SERIAL INTERFACE

Description

[0001] The invention relates to an electronics system with a microcontroller and an electrically connected interface circuit.

[0002] In US-A 2008 / 015799, US-A 2010 / 0026518, the "AN-960 APPLICATION NOTE RS-485 / RS-422 Circuit Implementation Guide INTRODUCTION", the "High Speed, Isolated RS-485 Transceiver with Integrated Transformer Driver ADM2485" or US-A 2011 / 0208440, electronics, in particular for one or more measuring instruments, or a measuring system with such electronics and one or more sensors connected to it, are shown.

[0003] The electronics – designed here as a signal transmitter of an industrial measurement and automation system that sends measurement data to a remote signal receiver – comprise a microprocessor or a microcontroller formed by it, as well as an electrically connected interface circuit. This interface circuit facilitates communication with an external signal receiver and / or transmitter, which may be non-proprietary or non-standardized. To provide the electrical power required during operation, possibly at different operating voltages, the electronics also include a corresponding power supply circuit. This power supply circuit, or the power supply circuit formed by it, can be mains-powered and / or battery-powered, for example.The electronics can therefore be electrically connected to an external power supply – itself also mains and / or battery powered – for example by means of a 2-wire line forming a 4-20 mA current loop or a serial fieldbus, and / or the electronics can be equipped with an internal, possibly also rechargeable electrochemical energy storage device.

[0004] The interface circuit of the aforementioned electronics each has a terminal for connecting to an external line and a signal input electrically connected to a signal output of the microcontroller. It is designed to convert a digital signal present at the signal input into a digital signal at the terminal, conforming, for example, to the EIA-485 standard (RS-485). Furthermore, the electronics shown in US-A 2008 / 015799 are also designed to receive and process a digital signal output by an external signal source and received at the interface circuit's terminal, specifically to execute one or more instructions contained therein in the microcontroller. In the electronics shown in US-A 2008 / 015799, signal transmission between the interface circuit and the microcontroller is galvanically isolated, for example, by means of an optocoupler.

[0005] To enable the sending and receiving of digital signals to one and the same terminal, the interface circuit can further be configured to operate in so-called alternating mode (half-duplex), such that in a receive-ready operating mode, the interface circuit receives a digital input signal present at the terminal and converts it into a binary output signal representing this signal, and outputs the same output signal to the microcontroller; and in a transmit-ready operating mode, the interface circuit receives a digital output signal output by the microcontroller and converts it into a binary output signal representing this signal, and outputs the same output signal to the terminal or a signal line connected thereto.When using the aforementioned 2-wire line for sending and receiving data, the data transmission can be controlled acyclically by means of a.

[0006] Data flow control procedures (handshake) are carried out, for example, in such a way that the interface circuit, unless a request directed to the electronics from a higher-level data processing unit connected to the aforementioned 2-wire line needs to be answered, is allowed to operate accordingly in the aforementioned operating mode that establishes readiness to receive.

[0007] As a result, the interface circuit must be kept constantly operational to ensure secure and error-free data transmission; this is especially true even when no data is being transmitted between the higher-level data processing unit and the electronics. This presents a particular disadvantage, significantly limiting and potentially even preventing implementation, particularly in the aforementioned case where the electronics are supplied with electrical energy solely via internal energy storage and / or a 2-wire connection, thus with low power in the range of less than 100 mW (≤ 4 mA · 25 V). This disadvantage is even more pronounced in the aforementioned case where signal transmission is to take place via galvanic isolation points provided in the interface circuit, thus with a nominally even higher power requirement.

[0008] Starting from the aforementioned prior art, one object of the invention is to improve electronics of the type in question in such a way that their respective interface has a low nominal power when operating in the receive-ready mode; in particular in such a way that the nominal power of the interface is sufficiently low to enable its use in electronics that are supplied at least temporarily with an electrical power of less than 100 mW.

[0009] To solve the problem, the invention consists of an electronic device, designed, for example, as a communication interface or as a remote I / O of a measuring system and / or battery-powered, comprising: a microcontroller with a control input, with at least one first control output and with a signal input, for example designed as an asynchronous serial interface (UART) or as a switching input; and an interface circuit with at least one first terminal, with a control output, with a first control input and with a signal output.

[0010] In the electronics according to the invention, The control output of the interface circuit is electrically connected to the control input of the microcontroller, the first control output of the microcontroller is electrically connected to the first control input of the interface circuit, and the signal output of the interface circuit is electrically connected to the signal input of the microcontroller.

[0011] Both the microcontroller and the interface circuit each have a first operating mode and at least one second operating mode, wherein the microcontroller is configured to output an instruction at the first control output in its first operating mode, which causes the interface circuit to operate in its first operating mode, and wherein the interface circuit is configured, at least in its first operating mode, to differentiate an input signal present at the first terminal, namely to convert it into a derivative signal representing a derivative of the input signal with respect to time, and to generate a binary control signal by means of the same derivative signal and to output it at the control output.Furthermore, the microcontroller is configured, in its second operating mode, to output an instruction at its first control output that causes the interface circuit to operate in its second operating mode. The interface circuit is also configured, in its second operating mode, to convert a digital input signal present at the first terminal (e.g., conforming to IEC 61158 CPF15:2007 and / or EIA-485) into a corresponding binary first output signal and to output this first output signal at the signal output. The microcontroller is also configured, in its second operating mode, to receive and process a digital input signal (e.g., conforming to UART) present at the signal input, for example, to execute an instruction contained in the input signal and / or to evaluate a message contained in the input signal.

[0012] Furthermore, the invention also comprises a communication system formed by means of such electronics, which additionally includes a signal transmitter electrically connected to the electronics and configured to send a digital signal, in particular conforming to IEC 61158 CPF15:2007, to the electronics; and / or the invention also comprises a measuring system formed by means of such electronics, which additionally includes a sensor electrically coupled to the electronics, wherein the microcontroller is configured, at least in its first operating mode, to receive and evaluate a sensor signal generated by the sensor, for example, to determine measured values ​​for at least one measured quantity detected by means of the sensor.

[0013] According to a first embodiment of the invention, it is further provided that the interface circuit is configured to react to a change in the digital input signal, for example, a change in a logic level of the input signal and / or a change in the signal edge of the input signal corresponding to a slope of more than 1 V / µs, by encoding an instruction (IRQ) into the control signal, which causes the microcontroller to operate in its second operating mode or which causes the microcontroller to switch from its first operating mode to its second operating mode;

[0014] According to a second embodiment of the invention, it is further provided that the microcontroller is configured to process the control signal of the interface circuit present at the control input in the first operating mode, for example, to react to an instruction causing a change from the first operating mode to the second operating mode by switching to the second operating mode.

[0015] According to a third embodiment of the invention, it is further provided that the interface circuit is configured in the first operating mode not to convert a digital input signal present at the first terminal into an output signal representing it, or not to output an output signal representing a digital input signal present at the first terminal at the signal output.

[0016] According to a fourth embodiment of the invention, it is further provided that the microcontroller is configured in the first operating mode not to process a digital input signal present at the signal input, for example, not to execute any instruction contained therein.

[0017] According to a fifth embodiment of the invention, it is further provided that the microcontroller is configured to switch from the second operating mode to the first operating mode in a time-controlled manner, for example if no digital and / or UART-compliant input signal is present at the signal input.

[0018] According to a sixth embodiment of the invention, it is further provided that the interface circuit and the microcontroller are configured to operate simultaneously in their respective second operating modes, such that the first output signal at the signal output of the interface circuit forms the digital input signal present at the signal input of the microcontroller, and that the microcontroller receives and processes the same first output signal.

[0019] According to a seventh embodiment of the invention, it is further provided that the interface circuit has a signal filter, for example a passive one, such as a high-pass filter.

[0020] According to an eighth embodiment of the invention, it is further provided that the interface circuit for differentiating the input signal applied to the first terminal has a high-pass filter, for example a passive filter and / or one with a cutoff frequency of more than 800 Hz.

[0021] According to a ninth embodiment of the invention, it is further provided that the interface circuit is configured to obtain electrical power required during operation at least temporarily and / or at least partially from the input signal applied to the first terminal, for example, to obtain electrical power required in the first operating mode exclusively from the input signal applied to the first terminal.

[0022] According to a tenth embodiment of the invention, it is further provided that the interface circuit in the first operating mode has a power requirement of less than 50 mW.

[0023] According to an eleventh embodiment of the invention, it is further provided that the interface circuit in the second operating mode has a power requirement that is higher than a power requirement that the interface circuit has in the first operating mode, for example, more than 300% of the power requirement of the interface circuit in the first operating mode and / or more than 150 mW.

[0024] According to a twelfth embodiment of the invention, the interface circuit is further configured to obtain both the electrical power required in the first operating mode and the power required in the second operating mode exclusively from the input signal applied to the first terminal.

[0025] According to a first further development of the invention, it is further provided that the microcontroller has a signal output, for example designed as an asynchronous serial interface (UART), and the interface circuit has a signal input, for example designed as an asynchronous serial interface (UART), and that the signal output of the microcontroller is electrically connected to the signal input of the interface.

[0026] According to an initial embodiment of the first further development, it is further provided that both the microcontroller and the interface circuit each have at least one third operating mode, such that the microcontroller is configured in its third operating mode to output a second digital output signal, for example, UART-compliant, at its signal output, and that the interface circuit is configured in its third operating mode to convert a digital input signal, for example, UART-compliant, present at its signal input into a third digital output signal, for example, compliant with IEC 61158 CPF15:2007 and / or EIA-485. The interface circuit can also be configured to output the third output signal at the first terminal in its third operating mode.Alternatively, the interface circuit can have a second connection terminal and the interface circuit can also be configured to output the third output signal at the same second connection terminal in the third operating mode, or, for example, not to convert an input signal present at the signal input into an output signal representing it in both the first and second operating modes, or not to output an input signal representing an input signal present at the signal input at the second connection terminal.

[0027] In a second embodiment of the first further development, it is further provided that the microcontroller has a second control output and the interface circuit has a second control input, and that the second control output of the microcontroller is electrically connected to the second control input of the interface circuit. In addition, the microcontroller can also be configured to output a command at the second control output in the third operating mode, which causes the interface circuit to operate in its third operating mode.

[0028] According to a third iteration of the first further development, the microcontroller is further configured to switch from the second to the third operating mode, controlled by the input signal at the signal input.

[0029] According to a fourth iteration of the first further development, the microcontroller is further equipped to automatically switch from the third operating mode to the first operating mode after the digital output signal has been issued at the signal output.

[0030] According to a fifth iteration of the first further development, the microcontroller is further configured not to process a digital input signal present at the signal input in the third operating mode, for example, not to execute any instruction received at the signal input.

[0031] According to a sixth iteration of the first further development, the interface circuit is further configured not to convert an input signal present at the signal input into an output signal representing it, or not to output an input signal representing an input signal present at the signal input at the first connection terminal, either in the first operating mode or in the second operating mode.

[0032] According to a seventh embodiment of the first further development, the interface circuit and the microcontroller are further configured to operate simultaneously in their respective third operating modes, such that the second output signal at the signal output of the microcontroller forms the digital input signal present at the signal input of the interface circuit, and that the interface circuit receives and processes the same second output signal, for example, converting it into the third output signal.

[0033] According to an eighth embodiment of the first further development, the interface circuit further comprises a monolithic transceiver (RS485), for example of type SN65HVD1781 from Texas Instruments Inc. 2019 or type THVD2450 from Texas Instruments Inc. 2019, which is compliant with, for example, IEC 61158 CPF15:2007 and / or EIA-485, and the first connection terminal of the interface circuit is formed by means of at least one of the BUS driver / receiver connections of the transceiver, the signal output of the interface circuit is formed by means of a digital output of the transceiver and the signal input of the interface circuit is formed by means of a digital input of the transceiver.

[0034] According to a second embodiment of the invention, the electronics further comprise: a supply circuit formed, for example, by means of an electrochemical and / or rechargeable energy storage device, and it is further provided that the supply circuit has at least one first supply terminal and is configured to provide an operating voltage for the microcontroller at the first supply terminal, and that the microcontroller has a supply terminal which is electrically connected to the first supply terminal of the supply circuit.

[0035] According to a first embodiment of the second further development, it is further provided that the supply circuit has a second supply terminal and is set up to provide an operating voltage for the interface circuit at the second supply terminal, and that the interface circuit has a supply terminal that is electrically connected to the second supply terminal of the supply circuit.

[0036] According to a first embodiment of the second further development, it is further provided that the interface circuit has an electronic main switch, formed, for example, by means of a semiconductor relay or by means of an insulating layer field-effect transistor, wherein both the first control input of the interface circuit and the supply terminal of the interface circuit are formed by means of the main switch.

[0037] According to a third further development of the invention, the interface circuit comprises a DC-DC converter, for example galvanically isolated, with a converter input and with a converter output, for example a flyback converter or a push-pull converter, and the DC-DC converter is configured to convert an input DC voltage applied at the converter input into an output DC voltage applied at the converter output with a voltage level that differs from the voltage level of the input DC voltage.

[0038] According to a fourth embodiment of the invention, the interface circuit further comprises a first optocoupler with an optical transmitting element and an optical receiving element, and it is further provided that the control output of the interface circuit is formed by means of the first optocoupler, such that its optical receiving element is electrically connected to the control input of the microcontroller.

[0039] According to a further embodiment of the fourth further development of the invention, the interface circuit also has a second optocoupler with an optical transmitting element and an optical receiving element, and it is further provided that the signal output of the interface circuit is formed by means of the second optocoupler, such that its optical receiving element is electrically connected to the signal input of the microcontroller.Furthermore, the interface circuit can also have at least one third optocoupler with an optical transmitter element and an optical receiver element, or for example, a third optocoupler with an optical transmitter element and an optical receiver element, and at least one fourth optocoupler, each with an optical transmitter element and an optical receiver element, wherein, for example, the first control input of the interface circuit can be formed by means of the third optocoupler, such that its optical receiver element is electrically connected to the first control output of the microcontroller.

[0040] A fundamental concept of the invention is to allow the interface circuit of the electronics, controlled by its microcontroller, to operate selectively in a first operating mode or, if required – for example, upon request from an external signal transmitter electrically connected to the interface circuit – in a second operating mode, such that in the first operating mode a passive readiness to receive a signal that may be received at the connection terminal is maintained, evaluating only at least one of its physical signal parameters and / or its temporal profile, and in the second operating mode an active readiness to receive a digital input signal that may be received at the connection terminal, possibly...The input signal is also converted accordingly, and reception readiness is established; this is done in particular in such a way that the interface circuit (only) in its second operating mode transmits a message contained in the input signal for the microcontroller, for example an instruction, to the microcontroller in a form that the microcontroller can evaluate. As a result of such a division of the functionality of the interface circuit with regard to its reception readiness compared to an occasional or...With an acyclic digital input signal, the energy consumption of the interface circuit can be significantly reduced by only allowing the interface circuit to operate in the comparatively energy-intensive second operating mode when needed, namely only after the digital input signal has been received; this can advantageously also be done in such a way that a reduction in the total electrical energy supplied by the external signal generator can be achieved during the operation of the electronics.

[0041] The invention and advantageous embodiments thereof are explained in more detail below with reference to exemplary embodiments illustrated in the figures of the drawing. Identical, equivalent, or similarly functioning parts are designated with the same reference numerals in all figures; where clarity requires it or it otherwise appears appropriate, previously mentioned reference numerals are omitted in subsequent figures. Further advantageous embodiments or developments, in particular combinations of aspects of the invention initially described only individually, will also become apparent from the figures of the drawing and / or from the claims themselves.

[0042] Specifically, we show: Fig. 1 shows a schematic, block-like diagram of an electronic system according to the invention; Fig. 2 shows a schematic, block-like diagram of a variant of an electronic system according to the invention. Fig. 1 ; Fig. 3 schematically, in the manner of a block diagram, another variant of an electronic system according to Fig. 1 ; Fig. 4 schematically in the manner of a block diagram for an electronics system according to Fig. 1 , 2 or 3 suitable interface circuits; and Figs. 5, 6, 7 each schematically show various components of an electronic circuit for use in accordance with a block diagram. Fig. 1 , 2 or 3 suitable interface circuits. In Fig. 1 , 2 and 3 Various embodiments of electronics formed by a microcontroller (µC) and an interface circuit (IF) connected to it are shown schematically. The electronics can, as also in the Fig. 1 , 2 or 3, each indicated, for example, as part of a communication system that additionally includes an electrically connected NLU signal transmitter, possibly located remotely from the electronics. The NLU signal transmitter could, for example, be a remote control ( Remote-I / O ), a programmable logic controller (PLC), a bus master in a fieldbus, for example according to the industry standard IEC 61158:1999, in particular according to one of the

[0043] The electronics can be a family of CPF1 (FOUNDATION FIELDBUS), CPF3 (PROFIBUS), CPF9 (HART), or CPF15 (MODBUS), or a radio module or adapter, for example, according to IEEE 802.15.4:2007 (WirelessHART), whereby the signal transmitter NLU can be mains-powered and / or battery-powered. Alternatively or additionally, the electronics can also be part of a measuring system—for example, a measuring and / or switching device for industrial measurement and automation technology—with a sensor MA electrically coupled to the electronics, for example, a flow sensor, which in turn is configured to detect at least one physical or chemical quantity and to provide at least one measurement signal s1 representing that quantity, in particular to make it available for processing in the electronics.The electronics can also be configured to receive and process the measurement signal s1 accordingly, for example, to determine at least one measured quantity, possibly digital measured values. Furthermore, the electronics can, as in the... Fign. 1 and 2 each indicated, be arranged within a protective housing H, which can also be attached directly to the aforementioned sensor MA, for example, to form a compact measuring device.

[0044] As from Fig. 1 , 2As can be seen from the diagrams 3 and 3, or from their combined representation, the interface circuit IF has at least one first terminal IF_ext1, one control output IF_ctl, one first control input IF_sw1, and one signal output IF_tx. Furthermore, the microcontroller µC has one control input µC_sw, at least one first control output µC_ctl1, and at least one signal input µC_rx. The control input µC_sw of the microcontroller µC could, for example, be an interrupt input typically provided in conventional microprocessors or microcontrollers, or the microcontroller µC could be configured to respond to a (control) instruction received at the control input µC_sw. (IRQ - interrupt request), for example in the form of a single bit, such as logic one, with at least a temporary interruption of an initially running program or the execution of a correspondingly predefined interrupt routine. (ISR - interrupt service routine, interrupt handler) to react. Alternatively or additionally, the signal input µC_rx can, for example, be used as a simple switching input or as an asynchronous serial interface. (UART - universal asynchronous receiver transmitter) be designed or implemented using a corresponding function block of the microcontroller (µC). As in each case in Fig. 1 , 2 and 3In schematic representation, the control output IF_ctl of the interface circuit IF is electrically connected to the control input µC_sw of the microcontroller µC, the signal output IF_tx of the interface circuit IF is electrically connected to the signal input µC_rx of the microcontroller µC, and the control output µC_ctl1 of the microcontroller µC is electrically connected to the control input IF_sw1 of the interface circuit IF. Furthermore, the terminal IF_ext1 of the interface circuit IF is configured to be electrically connected to an external signal line 2L, for example, such that the interface circuit IF, or the electronics formed by it, is connected via signal line 2L to a corresponding terminal of the aforementioned signal transmitter NLU. The electronics are also configured to receive a binary input signal e1 via terminal IF_ext1 of the interface circuit IF and, if necessary, to...The input signal e1 can be processed and evaluated accordingly using the interface circuit IF and the microcontroller µC. For example, it could be a binary (switching) signal transmitting a simple switching command from the NLU signal transmitter, or a digital signal transmitting a telegram sent by the NLU signal transmitter, which could also be compliant with the industry standard IEC 61158 CPF15:2007.

[0045] According to a further embodiment of the invention, the microcontroller µC further comprises a signal output µC_tx, which may, for example, also be configured as an asynchronous serial interface, and the interface circuit IF comprises a signal input IF_rx, which may, for example, also be configured as an asynchronous serial interface, just like the aforementioned signal output µC_tx. As in Fig. 2 As shown, the signal output µC_tx of the microcontroller and the signal input IF_rx of the interface IF are also electrically connected to each other.

[0046] In the electronics according to the invention, both the microcontroller µC and the interface circuit IF each have a first operating mode, namely an operating mode µC I or an operating mode IF I, and at least one second operating mode, namely an operating mode µC II or an operating mode IF II.

[0047] The microcontroller µC is specifically configured to output a command at its control output µC_ctl1 in its first operating mode µC I, which causes the interface circuit to operate in its operating mode IF I, for example, to switch to or activate the operating mode IF I. The aforementioned command can be, for example, a simple switching command or a statement to be executed in a program processed by the interface circuit IF.Furthermore, the microcontroller µC is also configured to output an instruction at the control output µC_ctl1 in its second operating mode µC II, which causes the interface circuit IF to operate in its second operating mode IF II, as well as to receive and process a digital input signal, for example a UART-compliant one, present at its signal input µC_rx; in particular, such that an instruction contained in the input signal present at the aforementioned signal input µC_rx, for example a simple switching command or a statement influencing a program running in the microcontroller µC, is executed by the microcontroller µC and / or a message contained in the same input signal is evaluated by the microcontroller µC.In the aforementioned case where the electronics are part of a measuring system, the microcontroller µC can also be configured to receive and evaluate the aforementioned sensor signal s1 generated by the sensor MA, at least in its first operating mode µC I, but also, for example, in both operating mode µC I and operating mode µC II, for example, to determine measured values ​​for the at least one measured quantity detected by the sensor MA.

[0048] In the electronics according to the invention, the interface circuit IF is again configured to differentiate, at least in the first operating mode IF I, the input signal e1 applied to its connection terminal IF_ext1, namely, as also in Fig. 4 The interface circuit IF, as described, is to convert the input signal e1 into a derivative signal a1 representing a derivative of the input signal e1 over time, and to generate a binary control signal using this derivative signal a1 and output it at the control output IF_ctl; specifically, the interface circuit IF reacts to a predetermined rate of change of the input signal e1, at least in the first operating mode IF I – for example, only in the first operating mode IF I – by encoding an instruction IRQ into the control signal IF_ctl, which causes the microcontroller µC to operate in its second operating mode µC II, or which causes the microcontroller µC to switch from its first operating mode µC I to its second operating mode µC II. The derivative signal a1 can, as also shown in Fig. 4 As indicated, in the event of a change in the logic level of the binary input signal e1, for example from logic zero to logic one, the level curve should exhibit a pulse-shaped profile corresponding to this change, or, in the case of a sudden change, a needle-shaped profile, such that the derivative signal a1 temporarily reaches or exceeds a minimum signal level encoding the aforementioned instruction IRQ. Furthermore, according to a further embodiment of the invention, the microcontroller is configured to process the control signal of the interface circuit IF present at the control input µC_sw in operating mode µC I, for example, to react to the aforementioned instruction IRQ, which initiates the change from operating mode µC I to operating mode µC II, with a corresponding change to operating mode µC II.

[0049] According to a further embodiment of the invention, the interface circuit IF is specifically configured to encode the aforementioned instruction IRQ into the control signal at the control output IF_ctl, or to output the same control signal at least temporarily with a corresponding signal level at the control output IF_ctl, if the rate of change of the input signal e1 corresponds to a signal edge with a slew rate of more than 1 V / µs and / or a rate of change normalized to the nominally achievable logic level of more than 90% / µs, and / or if the rate of change of the input signal e1 corresponds to a change in the logic level of a digital input signal conforming to the industry standard IEC 61158 CPF15:2007 (MODBUS) and / or EIA-485. According to a further embodiment of the invention, the interface circuit IF is also configured to output the derivative signal a1 directly as a control signal at the control output IF_ctl.To differentiate the input signal e1 or to generate the derivative signal a1, the interface circuit can, for example, include a corresponding signal filter, such as a first-order or possibly a higher-order high-pass filter. The (lower) cutoff frequency of such a high-pass filter can be set to a higher frequency than 800 Hz, particularly when used with a digital input signal conforming to the industry standard IEC 61158 CPF15:2007 and / or EIA-485.Furthermore, the interface circuit IF of the electronics according to the invention is also configured, in its second operating mode IF II, to convert a digital input signal present at the connection terminal IF_ext1, for example, conforming to IEC 61158 CPF15:2007 and / or EIA-485, namely the aforementioned input signal e1, into a binary first output signal sD1 representing this input signal and to output the same output signal sD1 at the signal output IF_tx, such that the output signal sD1 is present at the signal input µC_rx of the microcontroller µC or the aforementioned input signal forms the signal input µC_rx of the microcontroller µC. Accordingly, according to a further embodiment of the invention, the interface circuit IF and the microcontroller µC are also configured to operate, at least temporarily, simultaneously in their respective second operating modes IF II and IF II, respectively.to operate µC II; in particular, in such a way that the output signal at the signal output IF_tx of the interface circuit IF forms the digital input signal present at the signal input µc_rx of the microcontroller µC, and that the microcontroller µC receives and processes this first output signal. According to a further embodiment of the invention, the interface circuit is also configured, in its operating mode IF I, to block a digital input signal present at the terminal IF_ext1, i.e., not to convert it into an output signal representing it, or not to output a signal at the signal output IF_tx that represents a digital input signal present at the terminal IF_ext1, and / or the microcontroller µC is configured, in its operating mode µC I, to block a digital input signal present at the signal input µC_rx, i.e., not to process it, and in particular, not to execute any instructions contained therein.Furthermore, the microcontroller µC can advantageously be configured to switch from its operating mode µC II to its operating mode µC I in a time-controlled manner; this is particularly useful in the event that no digital input signal and / or no UART-compliant input signal is present at the signal input µC_rx.

[0050] In the aforementioned case, where the microcontroller µC has a signal output µC_tx and the interface circuit IF has a signal input IF_rx electrically connected to the same signal output µC_tx, according to a further embodiment of the invention, both the microcontroller µC and the interface circuit IF each have at least one third operating mode, namely an operating mode µC III and an operating mode IF III, respectively. The microcontroller µC is, as also in Fig. 3 As indicated, the microcontroller is also configured to output a second digital signal, sD2, at the signal output µC_tx in operating mode µC III. Furthermore, the interface circuit IF is configured to convert a digital input signal present at the signal input IF_rx into a third digital output signal, sD3, in operating mode IF III. Specifically, the interface circuit IF and the microcontroller µC are also configured to operate, at least temporarily, simultaneously in their respective third operating modes µC III and IF III, such that the output signal sD2 at the signal output µC_tx forms the digital input signal present at the signal input IF_rx, and that the interface circuit IF receives and processes this output signal sD2, for example, converting it into the output signal sD3. The output signal sD2 can, for example, be a UART-compliant digital signal.Alternatively or additionally, the output signal sD3 can be a digital signal conforming to one of the aforementioned industry standards IEC 61158 CPF15:2007 and / or EIA-485. In the aforementioned case where the electronics are part of a measurement system, the microcontroller µC can be specifically configured, in its operating mode µC III, to transmit measured values ​​for at least one measured quantity acquired by the sensor MA to the interface circuit IF via the output signal sD2. Alternatively, the interface circuit IF can also be configured to output measured values ​​received via the output signal sD2 using the output signal sD3.

[0051] Not least in the event that the aforementioned signal generator NLU is configured to transmit the input signal e1 and receive the output signal sD3 via signal line 2L and process them accordingly, and thus the communication system formed is intended to exchange data between the electronics and the signal generator NLU in a half-duplex mode, the interface circuit is further configured to output the output signal sD3 at the connection terminal IF_ext1 in its operating mode IF III. Alternatively, the interface circuit IF can be configured as described in Fig. 2 As indicated, the interface circuit IF can also have a second terminal IF_ext2, and in its operating mode IF III, it can output the aforementioned output signal sD3 at the same terminal IF_ext2, for example, to exchange data with the aforementioned signal generator NLU in a full-duplex operation. In this case, the interface circuit IF can also be configured to block any input signal present at the signal input IF_rx in both the first operating mode IF I and the second operating mode IF II, i.e., not to convert it into an output signal representing it, nor to output any signal at the aforementioned terminal IF_ext2 that represents an input signal present at the signal input IF_rx.

[0052] According to a further embodiment of the invention, the microcontroller µC is also configured to switch from the second operating mode µC II to the third operating mode µC III, controlled by the input signal sD1 at the signal input µC_rx, for example, to confirm the execution of an instruction encoded in the input signal sD1 with the output signal sD2 and / or to respond accordingly to a request explicitly contained in the input signal sD1 or at least implicitly transmitted therein. Alternatively or additionally, the microcontroller µC can also be configured to automatically switch from operating mode µC III back to operating mode µC I after the output of the digital output signal sD2 at the signal output µC_tx.Advantageously, the interface circuit IF can also be configured to block any input signal present at the signal input IF_rx in both its operating mode IF I and its operating mode IF II, namely not to convert it into an output signal representing it or not to output a signal at the connection terminal IF_ext1 that represents an input signal present at the signal input IF_rx, and / or the microcontroller µC can be configured in operating mode µC III not to process any digital input signal present at the signal input µC_rx or not to execute any instruction received at the signal input.

[0053] According to a further embodiment of the invention, the microcontroller µC further comprises a second control output µC_ctl2, and the interface circuit IF has a second control input IF_sw2 electrically connected to the same control output µC_ctl2. In the aforementioned case where the microcontroller µC and interface circuit IF each also have a third operating mode, the microcontroller µC is additionally configured to output a command at control output µC_ctl2 in its operating mode µC III, which in turn causes the interface circuit IF to operate in its operating mode IF III; this can be achieved, for example, by the microcontroller µC, in operating mode µC III, outputting a corresponding command for operating mode µC III and interface circuit IF at both control output µC_ctl2 and control output µC_ctl1.

[0054] For receiving and processing at least the digital input signal e1 arriving at the connection terminal IF_ext1, the interface circuit IF, according to a further embodiment of the invention, comprises an RS485 transceiver (transceiver) that is, for example, compatible with the industry standard IEC 61158 CPF15:2007 and / or EIA-485 and / or monolithic. This RS485 transceiver can, for example, be a monolithic, optionally also fault-protected RS485 transceiver, such as an SN65HVD1781 from Texas Instruments Inc., Dallas, Texas 75265, 2019, or a THVD2450 from Texas Instruments Inc., Dallas, Texas 75265, 2019. Furthermore, it is provided that, as also in Fig. 5 As shown schematically, the RS485 transceiver has at least two bus driver / receiver connections A, B, at least one digital output R, at least one digital input D, and at least one driver activation input DE. The connection terminal IF_ext1 of the interface circuit IF is formed by means of at least one of these bus driver / receiver connections A, B, and the signal output IF_tx of the interface circuit IF is formed by means of the digital output R. In the aforementioned case that the microcontroller µC also has a signal output µC_tx and the interface circuit IF has a signal input IF_rx electrically connected to the same signal output µC_tx, the signal input IF_rx of the interface circuit can also be formed by means of the aforementioned digital input D of the RS485 transceiver.In the other case mentioned, where the microcontroller µC has a control output µC_ctl2 and the interface circuit IF has a control input IF_sw2 electrically connected to the same control output µC_ctl2, the control input IF_sw2 of the interface circuit can also be formed by means of the aforementioned driver activation input DE of the transceiver RS485.

[0055] To provide the electrical power P1 required by the microcontroller µC during operation, the electronics, according to a further embodiment of the invention, also include a power supply circuit NRG with at least one first supply terminal U1. Furthermore, the microcontroller µC also has a corresponding supply terminal, which is electrically connected to the supply terminal U1 of the power supply circuit NRG. The power supply circuit NRG, which may be formed, for example, by means of an electrochemical and / or rechargeable energy storage device, is also configured to provide an operating voltage for the microcontroller µC at the supply terminal U1, for example, a unipolar or bipolar DC voltage. In contrast, the interface circuit IF is configured to supply the electrical power required during operation.The corresponding auxiliary energy is to be obtained, at least temporarily and / or at least partially, from the input signal e1 applied to its connection terminal IF_ext1. For this purpose, the aforementioned signal filter, which serves to differentiate the input signal e1, can advantageously also be a passive signal filter, for example, a passive high-pass filter formed by means of a simple series connection of one or more capacitors with one or more ohmic resistors, which may also additionally act as current-limiting resistors.

[0056] According to a further embodiment of the invention, the interface circuit in its operating mode IF I has a power requirement of less than 50 mW, and / or the interface circuit IF is configured to obtain the electrical power required in both its operating mode IF I and its operating mode IF II exclusively from the input signal e1 applied to the terminal IF_rx. In particular, the interface circuit IF can also be designed as a passive component of the electronics, namely configured to obtain the electrical power P2 required during operation completely or exclusively from the input signal e1 applied to its terminal IF_ext1. Alternatively, the interface circuit IF can also be configured to obtain a proportionate share of the electrical power or auxiliary energy required during operation from the supply circuit NRG and can supply the supply circuit NRG, as also described in the invention. Fig. 2 and 3 As indicated in each case, it should also be arranged to provide a proportion P2* of the electrical power required by the interface circuit IF during operation; this is particularly important if the interface circuit in its operating mode IF II has a power requirement that is higher than the electrical power nominally supplied to the electronics by the input signal e1, and / or if the interface circuit in its operating mode IF II has a power requirement (P2*) that is higher than the power requirement (P1) that the interface circuit has in its operating mode IF I, which, for example, is more than 150 mW.

[0057] To provide the electrical power P2* required during operation by the interface circuit, the NRG power supply circuit, according to a further embodiment of the invention, accordingly has a second power supply terminal U2, at which an operating voltage for the IF interface circuit, for example a unipolar or bipolar DC voltage, is temporarily provided during operation. The IF interface circuit also has a power supply terminal that is electrically connected to the power supply terminal U2 of the NRG power supply circuit. Particularly in the aforementioned case where the RS485 transceiver is provided in the IF interface circuit, the power supply terminal of the IF interface circuit can be, as also in Fig. 5 indicated or also from a summary of the Fig. 1 , 2 , 3 and 5It is readily apparent, for example, that the RS485 transceiver can also be formed by means of two supply connections V CC and GND. To stabilize and / or adjust the voltage level of the operating voltage applied to the aforementioned supply terminal, the interface circuit IF, as also described in Fig. 5 schematically represented, furthermore comprising a DC / DC converter, for example also galvanically isolated, with a converter input and with a converter output, wherein the DC / DC converter is configured to convert an input DC voltage applied at the converter input – here namely the aforementioned operating voltage applied at the supply terminal of the interface circuit IF – into an output DC voltage applied at the converter output – here serving as the internal operating voltage of the interface circuit IF – with a voltage level that differs from the voltage level of the input DC voltage. The DC / DC converter can, for example, be a flyback converter. (fly-back converter) and / or a push-pull converter (push-pull converter) be trained.

[0058] According to a further embodiment of the invention, an electronic main switch HS is also provided in the interface circuit IF, and the control input IF_sw1 of the interface circuit IF is formed by means of the main switch HS or a control electrode thereof. The main switch HS can, for example, be a semiconductor relay. (solid state relais) or by means of an insulated-layer field-effect transistor (IGFET), for example an n-channel MOSFET (NMOS) or another

[0059] Metal-oxide-semiconductor field-effect transistor (MOSFET). As in Fig. 5 As indicated, the aforementioned supply terminal V CC , GND of the interface circuit IF can, for example, be formed by means of the main switch HS. The main switch HS of the interface circuit IF is specifically designed to only switch the operating voltage provided by the aforementioned supply circuit NRG at the supply terminal U2 from the supply terminal of the interface circuit IF to other components of the interface circuit IF, such as the optional DC / DC converter and / or the optional RS485 transceiver, if the instruction activating the second operating mode IF II is present at the control input IF_sw1 of the interface circuit IF, and / or if the instruction activating the third operating mode IF III is present at the aforementioned control input IF_sw2, or at both control input IF_sw2 and control input IF_sw1 of the interface circuit IF.

[0060] In the aforementioned case where the interface circuit IF includes the DC / DC converter, the converter input of the DC / DC converter can be electrically connected to the electronic main switch HS, for example, in such a way that when the electronic main switch HS is switched on, the operating voltage provided by the supply circuit NRG for the interface circuit IF is present at the converter input as the input voltage of the DC / DC converter.

[0061] According to a further embodiment of the invention, the interface circuit IF comprises at least one first optocoupler OK1 with an optical transmitting element and an optical receiving element. As in Fig. 6 As shown schematically, the control output IF_ctl of the interface circuit IF is formed by means of the same optocoupler OK1, in that its optical receiver element is electrically connected to the control input µC_sw of the microcontroller µC. Furthermore, it is also provided that the interface circuit IF has a second optocoupler OK2, identical in construction to optocoupler OK1, with an optical transmitter element and an optical receiver element, and that the signal output IF_tx of the interface circuit IF is formed by means of the optocoupler OK2, in that its optical receiver element, as shown in Fig. 6 As indicated, the interface circuit IF is electrically connected to the signal input µC_rx of the microcontroller µC. According to a further development of the invention, the interface circuit IF also includes a third optocoupler OK3, identical in construction to, for example, the aforementioned optocoupler OK1 and / or the aforementioned optocoupler OK2, with an optical transmitting element and an optical receiving element. Finally, especially in the aforementioned case where the interface circuit IF is configured to derive the electrical power required during operation entirely or exclusively from the input signal e1 present at the terminal IF_ext1 (passive component), it is also provided that the control input IF_sw1 of the interface circuit IF is formed by means of the same optocoupler OK3, such that, as also in Fig. 6 As indicated, the optical receiver element is electrically connected to the control output µC_ctl1 of the microcontroller µC. By using the optocouplers OK1, OK2, and OK3 to form the control output IF_ctl, the signal output IF_tx, and the control input IF_sw1, the microcontroller µC and the interface circuit IF can advantageously be operated completely galvanically isolated from each other. This also results in complete galvanic isolation of the microcontroller µC and other electronic components not belonging to the interface circuit IF from external electrical circuits connected to the interface circuit, such as the aforementioned signal generator NLU.For the other aforementioned case, in which the interface circuit also has the second control input IF_sw2, according to another embodiment of the invention, that same control input IF_sw2 is formed by means of the aforementioned optocoupler OK3, such that, as also in . Fig. 7The diagram shows an interface circuit IF whose optical transmitter is electrically connected to the control output µC_ctl2 of the microcontroller µC. Furthermore, in this case, the interface circuit IF also includes a fourth optocoupler, OK4, with an optical transmitter and an optical receiver. The signal input IF_rx of the interface circuit IF is formed by the optocoupler OK4, such that its optical transmitter is electrically connected to the signal output µC_tx of the microcontroller µC. As a result, even when the interface circuit IF is electrically connected to the power supply circuit NRG, galvanic isolation between the microcontroller µC and the interface circuit IF can be established, at least when the interface circuit IF is operating in IF I mode.In the aforementioned case where the supply circuit NRG has a DC / DC converter designed as a flyback converter, the microcontroller µC and the interface circuit IF can thus be operated galvanically isolated from each other even when the interface circuit IF is operating in operating mode IF II, or possibly also when operating in operating mode IF III.

Claims

1. Electronics, in particular configured as a communication interface or remote I / O of a measuring system, and / or battery-powered electronics, comprising: - A microcontroller (µC) -- with a control input (µC_sw), -- with at least one first control output (µC_ctl1) -- and with a signal input (µC_rx); - and an interface circuit (IF) -- with at least one first connection terminal (IF_ext1), -- with a control output (IF_ctl), -- with a first control input (IF_sw1) -- and with a signal output (IF_tx); - wherein the control output of the interface circuit is electrically connected to the control input of the microcontroller; - wherein the first control output of the microcontroller is electrically connected to the first control input of the interface circuit; - and wherein the signal output of the interface circuit is electrically connected to the signal input of the microcontroller; - wherein the microcontroller and the interface circuit each have one first operating mode (µCI; IF1) and at least one second operating mode (µClI; IFII); - wherein the microcontroller is configured to issue an instruction at the first control output in the first operating mode (µCI), which causes the interface circuit to operate in its first operating mode; - wherein the interface circuit is configured, at least in the first operating mode (IFI), to differentiate an input signal (e1) present at the first connection terminal, that is to say to convert it into a differentiated signal (a1) representing a differentiation of the input signal over time, and to generate a binary control signal using said differentiated signal (a1) and output it at the control output (IF_ctl); - wherein the microcontroller is configured to issue an instruction at the first control output (µC_ctl1) in the second operating mode (µCII), which causes the interface circuit (IF) to operate in its second operating mode (IFII); - wherein the interface circuit is configured, in the second operating mode (IFII), to convert an, in particular IEC 61 158 CPF15:2007-compliant and / or EIA-485-compliant, digital input signal present at the first connection terminal (IF_ext1) into a binary first output signal (sD1) representing this, and to output said first output signal (sD1) at the signal output (IF_tx); - and wherein the microcontroller (µC) is configured, in the second operating mode (µCII), to receive an, in particular UART-compliant, digital input signal present at the signal input (µC_rx), and to process it, that is to say, in particular, to implement an instruction contained in the input signal and / or to analyze a message contained in the input signal.

2. The electronics as claimed in the preceding claim, - wherein the interface circuit is configured, in the first operating mode, not to convert a digital input signal present at the first connection terminal into an output signal representing this, and not to output at the signal output an output signal representing a digital input signal present at the first connection terminal; and / or - wherein the microcontroller is configured, in the first operating mode (µCI), to process the control signal of the interface circuit present at the control input (µC_sw), that is to say, in particular, to react to the instruction (IRQ) by switching to the second operating mode (µCII); and / or - wherein the microcontroller is configured, in the first operating mode, not to process a digital input signal present at the signal input, that is to say, in particular, not to implement an instruction it contains; and / or - wherein the microcontroller is configured to switch from the second operating mode to the first operating mode in a time-controlled manner, in particular if there is no digital and / or UART-compliant input signal present at the signal input; and / or - wherein the interface circuit and the microcontroller are configured to operate simultaneously in their respective second operating mode in such a way that the first output signal at the signal output of the interface circuit forms the digital input signal present at the signal input of the microcontroller, and in such a way that the microcontroller receives and processes said first output signal; and / or - wherein the interface circuit is configured to respond to a change in a logic level of an, in particular IEC 61158 CPF15:2007-compliant and / or EIA-485-compliant, digital input signal, in particular having a rate of change of more than 90% / µs standardized to the logic level nominally to be reached, and / or to a signal edge of a binary input signal having an edge steepness of more than 1 V / µs, by coding an instruction (IRQ) into the control signal, which causes the microcontroller (PC) to operate in its second operating mode (PC") or causes the microcontroller to switch from its first operating mode to its second operating mode; and / or - wherein the signal input (µC_rx) is configured as an asynchronous serial interface (UART) or as a switching input.

3. The electronics as claimed in one of the preceding claims, - wherein the microcontroller (µC) has a signal output (µC_tx), in particular configured as an asynchronous serial interface (UART), and the interface circuit (IF) has a signal input (IF_rx), in particular configured as an asynchronous serial interface (UART); - and wherein the signal output (µC_tx) of the microcontroller is electrically connected to the signal input of the interface.

4. The electronics as claimed in the preceding claim, - wherein the microcontroller and the interface circuit each have at least one third operating mode (µCIII; IFIII); - wherein the microcontroller (µC) is configured to output an, in particular UART-compliant, digital second output signal (sD2) at the signal output (µC_tx) in the third operating mode; - wherein the interface circuit (IF) is configured, in the third operating mode (IFIII), to convert an, in particular UART-compliant, digital input signal present at the signal input (IF_rx) into an, in particular IEC 61158 CPF15:2007-compliant and / or EIA-485-compliant, digital third output signal (sD3); - and wherein the interface circuit and the microcontroller are configured to operate simultaneously in their respective third operating mode (µCIII; IFIII) in such a way that the second output signal (sD2) at the signal output (µC_tx) of the microcontroller forms the digital input signal present at the signal input (IF_rx) of the interface circuit, and in such a way that the interface circuit receives and processes said second output signal (sD2), that is to say, in particular, converts it into the third output signal (sD3).

5. The electronics as claimed in claim 4, - wherein the interface circuit has a second connection terminal (IF_ext2) and is configured, in the third operating mode, to output the third output signal (sD3) to said second connection terminal, that is to say, in particular, neither in the first operating mode nor in the second operating mode, not to convert an input signal present at the signal input into an output signal representing this, and not to output at the second connection terminal an output signal representing an input signal present at the signal input; and / or - wherein the interface circuit is configured to output the third output signal at the first connection terminal in the third operating mode; and / or - wherein the microcontroller is configured to switch from the second operating mode to the third operating mode, controlled by the input signal (sD1) at the signal input (µC_rx); and / or - wherein the microcontroller is configured to switch independently from the third operating mode to the first operating mode after the digital output signal (sD2) is output at the signal output (µC_tx); and / or - wherein the interface circuit is configured, neither in the first operating mode nor in the second operating mode, not to convert an input signal present at the signal input (IF_rx) into an output signal representing this, and not to output at the first connection terminal (IF_ext1) an output signal representing an input signal present at the signal input; and / or - wherein the microcontroller is configured, in the third operating mode, not to process a digital input signal present at the signal input (µC_rx), that is to say, in particular, not to implement an instruction received at the signal input (µC_rx); and / or - wherein the interface circuit has an, in particular IEC 61158 CPF15:2007-compatible and / or EIA-485-compatible and / or monolithic, transceiver (RS485), in particular of type SN65HVD1781 from Texas Instruments Inc. 2019 or of type THVD2450 from Texas Instruments Inc. 2019, and the first connection terminal of the interface circuit is formed by means of at least one of the BUS driver / receiver connections of the transceiver (A, B), the signal output (IF_tx) of the interface circuit is formed by means of a digital output (R) of the transceiver, and the signal input (IF_rx) of the interface circuit is formed by means of a digital input (D) of the transceiver.

6. The electronics as claimed in either of claims 4 or 5, - wherein the microcontroller has a second control output (µC_ctl2), and the interface circuit has a second control input (IF_sw2); - and wherein the second control output of the microcontroller is electrically connected to the second control input of the interface circuit.

7. The electronics as claimed in the preceding claim, wherein the microcontroller is configured to issue an instruction at the second control output in the third operating mode, which causes the interface circuit to operate in its third operating mode.

8. The electronics as claimed in one of claims 1 to 3, wherein the interface circuit is configured to obtain the electrical power required both in the first operating mode and in the second operating mode in each case exclusively from the input signal (e1) present at the first connection terminal.

9. The electronics as claimed in one of the preceding claims, further comprising: - A supply circuit (NRG), in particular formed by means of an electrochemical and / or rechargeable energy storage unit, - wherein the supply circuit (NRG) has at least one first supply terminal (U1) and is configured to supply an operating voltage for the microcontroller at the first supply terminal; - and wherein the microcontroller has a supply terminal which is electrically connected to the first supply terminal (U1) of the supply circuit (NRG).

10. The electronics as claimed in the preceding claim, - wherein the supply circuit (NRG) has a second supply terminal (U2) and is configured to supply an operating voltage for the interface circuit at the second supply terminal; - and wherein the interface circuit has a supply terminal which is electrically connected to the second supply terminal of the supply circuit (NRG).

11. The electronics as claimed in claim 9 or 10, wherein the interface circuit has an electronic main switch (HS), in particular formed by means of a semiconductor relay or by means of an insulated-gate field-effect transistor, wherein both the first control input (IF_sw1) of the interface circuit and the supply terminal (VCC, GND) of the interface circuit (IF) are formed by means of the main switch (HS).

12. The electronics as claimed in one of the preceding claims, - wherein the interface circuit has an, in particular galvanically isolated, DC-to-DC converter (DC / DC) with a converter input and with a converter output, in particular a flyback converter or a push-pull converter, wherein the DC-to-DC converter is configured to convert a DC input voltage present at the converter input into a DC output voltage present at the converter output with a voltage level that differs from a voltage level of the DC input voltage; and / or - wherein the interface circuit has an, in particular passive, signal filter, in particular a high-pass filter; and / or - wherein the interface circuit for differentiating the input signal present at the first connection terminal (IF_ext1) has a high-pass filter, in particular a passive one and / or one with a limit frequency of more than 800 Hz; and / or - wherein the interface circuit is configured to obtain electrical power (auxiliary power) required during operation at least at times and / or at least in part from the input signal (e1) present at the first connection terminal, that is to say, in particular, to obtain electrical power required in the first operating mode exclusively from the input signal (e1) present at the first connection terminal; and / or - wherein the interface circuit has a power demand of less than 50 mW in the first operating mode; and / or - wherein the interface circuit in the second operating mode has a power demand which is higher than a power demand that the interface circuit has in the first operating mode, that is to say, in particular, is more than 300% of the power demand of the interface circuit in the first operating mode and / or is more than 150 mW.

13. The electronics as claimed in one of the preceding claims, wherein the interface circuit has a first optocoupler (OK1) with an optical transmitter element and an optical receiver element, wherein the control output of the interface circuit is formed by means of the first optocoupler in such a way that its optical receiver element is electrically connected to the control input of the microcontroller.

14. The electronics as claimed in the preceding claim, wherein the interface circuit has a second optocoupler (OK2) with an optical transmitter element and an optical receiver element, wherein the signal output of the interface circuit is formed by means of the second optocoupler in such a way that its optical receiver element is electrically connected to the signal input of the microcontroller.

15. The electronics as claimed in the preceding claim, wherein the interface circuit has a third optocoupler (OK3) with an optical transmitter element and an optical receiver element, in particular in such a way that the first control input of the interface circuit is formed by means of the third optocoupler in such a way that its optical receiver element is electrically connected to the first control output of the microcontroller.

16. The electronics as claimed in the preceding claim and either of claims 6 or 7, wherein the second control input of the interface circuit is formed by means of the third optocoupler in such a way that its optical transmitter element is electrically connected to the second control output of the microcontroller.

17. The electronics as claimed in the preceding claim, wherein the interface circuit has a fourth optocoupler (OK4) with an optical transmitter element and an optical receiver element, wherein the signal input of the interface circuit is formed by means of the fourth optocoupler in such a way that its optical transmitter element is electrically connected to the signal output of the microcontroller.

18. A communication system, comprising: - Electronics as claimed in one of claims 1 to 17; - and a transducer (NLU) electrically connected to the electronics; - wherein the transducer (NLU) is configured to send an, in particular IEC 61158 CPF15:2007-compliant, digital signal to the electronics.

19. A measuring system, comprising: - Electronics as claimed in one of claims 1 to 17; - and a sensor electrically connected to the electronics, wherein the microcontroller is configured to receive and analyze a sensor signal generated by the sensor, at least in the first operating mode, that is to say, in particular, to determine measured values for at least one measured variable recorded by the sensor.