EP1294214A2 - Method for lamp monitoring in light signalling systems and light signalling system - Google Patents

Abstract

The method involves detecting a current flowing through at least one light source (12a.., 20a..) or a correlated parameter during an initialization phase, determining and storing a reference value using the detected value, detecting the current etc. in an operating phase and determining a comparison value, comparing the comparison and reference values and evaluating the comparison result. AN Independent claim is also included for the following: a light call system for care applications.

Description

The invention relates to a method for monitoring the illuminant of Nurse call systems for the care sector. The invention also relates to a Nurse call system for the care sector with at least one illuminant driver and at least one lamp.

Nurse call systems for the nursing sector serve to visually call patients to be able to represent, for example by means of so-called room signal lights, that indicate a patient's call in the hallway.

Lamp drivers are used for the electrical equipment of motor vehicles known that have an integrated monitoring circuit, by means of a logical signal according to the state (ok / defective) the associated lamp can be generated. The monitoring circuit is for a lamp of a predetermined type at a predetermined one Installation location of the motor vehicle, for example a brake light lamp, designed.

Known nurse call systems for the care sector consist of flexible usable elements, and depending on the circumstances, to individual Driver modules different lamps or lamp combinations turned on. For example, to signal patient calls Incandescent lamps are used in so-called room signal lights. For further display functions, LEDs (Light Emitting Diode) can be used. Incandescent lamps have a limited lifespan in relation to the number of hours that can be achieved. in the Care area can fail a room signal light that goes undetected remains, have serious consequences for the patient if Overlooking a patient call results.

The invention is intended to provide a method for monitoring the illuminant a nurse call system as well as a flexibly usable nurse call system Illuminant monitoring can be created.

According to the invention, there is a method for monitoring the illuminant for this purpose of nurse call systems for the care sector with the following steps:

In an initialization phase, capturing one by at least one Illuminant flowing current or a correlated size, Determination and storage of a reference value based on the recorded Value, in an operating phase, detection of the flowing through the lamp Current or a correlated variable and determining one Comparative value, comparing that determined in the initialization phase Reference value with the comparison value determined in the operating phase and evaluating the comparison result.

These process steps make adaptive lamp monitoring achieved regardless of the number or type of to the Driver is on lamps. The reference value is only after installation of the nurse call system is determined and stored so that always one for the special installation situation and the special lamp type there is a meaningful reference value. In the initialization phase the reference value is automatically recorded. Are multiple lamps on one Driver switched on, so for each combination the switched on Illuminant automatically determines and stores a reference value, until all the storage locations provided are filled with reference values are. A current flowing through the lamp or lamps can be immediate be determined, it is also possible to determine one for this correlated quantity, for example a total current in a common Ground line.

In a further development of the invention, if the comparison value deviates from the reference value by more than a predetermined amount Warning message issued.

In this way, a warning message can be sent to a network, for example output and displayed on a monitoring station.

In a further development of the invention, there are different deviations the comparison value from the reference value different warning messages output.

In this way, aging processes in a Lamp are detected as far as they change the lamp current cause. For example, between a short circuit, a defect only one of two lamps of a lamp and one complete defect of the lamp can be distinguished.

In a development of the invention, the one flowing through the illuminant Current or the correlated variable in the initialization phase in switched on state and in the operating phase after each switch-on process of the illuminant detected.

In this way, a regular check of the functionality the illuminant performed, with more commonly used illuminants be checked more often. A cyclical check is also conceivable all illuminants or prioritized illuminants in a nurse call system, for example, even when switched off by means of a Test current, which is a statement about the functionality of the lamp allows, but does not make it visible.

In a further development of the invention, a voltage potential is created in front and behind the lamp is detected and the detected voltage potential is taken into account when evaluating the comparison result.

In this way, a filament breakage of an incandescent lamp, before and behind the illuminant leads to another potential, from one Defect in a supply line can be distinguished. General is through that Detect and take into account a potential before and after given the lamp the possibility of different defects to distinguish.

In a further development of the invention, a supply voltage is recorded and the detected supply voltage is used in determining the reference value and the comparison value.

In this way, the influence of a fluctuating supply voltage be balanced. For example, the saved one Reference value and the comparison value to a standard voltage normalized.

The problem underlying the invention is also solved by a light call system for the care sector with at least one illuminant driver and solved at least one lamp, in the means for detecting a current flowing through the lamp or one for this correlated size, storage means for one during an initialization phase recorded reference value and means for comparing the reference value recorded during the initialization phase with a During an operating phase, the comparison value of the Illuminant flowing current or the correlated size provided are.

Such a light call system can be used for adaptive lamp monitoring can be realized by current measurement. By setting a reference value only after installation of the nurse call system in an initialization phase identical elements of the nurse call system, namely illuminant drivers and monitoring circuits, can be used for different installation situations.

In a further development of the invention there are means for evaluating the comparison result and for outputting a state signal of the Illuminant provided.

In a further development of the invention are a network and at least one monitoring station connected to the network is provided, the status signal being sent to the network.

By providing a network, the nurse call system can be set up flexibly and a status signal can be selected from different monitoring stations be received. The status signal can, for example from multiple monitoring stations or indicators be received. Switching signals can also be sent via the network for the lamp drivers are transmitted.

In a development of the invention, the means for detecting the by the current flowing in the lamp or the correlated to it Size provided in a ground line of the lamp driver Current measuring resistor and a voltage measuring device.

These measures make it reliable with a simple structure and meaningful current measurement possible. By having a stream in one Ground line of the illuminant driver is measured must be in the Illuminant drivers themselves no measuring resistors are provided. As a result, commercially available illuminant drivers, for example in Form of integrated circuits. The current in the The ground line of the illuminant driver is a total current, which depends on Number of lamps switched on takes different values. These different values are used as reference values for each Switched on states or combinations assigned and saved.

In a development of the invention, the voltage measuring device has one Analog-digital converter for converting the measured voltage value on. The voltage measuring device is advantageously equipped with a Microprocessor for converting the voltage value into one Current value and provided for storing the current value. About that It is also advantageous that the voltage measuring device has a differential amplifier with low pass.

This creates the conditions during the initialization phase determine and save the reference value and later compare with the comparison value recorded during the operating phase to be able to. If there is more than one illuminant, there is one for each combination of the on or off state of the individual lamps Reference value recorded and saved. With consideration the influence of a fluctuating supply voltage Supply voltage excluded on the comparison result become. The measured voltage can be measured using the differential amplifier be reinforced and smoothed.

In a further development of the invention is a parallel to the current measuring resistor switched suppression circuit provided.

Such a suppression circuit serves to raise the low level of the driver during each switch-on phase of the lamps avoid. This is particularly important in the case of incandescent lamps have a high inrush current or cold current pulse. The suppression circuit ensures that the low level of the driver block in the instant switch-on through the arranged in the ground line Current measuring resistor is not raised inadmissible and the logical Function of the driver is not disturbed. The suppression circuit can, for example, the current measuring resistor in the switch-on phase bridge or have a voltage-limiting effect.

Fig. 1.

eine schematische Darstellung eines erfindungsgemäßen Lichtrufsystems, und

Fig. 2

eine detailliertere Darstellung des Differenzverstärkers der Fig. 1.

Further features and advantages of the invention result from the claims and the following description of a preferred embodiment of the invention in connection with the drawing. The drawing shows:

Fig. 1.

a schematic representation of a light call system according to the invention, and

Fig. 2

a detailed representation of the differential amplifier of FIG. 1st

In Fig. 1 is a section of a nurse call system with a Illuminant driver 10 and a lamp 12a shown. The lamp 12a is arranged for example in a room signal light and is from the driver 10 turned on when it is on a data line 14 receives a command to turn on the lamp 12. Such an order can, for example, be arranged on a patient's bed Go out button that is not shown in the figure. At the same time with the lamp 12a, lamps 12b, 12c are switched on.

The illuminant driver 10 is fed by means of a supply voltage V _cc and is electrically connected to the lamps 12a, 12b and 12c by means of a supply line 16. The lamps 12a, 12b and 12c are switched on in that the supply line 16 is connected to ground Gnd by means of the lamp driver 10. The lamp driver 10 is designed as an electronic driver module and has a power transistor with upstream logic and protective circuits against short circuit, overvoltage, overtemperature, etc. The lamps 12a, 12b are designed as incandescent lamps, the lamp 12c as an LED. In the combination of lamps 12a, 12b, 12c made of incandescent lamps and LEDs, the failure of each individual lamp can be recognized. In addition to the lamps 12a, 12b, 12c, other lamps 20a, 20b, 20c, which are connected to the lamp driver 10 via a supply line 22, are actuated by means of the lamp driver 10. In the same way as the lamp 12, the lamps 20a, 20b, 20c are switched on by the lamp driver 10 when it receives a corresponding signal via the data line 14. The data line 14 is part of a network.

A current measuring resistor 24 is switched into a ground line 18 of the illuminant driver 10. The voltage drop across this current measuring resistor 24 is detected by means of a voltage measuring device, which consists of a differential amplifier 25, an analog-digital converter 26 and a microprocessor 27. The detected voltage value, which was amplified and smoothed by the differential amplifier 25 and digitized by the analog-digital converter 26, is converted into a current value in the microprocessor 27. The supply voltage V _cc is expediently taken into account in the calculation of the current value, so that the calculated current value is independent of fluctuations in the supply voltage V _cc .

After installing the nurse call system, you will be in an initialization phase Reference values for a current flowing through the current measuring resistor 24 Current flowing through the lamps 12a, 12b, 12c and 20a, 20b, 20c flowing currents is correlated. In the present case it differs flowing through the current measuring resistor 24 Current from the sum of the lamps 12a, 12b, 12c, 20a, 20b, 20c currents flowing through from the circuits in the illuminant driver self-absorbed current, at least approximately is constant. In the initialization phase are automatically under Control of the illuminant driver 10 reference values for all possible Combinations of the switching state of the lamps 12 and 20 are determined and saved. With two lamps 12 and 20, these are four reference values, correspondingly both lamps 12, 20 on, both lamps 12, 20 off, lamp 12 on, lamp 20 off, and lamp 12 off, lamp 20 on. In the illuminant driver 10 and / or the microprocessor 27 are four storage locations for reference values for these four possible combinations intended. The initialization phase is then completed, if all four memory locations with a corresponding reference value are filled.

During operation of the nurse call system, one of the Lamps 12, 20 flowing through the current measuring resistor 24 Current determined as a comparison value. This determined comparison value according to the switched-on state of the two lamps 12, 20, compared with an assigned stored reference value. Lies a deviation between the reference value and the comparison value within predetermined limits, the lamp driver 10 and / or the Microprocessor 27 determines that the corresponding, just turned on Lamps 12, 20 are in order. There is a deviation from the comparison value of the reference value outside certain limits, gives the Illuminant driver 10 on a data line 30 or the microprocessor 27 on a data line 31 an error message "lamp defective". The data lines 30, 31 are part of a network via which the error message to suitable displays and / or monitoring workplaces is sent. In addition to a defective lamp, a Short circuit detected in the wiring of a lamp. This is particularly so important with optional additional lights that last longer Wiring can be connected.

In addition to the error message "lamp defective", the lamp driver 10 if the comparison value differs from the reference value, but the Deviation is within two predetermined limits, a warning message from which a change in the by the lamps 12a, 12b, 12c or 20a, 20b, 20c indicates flowing current. Such a change can, for example, by aging the lamps 12a, 12b, 12c or 20a, 20b, 20c and may terminate one early failure. By means of the illuminant driver 10 in one If a warning message is issued, a lamp can already be installed a failure can be replaced as a precaution.

In the case of nurse call systems for the care sector, in general Incandescent lamps used when switching on a high inrush current or have a cold current pulse. For example, flows when switched on the incandescent lamps 20a, 20b a high cold current pulse through the Supply line 22 and the ground line 18, the through the Cold current pulse at the current measuring resistor 24 caused voltage drop cause the low level of the lamp driver 10 in the switch-on phase is raised so far that the logical function the lamp driver 10, or its logic circuit, is disturbed.

To avoid this, a suppression circuit 32 is in parallel switched to the current measuring resistor 24. By means of the suppression circuit 32 will raise the low level of the lamp driver 10 limited in the switch-on phase, for example by means of zener diodes in the suppression circuit 32. Alternatively, the suppression circuit 32 controlled by the light source driver 10 via a data line and bridges the current measuring resistor in the switch-on phase 24th

2, the differential amplifier 25 is in more detail shown. The external circuitry of the operational amplifier acts as Low pass and leads to a smoothing of the current measuring resistor 24 tapped voltage signal. The smoothed and amplified voltage signal is then passed to the analog-to-digital converter 26.

Claims (14)

Procedure for monitoring light sources of nurse call systems for the care sector, with the steps: in an initialization phase, detecting a current flowing through at least one illuminant (12, 20) or a variable correlated to it, Determining and storing a reference value based on the recorded value, In an operating phase, detecting the current flowing through the illuminant (12, 20) or the size correlated to it and determining a comparison value, Comparing the reference value determined in the initialization phase with the comparison value determined in the operating phase and Evaluate the comparison result. Method for monitoring the illuminant according to claim 1, characterized by outputting a warning message when the comparison value deviates from the reference value by more than a predetermined amount. Method according to Claim 2, characterized in that different warning messages are output in the event of different deviations of the comparison value from the reference value. Method for illuminant monitoring according to one of the preceding claims, characterized in that the current flowing through the illuminant (12, 20) or the variable correlated to it is detected in the initialization phase in the switched-on state and in the operating phase after each switching-on process of the illuminant. Method according to one of the preceding claims, characterized by detecting a voltage potential in front of and behind the illuminant (12, 20) and taking the detected voltage potentials into account when evaluating the comparison result. Method according to one of the preceding claims, characterized by detecting a supply voltage and taking the detected supply voltage into account when determining the reference value and the comparison value. Light call system for the care sector, with at least one illuminant driver (10) and at least one illuminant (12, 20), characterized by means (24, 25, 26, 27) for detecting a current flowing through the illuminant (12, 20) or a current flowing through it correlated quantity, storage means (27) for a reference value acquired during an initialization phase and means (27) for comparing the reference value acquired during the initialization phase with a comparison value of the current flowing through the lighting means (12, 20) or the correlated quantity , Light call system according to claim 7, characterized in that means (27) are provided for evaluating the comparison result and for outputting a status signal of the lighting means (12, 20). Light call system according to claim 8, characterized in that a network (14, 30, 31) and at least one monitoring station connected to the network (14, 30, 31) are provided, the status signal being transmitted to the network (14, 30, 31) becomes. Light call system according to one of Claims 7 to 9, characterized in that the means for detecting the current flowing through the illuminant or the size correlated thereto are provided with a current measuring resistor (24) provided in a ground line of the illuminant driver (10) and a voltage measuring device (25, 26, 27). Light call system according to claim 10, characterized in that the voltage measuring device has an analog-digital converter (26) for converting the detected voltage measured value. Light call system according to one of the preceding claims, characterized in that the voltage measuring device has a microprocessor (27) for converting a voltage value into a current value and for storing the current value. Light call system according to one of the preceding claims, characterized in that the voltage measuring device has a differential amplifier (25) with low pass. Light call system according to one of Claims 10 to 13, characterized in that a suppression circuit (32) connected in parallel with the current measuring resistor (24) is provided.

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