DE102016122227B3 - TEST APPARATUS AND TEST METHOD - Google Patents

Abstract

The present invention discloses a test device (100, 200, 300) for safely testing an electrical load (101, 201, 301) with a predetermined trip current, comprising a current source (103, 203, 303) which is designed to generate an electrical test current ( 104, 204, 304) of a predetermined first current intensity, wherein the first current intensity is smaller than the predetermined tripping current, with a current limiter (105, 205, 305), the input side to the current source (103, 203, 303) is coupled and on the output side with the electrical load (101, 201, 301) can be coupled and is designed to limit the electrical test current (104, 204, 304) to a predetermined second current and the limited test current (106, 206, 306) to the electrical To direct consumers (101, 201, 301), wherein the second current intensity is smaller than the first current, and with a measuring device (107, 207, 307) connected to the electrical load (101, 201, 301) can be coupled and is designed to measure the electrical voltage (108, 208, 308) dropping across the electrical load (101, 201, 301) for testing the electrical load (101, 201, 301). Furthermore, the present invention discloses a corresponding test method.

Description

Technical area

The present invention relates to a test device for safe testing of an electrical load. Furthermore, the present invention relates to a corresponding test method.

Technical background

The present invention is explained below mainly in connection with the testing of pyrotechnic articles, but is not limited thereto.

Pyrotechnic articles are used in a variety of applications. For example, electrically triggerable pyrotechnic igniter are used in airbags to allow rapid inflation of the airbag. In such pyrotechnic detonators faulty tripping is to be avoided. Therefore, pyrotechnic igniters are usually subjected to a so-called EOL test (End Of Line) or end-of-line testing by the manufacturer. Such a test is carried out at the end of the production and is to ensure the correct function of the respective detonator. Further, e.g. during the pre-assembly of airbag assemblies, the continuous and correct connection between the airbag and the wiring harness, which later connects the airbag to the airbag control unit, is checked.

The systems for testing pyrotechnic igniters must comply with safety standards and the persons who operate them, e.g. to adequately protect against the effects of a misfire caused by the test or test device itself or a faulty device under test (DUT).

Normally, protective grids, enclosures and covers can be attached to the test equipment, which protect the operator in triggering such a pyrotechnic igniter.

However, such measures disturb the workflow and extend the test time. Consequently, it also creates an incentive for the operating personnel to bypass or manipulate the security measures.

Furthermore, the necessary adaptation of e.g. Protective gratings and covers to changed, new or different samples the flexibility and reusability of each test system.

• a) Mittel zur Erzeugung eines Messstromes (Im) mit einem vorbestimmten Wert,
• b) Mittel zur Überprüfung des vorbestimmten Wertes des Messstromes unter Umgehung der Zündpille,
• c) Mittel zur Beaufschlagung der Teilkomponente mit eingebauter Zündpille mit dem geprüften Messstrom für einen vorbestimmten Zeitraum und
• d) Mittel zur Bestimmung des Innenwiderstandes der Teilkomponente mit eingebauter Zündpille und Ableitung eines den Einbauzustand signalisierenden Prüfsignals durch Vergleich mit einem Sollwert aufweist.

The German patent application DE 10 2004 042 364 A1 describes a measuring device and a measuring method for non-destructive testing of a squib installed in a subcomponent, in particular a motor vehicle. In order to enable a simple and non-destructive inspection of the proper installation of a sub-component with integrated squib, it is disclosed that the measuring device

• a) means for generating a measuring current (Im) having a predetermined value,
• b) means for checking the predetermined value of the measuring current, bypassing the squib,
• c) means for acting on the subcomponent with built-in squib with the tested measuring current for a predetermined period of time and
• d) comprises means for determining the internal resistance of the sub-component with built-in squib and derivative of a test signal indicating the installation state by comparison with a desired value.

The international application WO 2016/146 280 A1 discloses a method and apparatus for servicing an actuator for an airbag control device. The method includes a step of impressing an electrical current flow through the actuator using an electrical voltage having a voltage value. The method also has a step of determining an electrical measuring current through the actuator. In this case, the electrical measuring current through the actuator occurs due to the impressed electrical current flow through the actuator. Furthermore, the method comprises a step of performing a comparison of the electrical measuring current through the actuator with a threshold value. In addition, the method comprises a step of adjusting the voltage value of the electrical voltage for impressing the electrical current flow through the actuator as a function of the comparison.

Description of the invention

The object of the present invention is therefore to enable a less expensive and functionally reliable testing of electrical consumers.

The object is solved by the subject matters of the independent claims.

Accordingly, a test device for safe testing of an electrical load with a predetermined trip current, for example, a pyrotechnic igniter is provided, which trigger when the tripping current or a tripping energy is exceeded, so ignite would. The tester has a power source that is formed is to generate an electrical test current of a predetermined first current, wherein the first current is less than the predetermined tripping current. Furthermore, the test apparatus has a current limiter, which is coupled on the input side to the power source and output side with the electrical load can be coupled, for example via appropriate test connections in the test apparatus, and is designed to limit the electrical test current to a predetermined second current and the limited test current to conduct to the electrical load, wherein the second current is less than the first current. Finally, the test apparatus has a measuring device which can be coupled to the electrical load, that is, when testing is coupled to the electrical load, and is designed to measure the voltage drop across the electrical load electrical voltage for testing the electrical load.

Further provided is a test method for safely testing an electrical load having a predetermined trip current with a test device having a current source and a current limiter connected in series with the current source. The method comprises generating an electrical test current of a predetermined first current, in particular with the current source, wherein the first current is less than the predetermined tripping current, limiting the electrical test current to a predetermined second current, in particular with the current limiter, wherein the second current less than the first current level, passing the limited test current to the electrical load, and measuring the voltage drop across the electrical load to test the electrical load.

With the testing apparatus according to the present invention, e.g. pyrotechnic articles, e.g. Airbag detonator, to be subjected to a test. For this purpose, the electrical load is applied to the limited test current and measured the voltage that drops across the electrical load. Based on the current of the limited test current and the measured voltage, the resistance of the electrical load can be calculated. The calculated resistance value allows a statement as to whether the electrical load is e.g. is properly connected to the respective supply lines and has the respective nominal resistance.

Pyrotechnic igniters usually have a highly flammable primary charge and a filament that ignites the primary charge during annealing. The filament thus represents a resistor or electrical load. In order to avoid ignition during the test of the electrical load, the tripping current or ignition current of the respective consumer must never be exceeded, not even in the event of a fault in the test system.

In the test apparatus according to the invention, therefore, the current source always outputs a test current of the first current intensity. The first current is smaller than the tripping current of the electrical load. The electrical load does not trip when it is charged with the test current of the first current.

In addition, the test current is limited by the current limiter to the second current, which is smaller than the first current. The electrical load can therefore not trigger when it is charged with the test current of the second current.

Thus, if the current source has a fault during a measurement and outputs an increased current, this is limited by the current limiter to the second current level and triggering of the electrical load is reliably prevented.

If, on the other hand, the current limiter has an error during a measurement and does not correctly limit the test current provided to the second current, the test current can reach at most the first current value. The electrical load will therefore not trigger in this case of error.

During a measurement, the test device according to the invention consequently always maintains a safe state in the case of a single fault in which the strength of the test current is below the magnitude of the tripping current.

The combination of the current source with the current limiter therefore reliably prevents the triggering of the electrical load in the case of a single fault. Thus, the test device according to the present invention allows a functionally safe and energy-limited testing of the electrical load.

In contrast to conventional methods, which are based on the principle that an overcurrent is first detected and then switched off, the present invention is not dependent on the electrical load and its electrical properties. Rather, regardless of the electrical load and e.g. the current flowing through the consumer a safe state taken.

Further, particularly advantageous embodiments and modifications of the invention will become apparent from the dependent claims and the following description, wherein the features of various embodiments may be combined to form new embodiments. In particular, the independent claims of a claim category can also be developed analogously to the dependent claims of another claim category.

In one embodiment, the test apparatus has a self-test device, which is designed to test the function of the current source and / or the function of the current limiter before starting a test of the electrical load, and the electrical

Consumer only with positively tested function, so if there is no error, to couple with the current limiter.

The testing apparatus of the present invention is not superficial for use in an application, e.g. in a vehicle, designed. In such applications, although e.g. when starting the vehicle, the function of the airbags checked. However, it is usually assumed that only the test equipment or the wiring or the consumer are defective. Multiple errors are therefore not taken into account.

The present invention may e.g. can also be used at a tape end test. Consequently, since the test of the electrical load takes place independently of an operation of the electrical load, an intensive test of the test device can be carried out before the electrical load itself is tested. At the end of the tape check, a defective DUT, ie a defective electrical load, is assumed as the rule or a safe event. Therefore, the test device must be designed so that even a combination of defective test device and DUT does not lead to a triggering of the DUT.

While in a test, e.g. in a vehicle in the event of a failure of the test system or the airbag, only a general airbag fault can be displayed, the present invention allows a user to inform who can wait and repair the test device in case of failure, in order to check the electrical load continue. The function of the test device can go beyond the mere information. Rather, the test device can assume a safe state. This safe condition can be maintained by the test apparatus, and e.g. stop the test. In the case of a present error of the test apparatus, the user may e.g. be forced to repair the system. This prevents further testing despite faults without maintenance.

The self-test can be performed in the test device according to the invention between all tests of electrical consumers or at certain intervals, also called test disks. Thus, during operation of the test apparatus, it can thus be ensured permanently that there is no error, that is, during e.g. several electrical consumers are tested.

In one embodiment, the self-test device has a first current sensor with a first switch arranged in series therewith. The first current sensor may be coupled on the input side to the output of the current source and the first switch may be coupled on the output side to an internal ground of the test device.

The current sensor may e.g. have a shunt resistor with a parallel voltage measurement. From the resistance value of the shunt resistor and the result of the voltage measurement, the current can be calculated. The first switch may e.g. a transistor that connects the shunt resistor to the internal ground as a low-side switch. It is understood that contactless current sensors can also be used as the current sensor, e.g. Hall sensors, flux sensors, current transformers and the like. This is particularly advantageous if the current intensities are so great that the losses in the shunt resistor become too large.

With the aid of the first current sensor, the current generated by the current source can be detected and e.g. even before the start of a test, a fault in the power source can be detected if it generates too high or too low a current.

If the power source operates correctly, it can - as explained below - be used, for example. the test of the current limiter are performed.

In one embodiment, the self-test device can have a second current sensor, which can be coupled on the input side to an output of the current limiter and can be coupled on the output side to the electrical consumer, to which a first connection of the electrical consumer can therefore be connected for testing. By measuring the limited test current leaving the current limiter, the correct function of the current limiter can be diagnosed at the same time. Is the limited test current less than generated by the power source test current, the current limiter is faultless. However, if the limited test current is equal to the test current generated by the current source, the current limiter is defective. This diagnostic function would not be possible if the value for the limited test current were greater than the value of the test current generated by the current source.

The second current sensor is used to test the current limiter. In contrast to the first current sensor, the second current sensor is located in the test circuit, ie the circuit which also contains the electrical load. Consequently, with the aid of the second current sensor, the output current of the current limiter can be detected not only before but also during a test.

With the current detected before the test, an error in the current limiter can be detected early. With the current detected during a test, the measured voltage drop across the electrical load can be used, e.g. whose resistance is calculated. By measuring the current between the current limiter and the electrical load consumer testing is independent of fluctuations, at least within acceptable limits, the output current of the current source and the current limiter, since the resistance of the electrical load from the current and voltage measurement can be calculated.

In particular, if, due to a fault, the output currents have a lower current than required, the testing of electrical consumers can be carried out, for example. continue until e.g. a service technician is available to service the tester. In case of failure but can also be taken the safe state. The test is no longer possible in this condition (inter alia to force the operator of the tester to reset the tester within a certain period of time).

In one embodiment, the self-test device may include a second switch that may be electrically connected between the output side terminal of the second current sensor and the internal ground. Also the second switch may e.g. a transistor that connects the second current sensor with the internal ground as a low-side switch. This makes it possible to measure the output current of the current limiter even if no electrical load is connected, so even before the test.

In combination with the first current sensor and the first switch, in the self-test, e.g. at first only the first switch is closed. The output current of the current source can then be detected via the first current sensor. If the current source is faultless, ie provides the desired current, the second switch can be closed and it can be checked whether the current limiter limits the output current of the current source accordingly. Only when these two phases of the self-test have been completed successfully can e.g. the electrical consumers are switched on.

In one embodiment, the test apparatus may comprise a third switch which can be coupled on the input side to the output of the current limiter or the second current sensor and on the output side to a first terminal of the electrical load, e.g. via appropriate test connections in the test device.

With the help of the third switch, the connection between the tester and the electrical load can be controlled or disconnected. Thus, the electrical load can be switched by the third switch, e.g. only be connected to the test device after the self-test has been completed. Furthermore, the electrical load can be separated from the test device in a controlled manner after the test. Mechanical connections can therefore be made and released when the electrical load is de-energized.

The test apparatus has low-side switches with the first and second switches. The third switch can be a high-side switch. This has the advantage that for the switches, at least in electronic design, inexpensive switching elements, e.g. Transistors, can be used and they can be switched with voltages that are as large as the supply voltage of the tester. In the event of a fault, there is no voltage in the test device that is greater than the supply voltage. Consequently, no greater voltage can reach the electrical load from the test device.

In one embodiment, the self-test device can have a third current sensor, which can be coupled on the input side to a second terminal of the electrical load and can be coupled on the output side to the internal ground of the test device.

The output side connected to the electrical load third current sensor allows current measurement in the low-side or ground path. With the help of this measurement, an external conclusion of the test circuit can be detected on other circuits. If such an external conclusion exists, the current flowing into the electrical consumer is not equal to the current flowing from the electrical consumer. The deviation arises from the fact that either power from the external circuit in the electrical Consumer or from the electrical load into the external circuit.

However, when using the third current sensor to detect external terminals, the internal ground must be coupled to an external ground. A potential-free test of the electrical load is not possible then.

Furthermore, the resistance of the shunt resistor used in the current sensor must be so large that the current through the load remains below the ignition current of the electrical load. It may also be provided only the resistance between the electrical load and the internal ground. This limits the current through the consumer when it has an end against an external voltage on one side and is connected to an external ground via the test device.

A diagnosis of such an external conclusion is e.g. possible by the tester also controlling the external voltage source which is still necessary for testing the DUT, e.g. at cockpits. These may e.g. controlled by external contactors. Before the external source is released, it can be tested whether an external conclusion exists. Furthermore, galvanic separation and subtraction of the current flowing into the electrical load and of the current flowing out of the electrical load can also take place. If the current flowing into the electrical load is not equal to the current flowing from the electrical load, then there is an external conclusion. Finally, current limiting, e.g. the above-mentioned resistance, on low side, ie on the internal ground, be provided with a corresponding diagnosis.

In one embodiment, the self-test device may have a fourth switch, which may be arranged parallel to the third current sensor, thus bridging it in the closed state.

As already explained above, the shunt resistor in the third current sensor may have a certain minimum size, so that the current is limited by the electrical load at an external end. However, a large resistance restricts the measuring range or falsifies the result. With the aid of the fourth switch, the third current sensor, ie also the shunt resistor, can be bridged for a normal test, e.g. after making sure that there is no external conclusion. Furthermore, with the fourth switch, the clamp voltage can be restricted to a predetermined value.

In an embodiment, the measuring device may be configured to provide measured values via a data link, e.g. a data bus or a data network to be transmitted to a control device of the test apparatus. The measuring device may also be integrated in a test adapter, which may be e.g. having a galvanically isolated communication interface.

Of course, the individual current sensors can also be coupled to the control device via a data connection. These may also be integrated in a test adapter, which may be e.g. having a galvanically isolated communication interface. This is particularly advantageous for the measurement of the voltage drop across the electrical load. In this way, the voltage drop can be detected close to the test object or DUT. This increases the robustness of the voltage measurement against external disturbances. At the same time, reliability and repeat accuracy are increased.

It is understood that the above-explained measurements and actuations of the switches in the test apparatus are provided with a control device, e.g. a controller, PC, a PLC or the like, which is coupled to the measuring device, the current sensors and the switches. Furthermore, a central control device can control or evaluate a plurality of test devices.

Voltages and currents may e.g. be measured using analog-to-digital converters or corresponding modules in a PLC or discrete logic.

Short description of the figures

The principle of the invention will be explained in more detail below with reference to the accompanying figures by way of example. The same components are provided with similar reference numerals in the various figures. Show it:

1 a block diagram of an embodiment of a test device according to the invention;

2 a block diagram of another embodiment of a test device according to the invention;

3 a block diagram of another embodiment of a test device according to the invention;

4 a flowchart of an embodiment of a test method according to the invention; and

5 a flowchart of another embodiment of a test method according to the invention.

Detailed description

1 shows a block diagram of a tester 100 , The tester 100 is used for electrical testing of the electrical load 101 , This can, for example, the pyrotechnic igniter 101 to be an airbag. Such detonators 101 have a filament that ignites an explosive charge when a predetermined tripping current is exceeded. It is therefore important to use this tripping current when testing the detonator 101 not to be exceeded.

The tester 100 has a voltage source 102 or power supply 102 on. This can be any voltage source that can provide a high enough voltage and a high enough current. The voltage source 102 the tester 100 is not earthed or coupled to an external ground. The examination of the detonator 101 So it is potential free.

With a first connection of the voltage source 102 coupled is a power source 103 , The power source 103 gives a test current 104 with a first current level, which is below the tripping current of the electrical load 101 lies. Would the electrical consumer 101 ie directly with the test current 104 yet he would not trigger or detonate.

To the power source 103 closes a current limiter 105 at. The current limiter 105 limits the test current 104 to a second amperage and gives a limited test current 106 out. The second current is below the first current. It is therefore also lower than the tripping current of the electrical load 101 ,

With the current limiter 105 coupled is the electrical load 101 via a first terminal, the second terminal of the electrical consumer 101 with the second connection of the voltage source 102 is coupled. The limited test current 106 thus flows through the electrical load 101 to the voltage source 102 ,

The flow of current in the electrical load 101 generates a voltage drop across the electrical load 101 , This falling voltage 108 is through the measuring device 107 recorded and used to test the electrical load 101 ,

For testing the electrical load 101 can be based on the measured voltage 108 and by the electrical consumer 101 flowing limited test current 106 whose resistance is calculated and compared with a set resistance. If the calculated resistance corresponds to the setpoint resistance, eg within a specified confidence interval of +/- 20%, +/- 10% or +/- 5%, the test is successful or the electrical load 101 error-free.

The arrangement of the test device 100 can be said to be functionally safe, as they are at a single fault of the power source 103 or the current limiter 105 the tripping current of the electrical load 101 can not exceed. The electrical consumer 101 So can not trigger in such a single error. Under a single error is an error in the tester 100 to understand in which only one source of error in the tester 100 is available.

The first current can e.g. 5 mA. The second current can e.g. 8 mA. Finally, the tripping current can be e.g. 10 mA. It is understood that these values are merely exemplary and may vary depending on the application.

2 shows a further embodiment of a tester 200 , The tester 200 based on the tester 100 and extends this to a self - test facility, which in 2 is explained on the basis of their elements, but for the sake of clarity is not shown separately and designated.

The elements of the self-test device serve, even before the test of the electrical load 201 , the tester 200 to check for errors yourself. The test of the test device 200 can do this before each test of an electrical consumer 201 or be carried out at certain intervals, for example when the consumer is energized for a long time and cyclically a test disk is executed. This can be avoided that the electrical consumer 201 is energized at all when the tester 200 has an error.

The self-test device has a first current sensor 209 on, the only example of a shunt resistor 210 and a voltage measurement 211 over the shunt resistor 210 having. It is understood that alternative any other type of current sensor can be used. Especially at higher currents and thus higher losses at the shunt resistor 210 For example, contactless current sensors can also be used.

The first current sensor 209 is in series with a first switch 212 between the output of the power source 203 and an internal mass 213 the tester 200 arranged. For example, the first switch 212 closed before the electrical load 201 with the tester 200 is coupled, the electrical test current flows 204 completely through the first current sensor 209 , With the help of the first current sensor 209 can therefore already before a test of an electrical consumer 201 the function of the power source 203 be checked. Flows eg from the power source 203 If the current is too high or too low, an error can be detected. The test of an electrical consumer 201 can then be canceled.

The self-test device also has a second current sensor 214 which also has, for example only, a shunt resistor and a voltage measurement across the shunt resistor. For the sake of clarity, the shunt resistor and the voltage measurement are not provided with further reference symbols. It goes without saying that alternative types of current sensors can also be used here. In particular, at higher currents and thus also higher losses at the shunt resistor eg contactless current sensors can be used.

The second current sensor 214 is between the output of the current limiter 205 and the electrical consumer 201 arranged, so lies in the test circuit. This means that even during the test of the electrical load 201 the limited test current 206 through the second current sensor 214 flows. A second switch 215 is between the output of the second current sensor 214 So on the side of the electrical consumer 201 , and the internal mass 213 arranged. Will be the second switch 214 eg before connecting the electrical load 201 , closed, the limited test current flows 206 through the second current sensor 214 over the second switch 215 to the internal mass 213 , So can the function of the current limiter 205 even before the test of an electrical consumer 201 being checked. Will be on the second switch 215 waived, the function of the current limiter can 205 eg at the same time as the beginning of the electrical load test 201 respectively. This is possible in particular if previously the correct function of the power source 203 was tested.

The tester 200 also has a third switch 216 on that between the second current sensor 214 , after the departure of the second switch 215 , and the electrical consumer 201 is arranged. The third switch 216 serves to the electrical consumer 201 controlled, so targeted, to the tester 200 to couple or disconnect from this. So can the mechanically already connected electrical consumers 201 eg only after a successful self-test of the test device 200 be electrically coupled with this.

The tester 200 also has a third current sensor 217 on top of that in the internal mass 213 measures flowing electricity. With the help of the second current sensor 214 and the third current sensor 217 can be compared, whether the same electricity in the electrical load 201 flows, which also flows out of this. So it can be a shunt or an external conclusion between the electrical consumer 201 or the test device 200 and an external source 250 or an external ground 251 (For clarity, only once provided with reference numerals) are recognized. To be able to measure such an external current flow, the internal ground must 213 with the external ground 251 get connected.

In particular, the fourth current sensor 217 or its shunt resistor can be dimensioned such that at an external end of the electrical load 201 by the electrical consumer 201 flowing electricity is limited so that the electrical load 201 does not trip, so remains below the tripping current.

The current sensors shown so far 209 . 214 and 217 use shunt resistors with a voltage measurement to determine the current. Since shunt resistors are in the circuit, they can falsify the measurement result or limit the measuring range. To the influence of the third current sensor 217 to eliminate the measurement is a fourth switch 218 provided in parallel with the third current sensor 217 is arranged. The fourth switch 218 thus bridges the third current sensor in the closed state 217 , Although not explicitly shown, a corresponding switch may also be used for the second current sensor 214 be provided.

Alternative to the third current sensor 217 can also be provided only a corresponding resistor that limits the current in the event of a fault, ie at an external end. After a positive test, ie if there is no external conclusion, the resistance for the measurement can be determined by the fourth switch 218 be bridged. It can then also the measuring device 207 used to detect an end to an external voltage source.

In terms of the test device 200 are exemplified three current sensors 209 . 214 and 217 and corresponding switches 212 . 215 . 216 , and 218 explained. It is understood that even a selection of current sensors 209 . 214 and 217 and corresponding switches 212 . 215 . 216 , and 218 can be used. For example, in one embodiment, only the first current sensor 209 with the first switch 212 or the second current sensor 214 with the second switch 215 or the third current sensor 217 with the fourth switch 218 be provided. Furthermore, in one embodiment, a combination, for example, from the first current sensor 209 with the first switch 212 or second current sensor 214 with the second switch 215 and the third current sensor 217 with the fourth switch 218 to be available. It can only be the first current sensor 209 with the first switch 212 and the second current sensor 214 with the second switch 215 as well as the third switch 216 be provided.

In the variants without the third current sensor 217 can also be applied to grounding or external ground 251 be waived.

The tester 200 enabled by the current sensors 209 . 214 and 217 as well as the switches 212 . 215 . 216 and 218 an intensive internal test of the test device 200 even before ever electricity from the tester 200 flows through the electrical load. If there is a positive internal test, that is, without errors, then, for example, the electrical load 201 being checked.

3 shows a block diagram of a tester 300 , The tester 300 based on the tester 100 , It is understood that the to the testing device 300 explained features also in connection with the tester 100 and the tester 200 can be used.

At the test device 300 is a control device 319 provided which the individual elements of the test apparatus 300 controls. For this purpose, the control device 319 commands 320 to the elements of the test device 300 transmit or data 321 , eg measured values or status messages, from the elements of the test device 300 receive. The control device 319 is outside the tester 300 shown. This is to show that the control device 319 locally independent of the other elements of the test device 300 can be arranged. For this purpose, the test device 300 For example, be coupled via digital or analog connections with the other elements. It is understood that the control device 319 but also within the tester 300 can be arranged.

As a control device 319 Any type of control that is capable of doing so can be used to control the processes of the test device 300 or the test of the electrical consumer 301 to control. For example, a controller, an embedded system, a PLC or discrete logic can be used.

The measuring device 307 is at the tester 300 from the other elements of the tester 300 discontinued and with the control device 319 via a data connection 322 coupled. The data connection 322 may be, for example, a data bus, a network or the like. This arrangement makes it possible to connect to the electrical load 301 falling voltage 308 very close to the electrical consumer 301 to eat. This makes the measurement more robust and less error prone.

4 shows a flowchart of a test method according to the invention for safe testing of an electrical load 101 . 201 . 301 with a predetermined trip current through a tester 100 . 200 . 300 that is a power source 103 . 203 . 303 and one with the power source 103 . 203 . 303 series-connected current limiters 105 . 205 . 305 having. It may, for example, one of the test devices described above 100 . 200 . 300 be used.

For ease of understanding, reference numerals will be used in the following description 1 - 3 retained as a reference.

In a first step S1 of generating an electrical test current 104 . 204 . 304 generates a predetermined first current. The first current is less than the predetermined tripping current.

In a second step S2 of the limitation, the electrical test current 104 . 204 . 304 limited to a predetermined second current, the second current is less than the first current.

In a third step S3 of conducting the limited test current 106 . 206 . 306 to the electrical consumer 101 . 201 . 301 directed.

Finally, in a fourth step S4 of measuring, the above is the electrical load 101 . 201 . 301 falling voltage 108 . 208 . 308 for testing the electrical consumer 101 . 201 . 301 measured.

Out of the by the electrical consumer 101 . 201 . 301 flowing limited test current 106 . 206 . 306 and the above the electrical consumer 101 . 201 . 301 declining electrical voltage 108 . 208 . 308 can then, for example, the resistance of the electrical load 101 . 201 . 301 be calculated and compared with a setpoint.

5 shows a flowchart of another test method for safe testing of an electrical load 101 . 201 . 301 ,

The procedure of 5 complements the procedure of 4 by a step S5 of testing, in which the function of the current source 103 . 203 . 303 and / or the function of the current limiter 105 . 205 . 305 before starting a test of the electrical load 101 . 201 . 301 being checked. A check of the electrical load 101 . 201 . 301 in steps S3 and S4 takes place only when positively tested function of the power source 103 . 203 . 303 and / or the current limiter 105 . 205 . 305 instead of. Is an error in the power source 103 . 203 . 303 or the current limiter 105 . 205 . 305 determined, the process goes into a safe state S6. This is the electrical consumer 101 . 201 . 301 not energized.

Testing S5 may be to measure the generated test current 104 . 204 . 304 , in particular between the power source 103 . 203 . 303 and an internal mass 213 the tester 100 . 200 . 300 , exhibit. Further, the test S5 may be the measurement of the limited test current 106 . 206 . 306 , in particular between the current limiter 105 . 205 . 305 and an internal mass 213 the tester 100 . 200 . 300 , exhibit. Finally, the testing may also measure a current between the electrical load 101 . 201 . 301 and the internal mass 213 the tester 100 . 200 . 300 exhibit.

As the devices and methods described in detail above are exemplary embodiments, they may be readily modified by one skilled in the art to a wide extent without departing from the scope of the invention. In particular, the mechanical arrangements and the size ratios of the individual elements to each other are merely exemplary.

LIST OF REFERENCE NUMBERS

100, 200, 300

Tester

101, 201, 301

electrical consumer

102, 202, 302

voltage source

103, 203, 303

power source

104, 204, 304

electrical test current

105, 205, 305

current limiter

106, 206, 306

limited test current

107, 207, 307

measuring device

108, 208, 308

tension

209

first current sensor

210

shunt resistor

211

voltage sensor

212

first switch

213

internal mass

214

second current sensor

215

second switch

216

third switch

217

third current sensor

218

fourth switch

250

external source

251

Dimensions

319

control device

320

commands

321

dates

322

Data Connection

S1-S5

steps

S6

safe condition

Claims (15)

Tester ( 100 . 200 . 300 ) for the safe testing of an electrical consumer ( 101 . 201 . 301 ) with a predetermined trip current, with a current source ( 103 . 203 . 303 ), which is designed to generate an electrical test current ( 104 . 204 . 304 ) of a predetermined first current intensity, wherein the first current intensity is smaller than the predetermined tripping current, with a current limiter ( 105 . 205 . 305 ), the input side with the power source ( 103 . 203 . 303 ) and on the output side with the electrical consumer ( 101 . 201 . 301 ) and is adapted to the electrical test current ( 104 . 204 . 304 ) to limit to a predetermined second current and the limited test current ( 106 . 206 . 306 ) to the electrical consumer ( 101 . 201 . 301 ), wherein the second current is less than the first current, and with a measuring device ( 107 . 207 . 307 ) connected to the electrical consumer ( 101 . 201 . 301 ) is coupled and is formed, the above the electrical load ( 101 . 201 . 301 ) falling voltage ( 108 . 208 . 308 ) for testing the electrical consumer ( 101 . 201 . 301 ) to eat. Tester ( 100 . 200 . 300 ) according to claim 1, with a self-test device, which is formed before the beginning of a test of the electrical load ( 101 . 201 . 301 ) the function of the power source ( 103 . 203 . 303 ) and / or the function of the current limiter ( 105 . 205 . 305 ) and the electrical consumer ( 101 . 201 . 301 ) only with positively tested function with the current limiter ( 105 . 205 . 305 ) to couple. Tester ( 100 . 200 . 300 ) according to claim 2, wherein the self-test device comprises a first current sensor ( 209 ) with a first switch arranged in series therewith ( 212 ), in particular wherein the first current sensor ( 209 ) on the input side with the output of the power source ( 103 . 203 . 303 ) and the first switch ( 212 ) on the output side with an internal ground ( 213 ) of the test device ( 100 . 200 . 300 ) is coupled. Tester ( 100 . 200 . 300 ) according to one of the preceding claims 2 and 3, wherein the self-test device comprises a second current sensor ( 214 ), the input side with an output of the current limiter ( 105 . 205 . 305 ) and on the output side with the electrical consumer ( 101 . 201 . 301 ) can be coupled. Tester ( 100 . 200 . 300 ) according to claim 4, wherein the self-test device comprises a second switch ( 215 ) electrically connected between the output side terminal of the second current sensor (FIG. 214 ) and the internal mass ( 213 ) is arranged. Tester ( 100 . 200 . 300 ) according to one of the preceding claims, with a third switch ( 216 ), which on the input side with the output of the current limiter ( 105 . 205 . 305 ) and the output side with a first terminal of the electrical load ( 101 . 201 . 301 ) can be coupled. Tester ( 100 . 200 . 300 ) according to one of the preceding claims 2 to 6, wherein the self-test device comprises a third current sensor ( 217 ), which on the input side with a second terminal of the electrical load ( 101 . 201 . 301 ) and the output side with the internal ground ( 213 ) of the test device ( 100 . 200 . 300 ) is coupled. Tester ( 100 . 200 . 300 ) according to claim 7, with a fourth switch ( 218 ), which is parallel to the third current sensor ( 217 ) is arranged. Tester ( 100 . 200 . 300 ) according to one of the preceding claims, wherein the measuring device ( 107 . 207 . 307 ), measured values via a data connection ( 322 ) to a control device ( 319 ) of the test device ( 100 . 200 . 300 ) transferred to. Test method for safely testing an electrical consumer ( 101 . 201 . 301 ) with a predetermined trip current with a test device ( 100 . 200 . 300 ), which is a power source ( 103 . 203 . 303 ) and one with the power source ( 103 . 203 . 303 ) in series current limiters ( 105 . 205 . 305 ), the method comprising: generating (S1) an electrical test current ( 104 . 204 . 304 ) of a predetermined first current intensity, wherein the first current intensity is smaller than the predetermined tripping current, limiting (S2) of the electrical test current ( 104 . 204 . 304 ) to a predetermined second current, wherein the second current is less than the first current, conducting (S3) of the limited test current ( 106 . 206 . 306 ) to the electrical consumer ( 101 . 201 . 301 ), and measuring (S4) the above the electrical load ( 101 . 201 . 301 ) falling voltage ( 108 . 208 . 308 ) for testing the electrical consumer ( 101 . 201 . 301 ). A test method according to claim 10, further comprising testing (S5) the function of the power source (S5) 103 . 203 . 303 ) and / or the function of the current limiter ( 105 . 205 . 305 ) before the beginning of an electrical consumer test ( 101 . 201 . 301 ) and checking the electrical load ( 101 . 201 . 301 ) only in the case of positively tested function, in particular by closing a switch ( 216 ) between the current limiter ( 105 . 205 . 305 ) and the electrical consumer ( 101 . 201 . 301 ). The test method of claim 11, wherein testing the function includes measuring the test current generated ( 104 . 204 . 304 ), especially between the power source ( 103 . 203 . 303 ) and an internal mass ( 213 ) of the test device ( 100 . 200 . 300 ), having. The test method of any preceding claim 11 and 12, wherein testing the function includes measuring the limited test current ( 106 . 206 . 306 ), in particular between the current limiter ( 105 . 205 . 305 ) and an internal mass ( 213 ) of the test device ( 100 . 200 . 300 ), having. A test method according to any one of claims 11 to 13, wherein testing the function comprises measuring a current between the electrical load ( 101 . 201 . 301 ) and the internal mass ( 213 ) of the test device ( 100 . 200 . 300 ) having. Test method according to one of the preceding claims 10 to 14, wherein measured values of the falling electrical voltage ( 108 . 208 . 308 ) via a data connection ( 322 ) to a control device ( 319 ) of the test device ( 100 . 200 . 300 ) be transmitted.

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