MEASURING DEVICE AND ASSOCIATED OPERATING PROCEDURE

Description

[0001] The invention relates to a measuring device with a sensor for detecting a room temperature or room humidity as an ambient variable. Furthermore, the measuring device comprises measuring electronics configured to read the sensor and record measured values ​​from the sensor. This measuring electronics is supplied with electrical operating voltage by an electrical energy storage device of the measuring device, with the measuring electronics being connected to the energy storage device via two connection terminals. The invention further relates to a corresponding method for temperature-optimized operation of such a measuring device.

[0002] Such measuring devices are already known and are often used as so-called data loggers, often in the form of a radio logger, to record and thus document measured values, such as temperature or room humidity, at a specific location over longer periods of time, particularly wirelessly.

[0003] Typical requirements in such applications include service lives of several years, during which the measuring device must operate error-free and maintenance-free without battery changes. This is further complicated by the fact that the temperature range in which the data logger is located can fluctuate between -25°C and +85°C, for example. This is particularly challenging with regard to long battery life, as batteries react very differently to significant temperature changes and there is a risk of battery failure.

[0004] Sensory devices with switchable electrical energy storage devices, in particular switchable buffer capacitors, are known, for example, from DE 10 2004 001 658 B4.

[0005] US 209 0341660 A1 proposes the use of temperature-dependent different operating modes for a device which is arranged within a motor-driven manual tool, namely a chainsaw with an internal combustion engine, and which records operating data of the chainsaw and stores them in a memory.

[0006] Based on this technical background, the invention is based on the task of improving the application possibilities of measuring devices as described above. In particular, the invention aims to extend the period during which such a measuring device can be operated safely and maintenance-free, independently of other energy sources.

[0007] To achieve this object, the features of claim 1 are provided according to the invention for a measuring device. In particular, to achieve the aforementioned object, the invention proposes that a buffer capacitor be provided, which can be charged by means of the energy storage device and which, in addition to the energy storage device, can supply an electrical current to the measuring electronics. Furthermore, the buffer capacitor is designed to be switchable on and off. For this purpose, a switching arrangement as described in claim 1 is provided.

[0008] In other words, the invention proposes providing the electrical operating voltage, as needed, not only via the energy storage device, but also with the help of the buffer capacitor that is then connected. For example, if the measuring electronics in question draws a large load current (current peak), the operating voltage might drop without the use of the buffer capacitor, which can occur particularly at low temperatures when the energy storage device can only provide certain maximum currents.

[0009] The described technical solution thus has the advantage that the buffer capacitor can buffer current peaks relative to the load current drawn by the measuring electronics during operation of the measuring device, thus providing additional current. This means that if such a current peak occurs, it does not have to be fully covered by the energy storage device; instead, the current is at least partially provided by the buffer capacitor.

[0010] An electrical switch, for example in the form of a relay or a transistor circuit, can be provided to switch the buffer capacitor on and off.

[0011] Furthermore, to achieve this objective, the invention provides for the buffer capacitor to be switched on depending on a detected ambient temperature. For this purpose, the measuring electronics are configured to continuously detect an ambient temperature using a temperature sensor, i.e., in particular, at regular intervals, and to electrically switch on the buffer capacitor as soon as the detected ambient temperature falls below a threshold temperature.

[0012] In such an embodiment, it is preferred if the measuring electronics are further configured to electrically switch off the buffer capacitor when the detected ambient temperature exceeds the limit temperature again.

[0013] Electrical shutdown here can be understood in particular as the buffer capacitor being decoupled from the measurement electronics and the energy storage device, so that it can no longer draw power from the energy storage device or supply power to the measurement electronics. However, if the buffer capacitor is connected, it can perform both of these functions.

[0014] The advantage of this solution is that the measuring device can independently use the buffer capacitor, depending on the current ambient temperature detected by the temperature sensor, either to absorb peaks in the load current of the measuring electronics and / or to electrically decouple the buffer capacitor from the electrical circuit of the measuring device, especially at higher temperatures above the said limit temperature, in order to avoid unwanted cross currents in the capacitor.

[0015] The invention recognizes that the use of a buffer capacitor is generally only useful at low temperatures, i.e., when the electrical energy storage device can deliver less power due to temperature. At higher temperatures, however, the energy storage device provides sufficient current, so the use of a buffer capacitor is unnecessary, which, in particular, helps prevent leakage currents.

[0016] The sensor of the measuring device that is operated by the energy storage device can be, in particular, the temperature sensor; but it can also be another sensor, for example, a humidity sensor.

[0017] One possible embodiment of the invention provides for a comparison logic that connects the buffer capacitor when the temperature falls below a first threshold and electrically disconnects the buffer capacitor when the temperature exceeds a second threshold. In such an embodiment, it is preferred for the comparison logic to control an electrical switch that electrically connects the buffer capacitor to the energy storage device and / or the measuring electronics.

[0018] The second temperature threshold can be identical to the first temperature threshold or can be a few degrees Celsius above the first temperature threshold.

[0019] The electrical energy storage device can, for example, be designed as a non-rechargeable electrochemical energy storage device. It is also possible to design the energy storage device as a rechargeable electrical accumulator.

[0020] One embodiment provides for the buffer capacitor to be electrically connected in parallel with the electrical energy storage device with respect to the measurement electronics. In this case, the buffer capacitor can share a common electrical ground with the energy storage device.

[0021] A measuring device according to the invention can, in particular, be designed or configured for automatically recurring recording of measured values ​​using the sensor according to a fixed and / or adjustable schedule. This allows measurement data to be recorded in an orderly manner over longer periods of time.

[0022] Using the electrical energy storage, the measuring device can continuously collect and record measured values ​​with the sensor, independent of other energy sources. This allows the measuring device to be used as a data logger.

[0023] It can thus be provided that the measuring device is designed as a portable hand-held measuring device and / or as an energy-autonomous measuring device, in particular in the form of a data logger.

[0024] To achieve the object stated at the outset, a method according to the invention is further proposed, as claimed in claim 9, with which temperature-optimized operation of a measuring device can be achieved. The measuring device has features as described at the outset. To achieve this object, the method provides that the measuring device independently and continuously detects an ambient temperature and, depending on the detected ambient temperature, electrically switches a buffer capacitor on and off in such a way that the buffer capacitor can draw electrical power from the internal electrical energy storage device as needed, particularly at low ambient temperatures below 0°C, and can make it available to operate the measuring electronics (in the event of high power demand). For this purpose, a switching arrangement, as described in more detail in claim 9, is connected in parallel to the two connection terminals via which the measuring electronics are connected to the energy storage device.

[0025] The method can be further developed by having the measuring device switch off the buffer capacitor when a certain temperature limit is exceeded. In this case, no electrical current can flow from the energy storage device to the buffer capacitor. This prevents, in particular, the energy storage device from being stressed by unwanted leakage or cross currents in the buffer capacitor, which would unnecessarily limit the measuring device's service life.

[0026] The invention will now be described in more detail using an exemplary embodiment, but is not limited to this example. Rather, further developments of the invention can be derived from the following description in conjunction with the general description, the claims, and the drawings.

[0027] It shows: Figure 1: a schematic, highly simplified representation of a measuring device according to the invention.

[0028] The only Figure 1 shows a schematic sketch of the electrical components of a measuring device 1 according to the invention. The measuring device 1 comprises a sensor 2 for detecting an environmental variable such as the room humidity and associated measuring electronics 3, which is configured to read out the sensor 2 and to detect measured values ​​of the sensor 2.

[0029] The measuring device 1 of the Figure 1 is designed as a data logger and is configured to automatically record measured values ​​at recurring intervals using sensor 2 and store these measured values ​​in an internal memory. Due to the electrical operating voltage provided by the electrical energy storage device 4, the measuring device 1 can thus be operated independently of other energy sources, allowing continuous measurement values ​​to be recorded and recorded using sensor 2.

[0030] As in the Figure 1As illustrated by the electrical connections, the measuring electronics 3 are supplied with an electrical operating voltage from an electrical energy storage device 4. A switching arrangement comprising a buffer capacitor 5 and an electrical switching means 7 connected in series therewith is connected in parallel to the two connecting terminals 8 of the measuring electronics 3, via which the latter is electrically connected to the energy storage device 4. The electrical switching means 7 is shown in the Figure 1 represented as an electrical switch and can be implemented, for example, with a semiconductor component or a relay.

[0031] Since the switching arrangement comprising buffer capacitor 5 and switching means 7 is also electrically connected to the energy storage device 4, the buffer capacitor 5 can be charged by means of the energy storage device 4 when the switching means 7 is switched accordingly, i.e., the switch 7 is closed. In this switching state, i.e., when both poles of the buffer capacitor 5 are electrically connected to the two terminals of the measuring electronics 3, the buffer capacitor 5 can supply an electrical (discharge) current to the measuring electronics 3 in addition to the energy storage device 4, thus stabilizing the operating voltage dropped across the two terminals 8 of the measuring electronics 3.

[0032] In other words, the buffer capacitor 5 (provided it has previously been sufficiently electrically charged from the energy storage device 4) can discharge into the two terminals 8 of the measuring electronics 3 as soon as the switching device 7 electrically connects the buffer capacitor 5. If necessary, however, the buffer capacitor 5 can also be switched off, i.e. electrically separated from the measuring electronics 3, by opening the switch 7, i.e. by switching the switching device 7 again. By electrically switching off the buffer capacitor 5 in this way, it can be electrically decoupled from the measuring electronics 3 and the energy storage device 4, so that the buffer capacitor 5 can no longer supply current to the measuring electronics 3, but can also no longer draw current from the energy storage device 4.Such a procedure can be advantageous in order to avoid energy consumption due to cross currents in the capacitor (leakage currents), since such cross currents can unnecessarily load the energy storage device 4, in particular when the additional current flow supplied by the capacitor 5 is not currently required, for example because no major current peaks occur in the power consumption of the measuring electronics 3.

[0033] In order to ensure that the buffer capacitor 5 is switched on and off intelligently and automatically, the measuring electronics 3 continuously measures the ambient temperature using an additional temperature sensor 6. If the ambient temperature thus detected falls below a predetermined limit temperature, the measuring electronics 3 switches on the buffer capacitor 5 by controlling the switching means 7 in a suitable manner, as indicated by the dotted arrow in Figure 1This means that at low temperatures, where current peaks can typically occur, the buffer capacitor 5 is available to buffer these current peaks (which occur in the consumption of the measuring electronics 3).

[0034] As soon as the ambient temperature detected by the measuring electronics 3 using the temperature sensor 6 rises above the said limit temperature again, the measuring electronics 3 switches off the buffer capacitor 5 by correspondingly re-activating the switching means 7, thereby interrupting the electrical connection between the buffer capacitor 5 and the measuring electronics 3. The limit temperature is selected such that the measuring electronics 3 can be sufficiently supplied with electrical current from the energy storage device 4 in the temperature range above the limit temperature. By switching off the buffer capacitor 5 at warmer temperatures, the total power consumption of the measuring device 1, which can only be drawn from the energy storage device 4 (since the capacitor 5 can only temporarily store electrical energy from the energy storage device 4), is reduced, resulting in a longer runtime or operating time of the measuring device 1.

[0035] It is easy to imagine based on the Figure 1 that, if, for example, the lower connection terminal 8 of the measuring electronics 3 is earthed, the buffer capacitor 5 shares a common electrical ground with the energy storage device 4.

[0036] The Figure 1The measuring device 1 shown thus also implements a method according to the invention for temperature-optimized operation of the measuring device 1. This is because the measuring device 1 independently and continuously detects the ambient temperature using the separate temperature sensor 6 and, depending on this detected ambient temperature, as previously explained, electrically switches the buffer capacitor 5 on or off by controlling the corresponding switching means 7. As a result, the buffer capacitor 5 is electrically connected to the terminals 8 of the measuring electronics 3 as needed, namely as soon as the detected ambient temperature drops below the said threshold value, and in this case can initially draw electrical power from the internal electrical energy storage 4 (= charging process of the capacitor 5) in order to then - if required - transfer the thus temporarily stored electrical energy in the form of a discharge current (discharging process of the capacitor 5) into the Figure 1shown switching arrangement and thus make it available to the measuring electronics 3 for its operation.

[0037] In summary, in order to extend the maintenance-free and self-sufficient operation of an electrical measuring device 1, which has an internal energy storage device 4 and measuring electronics 3 for reading out a sensor 2, the latter being designed to detect an ambient variable such as a room temperature or room humidity, it is proposed that, as required and depending on an ambient temperature detected by the measuring device 1, a buffer capacitor 5 is electrically connected to the energy storage device 4 with the aid of a suitable switching means 7 in such a way that the buffer capacitor 5 can draw electrical power from the energy storage device 4 and can make this power available again, in particular when an electrical operating voltage of the measuring device 1 drops, in order to buffer current peaks of a load current of the measuring electronics 3 (cf. Fig. 1 ). List of reference symbols

[0038] 1Measuring device 2Sensor 3Electronics 4Energy storage 5Buffer capacitor 6Temperature sensor 7Switching device 8Connection terminal (of 3)

Claims

1. Measuring device (1), comprising - a sensor (2) for detecting a room temperature or a room humidity as an ambient variable, - an energy store (4), - a buffer capacitor (5) and - measuring electronics (3) which are designed to read out the sensor (2) and to acquire measured values of the sensor (2) and are supplied with electrical operating voltage by the electrical energy store (4), - wherein the measuring electronics (3) is connected to the energy store (4) via two connection terminals (8), characterized - in that the buffer capacitor (5) can be charged by means of the energy store (4) and the buffer capacitor (5) can supply an electric current to the measuring electronics (3) in addition to the energy store (4), - in that the buffer capacitor (5) is configured to be connectable and disconnectable, wherein, for this purpose, a switching arrangement is connected in parallel to the two connection terminals (8), which comprises the buffer capacitor (5) and an electrical switching means (7) connected in series with the buffer capacitor (5), - so that the buffer capacitor (5) can be electrically connected by means of the switching means (7) and electrically disconnected from the measuring electronics (3) by opening the switching means (7), and - in that the measuring electronics (3) is designed to continuously, in particular at regular intervals, detect an ambient temperature with the aid of a temperature sensor (6) and to electrically connect the buffer capacitor (5) as soon as the detected ambient temperature falls below a limit temperature.

2. Measuring device (1) according to claim 1, wherein the measuring electronics (3) is configured to electrically disconnect the buffer capacitor (5) if the detected ambient temperature exceeds the limit temperature again.

3. Measuring device (1) according to one of the preceding claims, - wherein a comparison logic is formed which, when a first temperature threshold value is undershot, causes the buffer capacitor (5) to be connected and, when a second temperature threshold value is exceeded, causes the buffer capacitor (5) to be electrically disconnected, - preferably wherein the comparison logic controls an electrical switch for this purpose, which electrically connects the buffer capacitor (5) to the energy store (4) and / or the measuring electronics (3).

4. Measuring device (1) according to one of the preceding claims, wherein the electrical energy store (4) - is designed as a non-rechargeable electrochemical energy store or - as a rechargeable electrical battery.

5. Measuring device (1) according to one of the preceding claims, wherein the buffer capacitor (5) is connected electrically in parallel with the electrical energy store (4) with respect to the measuring electronics (3), - preferably and shares a common electrical ground with the energy store (4).

6. Measuring device (1) according to one of the preceding claims, wherein the measuring device (1) is designed for automatically recurring recording of measured values with the aid of the sensor (2) according to a fixed and / or adjustable time schedule.

7. Measuring device (1) according to one of the preceding claims, wherein the measuring device (1) can continuously detect and record measured values with the sensor (2) independently of other energy sources with the aid of the electrical energy store (4).

8. Measuring device (1) according to one of the preceding claims, wherein the measuring device (1) is designed as a portable handheld measuring device and / or as an energy-autonomous measuring device (1), in particular in the form of a data logger.

9. Method for temperature-optimized operation of a measuring device (1), comprising - a sensor (2) for detecting a temperature or room humidity as an ambient variable, - an energy store (4), - a buffer capacitor (5) and - measuring electronics (3) which are designed to read out the sensor (2) and to acquire measured values of the sensor (2) and are supplied with electrical operating voltage by the electrical energy store (4), - wherein the measuring electronics (3) is connected to the energy store (4) via two connection terminals (8), - in particular wherein the measuring device (1) is designed according to one of the preceding claims, characterized - in that the measuring device (1) independently and continuously detects an ambient temperature and - depending on the detected ambient temperature, electrically connects and disconnects the buffer capacitor (5) in such a way that the buffer capacitor (5) can draw electrical power from the internal electrical energy store (4) as required, in particular at low ambient temperatures below 0°C, and make it available for operating the measuring electronics (3) as required, - wherein, for this purpose, a switching arrangement is connected in parallel to the two connection terminals (8), which comprises the buffer capacitor (5) and an electrical switching device (7) connected in series with the buffer capacitor (5), - wherein the buffer capacitor (5) is electrically connected by means of the switching device (7) and electrically disconnected from the measuring electronics (3) by opening the switching device (7).

10. Method according to the preceding claim, - wherein the measuring device (1) switches off the buffer capacitor (5) when a certain limit temperature is exceeded, - in particular wherein then no electrical current flow from the energy store (4) into the buffer capacitor (5) is possible.