulse time length in the program step 100, where the pulse train or pulse time length is the information of the receiving unit 5 or Assigned to an instruction. The program is then terminated.

  In FIG. 3, a flow chart showing the flow of the method according to the invention in the transmitter 1 is shown based on an example of a program. In that case, in the following description, the current measuring resistor 40 as a monitoring unit monitors the outputs 10 and 15 of the transmitter 1, and the second operational amplifier 45 is named a detection unit, and the detection unit is the output terminal 10. 15, in other words, at the output terminal or output side of the transmitter 1, a change in the transmitter signal exceeding a predetermined area is detected as information transmitted from the receiving unit 5. It shall be. After the start of the program, the monitoring unit 40 monitors the output of the transmitter 1 by the voltage drop generated in the current measuring resistor 40 in this case. Then, the program proceeds to program step 205.

  In program step 205, the detection unit 45 checks whether the voltage drop across the current measuring resistor 40 exceeds a predetermined threshold. If over (y), the process branches to program step 210; otherwise (n), the process returns to program step 200.

  In the program step 210, the detection unit 45 generates a detection signal by jumping to its output terminal, for example, to a predetermined voltage value. The timer 55 measures the time length of this detection signal or a jump to a predetermined voltage. The program then proceeds to program step 215.

  In the program step 215, whether or not the comparison unit connected to the subsequent stage of the timer 55 corresponds to a plurality of predetermined values of the time length of the detection signal or voltage jump sent out by the detection unit 45. Check. If the time length of the detection signal or voltage jump corresponds to a plurality of predetermined values (y), the program proceeds to program step 220; otherwise (n), the program is terminated. The

  In program step 220, the evaluation unit connected to the subsequent stage of the comparison unit obtains the information assigned to the time length or the instruction of the receiving unit 5 assigned to the time length. In that case, possible instructions can be assigned to various time lengths and stored in a memory assigned to the appropriate evaluation unit of the transmitter 1. The program then proceeds to program step 225.

  In program step 225, the evaluation unit activates a function of the transmitter 1 that is associated with the detected command or the detected information. In this case, too, various functions of the receiving unit 5 and various information or instructions can be stored in the memory of the transmitter 1 assigned to the evaluation unit. The program is then terminated.

  Even when the various information or instructions of the receiving unit 5 are formed by different pulse trains generated by the receiving unit 5 rather than by different pulse time lengths of the only pulse generated by the receiving unit 5, It can process by the method similar to the above. In the latter case, the evaluation of the pulse duration measured by the timer 55 is a check of whether the detected pulse was generated by a disturbance or by closing the switch 30 of the receiving unit 5. Only used for. In this case, the evaluation unit forms a reception pulse train from the valid pulses of the reception unit 5 sent from the comparison unit, and the reception pulse train is assigned to various information or instructions of the reception unit 5 to be transmitted to the transmitter. 1 is compared with the pulse train stored in 1. When the received pulse train detected by the evaluation unit matches the stored pulse train, the function of the transmitter 1 assigned to the pulse train is activated. These functions can be assigned to various pulse trains of the transmitter 1 and stored.

  According to the example of FIG. 1, the first input terminal 85 of the receiving unit 5 is coupled to the reference potential 35 through the switch 30 for generating the information signal of the receiving unit 5. As an alternative, for this purpose, the first input terminal 85 can also be coupled through switch 30 to another pre-determined potential, in which case the potential is, for example, tested A current pulse or a voltage pulse at the output terminal of the transmitter 1 generated by coupling the first input terminal 85 with the potential on the table so that it can be detected by the transmitter 1 as well. That is, the output terminal of the transmitter 1 can be adjusted to provide a voltage or current that is outside a predetermined voltage range or current range. For this purpose, the first input terminal 85 of the receiving unit 5 can also be coupled through the switch 30, for example with a suitably determined supply voltage. Further, as an alternative, for this purpose, the first input terminal 85 described above can also be coupled through the switch 30 to a suitably selected power source accordingly. In addition, or as an alternative, the second input terminal 90 may be a pre-determined current source or pre-determined through a second switch that is controlled accordingly by a second control signal or by a control signal 80. It can also be combined with the applied potential.

  According to the invention, information is also transmitted from the receiving unit 5 to the transmitter 1 through the existing analog interface 60 for transmission of the transmitter signal from the transmitter 1 to the receiving unit 5 and thus without additional signal lines. The

FIG. 4 is a wiring diagram of a transmitter and a receiving unit coupled to each other through an analog interface. 2 is a first flow diagram for explaining the method according to the invention on the receiving unit side; 4 is a second flowchart for explaining the method according to the invention on the transmitter side;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transmitter 5 ... Reception unit 10, 15 ... Output terminal 20, 25 ... Analog signal line 30 ... Controllable switch 35 ... Reference potential 40 ... Current measurement resistance (monitoring means)
45. Operational amplifier (comparator, detection means)
50 ... Output stage (operational amplifier)
55 ... Timer 60 ... Analog interface 65 ... Protection capacitor 70 ... Low-pass filter 75 ... Pull-up resistor 80 ... Control signal 85, 90, 95 ... Input terminal VVS ... Supply voltage

Claims (8)

Analog signal lines (20, 20) between a transmitter (1) that generates an output signal at an output terminal (10, 15) via an output stage (50) and a receiving unit (5) that receives the output signal. 25) in the method of transmitting information via
Changing the output signal of the transmitter by transmitting at least one pulse signal generated by the receiving unit as information to the output terminal of the transmitter via the analog signal line;
Monitoring the change in the output signal at the output terminal of the transmitter by a monitoring unit (40) in the transmitter;
Detecting the at least one pulse signal transmitted from the receiving unit by a detection unit (45) in the transmitter from a change in an output signal at an output terminal of the transmitter;
An information transmission method characterized by The transmission method according to claim 1, wherein the at least one pulse signal is superimposed on an output signal at an output terminal of the transmitter as a current pulse or a voltage pulse. The current pulse or the voltage pulse is applied to a control signal (80) from a predetermined information source through a switch (30) connected between the analog signal line and a predetermined potential (35). The transmission method according to claim 2, wherein the transmission method is generated by operating with the use of the method. The output stage (50) of the transmitter drives the output terminal with a voltage within a predetermined voltage operation region, and causes a current within a predetermined current operation region to flow through the output terminal. The transmission method according to claim 1. The monitoring unit monitors a change in an output signal at an output terminal of the transmitter using at least one of a voltage in the predetermined voltage operation region and a current in the predetermined current operation region. And
The sensing unit is configured such that when the changed output signal at the output terminal of the transmitter is outside the predetermined voltage operating region or outside the predetermined current operating region. 5. The transmission method according to claim 4, wherein the at least one pulse signal transmitted from the receiving unit is detected.   The detection unit determines a time length of the at least one pulse signal, and detects information transmitted from the reception unit according to the determined time length. The transmission method described in 1.   7. The transmission method according to claim 1, wherein a predetermined function is executed in accordance with information detected by the detection unit. Analog signal lines (20, 20) between a transmitter (1) that generates an output signal at an output terminal (10, 15) via an output stage (50) and a receiving unit (5) that receives the output signal. 25) in the information transmission system via
Means (30, 35) for the receiving unit to change the output signal of the transmitter by transmitting at least one pulse signal as information to the output terminal of the transmitter via the analog signal line. )
A monitoring unit (40) for monitoring the change of the output signal at the output terminal of the transmitter; and the at least one of the at least one signal transmitted from the receiving unit from the change of the output signal at the output terminal of the transmitter. An information transmission system comprising a detection unit (45) for detecting a pulse signal

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