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
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage

Definitions

• the present invention relates to a measuring device for process technology, with a central unit for connecting various measuring modules, the central unit containing a central power supply to which the measuring modules can be connected.
• the present invention also relates to an operating method for a measuring device for process technology, with a central unit for connecting various measuring modules.
• measurement modules that can be connected to the central unit must also be supplied by such a power supply.
• these measuring modules have a wide variety of sensor types, which often require special supply voltages.
• This object is achieved according to the invention in a measuring device of the type mentioned at the outset by providing a module supply in the measuring module which generates one or more supply voltage (s) required by the measuring module from the central power supply.
• the central power supply can be designed to be relatively simple and, in particular, does not have to provide suitable supply voltages for each measuring module that can possibly be connected to and supplied by the measuring device. This reduces the cost of such a measuring device and reduces its susceptibility to errors because of the much less complex structure of the central power supply.
• the measuring device according to the invention is particularly suitable for use in measuring and / or cleaning and / or calibration systems, also in the field of
• Process automation intended for measuring pH values and / or redox potentials and / or other process variables.
• the central power supply can provide an alternating voltage from which connected measuring modules generate the required supply voltages with the aid of their respective module supply.
• a very simple variant of a module supply sees a transformer and possibly a rectifier circuit the module supply so that direct and alternating voltages can be generated in the measuring module.
• the rectifier circuit can contain, for example, a conventional bridge rectifier and filter networks and, if appropriate, voltage converters.
• the module supply expediently has its own fuse, so that an error state in a measuring module cannot disrupt the entire central supply of the measuring unit.
• the voltage required in the measuring module can be set by the choice of the transformation ratio of the transformer, in principle the generation of both a smaller and a larger secondary voltage compared to the voltage of the central supply is conceivable.
• a transmission ratio with the value one is also conceivable, whereby there is only a galvanic separation between the central supply and the measuring module or its module supply.
• the frequency of the supply voltage provided by the central supply can be, for example, 50 Hz, it being possible for the supply voltage to be obtained directly from a public power grid.
• Supply voltages of a higher frequency can also be used very advantageously in order to enable smaller designs for transformers which may be used with the same supply power.
• a further advantageous embodiment of the measuring device according to the invention provides that the central power supply can provide a DC voltage. This is particularly so then very useful if measuring modules contain microprocessors or other integrated electronic components that require a common supply voltage of, for example, 5 volts.
• the module supply has a switching power supply.
• switched-mode power supplies are particularly well suited, in particular, for supplying loads with high power consumption.
• Switched-mode power supplies also have a very wide input voltage range, so that the central power supply does not require a large amount of circuitry to generate the supply voltage in order to ensure the operation of a measuring module with a switched-mode power supply in the module supply.
• the switching power supply For use in measuring modules with sensitive sensors, the switching power supply must be shielded to reduce interference emissions.
• the operating frequency of the switched-mode power supply can also be selected significantly above the cut-off frequency of measurement signals or a filter network can be provided for the measurement signals.
• another embodiment of the invention provides that the central power supply has a first induction device and that the module supply has a second induction device. Since the electrical energy transmission in this variant of the invention is based on the induction principle, no electrical contacts have to be actuated in order to connect the measuring module to the central supply. This eliminates the risk of sparking if the contact is broken.
• a small distance between the first and the second is particularly useful in this embodiment Induction device, which is achieved, for example, by correspondingly interlocking housing sections of the central unit or the measuring module.
• a variant of the invention is also very advantageous, in which the voltage provided by the central power supply can be modulated with a useful signal in order to enable data communication between the central unit and the measuring module without having to provide separate transmission lines.
• the bandwidth of the useful signal must be selected taking into account the transfer function of the transformer.
• a further, very advantageous embodiment of the invention is characterized in that a feedback unit is provided in the measuring module, which generates a feedback signal from the supply voltage applied to the measuring module, which feedback signal can be fed to a central power supply controller and influences the supply voltage.
• the feedback unit has, for example, a voltage divider or another circuit for forming the feedback signal, which is designed in such a way that the feedback signal, when the supply voltage generated by the central unit matches the voltage required by the measuring module, corresponds to a reference voltage of the controller.
• the supply voltage can be adjusted using the control difference be readjusted.
• an operating method is specified for a measuring device for process technology, with a central unit for connecting various measuring modules, in which the central unit contains a central power supply to which the measuring modules can be connected, and in which one in the measuring module Module supply is provided, one or more supply voltage (s) required by the measuring module being generated by the module supply from the central power supply.
• An advantageous variant of the operating method according to the invention is characterized in that the supply voltage (s) are changed during operation. This can be done, for example, by a measuring module connecting a second transformer provided in its module supply to the central power supply, or also by changing control variables of a switching power supply.
• the second transformer can be, for example, a transformer with a large rated power that is only used temporarily. Switching off the second transformer during operation helps to keep the load on the central power supply as low as possible.
• the function of the measurement module is not limited to the acquisition of measured values.
• a measuring module can also have calculation units, output units or other data processing devices or devices that enable the measuring device to be expanded.
• FIG. 1 shows a first embodiment of the measuring device according to the invention
• FIG. 2 shows a second embodiment of the measuring device according to the invention.
• FIG. 3 shows a third embodiment of the measuring device according to the invention.
• FIG. 1 In the embodiment of the measuring device according to the invention shown in FIG. 1, a central unit 1 and two measuring modules 2, 3 are shown.
• the central unit 1 has a central power supply 4, which is used to supply the measuring modules 2, 3 with electrical energy.
• the central power supply 4 consists, for example, of a mains transformer, which may be protected with a self-healing overload protection or a fuse, and supplies an AC voltage with a frequency of 50 Hz.
• the measuring module 2 has a module supply 2 'and the measuring module 3 has a module supply 3'.
• the module supplies 2 ', 3' are connected to the central power supply 4 and process the AC voltage provided by the central power supply 4 in accordance with the supply voltages V_2, V_3 required in the measuring modules 2, 3.
• the module supply 2 has a transformer, which is directly connected to the central power supply 4.
• the transformer has a transmission ratio of one to two, ie the supply voltage V_2 on the secondary side of the transformer is twice as high as the AC voltage provided by the central supply 4, which is present on the primary side of the transformer.
• a measuring module can also have actuators.
• the measuring module 2 shown in FIG. 1 accordingly has a heating element (not shown) which is operated directly with the supply voltage V_2 of the module supply 2 '.
• a microprocessor also arranged in the measuring module 2 requires a stabilized direct voltage of five volts as the supply voltage, which is obtained from the supply voltage V_2 with the aid of a rectifier circuit and further components.
• the use of a voltage converter to generate / stabilize the DC voltage is also particularly favorable.
• the central power supply 4 can also provide the stabilized DC voltage that is often required for integrated circuits.
• the measuring module 3 requires a supply voltage V_3 which does not correspond to the supply voltage V_2 of the measuring module 2.
• the module supply 3 ' therefore has a transformer with a different transmission ratio. On the primary side, however, this transformer is connected in parallel to the transformer of the module supply 2 ', so that the same AC voltage is present on the primary side of both transformers.
• the module supply 3 ′ additionally has an auxiliary transformer (not shown), which is connected to the central power supply 4 in special process steps and controlled by the measuring module 3.
• the auxiliary transformer is thus only active when it is required, as a result of which unnecessary power loss is avoided in the measuring module 3.
• the measuring device it is possible to connect further measuring modules to the central unit 1 in addition to the measuring modules 2, 3. Since, according to the invention, the supply voltage required by a measuring module is provided by the module supply, supply voltage requirements of further measuring modules need not be taken into account when manufacturing or installing a measuring device.
• the embodiment of the invention shown in Figure 2 has a central unit 1 and a measuring module 2.
• the central power supply 4 of the central unit 1 has a first induction device 5, which can cooperate with a second induction device 6.
• the second induction device 6 is part of the module supply 2 ′ of the measuring module 2.
• the energy transmission according to the invention enables the measuring device to be operated even in potentially explosive environments since, in principle, there is no spark formation, e.g. when disconnecting electrical contacts is possible.
• the housings of the central unit 1 or the measuring modules 2 are encapsulated in a gas-tight manner in accordance with the legally prescribed degree of protection and advantageously have intermeshing housing sections in the area of the induction devices 5, 6, which enable particularly close arrangement of the induction devices 5, 6 relative to one another.
• circuits of the central unit 1 and / or of the measuring module 2 are designed intrinsically safe as so-called “Ex-i” circuits. In this case, no gas-tight housing is required .
• Central power supply 4 to modulate the voltage provided with a useful signal.
• Data communication between the central unit 1 and a measuring module 2, 3 can thus be implemented without having to provide additional lines for transmitting the useful signal.
• the embodiment of the invention depicted in FIG. 3 is characterized in that a feedback unit 7 is provided in the measuring module 2, which generates a feedback signal 7a from the supply voltage V_4 applied to the measuring module 2, which can be fed to a controller (not shown) of the central power supply 4 and affects the supply voltage V_4 or its generation in the controller of the central power supply 4.
• the feedback unit 7 has a voltage divider (not shown) which generates the feedback signal 7a.
• the regulator of the central power supply 4 has a reference voltage source (not shown), the reference voltage of which is compared with the feedback signal 7a.
• the voltage divider is designed such that the feedback signal 7a matches the reference voltage of the controller if the supply voltage V_4 generated by the central power supply 4 matches the voltage required by the measuring module 2.
• the voltage divider is to be designed differently for different measuring modules 2, for example only one element of the voltage divider being different from measuring module 2 to measuring module 2 depending on the supply voltage requirement.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Arrangements For Transmission Of Measured Signals (AREA)
• Testing Or Calibration Of Command Recording Devices (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 2002
  • 2002-04-13 DE DE10216330A patent/DE10216330B4/de not_active Expired - Lifetime
• 2003
  • 2003-04-11 AU AU2003222807A patent/AU2003222807A1/en not_active Abandoned
  • 2003-04-11 WO PCT/EP2003/003759 patent/WO2003087964A1/de active Application Filing
  • 2003-04-11 JP JP2003584842A patent/JP2005522706A/ja active Pending
  • 2003-04-11 US US10/510,233 patent/US7372374B2/en not_active Expired - Fee Related
  • 2003-04-11 RU RU2004133341/09A patent/RU2305868C2/ru not_active IP Right Cessation
  • 2003-04-11 EP EP03718747A patent/EP1495379A1/de not_active Ceased
  • 2003-04-11 CN CN038137658A patent/CN1659487A/zh active Pending

Non-Patent Citations (1)

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