JP5582673B2 - Parameterization method for pressure measuring device - Google Patents

Description

  The present invention relates to a pressure measuring device and a parameterizing method for the pressure measuring device.

  In the automotive field, pressure information is required to detect a driver's braking request in a vehicle brake system, particularly an ESP system. This pressure information is obtained by measuring the pressure in the main cylinder of the brake system via a pressure sensor. For this purpose, various means for attaching a pressure sensor to a so-called hydraulic mechanism with screws are known.

  Also known are means for at least partially housing the sensor in the casing of the hydraulic mechanism or hydraulic device. Such a sensor is proposed in International Application No. 2004/043754. By incorporating the pressure sensor into the pressure valve, the size of the structure is reduced, and it is not necessary to introduce additional protective measures for the complicated power supply network. At the same time, the reliability of pressure measurement is improved, and the manufacturing cost of the pressure sensor device is reduced. In order to achieve a reduction in construction space, the pressure sensor may be integrated into the pressure valve. However, in this case, the diameter of the pressure valve often increases.

In order to avoid such an increase in size, for example in EP 1093428 it is proposed to orient the pressure sensor in a transverse direction with respect to the notch for the pressure valve. From this specification a brake pressure control device is known in which the terminal opening of the pressure sensor is oriented in the casing transversely to the notch for the pressure valve. In this way, the disadvantage of partially accommodating the pressure sensor in the pressure valve is avoided, but the pressure sensor is disposed between the electromagnets, so the pressure valve spacing increases. The dimensions for the sensor casing will increase.
International Application No. 2004/043754 European Patent No. 1093428

  An object of the present invention is to improve the reliability of pressure measurement without increasing the structural dimensions.

  This problem has a sensing unit and an evaluation unit built into the pressure valve, the sensing unit and the evaluation unit are spatially separated and are mutually connected via an electrical plug connection. Solved by the connected configuration.

  The pressure measuring device having the configuration described in the characterizing portion of claim 1 of the present invention has an advantage that the sensing unit can be particularly small. As a result, the space required for the sensing unit is minimized, and the diameter of the pressure valve does not have to be increased even if the sensing unit is completely incorporated into the pressure valve of the brake system.

  The pressure measuring device of the present invention has a sensing unit and an evaluation unit incorporated in a pressure valve, the sensing unit and the evaluation unit are spatially separated, and an electrical plug connection is provided. Are connected to each other. Therefore, the sensing unit and the evaluation unit in the pressure valve are separated, and the data formed by the sensing unit is evaluated by a separate evaluation unit. This provides the advantage that the sensing unit can be made extremely small, robust and inexpensive. Since the sensing unit is completely integrated into the pressure valve, it is reliably protected from faults and there is little need to introduce measures for fault removal or protection. By separating the sensing unit and the evaluation unit spatially, the evaluation unit can be arranged at a position where sufficient space is obtained or in a protected environment. This eliminates the protective measures that usually have to be introduced and improves fault tolerance.

  The sensing unit is configured as an electrical measurement cell with a measurement bridge circuit. This measuring cell has only passive electrical elements. Furthermore, the measuring cell is provided with a protection circuit for reducing the sensitivity to disturbances, in particular electromagnetic interference. Advantageously, the connection via the bayonet connection can optionally be disconnected and reconnected. Thus, the components of the pressure measuring device, i.e. the sensing unit and the evaluation unit, can be exchanged individually. This is significant, for example, when any component fails.

  Advantageous embodiments of the pressure measuring device according to the invention are described in the dependent claims.

  Advantageously, the pressure measuring device is further provided with a separate control device with a memory, in which the parameters of the sensing unit are stored, and the evaluation unit is connected to the control device via an interface. Communication between the evaluation unit and the control device takes place via an interface. The interface can be configured as a bidirectional interface. A dedicated parameter of the sensing unit is stored in the memory of the control device. As a result, the dedicated parameters of the sensing unit can always be used. Advantageously, a non-volatile memory, for example an EEPROM, is used. In this way, the parameters can be maintained even when the vehicle engine is not ignited.

  In an advantageous embodiment of the invention, the evaluation unit is parameterizable and has a control register, to which the parameters of the sensing unit are transferred from the control device. In order for the evaluation unit and the sensing unit to work together accurately and without problem, the evaluation unit must be parameterizable and the dedicated parameters of the sensing unit must be available in the evaluation unit. The parameter concerned becomes calibration data of each sensing unit in the evaluation unit. In this way it is ensured that accurate measurement values are transmitted from the evaluation unit. By using the dedicated parameters of the sensing unit, various sensing units can be connected to one evaluation unit, or various evaluation units and one sensing unit can work together. The parameters stored in the memory of the control device are transmitted to the evaluation unit via the interface. The parameters of the sensing unit are written into the control register of the evaluation unit. As a result, a dedicated parameter for the sensing unit is obtained in the evaluation unit. Since the parameters are stored in the memory of the control device, the memory of the evaluation unit can be omitted. Therefore, the evaluation unit can be manufactured at a very low cost. If the memory is omitted, the dimensions of the evaluation unit can be greatly reduced. The evaluation unit is configured, for example, as an inexpensive ASICS without memory. Since the evaluation unit does not have its own memory, the dedicated parameters of the sensing unit must always be transmitted to the control register. This ensures that the latest parameters generated in the sensing unit are always obtained.

  Advantageously, the electrical plug connection connecting the sensing unit and the evaluation unit is a coaxial connector. By configuring the plug-in connection as a coaxial connector, the connection between the sensing unit and the evaluation unit is advantageously shielded and protected. The influence of external disturbances is attenuated or blocked, and communication between the sensing unit and the evaluation unit is not affected. The plug-in connection portion configured as a coaxial connector is multipolar, and a plurality of lines connecting the sensing unit and the evaluation unit can be simultaneously combined into one cable or one connection line. Since the coaxial connector is a standard part, it is not only very robust but also inexpensive. Since a cable shielded by a coaxial connector can be used, the entire path between the sensing unit and the evaluation unit is electromagnetically protected.

  Advantageously, the evaluation unit is arranged in the control device. Since the evaluation unit has no memory and only contains a few electronic components, it requires minimal space. The evaluation unit can be integrated as an ASIC. Further, the evaluation unit may be integrated in the control device so that a unique casing is not necessary. In addition to storing the parameters of the sensing unit, the control device itself can be responsible for other functions, such as control of the pressure measuring device and other components (open control or closed loop control).

  The invention further relates to a parameterization method for the pressure measuring device. The method of the invention has the advantage that the parameters stored in the control device are transmitted directly to the evaluation unit and re-examined with a new readout. This ensures that the transmitted dedicated parameters are correctly stored in the evaluation unit and that the pressure measuring device operates reliably and without problems. In the parameterizing method of the pressure measuring device of the present invention, that is, the sensing unit and the evaluation unit that is separate from the sensing unit, and the evaluation unit has an interface and a control register, The parameter of the sensing unit is transmitted to the interface of the evaluation unit. The parameters are then stored in the control register of the evaluation unit. In addition, the transmitted parameters are read from the control register of the evaluation unit by the control device, and subsequently the control device checks whether the setting of the control register of the evaluation unit is correct. Since the evaluation unit does not have its own memory, the parameters of the sensing unit are read from the memory of the control device and transmitted to the evaluation unit even when the engine of the vehicle is not ignited. This ensures that the latest parameters of the sensing unit are always used in the evaluation unit. By reading the parameters anew from the control register of the evaluation unit, the accuracy of the transmission is checked and a reliable operation of the pressure measuring device is ensured. A new reading of the parameter from the control register and transmission to the control device is not only performed once, but preferably is performed a plurality of times, and the accuracy of the stored parameters is repeatedly checked. Such inspections can be performed at set discrete times.

  Advantageously, the method of the invention further comprises the steps of transmitting a measurement signal from the sensing unit to the evaluation unit, adding a parameter stored in the control register to the measurement signal, forming a measurement value, and Transmitting the measured value from the evaluation unit to the control device. As a result, parameters belonging to the sensing unit are added to the signal transmitted from the sensing unit, and a measurement value is formed. The parameter is added to the measurement signal by, for example, using the offset voltage and the amplification factor as parameters, and parameterizing the amplifier in the evaluation unit using these parameters. In this way, the measurement signal obtained from the sensing unit is appropriately amplified and transmitted to the control device. This realizes separation of the sensing unit and the evaluation unit, and the control unit is supplied with already calibrated measurement values. The measurement technique used in the evaluation unit and the measurement signal evaluation technique are realized, for example, by an automatic zero set amplifier. That is, a known measurement technique can be used.

  Advantageously, according to the method of the invention, a parity check is regularly performed in the evaluation unit in order to check the correctness of the parameters stored in the control register, and if the parameters are incorrect, the interface is An error message is sent to the control device via The parity check in the evaluation unit can be performed by the control device instead of or in addition to the parameter reading from the control register. In this way, the evaluation unit can directly check the accuracy of the parameters stored in the control register. The monitoring can be carried out regularly or at very short time intervals, since the monitoring has little effort and does not affect the processing of the measurement values. This configuration also contributes to the reliability and robustness of the entire system.

  Advantageously, the method of the invention further comprises the steps of transmitting a dedicated parameter of the sensing unit to the control device and storing this parameter in the control device. When the entire system, i.e. the pressure measuring device and the control device is first assembled, the evaluation unit and the sensing unit must be coordinated with each other. At this time, the evaluation unit or the control device must identify and store parameters dedicated to the sensing unit to be used so that the pressure measuring device can operate without any problem. For this purpose, dedicated information of the sensing unit, for example, offset voltage or sensitivity is transmitted as a parameter to the control device. For example, the dedicated parameter is attached to the sensing unit in the form of a bar code, label or tag. By reading or typing the bar code automatically or manually and transmitting it, the parameters can be supplied to the controller.

  It is not only in the first assembly of the pressure measuring device that the parameters dedicated to the sensing unit need to be transmitted to the evaluation unit. If any of the sensing unit, evaluation unit, or control device fails or must be replaced for other reasons, the sensing unit dedicated parameters must be transmitted to the evaluation unit or control device.

  Advantageously, the transmission of parameters to the control device takes place via a diagnostic test device. Here, a test device used for diagnosis is additionally used to transmit the parameters of the sensing unit, for example, parameters applied to the outside of the sensing unit in the form of a bar code or other medium, to the control device . Since the control device stores the parameter in memory and transmits it to the evaluation unit, the parameter is also stored in the control register of the evaluation unit. The parameters are stored in a memory configured as an EEPROM. As soon as the ignition signal “ignition on” is generated, that is, as soon as the vehicle engine is started, the control device sends the parameters to the evaluation unit.

  Advantageously, the method of the invention further comprises the step of sending a start command from the control device to the interface of the evaluation unit, forming a test impulse by supplying a current defined in the evaluation unit to the sensing unit, thereby sensing Deliberately causing the unit to act, transmitting a response signal to the test impulse to the controller, and evaluating the response signal in the controller for inspection of the pressure measuring device. The sensing unit test and inspection start instructions are transmitted from the control unit to the interface of the evaluation unit. The interface accordingly controls a current source arranged in the evaluation unit and supplies a defined current to form a test impulse. For example, the test impulse is formed by unequilibrium the bond peeling identification part (Bondabrisserkennung). Accordingly, the sensing unit is intentionally unbalanced, and the measurement bridge circuit provided in the sensing unit is also unbalanced. At the same time, the test impulse is transmitted directly from the amplifier provided in the evaluation unit to the control device as a measurement value. The control unit evaluates and analyzes the measurement values formed by the test impulses using a diagnostic routine. The unbalanced measurement bridge circuit signal is returned to the control unit via the amplifier of the evaluation unit. This value can be used for analysis and inspection of the pressure measuring device.

  The present invention will be described in detail below with reference to examples.

  The structure of the pressure measuring device of the present invention applied to a vehicle brake system will be described with reference to FIG. The pressure measuring device in FIG. 1 includes a sensing unit 1 including a circuit as a measurement cell and an evaluation unit 2. The sensing unit 1 and the evaluation unit 2 are connected to each other via the plug-in connection portion 3. Since the plug-in connection part 3 is configured as a coaxial connector, it can be arbitrarily detached and reconnected. In this way, the sensing unit 1 and the evaluation unit 2 can be electrically connected to each other and can be spatially separated from each other. The sensing unit 1 is disposed in the pressure valve of the hydraulic mechanism, and the evaluation unit 2 is disposed outside the hydraulic mechanism.

  Furthermore, a control device 4 is connected to the evaluation unit 2. The control device 4 and the evaluation unit 2 may be arranged in one casing. Advantageously, the evaluation unit 2 is integrated in the casing of the control device 4.

  The sensing unit 1 has a measurement bridge circuit 5 composed of four measurement resistors 6. The measurement bridge circuit 5 is connected to a coaxial connector. One ESD varistor 7 and two series resistors 8 are provided as a protection circuit for the measurement bridge circuit 5. No further elements are required for the sensing unit 1. In particular, no memory, evaluation logic or other components are required in the sensing unit 1. The two series resistors 8 are connected to the signal line 9, and the measurement signal acquired by the measurement bridge circuit 5 is transmitted to the evaluation unit 2 via the coaxial connector.

  The evaluation unit 2 has an interface 10, and the dedicated parameters of the sensing unit are transmitted from the control device 4 to the evaluation unit 2 via this interface. At this time, the parameters transmitted to the evaluation unit 2 via the interface 10 are written to the control register 11. Further, the control device 4 can read out the dedicated parameter of the sensing unit from the control register 11 via the interface 10 again.

  The evaluation unit 2 further comprises a current source 12 connected to the interface 10. A start signal for triggering the formation of a test impulse in the current source 12 is transmitted from the control device 4 via the interface 10 and transmitted to the measurement bridge circuit 5 via the signal line 9. In this way, the measurement bridge circuit 5 is unbalanced (ie no longer tuned). The amplifier 13 is configured as an automatic zero set amplifier. The parameter value of the sensing unit is supplied to the amplifier 13 via the control register 11. The parameters here are in particular the offset voltage and the amplification factor, whereby the amplifier 13 is amplified by the measurement signal transmitted from the measurement bridge circuit 5 and a measurement value is formed. The measured value is supplied to the low pass 15 via a so-called clamp 14.

  The low-pass 15 may additionally be coupled to other diagnostic elements and / or an A / D converter (not shown), thereby converting analog measurements into digital measurements, indicated by arrow A As shown in FIG. Therefore, not only analog values but also digital values can be transmitted directly to the control device 4.

  The control device 4 has a memory 16 and a microcontroller 17 and performs processing of measured values and control of the evaluation unit 2. Since the microcontroller 17 can take charge of the functions of other elements, the control device 4 can control not only the pressure measuring device but also other elements. Furthermore, the control device 4 may include other components.

  The memory 16 is configured as an EEPROM in this embodiment. However, as long as the memory 16 is configured as a non-volatile memory, a memory known from the prior art may be used.

It is the schematic of the pressure measuring apparatus provided with the sensing unit, the evaluation unit, and the control apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Sensing unit, 2 Evaluation unit, 3 Plug connection part, 4 Control apparatus, 5 Measurement bridge circuit, 6 Measurement resistance, 7 ESD varistor, 8 Series resistance, 9 Signal line, 10 Interface, 11 Control register, 12 Current source, 13 Amplifier, 14 Clamp, 15 Low pass, 16 Memory, 17 Microcontroller

Claims (6)

A sensing unit (1) and a separate evaluation unit (2) spatially separated from the sensing unit , the evaluation unit having an interface (10) and a control register (11) In the parameterization method of the measuring device,
Transmitting parameters from the control device (4) to the interface (10) of the evaluation unit (2);
Storing the parameters in the control register (11) of the evaluation unit (2);
Reading the parameters from the control register (11) of the evaluation unit (2) by means of the control device (4);
Checking the accuracy of the parameters read from the control register (11) of the evaluation unit (2);
Transmitting a measurement signal from the sensing unit (1) to the evaluation unit (2);
Adding the parameter stored in the control register (11) to the measurement signal;
Forming a measurement;
Transmitting the measured value from the evaluation unit (2) to the control device (4);
A parameterizing method for a pressure measuring device, comprising: In order to check the accuracy of the parameters stored in the control register (11), a parity check is regularly performed in the evaluation unit (2). If the parameters are not correct, control is performed via the interface (10). The method according to claim 1 , wherein an error message is sent to the device. Transmitting parameters dedicated to the sensing unit (1) to the control device (4);
Storing the parameters in the control device (4);
Further comprising, according to claim 1 or 2 wherein the. 4. The method according to claim 3 , wherein the transmission of parameters to the control device (4) takes place via a diagnostic test device. Transmitting a start command from the control device (4) to the interface (10) of the evaluation unit (2);
Forming a test impulse by supplying a current defined in the evaluation unit (2) to the sensing unit (1), thereby causing the sensing unit (1) to act intentionally;
Transmitting a response signal to the test impulse to the control device (4);
Evaluating the response signal in the control device (4) for inspection of the pressure measuring device;
The method according to any one of claims 1 to 4 , further comprising: The method is performed in the brake system of a vehicle, any one process of claim 1 to 5.

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