Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
  • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
• • 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
  • G01D11/00—Component parts of measuring arrangements not specially adapted for a specific variable
  • G01D11/24—Housings ; Casings for instruments
  • G01D11/245—Housings for sensors
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
  • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
  • G05F1/10—Regulating voltage or current
  • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
  • G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
  • G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
  • G05F1/569—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for protection
  • G05F1/571—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for protection with overvoltage detector
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
  • G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
  • G05F3/02—Regulating voltage or current
  • G05F3/08—Regulating voltage or current wherein the variable is dc
  • G05F3/10—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics
  • G05F3/16—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices
  • G05F3/18—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using Zener diodes
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
  • H02H9/008—Intrinsically safe circuits
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
  • H02H11/002—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of inverted polarity or connection; with switching for obtaining correct connection

Definitions

• the present invention relates to a device for determining and / or monitoring at least one process variable of a medium in a container at least with a sensor unit and an electronic unit.
• the device according to the invention is, in particular, a field device which is used to monitor and / or determine at least one
• the medium is for example a liquid or a gas.
• the term container means all devices known to the person skilled in the art which are designed to hold and / or guide a medium, for example containers or pipelines.
• the sensor unit of the field device at least partially and at least temporarily comes into contact with the process and serves to detect a signal representing the respective process variable.
• the electronics unit in turn serves, for example, the
• the electronic unit For communication with a higher-level unit, for example a data processing unit, or a process control room, the electronic unit typically comprises a transceiver unit, which in particular the
• all measuring devices are referred to as field devices which are used close to the process and supply or process process-relevant information, including remote I / Os, radio adapters or generally electronic components which are arranged on the field level.
• field devices which are used close to the process and supply or process process-relevant information, including remote I / Os, radio adapters or generally electronic components which are arranged on the field level.
• a large number of such field devices are manufactured and distributed by companies of the Endress + Hauser Group.
• the field device may be a fill level measuring device, flowmeter, pressure and temperature measuring devices, pH and / or pH redox potential measuring device, or else a conductivity measuring device, which detects the respectively corresponding detection
• Process variables such as a level, a flow, the pressure, the temperature, a pH, a redox potential, or a conductivity is used.
• Process variables such as a level, a flow, the pressure, the temperature, a pH, a redox potential, or a conductivity is used.
• Flowmeters are, in particular, Coriolis, ultrasonic, vortex, thermal and / or magnetic-inductive flowmeters.
• Level gauges in turn are particularly suitable as microwave level gauges, ultrasonic level gauges, time domain reflectometric level gauges (TDR), radiometric level gauges, capacitive level gauges, conductive
• EMC electromagnetic compatibility
• limit values for an interference emission for example, the length of the supply lines, as well as the question of whether the respective field device can be connected to a local DC power supply or not to
• the present invention is therefore based on the object of specifying a measuring device for which a high electromagnetic compatibility can be ensured in a simple and cost-effective manner for different applications.
• a device for determining and / or monitoring at least one process variable of a medium in a container at least with a sensor unit and an electronic unit which electronic unit has a transceiver unit and a transceiver protection unit for limiting an input voltage of the transceiver unit to a predeterminable transceiver voltage value.
• the inventive transceiver protection unit comprises a first limiting unit and a transistor unit with at least one transistor,
• the transistor unit is connected in series with the transceiver unit
• the first limiting unit is connected in parallel to the transceiver unit and connected to a control terminal of the transistor
• the first limiting unit is designed, in the event that a supply voltage for the electronics unit exceeds a predefinable limit value, to control an input voltage for the control terminal of the transistor to a predefinable control value, such that the input voltage of the transceiver unit to the first predetermined
• Transceiver voltage value is limited.
• the transceiver unit preferably has a control unit for controlling an input and / or output voltage of the transceiver unit and at least one connection element.
• the connection element is preferably an input, an output or a combined input and output.
• transceiver units of field devices are usually designed only for low transient energies, as they will connect locally within a device to its own supply. Depending on the classification, normative so-called surge and burst sources with different internal resistances are used here. A protection of the transceiver unit before
• the achievable voltage limitation that is, the respective achievable maximum value for the input voltage of the transceiver unit
• the achievable voltage limitation depends on the current flowing through the diodes and the internal resistance.
• the maximum value for the input voltage of the transceiver unit disadvantageously increases.
• such a voltage limitation is correspondingly insufficient, or the maximum permissible power of the diodes can be quickly exceeded.
• varistors have the disadvantage that they can no longer maintain a sufficient voltage limitation at high currents. With gas unloaders in turn there is a big disadvantage in that until the ignition of the arc
• the present invention proposes the use of a
• Transceiver protection unit before which is a transistor unit and at least a first
• transceiver protection unit becomes the input voltage the transceiver unit limited to a specifiable transceiver voltage value.
• Transceiver protection unit thus protects the transceiver unit from overvoltages. If the supply voltage at least temporarily exceeds a predefinable limit value, for example due to the occurrence of a surge or burst, the input voltage of the transceiver unit is limited to the specifiable transceiver voltage value.
• the transistor is a bipolar transistor with at least one, in particular ohmic, resistor, or a field effect transistor.
• the control terminal of the transistor is accordingly preferably a base or a gate of the transistor.
• the first limiting unit comprises at least one voltage-limiting element, for example a diode, in particular a Zener diode or an avalanche diode or a varistor.
• An advantageous embodiment includes that the device comprises a second limiting unit for limiting the input voltage of the transceiver unit, which second
• Limiting unit is connected between a first and a second supply line of the transceiver unit.
• the second limiting unit is also arranged in front of the transistor unit and the first limiting unit.
• the second limiting unit thus ensures a preliminary limitation of the input voltage of the transceiver unit. It is advantageous if the second limiting unit comprises at least one voltage-limiting element, in particular a varistor, a gas discharger, or a diode, in particular a suppressor diode, in particular a Transzorb diode.
• the device comprises a third limiting unit for limiting a voltage applied to a connection element of the transceiver unit.
• This connection element is an additional one
• Connection element for example an In / Out connection.
• at least one further connecting element of the transceiver unit can be protected against, in particular transient, overvoltages.
• the third limiting unit comprises at least one voltage-limiting element, in particular a diode, for example a suppressor diode, in particular a Transzorb diode, or a varistor.
• the device comprises a rectification unit for rectifying the input voltage of the transceiver unit.
• the rectification unit may be, for example, a rectification circuit, in particular a
• the rectification unit is furthermore preferably connected upstream of the limiting units and the transistor unit.
• a further particularly preferred embodiment includes that the device comprises a reverse protection unit, which is designed to hide at least a signal component of the supply voltage with a polarity opposite to the polarity of the input voltage of the transceiver unit polarity. From time to time, the supply signal or the supply voltage can have signal components with opposite polarity, in particular so-called bursts or surges, ie voltage pulses. These are hidden by the Reversetik- unit from the supply signal and thus do not reach the transceiver unit. With regard to the reverse protection unit, it is advantageous if the reverse protection unit comprises at least two diodes.
• a first diode is then connected in series with the first limiting unit, and a second diode is arranged between the transistor unit and the transceiver unit.
• Circuit arrangement for limiting the voltage are taken into account.
• an input and an output of the transceiver unit are realized via a single connection element, wherein the electronic unit has at least one switching element.
• the input of the transceiver unit via a first
• Connection element and the output of the transceiver unit can be realized via a second connection element. It is advantageous if the electronics unit is designed to provide the sensor unit with a
• the electronic unit can determine and / or monitor the process variable on the basis of the received signal, and generate a corresponding measurement signal and forward it to a higher-order unit by means of the transceiver unit.
• the Receive signal directly for further evaluation by means of the transceiver unit are forwarded to a higher-level unit.
• the transceiver unit is configured at least partially in the form of an integrated circuit.
• FIG. 1 is a schematic representation of an electronics unit of a field device with a transceiver unit according to the prior art
• FIG. 2 shows a schematic representation of an electronic unit of a field device with a transceiver unit with an additional voltage limitation according to the prior art
• FIG. 3 shows a schematic representation of an electronic unit according to the invention with a
• FIG. 5 shows a schematic representation of an electronic unit according to the invention with a
• Transceiver protection unit in a third embodiment.
• FIG. 1 shows a schematic representation of an electronics unit 1 of a field device. Not shown in this view is the sensor unit.
• the field device shown is a so-called three-wire field device with three connecting lines or connecting elements (5a, 5b, 5c) in this specific example without limiting the generality.
• the electronic unit 1 of the field device 1 has a transceiver unit 2, a computing unit 3 and a measuring part 4.
• the measuring part is preferably electronic components which serve to detect the respective measured variable received by the sensor element and convert it into an electrical signal ,
• the transceiver unit 2 in turn serves among other things
• the transceiver unit 2 has a control unit 2a. Since conventional transceiver units 2 are designed only for relatively low transients, the scope of an electronic unit 1 as shown in Fig. 1, limited. In particular for the protection of the transceiver unit, it has become known from the prior art to implement one or more voltage-limiting elements which extend the application range for a corresponding electronic unit 1 with transceiver unit 2. Frequently, diodes 6a, 6b, 6c are used for this purpose, as shown by way of example in FIG. As already mentioned, these measures known from the prior art for protecting the transceiver unit have various disadvantages which are overcome by the solution according to the invention.
• FIG. 1 A first embodiment of an electronic unit 1 according to the invention is shown in FIG. 1
• the electronics unit has a transceiver protection unit 7 comprising a transistor unit 8 and a first limiting unit 9.
• the transistor unit 8 comprises a bipolar transistor 8a with an ohmic resistance 8b.
• the transistor unit 8 is connected in series with the transceiver unit 2.
• the first limiting unit 9 has as a voltage-limiting element a diode 9a and is connected to the base of the transistor 8a.
• the diode 9a becomes conductive.
• the diode controls an input voltage for the control terminal of the transistor 8a to a predetermined control value.
• the transistor becomes more highly resistive and a higher voltage component of the supply voltage drops across the transistor 8a.
• the input voltage UTE of the transceiver unit 2 is made up of the difference between the values dropping at the first limiting unit 9 Voltage Ug and the voltage drop across the transistor unit 8 Ue together:
• the reverse voltage of the diode 9a is preferably selected to be larger than that
• Supply voltage and less than a maximum allowable voltage of the transceiver unit 2 is. If the supply voltage exceeds a definable limit value, which in this particular example is given by the blocking voltage of the diode 9a, the diode 9a becomes conductive and thus controls the input voltage for the gate of the transistor 8 to the predefinable control value. As a result, the current flowing through the transistor 8 decreases and a higher voltage component drops across the transistor 8. This voltage component is always just so large that the input voltage UTE of the transceiver unit 2 corresponds to the specifiable transceiver Voltage value, which is also usually smaller than the maximum permissible value for the input voltage of the transceiver unit 2 is selected does not exceed.
• a definable limit value which in this particular example is given by the blocking voltage of the diode 9a
• the second limiting unit 11 has a varistor 11a.
• the second limiting unit 11 is arranged in front of the first limiting unit 9 and connected between a first 5a and a second supply line 5b of the transceiver unit 2, or of the electronic unit 1.
• the second limiting unit 11 thus provides for a preliminary limitation of the supply voltage.
• the third limiting unit 12 serves to limit a voltage applied to an in / out connection element of the transceiver unit 2 against transient overvoltages.
• the device further comprises a reverse protection unit 10, which is designed to at least a signal component of the supply voltage with one of the polarity of the input voltage of the
• the reverse protection unit 10 comprises a first 10a and a second diode 10b.
• the first diode 10 a is connected in series with the first limiting unit 9, while the second diode 10 b is arranged between the transistor unit 8 and the transceiver unit 2.
• the reverse protection unit protects in
• FIG. 5 shows an embodiment in which the transistor unit 8 is in the positive branch.
• the mode of operation of the individual components is analogous to the respective functions in FIGS. 3 and 4. Therefore, in the context of FIG. 5, this will not be discussed again in detail.
• the reversing protection unit 10 which likewise has two diodes 10a and 10b, protects the device from positive transients in the case of FIG.
• the transceiver protection unit comprises a reverse protection circuit 10
• transients of different polarity can be taken into account with the same circuit arrangement.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Radar, Positioning & Navigation (AREA)
• Automation & Control Theory (AREA)
• Nonlinear Science (AREA)
• Emergency Protection Circuit Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=63637894

Family Applications (1)

Country Status (5)

Family Cites Families (26)

• 2017
  • 2017-10-26 DE DE102017125129.4A patent/DE102017125129A1/de not_active Withdrawn
• 2018
  • 2018-09-17 US US16/759,586 patent/US11233392B2/en active Active
  • 2018-09-17 EP EP18772790.4A patent/EP3701611A1/de active Pending
  • 2018-09-17 WO PCT/EP2018/075022 patent/WO2019081127A1/de unknown
  • 2018-09-17 CN CN201880068442.6A patent/CN111527662B/zh active Active

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