Field device energy management unit

Abstract

The invention relates to a field device energy management unit, the field device having an energy store for temporarily storing energy of a load of the field device, the field device energy management unit comprising: a first current path, which can be connected at the input side to the energy store or is connected thereto, and a first diode is arranged in the first current path at the output side, the cathode of which can be connected to the load of the field device or is connected thereto; at least one second current path, which can be connected at the input side to a power supply of the field device or is connected thereto, and a second diode is arranged in the second current path at the output side, the cathode of which can be connected to the load of the field device or is connected thereto; wherein the first and second diodes can be operated such that in the case of low energy consumption of the load, the first diode is switched on in the blocking direction and the second diode is switched on in the conducting direction, and in the case of high energy consumption of the load, the first diode is switched on in the conducting direction.

Description

TECHNICAL FIELD

[0001] The present application relates to a field device energy management unit for a field device according to the application, a field device having such a unit according to the application, a function module for a field device having such a unit according to the application, and a method for operating such a field device energy management unit according to the application. BACKGROUND

[0002] In the field of industrial process automation, it is common to use devices which are arranged in the field, i.e. near the process to be monitored or to be controlled, and thus outside the control room for controlling the process. Such devices are referred to as field devices. For example, the devices provide information about the process (e.g. measured values of temperature, pressure, flow) and / or influence the process (e.g. adjustment of a valve position). Field devices which provide information about the process are often also referred to as sensors or transducers. Field devices which influence the process are often also referred to as actuators or actuators.

[0003] Field devices are usually not arranged in a protected switch cabinet, but are directly exposed to harsh environmental conditions and also process safety requirements. This leads to the fact that high quality, robustness and availability requirements are placed on the field devices. The field devices must usually be available for a large temperature range and meet requirements for intrinsic safety and explosion protection.

[0004] "Smart" or intelligent field devices with extensive communication, diagnostic, configuration and parameterization options and for data preprocessing functions are also increasingly used.

[0005] Field devices are usually connected to the lowest level of an industrial communication network, e.g. to a fieldbus, and can provide process information to superordinate devices, e.g. control and / or regulation devices for the process or monitoring and diagnostic devices, or receive adjustment parameters via this. Intelligent field devices can also provide information about themselves (operating status, configuration, software version, firmware version) to a superordinate process device management system. Examples of the communication mechanisms used here are HART (Highway Addressable Remote Transducer), PROFIBUS (Process Field Bus), CAN (Controller Area Network) or Ethernet-based: PROFINET, Ethernet IP, MODUBUS TCP, Time-Sensitive Networking (TSN) or Single Pair Ethernet.

[0006] In general, all other devices which are arranged near the field process and connected to the communication system, e.g. to a fieldbus, are also included in the field devices in the broadest sense. Examples of this are remote I / Os, which connect analog or binary sensors or actuators to the communication system, or also to a gateway or link device.

[0007] A special challenge for many field devices is - especially according to safety requirements like explosion protection - that the delivery of electrical energy for their operation is limited.

[0008] In order to save wiring, here the energy supply and the communication are usually carried out via a common conductor system. For example, the so-called two-conductor technology (or also two-wire technology) is used, in which the transmission of the communication signals and the provision of the electrical current for the energy supply of the field device are carried out via a common wire pair. Here, a first wire or a first conductor is used for the forward direction and a second wire or a second conductor is used for the return direction. An example of this is a two-conductor loop according to the 4 mA to 20 mA standard. Communication according to the four-conductor technology can also be used.

[0009] Increasingly, Power over Ethernet (PoE) and Single Pair Ethernet (SPE) are also being used, in which network-enabled devices are also supplied with electrical energy via an Ethernet cable. In the future, then, Ethernet Advanced Physical Layer (APL) is used, in which communication and energy supply are carried out via a unique two-core cable, and which is particularly suitable for the specific requirements of the process industry.

[0010] Therefore, in field devices with a limited deliverable energy, the available energy budget must be used as optimally as possible. In particular in 4 mA to 20 mA field devices, every micro Watt counts. Furthermore, in many applications, the energy distribution is not only static, but also dynamic. Often, more energy is required for a short time than is currently available to the field device. For this purpose, energy is collected and temporarily stored in an energy store (for example in a capacitor, a battery).

[0011] Therefore, for example from DE 10 2015 115 275 A1, a field device with a radar-based fill level measurement with a sensor module for the fill level measurement and a communication module is already known. The sensor module requires more energy for the measurement function than is deliverable to the field device via the two-conductor bus. Therefore, a storage capacitor is assigned to the sensor module, which is charged from the two-conductor bus between the measurement phases. A measurement is only carried out when the state of charge of the storage capacitor moves in a determined range. Likewise, there can be a communication module, which requires more energy for the transmission / reception than is permanently and continuously available. In order to measure the state of charge of the storage capacitor, the voltage over the storage capacitor is measured.

[0012] In principle, for the energy collected from the system of the field device, no more energy should be extracted than is present, so that the other loads of the system can continue to operate. A load that temporarily requires more energy must still be supplied with less energy during the remaining time (for example in a sleep mode in a microcontroller).

[0013] Moreover, only very limited additional energy (e.g. 100 μW) is available for extending the functionality of the field device, for example by means of a functional module or a display, without impairing the remaining functionality of the field device. By the disadvantageous efficiency of the conversion and storage of energy in the energy store, the available energy is further reduced, so that a plurality of functional extensions cannot be implemented. Usually, only a reactivation of the field device is possible in order to provide more energy for the functional extension.

[0014] For example, in order to make the collection and temporary storage of energy as efficient as possible, the system supply voltage of the field device is boosted by means of a boost converter, in order to subsequently store the electrical charge on a capacitor, since the energy is quadratic in the voltage in the capacitor.

[0015] However, during the entire charging time of the energy store, the current drawn from the system of the field device must not exceed a certain limit value. Therefore, the process must be continuously monitored and controlled by means of a back-reading current, for example by means of an analog-digital converter.

[0016] In order to be able to use the stored energy, the voltage can then be boosted again by means of a step-down converter, in order to adapt the energy to the operating voltage of the module to be supplied. Depending on the time and how much energy is required, the energy from the energy store is connected to the load or disconnected from the load via a switch and the associated control logic. For this purpose, the voltage value at the energy store must be measured or determined via a comparator.

[0017] Therefore, in order to control and monitor the collection and temporary storage of energy and in order to switch processes for energy distribution, i.e. for energy management of the field device, a plurality of electronic components of the logic means for evaluation and control and expenditure are required. Moreover, the components required for this require space and energy. SUMMARY

[0018] It is therefore an object of the present application to realize a low-expenditure and mainly also energy-efficient energy management in a field device having an energy store.

[0019] This object is achieved by a field device energy management unit according to the present application. Advantageous design variants of the field device energy management unit are the subject of the present application. A field device having such a unit is the subject of the present application. A functional module for a field device having such a unit is the subject of the present application. A method for operating such a field device energy management unit is the subject of the present application.

[0020] The field device energy management unit according to the present application for a field device having an energy store for temporarily storing energy for a load of the field device comprises:

[0021] - A first current path, which may be connected to an energy storage device on the input side or connected to an energy storage device, and a first diode arranged on the output side in the current path, the cathode of the first diode may be connected to the load of a field device or connected to the load of a field device.

[0022] - At least one second current path, which can be connected to the power supply of the field device on the input side or to the power supply of the field device, and a second diode is arranged on the output side in the second current path, the cathode of the second diode being connected to the load of the field device or to the load of the field device.

[0023] -The first diode and the second diode can operate such that when the energy consumption of the load is low, the first diode is turned on in the cutoff direction and the second diode is turned on in the conduction direction, and when the energy consumption of the load is high, the first diode is turned on in the conduction direction.

[0024] Therefore, there are at least two current paths decoupled by diodes to supply energy to the load. Through these two current paths and the selective operation of the diodes in the on or off direction, dynamic current conduction and energy extraction can be automatically performed based on the charging state of the energy storage device and the operating state of the load. This allows the low energy consumption of the load to be met directly from the power supply via the second current path, which can also be supplied from the power supply of the field device. Because this energy does not have to take the lossy path via the energy storage device and, if necessary, the associated boost / buck converter, the energy can be supplied to the load very efficiently and energy-savingly. Conversely, the high energy consumption of the load, which is no longer met from the power supply of the field device, is met only or additionally automatically from the energy storage device via the first current path.

[0025] Here, the selective operation of the two diodes in the conduction or cutoff direction can be simply achieved by correspondingly setting the voltage ratio (i.e., voltage drop) across the diodes. This voltage ratio is derived from the voltage potential difference between the corresponding anode and cathode. The voltage potential at the anode of the first diode is primarily affected by the voltage of the energy storage device, and consequently by its state of charge. The voltage potential at the anode of the second diode is primarily affected by the voltage of the voltage source.

[0026] The voltage potential at the two cathodes is the same as the voltage potential at the input of the load, and is determined by the voltage drop at the load. Therefore, if the load has only low energy consumption, the voltage potential at the cathodes is high. Conversely, if the load has high current consumption and thus its input voltage drops, the voltage potential is low.

[0027] Thus, no voltage measurement is necessary at the energy store and no switches with corresponding control logic for switching the energy distribution between the power supply, the energy store and the load are necessary, since the diodes "automatically" switch the energy distribution or the current conduction depending on the voltage ratio applied at them.

[0028] The term "load" here relates to an electrical load. The load here can also be a plurality of loads, but which in fact act as a single load from the perspective of the energy management unit.

[0029] There can also be one or more further second current paths which can be connected to a further power supply of the field device on the input side or can be connected to a further power supply of the field device and in which or on the output side of which a diode is arranged which cathode can be connected to a load of the field device or can be connected to a load of the field device. For example, a further current path is connected or can be connected to a power supply of the field device in the form of a backup battery on the input side. Thereby, in the event of a failure of the conventional power supply from the outside and at the same time a discharge of the energy store, an emergency power supply is also provided for the load.

[0030] The energy store can be, for example, a capacitor, a super capacitor, an accumulator or a battery.

[0031] The diode can be, for example, a classic semiconductor component or an electronic circuit with diode properties.

[0032] For charging the energy store with current from the power supply, there is advantageously a third current path which can be connected to a power supply of the field device on the input side or can be connected to a power supply of the field device and which can be connected to the energy store on the output side or can be connected to the energy store.

[0033] For limiting the energy drawn from the power supply or from the field device by the second current path, a first current-limiting element is advantageously arranged in the second current path.

[0034] For limiting the energy drawn from the power supply or from the field device by the third current path, a second current-limiting element is advantageously arranged in the third current path.

[0035] In the use of such current-limiting elements, it is possible to dispense with the measurement and monitoring of the current drawn from the voltage source and the switches for interrupting the current in the event of an excess limit value.

[0036] According to a particularly advantageous design, the one or more current-limiting elements are configured as current sources. A current source is understood to be an active circuit element which is able to supply a substantially constant amount of current to a circuit, independently of the voltage present at its terminals. For example, a current source can be built using a bipolar transistor, a field effect transistor or an operational amplifier.

[0037] According to a further advantageous design, a step-up converter is arranged in the third current path. Thereby, the voltage of the voltage source can be step-up converted, so that more energy can be stored in the energy store.

[0038] In order to transform the voltage of the energy store to a value which is suitable for the load, a converter can be provided in the first current path between the energy store and the diode. Here, the converter can be a step-down converter. A step-down / step-up converter can also be used, which reduces the voltage (step-down behavior) or increases the voltage (step-up behavior) depending on the state of charge of the capacitor. Such a step-down / step-up converter is particularly advantageous when the energy store is charged directly from the power supply.

[0039] Preferably, a fourth current path is additionally present, which connects the second current path and the third current path to one another. If the load does not require the current provided via the second current path in full, the excess current can be transferred via the fourth current path into the third current path, in turn for energy storage.

[0040] Advantageously, the fourth current path is connected to the second current path after the first current-limiting element on the input side and to the third current path after the second current-limiting element on the output side. Thereby, for the energy transfer, the current extraction from the power supply is also limited in a simple manner.

[0041] In order to prevent an undesired amount of current from the third current path to the second current path, advantageously a third diode is arranged in the fourth current path, the anode of which is connected to the second current path and the cathode of which is connected to the third current path.

[0042] According to a particularly advantageous design, the energy store is configured to temporarily store energy for the energy requirement of the load, which is greater than the amount of energy which can be provided by the power supply, in particular greater than the amount of energy which can be provided externally to the field device.

[0043] The load can advantageously be a communication module, in particular a wireless module, a display, a sensor module, a measurement data processing module, a control module or a regulating module.

[0044] For example, the communication module can be used to transmit measurement values to a superordinate device and / or to receive rating values from such a device. The communication can take place wired or wirelessly. For example, the wireless module can work according to the WirelessHART, Bluetooth Low Energy, 3G, 4G or 5G standard.

[0045] A display, for example a display screen, can be used for parameterization, configuration and diagnosis of the field device.

[0046] A sensor module can be used to detect a physical process variable, for example temperature, pressure, flow, vibration, level, etc.

[0047] A measurement data processing module can be used to analyze measurement data on site. For example, statistical evaluations, KPI derivations and classifications can be carried out on the measurement data according to EN 10816-6, EN 10816-7, EN 10816-3. With the aid of machine learning, anomalies in the measurement data can be identified and predictions about the future course of the measurement data can be made.

[0048] A control module can be used to output rating values to set a manipulated variable, for example a valve position, of a process. A regulating module is correspondingly used to output rating values to regulate a process variable.

[0049] The field device according to the application has an energy store for temporarily storing energy for a load of the field device, in particular for temporarily storing energy for an energy requirement of the load, which is greater than the amount of energy that can be provided by the field device, the field device comprising the aforementioned energy management unit.

[0050] The functional module for a field device according to the application comprises:

[0051] - a load,

[0052] - an energy store for temporarily storing energy for the load, in particular for an energy requirement of the load, which is greater than the amount of energy that can be provided by the field device, and

[0053] - the aforementioned energy management unit.

[0054] The energy management unit is thus integrated into the module together with the energy store and the load. The functional module is preferably configured as a communication module, in particular a wireless module, a display, a sensor module, a measurement data processing module, a control module or a regulating module. Preferably, the functional module is a module that can be retrofitted at the field device. Advantageously, the functional module can be detachably fixed at the field device.

[0055] In the method according to the application for operating the field device energy management unit according to the above, the first diode and the second diode are operated such that the load is supplied with energy only via the second current path in the case of low energy consumption and, in the case of high energy consumption, only or additionally via the first current path. BRIEF DESCRIPTION OF DRAWINGS

[0056] The application and further advantageous design of the application according to the features of the application are explained in more detail below with regard to embodiments in the drawings; in which:

[0057] Figure 1 A field device with an energy management unit according to the prior art is shown,

[0058] Figure 2 A first embodiment of a field device with an energy management unit according to the application is shown, and

[0059] Figure 3 A second embodiment of a field device with an energy management unit according to the application is shown. DETAILED DESCRIPTION

[0060] For simplicity, a single conductor view is chosen in the drawings, respectively. Of course, in reality there are at least two conductors (forward conductor and reverse conductor).

[0061] Figure 1 A field device 1 with an energy management unit 2 according to the prior art is shown in a simplified schematic view. The field device 1 comprises an energy store in the form of a capacitor 3, a load 4, a power supply 5, a boost converter 8 and a buck converter 9.

[0062] The power supply 5 provides an output voltage U and supplies energy from the outside via energy supply terminals 6 of the field device. For example, a two-conductor loop 7 with a 4 mA to 20 mA current interface is connected at the energy supply terminals 6, which has a common transmission of energy and communication.

[0063] The load 4 can be a "smart" load, which for example has its own communication options for other components of the field device, its own control means (for example by means of a microcontroller), its own data processing capabilities, options for configuration or parameterization, etc.

[0064] The load 4 has at least two operating modes: a first operating mode with low energy consumption and a second operating mode with high energy consumption. In the case of a sensor module, for example, the first operating mode can be a sleep mode and the second operating mode can be actual measurement activity. In the case of a wireless module, for example, the first operating mode can be a sleep mode and the second operating mode can be actual transmission and reception activity.

[0065] If the (temporary) energy requirement for the load 4 is greater than the amount of energy that can be provided by the power supply 5, the capacitor 3 is used in the second operating mode for temporary storage of the energy for the (temporary) energy requirement of the load 4. Alternatively, it can also be a battery. A super capacitor can also be used.

[0066] Such a capacitor 3 is also generally referred to as a buffer capacitor and is distinguished from a filter capacitor or smoothing capacitor.

[0067] For energy management, the field device 1 comprises a first current path 11, a second current path 12, a third current path 13 and a fourth current path 14.

[0068] The first current path 11 is connected at the input side to the capacitor 3 and at the output side to the input of the step-down converter 9. A switch S1 is arranged in the first current path 11.

[0069] The second current path 12 is connected at the input side to the power supply 5 and at the output side to the input of the step-down converter 9. A switch S2 is arranged in the second current path 12.

[0070] The third current path 13 is connected at the input side to the power supply 5 and at the output side to the capacitor 5. A step-up converter 8 is arranged in the third current path 12.

[0071] In the case of a high energy requirement of the load 4, the first current path 11 is used to supply the load 4 with energy from the capacitor 3. In the case of a low energy requirement of the load 4, the second current path 12 is used to supply the load 4 directly with energy from the power supply 5. The third current path 13 is used to charge the capacitor 3 with energy from the power supply 5.

[0072] In order to make the collection and temporary storage of energy as efficient as possible, the output voltage U of the power supply 5 is step-up converted via the third current path 13 by means of the step-up converter 8 in order to subsequently store the electrical charge on the capacitor 3, since the energy in the capacitor 3 is the square of the voltage.

[0073] In order to be able to use the energy stored in the capacitor 3, the voltage is then step-down converted via the first current path by means of the step-down converter 9 in order to adapt it to the operating voltage of the load 4 to be supplied.

[0074] It is also possible to dispense with the step-up converter 8 and instead to charge the capacitor 3 directly from the power supply 5. In order to then transform the voltage of the capacitor 3 to a value suitable for the load 4, a step-down / step-up converter can also be arranged in the first current path 21 between the capacitor 3 and the diode D1, which reduces the voltage (Step-Down behaviour) or increases the voltage (Step-Up behaviour) depending on the state of charge of the capacitor 3.

[0075] However, during the entire charging time of the capacitor 3, in the case of current extraction from the power supply 5, a certain limit value must not be exceeded. Therefore, the process must be continuously monitored by means of current monitoring, for example by means of the measuring resistor M1 and a monitoring and control device 16 integrated into the load 4, and in the case of an exceeded limit value the current extraction is interrupted by means of the monitoring and control device 16 switching off the switch S1.

[0076] Depending on when and how much energy is required by the load 4, the energy is delivered by means of the monitoring and control device 16 to the load via the switches S1 and S2 or via the first current path 11 (switch S1 closed, switch S2 open) or via the second current path (switch S1 open, switch S2 closed). For this purpose, the voltage value at the capacitor 3 is measured by means of the monitoring and control device 16 via the measuring resistor M2.

[0077] Therefore, in order to control and monitor the collection and temporary storage of energy and in order to switch processes for the energy distribution, for example for the energy management of field devices, a plurality of electronic components and the expenditure of logic means for evaluation and control are required. Furthermore, the components required for this also require space and energy.

[0078] In contrast thereto, Figure 2 A first embodiment of a field device with an energy management unit 20 according to the application is shown, wherein, in contrast to the prior art, Figure 1 The same elements are also provided with the same reference numerals.

[0079] The field device energy management unit comprises a first current path 21, a second current path 22, a third current path 23 and a fourth current path 24.

[0080] The first current path 21 can be connected on the input side to the capacitor 3 or to the capacitor 3, and a first diode D1 is arranged in the first current path on the output side, the cathode of which can be connected to the load 4 or to the load 4. The first current path 21 serves to supply the load 4 with energy from the capacitor 3.

[0081] The second current path 22 can be connected on the input side to the power supply 5 of the field device 1 or to the power supply 5 of the field device 1, and a second diode D2 is arranged in the second current path on the output side, the cathode of which can be connected to the load 4 or to the load 4. The second current path 22 serves to supply the load 4 directly with energy from the power supply 5.

[0082] The third current path 23 can be connected on the input side to the power supply 5 of the field device or to the power supply 5 of the field device and can be connected on the output side to the capacitor 3 or to the capacitor 3. The third current path 23 serves to charge the capacitor 3 with current from the power supply 5.

[0083] In order to limit the extraction of energy from the power supply 5 or from the field device 1 by the second current path 22, a first current-limiting element is arranged in the form of a current source II in the second current path 22.

[0084] In order to limit the extraction of energy from the power supply 5 or from the field device 1 by the third current path 23, a second current-limiting element is arranged in the form of a current source I2 in the third current path 23.

[0085] The current sources II, I2 are active circuit elements which can provide a substantially constant amount of current independently of the voltage formed at their interfaces. For example, the current sources can be constructed using bipolar transistors, field effect transistors or operational amplifiers.

[0086] A step-up converter 8 is arranged in the third current path 23. Thereby, the voltage of the voltage source 5 can be step-up converted in order to store more energy in the capacitor 3.

[0087] In the first current path 21, a step-down converter 9 is arranged between the capacitor 3 and the diode Dl. Thereby, the voltage of the capacitor can be step-down converted to a value which is suitable for the operation of the diode Dl and the load 4.

[0088] Here, the first diode Dl and the second diode D2 can be operated such that, in the case of a low energy consumption of the load 4, the first diode Dl is switched on in the blocking direction and the second diode D2 is switched on in the conducting direction, and, in the case of a high energy consumption of the load 4, the first diode Dl is switched on in the conducting direction.

[0089] There are thus two current paths 21, 22 which are decoupled by the diodes Dl, D2 in order to supply the load 4 with energy. Via the two current paths 21, 22 and the selective operation of the diodes in the conducting or blocking direction, a dynamic current conduction and energy extraction can be set automatically depending on the state of charge of the capacitor 3 and the operating state of the load 4, such that a low energy consumption of the load 4 is satisfied directly from the power supply 5 via the second current path 21, which can also be provided from the power supply 5 of the field device. Since this energy does not have to take the lossy path via the capacitor 3 and the converters 8, 9, it can be provided to the load 4 in a very energy-efficient manner. In contrast, a high energy consumption of the load 4 which can no longer be satisfied from the power supply 5 is satisfied only or additionally automatically from the capacitor 3 via the first current path 21.

[0090] Thus, the first diode D1 and the second diode D2 are operated such that in case of low energy consumption the load 4 is supplied with energy only via the second current path 22 and in case of high energy consumption the load 4 is supplied with energy only or additionally via the first current path 21.

[0091] Here, the selective operation of the two diodes D1, D2 in the conducting direction or in the blocking direction can simply be performed by setting the voltage ratio, i.e. the voltage drop, via the diodes D1, D2 accordingly. The voltage ratio results from the voltage potential difference of the respective anode and cathode. The voltage potential of the anode of the first diode D1 is mainly influenced by the voltage of the capacitor 3 (adapted by the buck converter 9) and thus by its state of charge. The voltage potential of the anode of the second diode D2 is mainly influenced by the voltage U of the power supply.

[0092] The voltage potential at both cathodes is the same as the voltage potential at the input of the load 4 and is determined by the voltage drop at the load 4. Thus, if the load has only low energy consumption, the voltage potential at the cathodes is high. In contrast, if the load has high current consumption and thus its input voltage drops, the voltage potential is low.

[0093] For example, the power supply 5 provides an output voltage U of 2 V to 3 V. The voltage at the anode of the diode D1 is set to a voltage potential of 1.8 V. In case of very low energy consumption of the load 4, only a very small current flows into the load 4. Thereby, at the input of the load 4 the voltage of the power supply 5 is set approximately, i.e. 2 V to 3 V. The diode D2 is thereby operated in the conducting direction and the diode D1 is thereby operated in the blocking direction. Thus, the energy supply of the load 4 is only done from the power supply 5 via the second current path 22.

[0094] In case of a switch of the load 4 to high energy consumption, the voltage at the cathode of the diode D2 or at the input of the load 4 drops, because the current source II is not able to provide enough current. Thereby, a voltage potential of less than 1.8 V at the input of the load 4 or at the cathodes of the diodes D1, D2 and the diode D1 is now operated in the conducting direction. Now, the energy supply of the load 4 is additionally done from the capacitor 3 via the first current path 21, too. As soon as the energy consumption of the load 4 drops again to a low value, which leads to a voltage potential of more than 1.8 V at the input of the load 4 or at the cathodes of the diodes D1, D2, the diode D1 is operated again in the blocking direction and thus automatically switches off the energy supply of the load 4 via the first current path 21 and thus the energy supply of the load 4 is only done via the second current path 22.

[0095] Thus, no voltage measurement is necessary at the capacitor, and also no switches with corresponding control logic for switching the energy distribution between the power supply 5, the capacitor 3 and the load 4 are necessary, since the diodes D1, D2 "automatically" switch the energy distribution or the current conduction depending on the voltage ratio applied at them.

[0096] If necessary, a converter, for example a step-down converter, can also be arranged in the second current path 22 in order to adapt the voltage U of the power supply to the load 4 and in order to set the voltage ratio at the diodes D1, D2.

[0097] By using the current sources II, I2, it is possible to dispense with a measurement and monitoring of the current drawn from the power supply 5 and a switch for interrupting the current in the event of an excess limit value.

[0098] The fourth current path 24 connects the second current path 22 and the third current path 23 to one another. To this end, the fourth current path 24 is connected to the second current path 22 after the first current source II on the input side and to the third current path 23 after the second current source I2 on the output side. If the load 3 does not require the current provided via the second current path 22 in full, the excess current can be diverted via the fourth current path 24 into the third current path 23 and further into the capacitor 3 for energy storage. In order to prevent an undesired amount of current from the third current path 23 to the second current path 22, a third diode D3 is arranged in the fourth current path 24, the anode of which is connected to the second current path 22 and the cathode of which is connected to the third current path 23.

[0099] The load 4 can be, for example, a sensor module, a device for transmitting measurement values and diagnostic information to a superior and / or a communication module for receiving rating values and parameter values from a superior, in particular a wireless module for wireless transmission of the values and information, a display, for example a display screen, a measurement data processing module, a control module or a regulating module. The load 4 can thus be a "smart" load, which has, for example, its own communication options for other components of the field device, its own control device, for example by means of a microcontroller, its own data processing capability, options for configuration or parameterization, etc.

[0100] Instead of only one (electrical) load 4, there can also be a plurality of (electrical) loads, but which in fact function as a single load from the point of view of the energy management unit.

[0101] Here, all components 3, 4, 5, 8, 9, D1, D2, D3, I1, I2 can be enclosed by the housing of the field device 1. However, it is also possible that one or some of the components are arranged outside the housing, or at a distance from the other components in the case of operation, and are connected to one another via cables and corresponding interfaces. For example, the load can be provided in the form of a wireless module outside the housing of the field device in order to achieve a better transmission range, and is connected to the energy management unit via a cable. In a similar manner, the load can also be arranged in the form of a sensor element very close to the physical process to be measured, and thus at a distance from the energy management unit, and is connected to the corresponding interface of the energy management unit using a cable.

[0102] The load 4, the capacitor 3 and the energy management unit 20 can also be combined into a unique structural unit of the field device 1, in particular into a functional module 40. Thus, the energy management unit 20 is integrated into a module 40 together with the capacitor 3 and the load 4. The functional module 40 is preferably configured as a communication module, in particular a wireless module, a display, a sensor module, a measurement data processing module, a control module or a regulating module. Preferably, it is a module which can be retrofitted at the field device 1. Advantageously, the functional module 40 can be detachably fixed at the field device 1.

[0103] Here, there can also be one or more further second current paths which can be connected to a further power supply of the field device at the input side or to a further power supply of the field device, respectively, and in which or at the output side of which a diode is arranged which cathode can be connected to the load 4 of the field device 1 or to the load 4 of the field device 1, respectively.

[0104] For example, as shown in Figure 3 A further second current path 32 with a diode D4 is connected or can be connected at the input side to a further power supply 35 of the field device 1 in the form of a backup battery. Thereby, in the event of a failure of the conventional power supply 5 from the outside and a discharge of the capacitor 3, an emergency supply for the load can also be switched to dynamically and automatically.

[0105] As has been shown, by means of the energy management unit 20 a low-cost and primarily highly efficient energy-saving dynamic energy management can be carried out in a field device with an energy store.

Claims

1. Field device energy management unit (20) for a field device (1), the field device having an energy store (3) for temporary storage of energy for a load (4) of the field device (1), the field device energy management unit comprising: - a first current path (21) which is connected on the input side to the energy store (3) or can be connected to the energy store and in which a first diode (Dl) is arranged on the output side, the cathode of which is connected to the load (4) of the field device (1) or can be connected to the load of the field device, - at least one second current path (22) which is connected on the input side to a power supply (5) of the field device (1) or can be connected to the power supply of the field device and in which a second diode (D2) is arranged on the output side, the cathode of which is connected to the load (4) of the field device (1) or can be connected to the load of the field device, - wherein the first diode (Dl) and the second diode (D2) can be operated such that, in the case of low energy consumption of the load (4), the first diode (Dl) is switched on in the blocking direction and the second diode (D2) is switched on in the conducting direction, and in the case of high energy consumption of the load (4), the first diode (Dl) is switched on in the conducting direction.

2. The field device energy management unit (20) of claim 1, wherein, The energy store is used for temporary storage of energy for the energy requirement of the load (4), which is greater than the amount of energy that can be provided by the field device (1).

3. Field device energy management unit (20) according to claim 1, the energy management unit having a third current path (23) which is connected on the input side to the power supply (5) of the field device (1) or can be connected to the power supply of the field device and which is connected on the output side to the energy store (3) or can be connected to the energy store.

4. The field device energy management unit (20) of claim 3, wherein, A first current-limiting element (Il) is arranged in the second current path (22).

5. The field device energy management unit (20) of claim 4, wherein, A second current-limiting element (I2) is arranged in the third current path (23).

6. The field device energy management unit (20) of claim 5, wherein, The first current-limiting element (Il) and the second current-limiting element (I2) are configured as current sources.

7. The field device energy management unit (20) of any one of claims 1 to 6, wherein, A converter (9) is arranged in the first current path (21) between the energy store (3) and the first diode (Dl).

8. The field device energy management unit (20) of claim 3, wherein, A step-up converter (8) is arranged in the third current path (23).

9. Field device energy management unit (20) according to claim 3, the energy management unit having a fourth current path (24) which connects the second current path (21) and the third current path (23) to one another.

10. The field device energy management unit (20) of claim 5, wherein, The energy management unit has a fourth current path (24) which connects the second current path (21) and the third current path (23) to one another, the fourth current path (24) being connected on the input side to the second current path (22) downstream of the first current-limiting element (11) and the fourth current path being connected on the output side to the third current path (23) downstream of the second current-limiting element (12).

11. The field device energy management unit (20) of claim 9 or 10, wherein, A third diode (D3) is arranged in the fourth current path (24), the anode of the third diode being connected to the second current path (22) and the cathode of the third diode being connected to the third current path (23).

12. The field device energy management unit (20) of any one of claims 1 to 6, wherein, The energy store (3) is configured for temporary storage of energy for energy requirements of the load (4), the energy requirements being greater than the amount of energy that can be provided by the power supply (5).

13. The field device energy management unit (20) of claim 12, wherein, The energy store (3) is configured for temporary storage of energy for energy requirements of the load (4), the energy requirements being greater than the amount of energy that can be provided externally to the field device (1).

14. The field device energy management unit (20) of any one of claims 1 to 6, wherein, The load (4) is a communication module, a display, a sensor module, a measurement data processing module, a control module or a regulating module.

15. A field device (1) having an energy store (3) for temporary storage of energy for a load (4) of the field device (1) and an energy management unit (20) according to any one of claims 1 to 14.

16. The field device (1) according to claim 15, wherein The energy store is for temporary storage of energy for energy requirements of the load (4), the energy requirements being greater than the amount of energy that can be provided by the field device (1).

17. A functional module (40) for a field device (1), the functional module comprising: - a load (4), - an energy store (3) for temporary storage of energy for the load (4), - an energy management unit (20) according to any one of claims 1 to 14.

18. The functional module (40) according to claim 17, wherein The functional module (40) is a communication module, a display, a sensor module, a measurement data processing module, a control module or a regulating module.

19. The functional module (40) according to claim 17, wherein The energy store is for temporary storage of energy for energy requirements of the load (4), the energy requirements being greater than the amount of energy that can be provided by the field device (1) to the functional module (40).

20. A method for operating a field device energy management unit (20) according to any one of claims 1 to 14, wherein, A first diode (D1) and a second diode (D2) are operated such that the load (4) is supplied with energy only via the second current path (22) in the case of low energy consumption and the load is supplied with energy only via the first current path (21) or additionally via the first current path (21) in the case of high energy consumption.

Images