Method and device for supplying a sensor with a regulated sensor supply voltage

0001The invention relates to a method and a device for supplying a sensor with a regulated sensor supply voltage.

0002Sensors whose operating voltage or supply voltage is lower than that of a Power source voltage supplied, for example, via a voltage transformer are supplied. This makes it possible to connect the sensors to a network comprising a higher voltage leads, than the operating voltage of the sensor is. In particular, during installation of sensors with an operating voltage of about 12V in a commercial vehicle, which Onboard power supply, a higher voltage of about 24V, there is the risk of not identifiable Disorders such as, for example, by a short circuit in the wiring harness due Verquetschungen or caused by chafing with neighboring lines. The misuse the sensor can to its destruction or making false sensor signals to lead.

0003The object of the invention is to provide a method and a device of the type mentioned create, where monitoring of the supply voltage, with which the sensor is operated, is achieved.

0004This object is in the process by the characterizing features of patent claim 1 and in the apparatus by the characterizing features of claim 5 dissolved.

0005In the invention, the sensor supply voltage, operated with which the sensor is collected, analyzed and output immediately as a status signal. It is by means an evaluation device which may be formed as a logic circuit, a first notification signal when it exceeds a predetermined tuned to the sensor operating range leave the sensor supply voltage.

0006When below the predetermined operating range of the sensor supply is a issued second alarm signal. A third signal is generated if the sensor supply voltage within the coordinated with the sensor operating range.

0007The alarm signals are transmitted in a reporting line between the evaluation and a control unit provided. The control unit evaluates the first two status signals for an error display and the third alarm signal for the continued Operating or release from the operation of the voltage converter and sensor. The control unit nor can the function of a process controller, the measured values ​​supplied by the sensor evaluates for process variables, have.

0008Due to the so obtained control of the sensor supply voltage is, for example, possible to bring 12V sensors in commercial vehicles with 24V electrical system used. Due to the achieved in the invention error detection, which immediately at the output can take place of the voltage converter, one achieves a reliable monitoring of the supply of the sensor and sensor operation. Moreover, one achieved with the aid of a digital error signal to vary the sources of error. Preferably has the first alarm signal at a high level, especially the level of converter supply voltage for example, about 24V and the second status signal has a low level, in particular about ground (0 V) potential.

0009The third alarm signal, with the aid of a frequency generator between the two potentials the first and the second signal, in particular between the ground and the potential the converter supply, be clocked.

0010Reference to the figures the invention is explained in more detail using an exemplary embodiment.

0011It shows<dl tsize="6"><dt>Fig. 1</dt><dd>a block diagram of an apparatus for supplying voltage to a sensor shaft cher one embodiment of the invention;</dd><dt>FIG. 2</dt><dd>in block diagram representation of a monitored voltage converter device which . In the embodiment of Figure 1 is used; and</dd><dt>Fig. 3</dt><dd>in block diagram a control unit, which in the embodiment of FIG. 1 is used.</dd></dl>

0012In the Fig. 1 is a block diagram of the overall arrangement of the power supply for a sensor 17 is shown. The sensor 17 is used for example for the detection of process variables. In particular, the sensor 17 may in a commercial vehicle, for example as a steering angle sensor in a steering column, are used. The time required for the operation Sensor supply voltage is supplied via a supply line sensor 22nd by means of a monitoring voltage transformer device 10, which has a preferably electronically has regulated voltage converter 12 (Fig. 2), the DC voltage at the output is of the voltage converter 12 to the sensor 17 for operating the appropriate voltage brought. For example, the DC voltage has a value of 24V, as he is common on board nets of commercial vehicles. This supply voltage is used to supply the DC converter 12 and is supplied via a converter supply line 21st Of the Voltage converter 12 regulates the DC voltage at 12V for operating the sensor 17th

0013The sensor 17 is a sensor via a signal line 26 or 26 with Messgrößensiganlleitung Control unit 13, which may also have the function of a process controller connected. serve the signals supplied by the sensor 17 via a sensor signal line 26 for process control, for example when driving a commercial vehicle. Due to the spatial Separation of the sensor 17 from the controller 13 faults can be at the sensor supply arise. These disturbances can by crimping or fraying of Lines with neighboring lines or by false jamming caused. This may mean, for example, that the sensor supply voltage in the Sensor supply line 22 due to influences from the converter supply line 21 is too high and having, for example, a Störbeaufschlagung with about 20V. Further, the sensor supply voltage in line 22 is too low, for example at about 7V, be. Such Troubles due of line breaks in the converter supply line 21, a ground line 20 and the like are caused.

0014To detect such faults, is, as can be seen from FIG. 2, to the output the voltage converter 12 an evaluation 11 which Auswertelogikschaltung a having, connected. For normal operation of the sensor 17 is an area of ​​the supply voltage provided, within which the sensor 17 is functioning properly. With a 12V sensor of this range, for example 9V to 14V can range.

0015If due to a malfunction, the sensor supply voltage in the embodiment shown > 14V is, causes the evaluation logic at the switch output 27, by a is implemented electronic switch, the voltage converting means 10 in one with the Switching output 27 associated signaling line 18, a first alarm signal with a constant high level, which preferably corresponds to the converter supply voltage 21 (V 24). If the sensor supply voltage on the line 22 <9 V, the switching output is 27 from the evaluation unit 11 is controlled such that the signaling line 18 a second message signal leads to a low level, preferably ground (0 V) potential.

0016If the sensor supply voltage is within the operating range of 9V to 14V, the control input of the switch output 27 is clocked by a frequency generator, so that the signaling line 18, for example, 30 Hz, between ground potential and the potential the converter supply line 21 is clocked for a third notification signal. With the help of Evaluation logic described is achieved without software the need to monitor Sensor supply.

0017The sensing line 18 is connected to an evaluation device 16, which in the control unit 13 may be provided (Fig. 3). The reporting line 18 is connected via a pull-down resistor 29 out against mass 20th The evaluation device 16 is preferably a digital evaluation logic for detection and differentiation of status signals delivered in the reporting line 18 educated. The first alarm signal comes at too high a sensor supply voltage is, may give an indication of a faulty sensor. In a memory 23 for the Error handling is stored at a specific memory of this status signal.

0018If the second alarm signal (low) is supplied via the signal line 18, it may indicate to a disturbance in the pipe system, which for the supply converter and / or sensor supply serving point. This signal is also stored in memory according to the 23rd In presence of an error in the error memory 23, which with a to the control unit 13 connected fault display device 19 is connected, is a function of the first or second alarm signal if an error message. Possibly can a lock- / enable circuit 24 for blocking the control unit function, which may be connected to the memory 23, are activated. If necessary, a Switching logic 25, a switch 28 are opened in the converter supply line 21, so that the sensor operation is interrupted.

0019If the signaling line 18, the third alarm signal preferably between the converter supply potential and ground potential is clocked, delivers, it indicates normal Sensor operating at. The control unit function is released or continued.

0020It can also be checked whether the signaling line 18 is in good working condition. To this end, is prior to the switching of the sensor 17 by closing the switch 28, the potential of the Signaling line 18 tested. If this potential is at ground (0 V) potential, is Release the control device function via the switching logic 25 of the switch 28 in the converter supply line 21 closed. It is with correct sensor supply within the Range of 9V to 14V, the signaling line 18 to the clocked alternating signal (third notification signal) is such that the control unit function of the lock- / enable circuit 24 is released.

0021Each destruction of the signaling line 18, for example by a short to ground potential the ground line 20, to an electrical outlet or by cable breakage leads to a switch the clocked alternating signal at the corresponding constant potential of the first or the second signal. These are, as described above, evaluated in the control device. 13

0022The evaluation of the interference signals supplied by the sensing line 18 (first notification signal or second notification signal) may further for switching off the electronic stability program (ESP) lead. Moreover, the electronic brake system, an error message will be given. It These are more safety-critical function of the controller. 13

LIST OF REFERENCE NUMBERS

0023<dl tsize="2" compact="compact"><dt>10</dt><dd>Control voltage transformer device</dd><dt>11</dt><dd>evaluation</dd><dt>12</dt><dd>voltage converter</dd><dt>13</dt><dd>control unit</dd><dt>15</dt><dd>frequency generator</dd><dt>16</dt><dd>evaluation</dd><dt>17</dt><dd>sensor</dd><dt>18</dt><dd>signaling line</dd><dt>19</dt><dd>Error indicator</dd><dt>20</dt><dd>ground line</dd><dt>21</dt><dd>Converter supply line</dd><dt>22</dt><dd>Sensor supply line</dd><dt>23</dt><dd>Memory for error handling</dd><dt>24</dt><dd>Lock- / enable circuit</dd><dt>25</dt><dd>switching logic</dd><dt>26</dt><dd>Sensor signal line</dd><dt>27</dt><dd>Switching output, an electronic switch</dd><dt>28</dt><dd>switch</dd><dt>29</dt><dd>pulldown resistor</dd></dl>