Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D1/00—Measuring arrangements giving results other than momentary value of variable, of general application
  • G01D1/18—Measuring arrangements giving results other than momentary value of variable, of general application with arrangements for signalling that a predetermined value of an unspecified parameter has been exceeded
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm

Definitions

• the invention relates to a sensor device, in particular a limit value sensor device, with a sensor device for detecting a measured variable and a switching device assigned to the sensor device for switching a load circuit
• the term sensor device is understood in principle to mean any type of sensor device which essentially consists of a corresponding measuring sensor, the mechanical construction and a corresponding adaptation electronics.
• This adaptation electronics consequently also has the corresponding output circuit, which is provided for controlling a load circuit assigned to the sensor device at the output.
• a limit value sensor device which actuates one or more switching outputs when a predetermined value, which can be analog or binary, is reached.
• a limit value sensor device therefore combines a measuring sensor or transmitter with the adaptation electronics, which has the evaluation and output function, within the corresponding sensor device.
• Such sensor devices are understood below to mean, for example, inductive and capacitive proximity switches, optoelectronic sensors, ultrasonic proximity switches, magnetic and magnetic field sensors as well as level sensors.
• the switching device in the output circuit which is provided for controlling a load circuit or a corresponding load, is constructed either as a transistor or transistor stage or as an electro-mechanical relay. If the transistor solution was chosen as the switching device, it was possible to do this on a layout with the corresponding adaptation electronics of the sensor.
• a very significant disadvantage was that there was no galvanic decoupling between the control circuit and the load circuit with a simple, inexpensive construction. Potential carry-over could therefore occur.
• the transistor also has the problem that it cannot switch AC voltages.
• micromechanical relays based on silicon are described in DE 198 54 450 AI and DE 42 05 029 Cl. In essence, methods of semiconductor technology, in particular silicon technology, are used. The micro-relays are characterized by an electrostatic switching principle and thus by very low control powers.
• JP 06 060 788 A A piezoelectric micro-relay with reduced energy consumption is disclosed in JP 06 060 788 A.
• CD y P P3 y y i-J SD O P- ⁇ -J ⁇ ⁇ O co fD et s: ⁇ -. y ⁇ P- iQ ⁇ d ri- o y o ⁇ 3 i-J y EP I-J P-. * ⁇ J y rf y ⁇ o l-J P- ⁇ fD y ⁇ ⁇ ⁇ ⁇ o ⁇ P y ⁇ Q P- ⁇ N y co ⁇
• Switching device for controlling it and the output circuit, which, in addition, is modular in terms of circuit technology, e.g. can be expanded for switching several, even different, load circuits.
• This switching device is expediently implemented as a micro-device in the form of a micro-relay MR on the basis of materials and methods as are customary in micro-mechanics and / or in semiconductor production.
• a micro relay e.g. selected on silicon basis, which a suitable layer structure e.g. similar to that of semiconductor components, and the layers of which are structured in terms of process technology such that the actually switching mechanical element can be actuated by electrostatic or piezoelectric forces, that is to say a change in charge.
• a typical drive power can therefore be in the range of about 10 ⁇ W.
• this silicon micro relay can be similar to the type of a leaf spring function, a bending beam or the like. work. In US patent 05638946 a relay with a bending beam is described as an example.
• the design of the switching device as a micro device also makes it possible to implement an integrated version with the sensor device or its adaptation electronics, embodiments as a component or assembly, e.g. on the circuit board of the sensor device or as an SMD or in the realization as a chip together with the further adaptation electronics of the sensor device, as well as as a separate chip.
• the direction of action can be reversed simply by inserting the MR appropriately at different positions in the circuit diagram, without the need for additional components or additional circuitry to achieve this flexibility.
• the layout effort and the size of the resulting assembly for the sensor device can therefore be kept to a minimum, especially since • all components used can be used as SMDs.
• the sensor device with a micro relay therefore not only enables
• Fig. Ld, le the design option of a micro-relay on a chip with the switching element as a closer;
• 3a, 3b the basic external wiring options of a micro relay
• 5a, 5b an analog embodiment according to FIGS. 4 with a simplified load circuit
• 6a, 6b Embodiments of a micro relay with an internal galvanic connection and a reversal of the direction of action;
• Fig.10a, 10b Possibilities of programmable reversal of the direction of action of a micro relay via bridge elements or a rectifier bridge.
• the sensor device is considered to consist of an assembly with the corresponding sensor, e.g. an inductive sensor, understood, which is assigned a corresponding adaptation electronics with an output circuit.
• This output circuit has at least one corresponding switching device, which is preferably a micro-relay MR, and has at least one switching element for switching the downstream load circuit.
• a corresponding micro-relay 1 is shown in simplified form and symbolically in FIGS.
• the possibilities of designing the micro relay as a chip with external wiring alternatives have also been briefly discussed.
• the figures la to le relate, for example, the micro relay 1 as a "make contact".
• the micro-relay 1 is shown schematically with its connections in FIG. 1 a, the bordered block showing an amplifier 3 which is continuously supplied with a supply voltage between the connections VDD and VSS.
• This amplifier 3 receives an input signal 4 and acts on the output side on the actual switch 2, which is open in the illustration according to FIG.
• micro-relay 1 is used symbolically in the function of a make contact according to FIG. 1b.
• Fig. Lc another embodiment of a micro-relay 1 is shown as a closer, in which the separate control input is omitted and the switching function is carried out by applying a corresponding supply voltage or by reaching a corresponding voltage difference.
• an input of the amplifier 3 is connected to the connection VDD.
• this other embodiment shows an input of the amplifier designed as an inverter lying on the VSS connection.
• the other supply voltage connection VDD is connected to the inverter via a diode 8 as reverse polarity protection.
• the diode 8 could also be omitted.
• the micro-relay 1 can also be designed as an "opener", which is shown in FIGS. 2a, 2b.
• the micro relay 1 is equipped with a separate signal input 4 and with a continuous voltage supply between VDD and VSS.
• this separate signal input can also be omitted, the control then taking place via the corresponding supply voltage and e.g. Activation can be achieved by opening the switch if there is a control voltage at the input connections of the micro-relay.
• a chip-internal configuration can be implemented with the micro-relay as an opener in the same way as with the closer according to the figures ld and le.
• the output circuit 10 which can also be referred to as the device circuit GK, shows on the one hand a micro-relay 1 corresponding to the illustration in FIG. 1b.
• This micro-relay receives its continuous DC voltage supply via the connection terminals 12, 13 from a DC voltage source 11.
• the load circuit is shown schematically here with a load 15 and a DC voltage source 16 which can be switched via the output connections 5 and 6 of the micro-relay 1. Due to the electrical isolation at switch 2 of micro relay 1, the load circuit can be connected to any potential within the dielectric strength of micro relay 1.
• FIG. 3b shows the same structure as FIG. 3a, but the load circuit LK is shown schematically with an alternating voltage source 17.
• the load circuit LK can also be acted upon in terms of AC voltage due to the electrical isolation from the control circuit of the micro-relay 1.
• the load circuit LK can therefore be supplied with any time-variant and / or any polarized voltage and is therefore also suitable, for example, for switched data lines or for interfaces.
• FIGS. 3a, 3b therefore show schematically the use of the micro-relay 1 with the highest degree of freedom with regard to the connection of the output circuit 10 or device circuit GK to the load circuit LK.
• the application options also require extensive external wiring.
• the output circuit 10 or device circuit GK and the load circuit LK have no galvanic connection, as shown.
• the output circuit 10 and the load circuit LK have a galvanic connection outside the sensor device or the output circuit 10 or within the output circuit 10, for example an identical reference potential or a summation of voltages when the same reference potential.
• the free output 5 or 6 can either be p-switching or n-switching. P-switching means switching to a positive potential or n-switching means switching to a negative potential.
• the output circuit 10 or the load circuit can have different voltage values or amplitudes.
• the output circuit and the load circuit can be polarized in the same or opposite directions.
• the load circuit can also be of alternating polarity in relation to the output circuit.
• a galvanic connection between the output circuit 10 of the sensor device and the load circuit LK is required, this can advantageously be done internally in the sensor device or the output circuit 10 by means of a galvanic connection 21 between the switch 2 of the micro-relay 1 and the connection terminal 13 with respect to the potential VSS can be solved.
• the further wiring of the load circuit or the load 15 is then at the output terminal 5 and, on the other hand, is connected to the potential of the connection terminal 13. In the example according to FIG. 4a, this is done via a DC voltage source 16 located in the load circuit LK, to which an AC voltage of the AC voltage source 17 'is superimposed.
• the variant according to FIG. 4b differs from the example according to FIG. 4a in that the internal galvanic connection 22 is led to the positive connection terminal 12 within the output circuit 10.
• the load circuit LK is therefore connected to the output connection 6 and the connection terminal 12, which is connected to the positive potential of the DC supply voltage 11.
• the potential applied to the load circuit LK can lie inside or outside the DC supply voltage 11, in accordance with the circuitry shown.
• the output circuit 10 of the sensor device which is equipped with three connections in FIGS. 4a and 4b and can accordingly also be referred to as a 3-wire sensor, therefore allows for the advantages, taking into account the internal galvanic connection 21 and 22, as in the examples 3a, 3b have been named.
• the non-binding output can be designed p- or n-switching.
• Load circuit LK and output circuit 10 can have different voltage values and amplitudes and / or can be polarized in the same or opposite directions.
• the load circuit LK can have an alternating polarity with respect to the output circuit 10 and can also be supplied with any time variant and / or any polarized voltage.
• FIGS. 5a and 5b A further simplification is shown in the examples according to FIGS. 5a and 5b.
• the load 15 of the load circuit is connected to the output connection 5 and on the other hand to the connection terminal 12 to the positive potential of the DC supply voltage 11.
• the load 15 lies between the output connection 6 at the connection terminal 13 or negative potential of the DC supply voltage 11.
• FIG. 6a A further development of the output circuit 10 according to FIGS. 4a, 4b is shown in FIG. 6a.
• the reference potential for the load circuit is now designed to be switchable.
• a changeover switch 24 is provided between the supply potential VDD at the connection terminal 12 and the potential VSS at the connection terminal 13.
• This changeover switch 24 can be switchable via a reversal of the direction of action WRU at the WRU connection 25.
• the output connection 6 for the load circuit reaches the potential VDD in the position according to FIG. 6a. If the reversal of the direction of action was actuated and the switch 24 was switched, the potential VSS would therefore be able to be applied to the output connection 6.
• the corresponding output 6 of the micro-relay 1 can therefore optionally be connected to one or the other pole of the supply voltage, that is to say designed to be p-switching and n-switching.
• the switch 24 itself can be designed in any suitable form, e.g. as an internal bridge, as switching logic or other internal wiring programming.
• switch 24 instead of the switch 24 according to FIG. 6a, the same functionality can be achieved with the internal circuitry according to FIG. 6b by using two simple switches 26 and 27, which can also be designed as additional micro-relays.
• FIGS. 4a, 4b The advantages and wiring options given for FIGS. 4a, 4b are therefore retained, but are further expanded with regard to p-switching or n-switching.
• the design of the 3-wire sensor with a push-pull output 29 is shown in the example. 7a, the output circuit 10 of the sensor device is equipped with a second micro-relay 14, which is designed as an opener.
• the upper micro-relay 1 corresponds to the internal circuitry shown in FIG. 4b.
• the lower, second micro Relay 14 has an internal circuitry corresponding to the example according to FIG. 4a, the micro-relay itself being designed as an opener.
• the corresponding connections 5 and 6 of the two micro relays are routed to the push-pull output 29. Both micro-relays 1, 14 receive the same control signal via a signal connection 4.
• the potential VSS from the connection terminal 13 is at the push-pull output 29 in one switching state.
• the micro-relay 14 opens and the micro-relay 1 closes, whereby the push-pull output 29 receives the potential VDD from the connection terminal 12 ,
• the push-pull output 29 can therefore work alternately p- and n- 'switching. Due to this mode of operation, no further freewheeling diode is required for inductive loads. This reduces the power loss to be dissipated in the sensor device, in particular at high switching frequencies.
• a further increase in the functionality of the circuit according to FIG. 7a is achieved in that a controllable reversal of the direction of action WRU is additionally provided at a connection 25.
• the WRU connection 25 and the signal connection are given to a logic 28 which controls the respective micro-relays 1, 14.
• the circuit according to FIG. 7b with a controlling WRU and possibly additional logic therefore enables output variants with any combination of n-switching, p-switching, opener and closer in a sensor or in its output circuit 10.
• control logic also makes it possible, for example, to use micro-relays of the same type, so that, for example, both micro-relays can be designed either as normally open or normally closed.
• the WRU can also be implemented by internal or external bridges.
• the circuit shown in FIGS. 7a, 7b can advantageously be expanded relatively easily into a two-channel, floating form.
• the two output connections of the micro-relays 1, 14 shown in FIG. 7a are led to the outside, as shown in FIG. 8a.
• the upper micro-relay 1 is designed as a make contact and the lower micro-relay 14 as a break contact, the relays 1, 14 being controllable via a common signal line 4 and thus switching in an equivalent manner.
• both output lines 5, 6 and 5 ', 6 ⁇ of the micro relay are routed to the outside.
• the optional connection with the corresponding reference potential VDD or VSS is created by the fact that the switch 24 internally establishes a connection either with the terminal 12 or 13 (FIG. 8c).
• FIG. 9a A simplified wiring of the input for a conventional electro-mechanical relay is shown in FIG. 9a.
• a load resistor 34 in series with a transistor 35, the emitter of which is led to the connection 33.
• a corresponding signal is obtained at the connection 36.
• the resistor 34 would have to be chosen so low that these Type of connection prohibited by the much too high cross current.
• Other alternatives such as the control of an electro-mechanical relay via the output stages of corresponding operational amplifiers, comparators or via logic, were also designed for the generation of high driver currents his. A further difficulty arises when a reversal of the direction of action is desired for the corresponding relay, since this in any case requires additional components and thus an increase in price.
• the micro-relay 1 can be connected between the positive connection 32 and the connection 36, which is located at the collector of the transistor 35, as shown in FIG. 9b.
• the micro-relay 1 is connected to the negative supply voltage 33. Because of this freedom of choice for the input circuitry of the micro-relay 1, a desired reversal of the direction of action can be achieved without additional components and therefore very inexpensively. Since the input resistance of the micro-relay 1 can always be assumed to be much larger than the resistance value of the working resistor 34, no problems arise with regard to the dimensioning of the working resistor.
• FIGS. 9b and 9c therefore show how a reversal of the direction of action can be achieved solely by varying the position of the micro-relay 1 in the circuit diagram.
• the micro-relay 1 can be placed parallel to the load resistor 34 as well as parallel to the transistor 35. This applies regardless of whether micro-relay 1 is implemented as a make or break contact.
• a corresponding layout of the substrate is used for this ⁇ w et y P- WN P- co et K ⁇ y et H ⁇ - P- ⁇ dyy ⁇ - • d ⁇ P- p- ⁇ d P- H yyy Hi oy Cd H y ⁇ q y P- y O ⁇
• P P- s P. P > y r- 1 y c ⁇ ⁇ yy 'co P- ⁇ S- S. vQ P- o ⁇ y P-
• the corresponding wiring is shown schematically in Fig. 10b.
• the rectifier bridge 46 is connected to the micro-relay 1 with its direct voltage connections. Furthermore, the signal connection 4 and, switchable via the changeover switch 47, a corresponding connection of the supply voltage 32 or 33 is connected to the rectifier bridge.
• the reversal of the direction of action can be effected in the latter case of the circuitry according to FIG. 10 b either by the optional insertion of a bridge, which can be accessible externally, or by control logic at the corresponding control input 31. With corresponding specifications, this control can also influence the reversal of the direction of action while the sensor device is in operation. A fixed connection of the control input with a reference potential is also possible.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Electronic Switches (AREA)
• Arrangements For Transmission Of Measured Signals (AREA)
• Testing Or Calibration Of Command Recording Devices (AREA)
• Relay Circuits (AREA)

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Citations (4)

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• 2000
  • 2000-09-22 DE DE10047113A patent/DE10047113C2/de not_active Revoked
• 2001
  • 2001-09-19 EP EP01974266A patent/EP1319168B1/de not_active Expired - Lifetime
  • 2001-09-19 JP JP2002532890A patent/JP2004510970A/ja active Pending
  • 2001-09-19 AU AU9382301A patent/AU9382301A/xx active Pending
  • 2001-09-19 WO PCT/EP2001/010841 patent/WO2002029364A1/de not_active Ceased
  • 2001-09-19 AU AU2001293823A patent/AU2001293823B9/en not_active Ceased
  • 2001-09-19 DE DE50110171T patent/DE50110171D1/de not_active Expired - Lifetime
  • 2001-09-19 CA CA002422559A patent/CA2422559C/en not_active Expired - Fee Related
  • 2001-09-19 CN CNA018193110A patent/CN1476529A/zh active Pending
  • 2001-09-19 US US10/380,472 patent/US7139159B2/en not_active Expired - Fee Related

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