Measuring arrangement with a connecting element

Abstract

The present invention relates to a measuring arrangement (490) with a measuring bridge (400) and an electrical connecting element (49) for a flow sensor. The flow sensor is designed for flow rate measurement based on the hot-wire anemometry measuring principle. A number of electrical contact arrangements (45, 46, 47) arranged on a support element (200) with a common equipotential surface (22) serve for electrical contacting of support elements (44) and resistance measuring sensors C1 (55), W2 (66), W1 (77).

Description

[0001] The present invention relates to an electrical connecting element for a measuring arrangement with a flow sensor.

[0002] The function of the flow sensor is based on thermal anemometry, in particular in a design as thermal anemometry with a plurality of hot wires arranged on support elements, the so-called hot wire anemometry.

[0003] From DE 25 05 669 C3 a sensor emerges which is used specifically in medical technology to compensate for the influence of the temperature of the measuring gas, measured by means of a resistance sensor designed as a wire, on the measuring signal of the hot wire when measuring the respiratory gas volume flow in a Wheatstone bridge circuit.

[0004] Measuring respiratory gas flow rate is a standard feature of virtually all modern ventilators and anesthesia machines. In hot-wire anemometry, a thin, heated wire, called a hot wire, is cooled by the flow of the measurement or respiratory gas. The change in resistance of the hot wire is a measure of the gas flow rate.

[0005] From DE 101 33 120 A1 a circuit arrangement with two measuring bridges is known which is able to determine both a flow rate and its flow direction on the basis of a number of three resistance measuring sensors designed as platinum wires in a flow chamber designed as a measuring cuvette.

[0006] Two of the platinum wires are used for flow measurement, the third resistance sensor is used for temperature compensation, as described in DE 25 05 669 C3.

[0007] The circuit arrangement of DE 101 33 120 A1 enables temperature compensation with only one resistance sensor with respect to the gas temperatures of the gases present in the flow space for both resistance sensors.

[0008] To determine the flow direction, a shadow body is provided in the flow space, so that one of the three platinum wires in one flow direction, lying in its shadow, experiences a different flow than in the opposite flow direction.

[0009] A disadvantage of this is that the shadow body – especially at larger flow rates – contributes to a significant pressure drop in the measuring cuvette.

[0010] Therefore, it is advantageous to determine the flow direction by evaluating the heat transfer between two resistance sensors of the flow sensor without requiring a shadow body.

[0011] In order to enable an evaluation of the heat transfer with good reproducibility and sufficient accuracy, it is essential that the electrical signals between the resistance sensors in the flow sensor and in the electronic components are transmitted with minimal interference, distortion or loss.

[0012] Starting from the prior art, the present invention is dedicated to the task of specifying an embodiment of an electrical connection of a flow sensor with a measuring bridge, which enables an error-minimized evaluation of a determination of a flow rate and a determination of a flow direction.

[0013] The problem is solved by a measuring arrangement with a measuring bridge and with an electrical connecting element having the features of claim 1.

[0014] The problem is further solved by a measuring arrangement with a measuring bridge and with an electrical connecting element having the features of claim 2.

[0015] Advantageous embodiments of the invention are set out in the dependent claims and are explained in more detail in the following description with partial reference to the figures.

[0016] The described embodiments each represent special configurations, both individually and in combination or combinations with one another. The invention also encompasses all further embodiments and their advantages that may arise from combining or combining several embodiments, even though not all possible combinations of embodiments are described in detail.

[0017] According to a first aspect of the invention, the problem is solved by a measuring arrangement with at least four support elements. At least two resistance sensors are arranged on the at least four support elements. The measuring arrangement according to the invention comprises a measuring bridge and an electrical connecting element. The electrical connecting element serves to form a plurality of electrical plug connections between the measuring bridge and a flow sensor. The flow sensor is configured with the at least two resistance sensors for flow measurement according to the principle of hot-wire anemometry.

[0018] The measuring arrangement according to the first aspect of the invention has at least four support elements on which the at least two resistance measuring sensors of the flow sensor are arranged.

[0019] According to a further aspect of the invention, the problem is solved by a measuring arrangement with at least six support elements. At least three resistance measuring sensors are arranged on the at least six support elements.

[0020] This measuring arrangement according to the further aspect of the invention—like the measuring arrangement according to the first inventive aspect—comprising a measuring bridge and an electrical connecting element. The electrical connecting element serves to form a plurality of electrical plug connections between the measuring bridge and a flow sensor. The flow sensor is configured with at least three resistance measuring elements for flow measurement according to the principle of hot-wire anemometry.

[0021] The aspects that are addressed in the same way in the solutions to the first and the further inventive aspects are now explained in more detail in a joint description within a common context. The common advantages are mentioned, and—where applicable and expedient—differences between the first and the further inventive aspects are noted.

[0022] The measuring setup with the measuring bridge is based on the principle of a Wheatstone bridge, often also referred to as a Wheatstone resistance measuring bridge. A Wheatstone bridge is an electrical circuit used for accurate measurements of unknown resistance values. It typically consists of four resistors forming such a bridge circuit.

[0023] Often, one of the resistors is a temperature-sensitive resistor, such as a very precise platinum resistor, so that even the smallest temperature changes in the platinum resistor can be measured very precisely and accurately using the bridge circuit and then analyzed. In thermal anemometry, a measuring bridge is combined with at least one hot-wire anemometer as a resistance sensor.

[0024] The hot-wire sensor is typically a very fine platinum wire which, during operation of the bridge circuit, is heated to a temperature above ambient. When the hot wire is exposed to a flow, heat is transferred from the wire to the flow. This heat transfer results in a change in the wire's resistance, which is measured in the bridge circuit. Depending on the bridge's operating mode, this change can be evaluated in constant current anemometry (CCA) or constant temperature anemometry (CTA) to determine the flow velocity or flow rate in a flow channel of the sensor.

[0025] The support elements are components of the flow sensor and, together with the resistance measuring elements, protrude into the flow channel of the flow sensor on the sensor side. These support elements can therefore also be referred to as sensor-side support elements. The support elements are contacted by the electrical connecting element. This contacting by the electrical connecting element can, in addition to electrical contact, also include a mechanical coupling of the flow sensor to the measuring bridge.

[0026] The preferred measuring sensors, for example those made of platinum wires, can be arranged as a clamping mechanism on the support elements, oriented towards the flow channel of the flow sensor. The attachment of the resistance measuring sensors to or on the support elements can preferably be achieved, for example, by means of a welded or soldered connection.

[0027] The electrical connection element has a support element. The support element has a common equipotential surface.

[0028] According to the first inventive aspect, the electrical connecting element has a number of at least four electrical contact arrangements arranged on the support element. According to the first inventive aspect, this equipotential surface electrically connects a number of at least two of the four contact arrangements on the support element to one another.

[0029] According to the further inventive aspect, the electrical connecting element has a number of at least six electrical contact arrangements arranged on the support element.

[0030] According to the further inventive aspect, this equipotential surface electrically connects a number of at least three contact arrangements of the six contact arrangements on the carrier element.

[0031] The electrical contact arrangements allow for direct electrical contact with the support elements or electrical contact with the support elements via an optional wiring connection, such as a cable lead. Using this wiring connection – preferably and especially with a flexible design – the electrical connection element, and thus also the flow sensor, can be positioned remotely from the measuring bridge, for example, close to the head area or close to the mouth / nose area of ​​a patient.

[0032] In such a configuration, the measuring arrangement with the electrical connecting element and the electrical contact arrangements, the cable connections and the measuring bridge can enable flow measurement close to the patient, for example at the so-called Y-piece.

[0033] The measuring bridge can be designed as part of a medical measuring device, part of a ventilator, or part of an anesthesia device.

[0034] The equipotential surface, as part of the support element in the electrical connection element, creates a very low-resistance connection and thus a balance between the electrical potentials of the electrical contacts of the support elements electrically connected to each other by the equipotential surface.

[0035] By combining several support elements in the equipotential surface, the electrical potentials of these support elements are connected to each other with low resistance to form a common electrical potential.

[0036] This very low-resistance coupling via the equipotential surface offers the advantage that the effects of contact resistances, which can be different, variable and random during operation of the measuring arrangement due to plugging and unplugging - especially multiple plugging of the support elements to the contact arrangements - can be reduced in their effect with regard to the accuracy of the flow measurement.

[0037] The equipotential surface in the measuring arrangement enables the supply of bridge supply energy from the measuring bridge to the resistance measuring sensors on the electrical connecting element without potential differences between the jointly electrically coupled support elements of the flow sensor.

[0038] A further advantage of arranging the equipotential surface in the electrical connection element or as a component of the electrical connection element is that, in comparison, individual contacting of all support elements would result in a separate continuation of one and / or two conductors in a cable connection to the measuring bridge, resulting in a multi-core cable with a large number of conductors.

[0039] Here is an example using the measuring setup with six support elements: In the case of individual contact with two conductors each, with two contact arrangements per support element, a cable for connecting the connecting element would result in a number of twelve conductors.

[0040] When combining contact arrangements of three support elements in the equipotential surface, two conductors are required, and with two conductors each with two contact arrangements for three support elements each, a total of six conductors remain, resulting in a total of eight conductors for the six support elements.

[0041] A direct advantage of this is that such a cable with eight conductors in diameter can be manufactured approximately fifty percent smaller. This results in such a cable being lighter, more flexible, and less expensive, and easier for the user to handle.

[0042] In a particularly preferred embodiment, the electrical connecting element has contacts with double contact elements. The electrical contact arrangements are designed as double contact elements with a number of two contact arrangements and are arranged on the carrier element. Each of the double contact elements is designed to receive the same support element of the corresponding resistance sensor.

[0043] In this way, the support elements are each electrically connected to the measuring bridge via two electrical contacts. At least from the support elements that are not connected to each other via the equipotential surface, separate conductor connections – for example, as wires or strands of a connecting cable – can be led to the measuring bridge using the double contact elements.

[0044] The separately routed cable connections make it possible to separate current-carrying, i.e., energy-supplying, cable paths from measuring lines along the entire connection from the support elements to the measuring bridge, so that there are no voltage drops on the measuring lines of a magnitude that could adversely affect the accuracy of the operation of the measuring bridge for flow measurement.

[0045] The combination of the double contact elements and the equipotential surface results in a cumulative advantage: it is possible to guide measurement signals from the flow sensor to the measuring bridge without interference from equalizing currents between the sensors in the connecting element and the cable connection.

[0046] In a particularly preferred embodiment of the measuring arrangement, the double contact elements can be configured by means of the support element to form a connection to the conductor connections of a connecting cable. The connecting cable can be configured with these conductor connections to form an electrical contact with the measuring bridge.

[0047] In a particularly preferred embodiment of the measuring arrangement, an arrangement consisting of an electrical test contact element and a sensor-side test contact can be provided.

[0048] The electrical test contact element can be arranged on the electrical connecting element or on the support element and is designed to form an electrical connection between a measuring bridge and the sensor-side test contact.

[0049] The electrical test contact element is designed in relation to the sensor-side test contact and the support elements such that, when the flow sensor is connected to the electrical connecting element, an electrically lagging connection is established between the sensor-side test contact and the electrical test contact element compared to the electrical connection between all double contact elements and their associated support elements. This design of a contact configuration consisting of the test contact element on the connecting element and the sensor-side test contact ensures that during a plugging operation, the support elements are fully inserted and connected to the double contact elements, resulting in a stable electrical connection.The secure, wobble-free contact of all support elements with the double contact elements can be detected because the electrical connection between the test contact element and the sensor-side test contact is only established once the support elements have been fully inserted and connected to the double contact elements. By checking this electrical connection between the test contact element and the sensor-side test contact using a continuity test, it can be verified whether the insertion process was successful and resulted in an electrically conductive connection between the test contact element and the sensor-side test contact.

[0050] In a particularly preferred embodiment of the measuring arrangement, a control unit can be provided which, upon connection of the flow sensor to the electrical connecting element, initiates the activation of an electrical power supply or an electrical voltage supply to the measuring bridge when contact is made between the sensor-side test contact and the electrical test contact element. This advantageously results in the safety-related aspect for the operation of the measuring arrangement described below. The control unit can be suitably configured to perform an electrical continuity test or resistance measurement of the connection between the test contact element and the sensor-side test contact in order to verify whether the connection process between the test contact element and the sensor-side test contact was successful.

[0051] If the plugging process between the test contact element and the sensor-side test contact was successful and a stable electrical connection between the support elements and the double contact elements was established, the control unit initiates an activation of the electrical power supply or the electrical voltage supply of the measuring bridge.

[0052] The control unit thus causes - for example by means of an electronic (FET, transistor) or a mechanical (relay) switching element - the electrical power supply to be switched on to the combination of measuring bridge, cable connection and the flow sensor with the support elements and the resistance measuring sensors.

[0053] In a particularly preferred embodiment of the measuring arrangement, the control unit can be configured for electrical resistance measurement. The control unit can initiate or perform a resistance measurement on at least one of the resistance sensors C1, W2, W1 of the flow sensor in order to determine and store a data set of current sensor-specific values.

[0054] The control unit is further developed accordingly to perform an electrical resistance measurement of the resistance measuring sensors arranged on the support elements, in addition to and / or as an alternative to the electrical continuity test between the test contact element and the sensor-side test contact.

[0055] The control unit can further be designed to indicate and detect voltage signals from the measuring bridge, such as voltage signals that can be measured at a precision measuring resistor or at several precision measuring resistors, and a current flow in the measuring bridge through the precision measuring resistor or precision measuring resistors and the resistance measuring sensors arranged in series with the precision resistor or several precision resistors, i.e., for example, platinum hot wires, and based on this, to determine a current flow state at a resistance measuring sensor or current flow states at several resistance measuring sensors.Based on the currently determined flow state or flow states, the control unit can implement a flow measurement function or a flow rate measurement function and thus, together with the support elements, the resistance measuring sensors, the electrical connecting element, the cable connections, the double contacts and the equipotential surface, represent the entire measuring arrangement for flow measurement, i.e., a flow sensor.

[0056] In an optional embodiment, such a flow sensor can be supplemented with a pairing or combination of the test contact element and the sensor-side test contact.

[0057] In advantageous embodiments of the described configurations, the double contacts can be used in such a way that the operating current from the measuring bridge is guided through one contact of the double contacts via the conductor connections and the electrical connecting element to the respective resistance measuring sensor on the support elements, and the electrical resistance measurement is carried out through the other contact of the double contacts.

[0058] This type of measurement technique is also known as a four-wire measurement setup with four leads (Drive_1, Drive_2, Sense_1, Sense_2). In this setup, a known electrical current flows through the resistor being measured via two power supply leads (Drive_1, Drive_2). The voltage drop across this resistor is measured via two additional leads (Sense_1, Sense_2) with a high resistance. The advantage of this method is that voltage drops caused by the resistance of the power supply leads (Drive_1, Drive_2) do not distort the measured resistance value.

[0059] Furthermore, the control unit can be designed to measure not only the resistance of the resistance sensors and the measuring voltages across the precision resistance resistors, but also other voltage signals from the measuring bridge. These include, for example, the supply voltage and / or the bridge feed voltage.

[0060] Details regarding the voltages of the measuring bridge, such as measuring voltages across precision resistors, supply voltage, or bridge feed voltage, are derived from the Fig. 4 in the context of the associated reference numbers and designations in the reference number list, as well as the description of the figures.

[0061] In a particularly preferred embodiment of the measuring arrangement, a comparison data set can be stored in a data storage element. The data storage element can be designed as an extension of the sensor-side test contact or coupled to the sensor-side test contact or the support element.

[0062] Such a data storage element can, for example, be designed as an EPROM, EEPROM or an RFID tag and be configured to store a data set.

[0063] The data set can contain, for example, data such as the flow sensor's manufacturing date, expiration date, characteristic data, or at least one characteristic curve of the flow sensor. The data set can also be configured as a comparison data set, which the control unit can use to compare it with current data acquired during the flow sensor's operation or with other data.

[0064] In a particularly preferred embodiment of the measuring arrangement, the control unit can be configured to perform a comparison of the current sensor-specific values ​​with values ​​from a reference data set. Such a comparison—especially when using characteristic data or curves—can serve, on the one hand, to correct flow measurements, and on the other hand, to determine the state of the flow sensor or to ascertain its operational readiness. The reference data set can, for example, include the following data: • Sensor-specific data that can be determined during a check as part of a zero adjustment of the flow sensor; • sensor-specific data that can be determined during a check as part of the production of the flow sensor; • sensor-specific historical data that could be determined during a measurement operation of the flow sensor; • Typical operating data for the flow sensor or measuring bridge (400) during measurement operation.

[0065] In a particularly preferred embodiment of the measuring arrangement, the sensor-specific or operating-typical data can include the following parameters: • Cold resistance readings of resistance sensors C1, W2, W1; • Warm resistance readings of the resistance sensors C1, W2, W1; • Voltage signals from the measuring bridge, which indicate a current flow through one of the resistance sensors; • Voltage signals from the measuring bridge, which indicate a current flow through a precision measuring resistor; • Voltage signals from the measuring bridge, which indicate an operating state of the measuring bridge.

[0066] The voltage signals include, for example, a power supply voltage (U+) and / or a bridge supply voltage, as well as measuring voltages at the precision measuring resistors of the measuring bridge.

[0067] In the context of the present invention, "cold resistances" refers to measured resistance values ​​of the resistance sensors, in particular the platinum resistance wires, which were determined during energization with a measuring current that causes a temperature level of the resistance sensors that is essentially identical to the ambient temperature in a range of approximately 20°C to 30°C or up to approximately 10°C above the ambient temperature.

[0068] In the context of the present invention, "hot resistances" refers to measured resistance values ​​of the resistance sensors, which were determined during energization with a measuring current that causes a temperature level of the resistance sensors in a range of approximately 50°C to 150°C above the ambient temperature.

[0069] For details regarding the voltages of the measuring bridge, measuring voltages at precision resistors, supply voltage, bridge feed voltage and other aspects of the measuring bridge, please refer to the following section of the description. Fig. 4 in the context of the reference number list and the descriptions of the figures.

[0070] In a particularly preferred embodiment of the measuring arrangement, the control unit can be configured to determine, based on the comparison, a measure that indicates the operational readiness of the flow sensor and to provide an output signal indicating this operational readiness. The provided output signal can supply information to both a user and a system superior to the measuring arrangement, such as a ventilation system, an anesthesia system, or a data network, as to whether the measuring arrangement and / or the flow sensor is fundamentally operational or not, and / or information about the measurement accuracy of the flow sensor during current operation or what can be expected in subsequent operation.

[0071] The present invention will now be explained in more detail with reference to the following figures and the accompanying description without limitations of the general inventive concept.

[0072] They show: the Fig. 1: a schematic representation of an electrical plug connection; the Fig. 2: a schematic overview of the electrical connector with a measuring bridge; the Fig. 3: A schematic representation of a variant of the electrical connector according to the Fig. 1; the Fig. 4: a flow sensor integrated into a measuring bridge.

[0073] The Fig. Figure 1 shows a schematic representation of an electrical connector 49 with redundant contacts 45, 46, 47 for a flow sensor. Shown are resistance measuring sensors C1 55, W2 66, W1 77, formed as platinum wires and mounted on support elements 44 and soldered or welded on, with contacts 46 adapted to the support elements 44, each with two double contact elements 45, 47. In an exemplary embodiment, if the support elements 44 are designed as round rods or pins 44', the contacts 46 are designed as round sockets 46', as exemplified by the socket 45' for all contacts 46, 46' of this Fig. 1 For the sake of clarity in the drawing, only the resistance measuring sensor W1 77 is shown as an example.

[0074] Each of the support elements 44 is contacted by the two double contact elements 45, 47, resulting in a double contact and each of the resistance measuring sensors C1 55, W2 66, W1 77 - i.e. each of the platinum wires - is electrically connected to a common connecting element 48 by means of four contacts.

[0075] The resistance sensors C1 55, W2 66, W1 77 are electrically connected from the common connecting element 48 to a measuring bridge 400 by means of contact points 42, 43 and electrical conductor connections 41, 41', which in this Fig. 1 is only indicated by some electronic components 56, 57, 58, 80, 80', 90.

[0076] The contact points 42 guide the double contact elements 45, 47 each - in this Fig. 1 shown as an example for a support element 44 of the resistance measuring sensor C1 55 - electrically connected via an equipotential surface 22 arranged in the common connecting element 48 to the measuring bridge 400 via the line connections 41.

[0077] The contact points 43 guide the double contact elements 45, 47 each - in this Fig. 1 shown as an example of a support element 44 of the resistance measuring sensor W2 77 - separately in the common connecting element 48 via the line connections 41' to the measuring bridge 400.

[0078] Further illustrations and explanations regarding the electrical connector 49 with the equipotential surface 22 result from the Fig. 2.

[0079] Further details and explanations regarding the measuring bridge 400 can be found in the Fig. 2 and in particular from the Fig. 4.

[0080] The Fig. Figure 2 shows a schematic representation of the electrical connecting element 48 according to the Fig. 1 with an equipotential surface 22 as part of an electrical connector 49 for a flow sensor for contacting the resistance measuring sensors C1 55, W2 66, W1 77 according to the Fig. 1 with a measuring bridge 400. The measuring bridge 400, the electrical connector 49 and the resistance measuring sensors C1 55, W2 66, W1 77 together form a measuring arrangement 490 for a flow measurement. Identical elements in the Fig. 1 and Fig. 2 are in the Fig. 1 and the Fig. 2 with the same reference numbers.

[0081] The electrical connecting element 48 forms one side of a connecting cable with conductor connections 41, 41' and 81 ( Fig. 3) and enables sensor-side contacting of three resistance measuring sensors C1 55, W2 66, W1 77 of a flow sensor.

[0082] The other end of the connecting cable is equipped with contact points 40, the type and design of which are not further defined, via line connections 41, 41' and 81 ( Fig. 3) connected to a measuring bridge 400 with a control unit 100 and electronic components 56, 57, 58, 67, 75, 78, 79, 80, 80' with a power supply (+U) 90 and with ground potential (0V) 99.

[0083] In addition, electrical connection points for further contacting the resistance sensors of the flow sensor and, by way of example, some electronic components of the measuring bridge 400 such as resistors, resistor networks, amplifier circuits (op-amps), field-effect transistors (FETs) are indicated, which are intended to illustrate how the electrical contacts and connections with the resistance sensors C1 55, W2 66, W1 77 and a measuring bridge 400, 408 ( Fig. 3) can work together, for example, to function as a flow sensor.

[0084] The basic function as a flow sensor with a measuring bridge 400 is defined by the Fig. 4 clarifies, so that in the description of this Fig. 2 the focus is on explaining the interaction of the contacting of the resistance measuring sensors C1 55, W2 66, W1 77 by electrical contact points 42, 43 and by the equipotential surface 22 with the measuring bridge 400.

[0085] Electrical contacts are shown, as they are used in the Fig. Figure 1 shows and explains in more detail the redundant contacting of three resistance sensors C1 55, W2 66, W1 77. Each of the three resistance sensors C1 55, W2 66, W1 77 is electrically conductively mounted on two measuring supports 44.

[0086] Three of the six measuring supports 44 are each contacted separately via the contact points 43 with double contact elements 45, 47 - preferably designed as sockets - and each is connected separately to the measuring bridge 400 via individual line connections 41'.

[0087] Three of the six measuring supports 44 are each contacted with double contact elements 45, 47 – preferably designed as sockets – with the equipotential surface 22 and brought together centrally, so that all three resistance sensors C1 55, W2 66, W1 77 each have an identical voltage potential on one side. The contact points 42 electrically connect the double contact elements 45, 47 via the equipotential surface 22 and via the conductor connections 41 to the measuring bridge 400.

[0088] The voltage drops across resistors 75 and 67 in the measuring bridge 400 are provided to the control unit 100 as voltage signals U1 71 and U2 62 and evaluated by the control unit 100 for a qualitative determination 103 of the flow rate and a direction detection 102 of the flow rate. The control unit 100 can also be configured to include data and / or information related to the flow sensor, such as parameters or properties 101 of the three resistance sensors C1 55, W2 66, and W1 77, for evaluation and thus determine an operating state 104 and / or fault states of the flow sensor with the resistance sensors C1 55, W2 66, and W1 77, measuring bridge 400, and connecting cables 41, 41', and 81. Fig. 3), Contact points 40, 42, 43, 82 ( Fig. 3) to determine or detect contact arrangements 46 with the double contact elements 45, 47 in conjunction with the support elements 44.

[0089] Examples of properties of the three resistance sensors C1 55, W2 66, W1 77 include resistance values ​​such as platinum hot resistances, platinum cold resistances, characteristic curves or support points of characteristic curves of the resistance sensors C1 55, W2 66, W1 77 or typical voltage signals 62, 71 of the measuring bridge 400.

[0090] The data and / or information in the context of the flow sensor, such as properties of the three resistance sensors C1 55, W2 66, W1 77, can be stored in a data memory, which can be arranged, for example, as an EEPROM on the flow sensor and is configured to transmit data and / or information as a data record Z via the electrical connector 49 and contact points 82 ( Fig. 3) in an extended measuring bridge 408 ( Fig. 3) to provide to control unit 100.

[0091] The common connecting element 48 with the double contact elements 45, 46, the equipotential surface 22 and the contact points 42, 43 can be formed by means of a carrier element 200, for example in the form of a printed circuit board (PCB), which can be arranged in the electrical connector 49. The electrical connector 49 can preferably be designed as an electrical connecting element with a multi-pole housing in which the carrier element 200 is also arranged.

[0092] The Fig. Figure 3 shows a schematic representation of a variant of the electrical connector 49 according to the Fig. 1 for a flow sensor with a test contact element 33 and a sensor-side test contact 88 with the measuring bridge 400 according to the Fig. 2 as well as with an extended measuring bridge 408. Identical elements in the Fig. 1, Fig. 2, and Fig. 3 are in the Fig. 1, Fig. 2 and the Fig. 3 with the same reference numbers.

[0093] The diagram schematically illustrates how, when the support elements 44 of the resistance measuring sensors C1 55, W2 66, W1 77 are connected to the double contact elements 45, 47, an electrical connection is established between the sensor-side test contact 88 and the test contact element 33, either immediately following or subsequently after the electrical contact between the support elements 44 and the double contact elements 45, 47. The contact closure between the sensor-side test contact 88 and the test contact element 33 via contact points 82 and connecting lines 81 can be evaluated by the extended measuring bridge 403 using a comparator circuit with electronic components 83, 84 and provided as a status signal 85 to the control unit 100.

[0094] The control unit 100 can convert the status signal 85 into a switching signal 85' and use the switching signal 85' to activate a switching element 89 in order to switch and enable the supply voltage 90 of the measuring bridge 400 to the resistance sensors C1 55, W2 66, W1 77, thus starting the operation of the flow sensor. This results in the advantageous situation that electrical energy is only applied to the resistance sensors C1 55, W2 66, W1 77 if there is a truly secure and successful electrical connection at all contact points 42, 43 of the common connecting element 48 of the electrical connector 49 with the measuring bridge 400. This effectively prevents possible contact problems occurring during the electrical connection between the measuring bridge and the common connecting element 48, and thus possible malfunctions or damage to the resistance measuring sensors C1 55, W2 66, W1 77.

[0095] The Fig. Figure 4 shows an exemplary and schematic representation of a flow sensor integrated into a measuring bridge 400 in a basic functional configuration. The flow sensor is shown with three resistance measuring sensors C1 55, W2 66, W1 77 in a configuration with electronic components, without a representation of a measuring cuvette as the flow chamber and without an explicit representation of the electrical connectors according to the [reference to relevant section]. Fig. 1, Fig. 2, Fig. 3. Same elements in the Fig. 1, Fig. 2, Fig. 3 and 4 are in the Fig. 1, Fig. 2, Fig. 3 and the Fig. 4 with the same reference numerals. This configuration shown can, in principle, be used for sensor operation in a constant temperature anemometry (CTA) operating mode.

[0096] Shown are three platinum wires mounted on support elements 44 ( Fig. 1) Clamped and soldered or welded resistance sensors C1 55, W2 66, W1 77. The three resistance sensors C1 55, W2 66, W1 77 are arranged together in a measuring cuvette, which can be flowed through in two directions.

[0097] The C1 55 resistance sensor is used in sensor operation as a resistance sensor to compensate for the temperature of a measuring gas flowing in the measuring cuvette of the flow sensor.

[0098] The resistance sensor W1 77 is used in sensor mode of the measuring bridge 400 to detect the flow rate of the sample gas flowing in the measuring cuvette of the flow sensor. The resistance sensor W2 66 is used in sensor mode to detect the flow direction of the sample gas flowing in the measuring cuvette of the flow sensor.

[0099] The electronic components with balancing resistor 56, further resistors 67, 75, resistor networks 57, 58, 78, 79, a circuit (OP-AMP) 80' for generating a control deviation and an active actuating and switching element (FET) 80 enable a supply 90 of the measuring bridge 400 to be controlled in such a way that a temperature with a constant difference above the temperature of the measuring gas flowing through the measuring cuvette is given at the resistance sensor W1 77.

[0100] The balancing resistor 56 serves to adjust the circuit components 57, 58, 67, 75, 78, 79, 80, 90 with the resistance sensors C1 55, W2 66, W1 77 to a defined operating point without a current at the resistance sensors C1 55, W2 66, W1 77.

[0101] The adjusting resistor 56 can be configured in an alternative form as an adjusting element, for example as an analog or digital resistance potentiometer or as an arrangement with a digital / analog converter, thus enabling automated adjustment, for example by a control unit 100 ( Fig. 2) is possible using a microcontroller control.

[0102] The resistors 67, 75 are preferably designed as precision measuring resistors, since the voltage signals U1 71, U2 62 at these resistors correspond to the changes in electrical current flowing when the flow into the measuring bridge 400 changes, which represent a measure of changes or increases in the flow rate at the resistance measuring sensors W2 66, W1 77.

[0103] A qualitative determination 102 ( Fig. 2) the flow rate can be controlled by a control unit 100 ( Fig. 2) by means of an evaluation of the voltage signals U1 71, U2 62.

[0104] A direction detection 102 ( Fig. 2) the flow rate can be controlled by a control unit 100 ( Fig. 2) by comparing the voltage signals U1 71, U2 62. These voltage signals U1 71, U2 62 reflect whether, in a flow state, heat is transferred from resistance sensor W2 66 to resistance sensor W1 77 due to the flow rate, or whether heat is transferred from resistance sensor W1 77 to resistance sensor W2 66.

[0105] In this way, in addition to a quantity of 103 ( Fig. 2) the flow rate a flow direction 102 ( Fig. 2) the flow rate is detected in the flow sensor. Reference number list 22 Equipotential surface 33 Monitoring contact 41, 41' Line connections 42, 43 contact points 44 support elements, pins 45 double contact elements, elements of double sockets 46 Contact arrangement, socket-pin arrangements 47 double contact elements, elements of double sockets 48 common connecting element 49 electrical connecting element, electrical plug connection 55 Resistance measuring sensors C1 56 Balancing resistor, balancing element 57, 58 Resistance network, resistors 62 Measuring voltage U2 66 Resistance measuring sensors W2 67 Resistance, precision measuring resistor 71 Measuring voltage U1 75 resistor, precision measuring resistor 77 Resistance measuring sensor W1 78, 79 Resistance network, resistors 80, 80' active actuator and switching element (FET), (op-amp) 81 line connections 82 contact points 83, 84 electronic components, resistors 85 Status signal 85' Switching signal 88 sensor-side test contact 89 Switching element 90 Supply voltage, energy input, voltage source, U+ 90' Bridge supply voltage 99 Ground potential, 0V 100 control unit 101 Data storage devices, EPROM, EEPROM, RFID 102 Direction of flow rate 103 Amount of flow rate 104 Indicator of an operating state or fault state 200 carrier element, circuit board 300 mm difference in distance: sensor-side test contact <-> support elements 400 measuring bridge 408 extended measuring bridge QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 25 05 669 C3 [0003, 0006] DE 101 33 120 A1 [0005, 0007]

Claims

[1] Measuring arrangement (490) with a measuring bridge (400) and an electrical connecting element (49) for a flow sensor to form a plurality of electrical plug connections between the measuring bridge (400) and a number of at least four support elements (44) of at least two resistance measuring sensors C1 (55), W1 (77) of the flow sensor, which is designed according to a hot-wire anemometry measuring principle for flow rate measurement, with a number of at least four electrical contact arrangements (46) arranged on a support element (200), wherein the support element (200) has at least one common equipotential surface (22) which electrically connects a number of at least two contact arrangements (46) of the four contact arrangements (46) to each other. [2] Measuring arrangement (490) with a measuring bridge (400) and an electrical connecting element (49) for a flow sensor to form electrical plug connections between the measuring bridge (400) and a number of at least six support elements (44) of three resistance measuring sensors C1 (55), W2 (66), W1 (77) of the flow sensor, which is designed according to a hot-wire anemometry measuring principle for flow rate measurement, with a number of at least six electrical contact arrangements (46) arranged on a support element (200), wherein the support element (200) has at least one common equipotential surface (22) which electrically connects a number of at least three contact arrangements (46) of the six contact arrangements (46) to each other. [3] Measuring arrangement (490) according to claim 1 or according to claim 2, wherein the electrical contact arrangements (46) are designed as double contact elements (45, 47) with a number of two contact arrangements and are arranged on the carrier element (200), wherein each of the double contact elements (45, 47) is designed to receive the same support element (44) of the corresponding resistance measuring sensor. [4] Measuring arrangement (490) according to one of claims 1 to 3, wherein the double contact elements (45, 47) are formed by means of the carrier element (200) to form a connection to line connections (41, 41') of a connecting cable and wherein the connecting cable with the line connections (41, 41') is formed to form an electrical contact with the measuring bridge (400). [5] Measuring arrangement (490) according to one of claims 1 to 4, wherein an electrical test contact element (33) is arranged on the electrical connecting element (49) or on the support element (200) to form an electrical connection between a measuring bridge (400, 408) and a sensor-side test contact (88) on the support element (200), wherein the electrical test contact element (33) is designed in relation to the sensor-side test contact (88) and the support elements (44) such that when the flow sensor is connected to the electrical connecting element (49) an electrically lagging connection (300) is formed between the sensor-side test contact (88) and the electrical test contact element (33) compared to the electrical connection between all double contact elements (45, 47) and the associated support elements (44). [6] Measuring arrangement (490) according to claim 5, wherein the measuring arrangement (490) has a control unit (100) which, when the flow sensor is connected to the electrical connecting element (49), initiates an activation of an electrical power supply or electrical voltage supply (90) of the measuring bridge (400, 408) upon contact closure between the sensor-side test contact (88) and the electrical test contact element (33). [7] Measuring arrangement (490) according to claim 6, wherein the control unit (100) is configured to initiate or perform an electrical resistance measurement on at least one of the resistance measuring sensors C1 (55), W2 (66), W1 (77) of the flow sensor and to determine and keep available a data set of current sensor-specific values. [8] Measuring arrangement (490) according to one of claims 1 to 7, wherein a comparison data set is stored in a data storage element (101), wherein the data storage element (101) complements the sensor-side test contact (88) or the data storage element (101) is coupled to the sensor-side test contact (88) or to the carrier element (200). [9] Measuring arrangement (490) according to claim 7 or according to claim 8, wherein the control unit (100) is configured to perform a comparison with the data set of current sensor-specific values ​​with values ​​of a comparison data set, wherein the comparison data set: • Sensor-specific data that can be determined during a check as part of a zero adjustment of the flow sensor; • sensor-specific data that can be determined during a check as part of the production of the flow sensor; • sensor-specific historical data that could be determined during a measurement operation of the flow sensor; • for the flow sensor or measuring bridge (400) in measuring operation includes typical operating data. [10] Measuring arrangement (490) according to claim 9, wherein the sensor-specific or operating-typical data: • Cold resistance measurements of resistance sensors C1 (55), W2 (66), W1 (77) or • Warm resistance measurements of the resistance sensors C1 (55), W2 (66), W1 (77) or • Voltage signals (62, 71) of the measuring bridge (400), which indicate a current flow through one of the resistance sensors; • Voltage signals from the measuring bridge, which indicate a current flow through a precision measuring resistor; • Voltage signals (90, 90') of the measuring bridge (400), which indicate an operating state to indicate the measuring bridge include. [11] Measuring arrangement (490) according to claim 9 or according to claim 10, wherein the control unit (100) is trained, to determine a measure based on the comparison that indicates the operational readiness of the flow sensor, and to provide an output signal that indicates the operational readiness.

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