Personal protection measuring device

Abstract

A personal protection measuring device for protecting persons in electromagnetic fields, comprising a sensor unit including one or more sensor elements used as E-field and/or H-field sensors, an electronic control and evaluation unit and a display, wherein the sensors comprise resistors and diodes connected in series, wherein a test apparatus is provided for checking the functional capability of the sensor elements independently from external surrounding electromagnetic fields.

Claims

1. A personal protection measuring device for protecting persons in electromagnetic fields, comprising a sensor unit including one or more sensor elements used as E-field and/or H-field sensors, an electronic control and evaluation unit and a display, the sensors comprising resistors and diodes connected in series, wherein a test apparatus for checking the functional capability of the sensor elements independently from external surrounding electromagnetic fields.

2. The personal protection measuring device according to claim 1, wherein the test apparatus comprises a signal generator for generating a test signal at the sensor unit, and an evaluation apparatus for comparing the test signal at the sensor unit to a stored reference signal or reference value.

3. The personal protection measuring device according to claim 2, wherein the test signal has a characteristic which differs from that of the sensor voltage generated by the electromagnetic field.

4. The personal protection measuring device according to claim 2, wherein the reference signal or the reference value is device-specific.

5. The personal protection measuring device according to claim 1, wherein after the device has been switched on, the control and evaluation unit, ascertains the present field strength and the no-load test signal for establishing the present device condition.

6. The personal protection measuring device according to claim 1, wherein after the present device condition has been established, the control and evaluation unit, applies a test signal to the sensor unit via the test apparatus, and ascertains a signal dependent thereon or a signal value dependent thereon.

7. The personal protection measuring device according to claim 6, wherein the control and evaluation unit compares the ascertained signal, or the ascertained signal value, to the stored reference signal or reference signal value from the sensor unit, and either starts the normal measuring operation or switches the personal protection measuring device off, as a function of the comparison.

8. The personal protection measuring device according to claim 7, wherein, prior to the shut-off, the control and evaluation unit prompts the output of a defined signal acoustically and/or visually.

9. The personal protection measuring device according to claim 1, wherein the test apparatus comprises a voltage generator for generating a test voltage at the sensor unit, and an evaluation apparatus for comparing the voltage drop across the sensor unit to a stored reference voltage value.

10. The personal protection device according to claim 9, wherein the test voltage has a voltage level that differs from the sensor voltage generated by the electromagnetic field.

11. A method for operating a personal protection measuring device according claim 1, wherein the device condition with respect to the present field strength, and the test voltage in the idle state, is ascertained after the personal protection measuring device has been switched on, and thereafter the test voltage is applied to the sensor unit and is measured and compared to one or more reference voltages and, as a function of the comparison result, the normal measuring operation is started or the personal protection measuring device is shut off.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0018] The FIGURE is a schematic block diagram of a personal protection measuring device according to an exemplary embodiment.

DETAILED DESCRIPTION

[0019] The invention will be briefly described hereafter based on the FIGURE. Based on a schematic block diagram, the FIGURE shows the composition as it may be implemented, for example, in a personal protection measuring device 1 in the form of a personal monitor that is worn on the body. In this exemplary embodiment, in addition to the sensor unit 3, which is composed of multiple sensor elements, and the control and evaluation unit 5, which is present as a rule, and a visual display 4, a test signal generator 7 comprising an associated switching apparatus 6 is integrated in a housing 2, which is indicated by dotted lines, and electrically connected. In this exemplary embodiment, the sensor unit 3, in the known manner, comprises an E-field sensor and an H-field sensor, each of which has a three-axis (isotropic) design. All three axes are respectively connected in series and comprise resistors and diodes connected in series. Of course, the control and evaluation unit itself also comprises operating elements, unless these are implemented via the display, and suitable storage means. A test apparatus, which in the exemplary embodiment comprises the test signal generator 7, the switch 6, and the control and evaluation unit 5 as the evaluation apparatus, is provided for checking the personal protection measuring device 1 for functional capability. In the exemplary embodiment, the test signal generator 7 supplies a DC voltage, which is applied to the sensor unit 3 via the switch 6. The control and evaluation unit 5, which is also connected to the test signal generator 7 and the switching apparatus 6, compares the voltage present at the sensor unit 3 to a stored reference voltage to establish whether the sensor unit 3 is damaged. If the voltage at the sensor unit 3 is within a certain predefined range compared to the stored reference voltage, the normal measuring operation is started after a settling time has been taken into consideration. If the voltage at the sensor unit 3 is too high compared to the reference voltage, it is to be assumed that an open circuit is present or, in the other case, a short circuit of one or more diodes. Both cause a defined signal tone to be emitted via an acoustic signal transmitter 8. Moreover, an entry occurs in a data memory (data logger), which is integrated into the control and evaluation unit 5, containing the measured values from the check (sensor voltage prior to the check, unloaded/loaded test voltage, and temperature). Thereafter, the personal protection measuring device 1 shuts off.