Radio module for a field device

Abstract

Radio module (FM) for a field device (F1), wherein the radio module (FM) contains a process plan (AP) according to which process data, in particular measurement data, are retrieved from the field device (F1) by means of the radio module (FM) and wirelessly transmitted to a higher-level unit, wherein the radio module (FM) includes an interface (FS) with multiple signal lines, where communication between the radio module (FM) and the field device (F1) takes place via a first signal line, wherein the radio module (FM) transmits control signals to the field device (F1) according to the sequence plan (AP), which serve to control the power consumption of the field device (F1), wherein the field device (F1) has different operating modes, and the control signals serve to switch the field device (F1) from a first operating mode to a second operating mode, wherein the power consumption of the field device (F1) differs in the respective operating mode, wherein the control signals are transmitted via a second signal line, which serves to transmit data between the field device (F1) and the radio module (FM), wherein energy is transmitted from the radio module (FM) to the field device (F1) via a third signal line, and the signal lines are designed to be separate from each other.

Description

[0001] The invention relates to a radio module for a field device and to a method for operating a field device.

[0002] A number of radio modules are already known from the prior art, which serve to retrofit a field device with a radio module and thus to establish a wireless communication connection with the field device.

[0003] Such a radio module is known, for example, from EP 1754116 B1, which radio module can be detachably connected to the sensor electronics of the field device via a field device interface or a conventional digital switching output.

[0004] Furthermore, a device consisting of a radio module and a field device is known from EP 1442338 B1, wherein the radio module can be connected to a fieldbus interface of the field device.

[0005] Furthermore, it has become known that the radio module includes a power supply by means of which the connected field device can be supplied with electrical energy. This power supply is provided by a power source with limited capacity, such as a battery or rechargeable battery.

[0006] The object of the present invention is therefore to extend the operating or service life of a field device that has a radio module with a power source, or generally to save energy.

[0007] The task is solved by a radio module for a field device and a method for operating a field device.

[0008] With regard to the radio module, the problem is solved by a radio module for a field device according to claim 1. This allows the power consumption of the field device to be controlled or regulated depending on the function or scope of functions required by the field device. For example, it is only necessary to transmit a radio signal via the radio module at certain times or under certain predefined conditions specified in the schedule. At certain times or under certain conditions, it is therefore not necessary for the field device to, for example, determine or process a measured value or perform certain functions. Thus, an aspect of the invention is to reduce the power consumption of the field device during these phases, such as for a specific period or until certain predefined conditions are met.

[0009] According to the invention, the interface consists of three signal lines.

[0010] The sequence of events can be in the form of a table, for example, which includes times and / or time periods, and / or conditions, such as the presence of a diagnostic request or an error message from the field device. Preferably, the sequence of events is stored in a memory unit of the radio module. The sequence of events can also be transferred from the field device to the radio module, for example, after the radio module has been connected to the field device, from a memory unit of the field device.

[0011] According to the invention, the control signals are transmitted via a second signal line, which serves to transmit data between the field device and the radio module. The control signal(s) can preferably be digital signals that are transmitted via the signal line from a microcontroller (µC) of the radio module to a microcontroller (µC) of the field device.

[0012] Preferably, the interface can transmit control signals for controlling the power consumption of the field device, as well as process-relevant data such as measured values ​​or parameters or parameter values, and also the power supply, i.e., the power consumption of the field device.

[0013] In another embodiment of the radio module, the radio module includes a power source that supplies both the field device and the radio module with electrical energy. Preferably, both the radio module and the field device are supplied with electrical energy exclusively from the field device's power source. The power source is, for example, a battery, a rechargeable battery, or a fuel cell—an energy source with limited capacity.

[0014] According to the invention, the field device has various operating modes, and the control signals serve to switch the field device from a first operating mode to a second operating mode, with the power consumption of the field device differing in each operating mode. For example, the field device can be configured to the radio module, or the various operating modes of the field device can be known to the radio module and, for example, stored in the flowchart or elsewhere in the radio module. In other words, the radio module is known so that, depending on the flowchart and the process-relevant data required by the field device, it specifies the required operating mode by, for example, transmitting a corresponding control signal from the radio module to the field device, or more precisely, to the operating electronics of the field device.

[0015] In another embodiment of the radio module, the first operating mode is a power-saving mode, such as a sleep mode, a hibernation mode, or a standby mode. Furthermore, it can simply be a mode of the field device in which the acquisition of a measured value is omitted in order to save energy.

[0016] In a further embodiment of the radio module, the second operating mode serves to determine a process variable and to wirelessly transmit corresponding process data via the radio module.

[0017] For example, a situation may arise that requires communication via the radio module, but in which no data needs to be retrieved from the field device at that time. Therefore, it is not necessary for the field device to be powered by the radio module's power source at that moment.

[0018] In another embodiment of the radio module, the schedule determines at which times a process value is transmitted via the radio module or at which time a process value is retrieved from the field device.

[0019] In another embodiment of the radio module, the radio module can be connected to a field device internal bus via the interface.

[0020] In another embodiment of the radio module, the radio module is designed as an adapter for retrofitting the field device with a wireless communication interface.

[0021] In another embodiment of the radio module, the interface between the field device and the radio module is an inductive interface.

[0022] In another embodiment of the radio module, the radio module and the field device can be connected to each other via a power control bus, i.e., a power management bus.

[0023] The problem is further solved by a field device with an interface for data transmission according to claim 10.

[0024] In one embodiment of the field device, the field device is a measuring instrument.

[0025] In another embodiment of the radio module, the field device is supplied with electrical energy via the radio module, which is transmitted via the interface.

[0026] With regard to the method, the problem is solved by a method for operating a field device according to claim 13.

[0027] The invention is explained in more detail with reference to the following drawings. They show: Fig. 1: a schematic representation of a radio module connected to a field device, and Fig. 2: A schematic representation of the interface for data transmission between the field device and the radio module.

[0028] Fig. Figure 1 shows a field device F1 to which a radio module FM is connected.

[0029] The field device includes a sensor (MA) used to detect, determine, or measure a quantity of a substance. The measurement signal generated by the sensor (MA) is fed, for example, via an analog-to-digital converter (A / D) to an operating electronics unit (BE).

[0030] The operating electronics BE can, for example, have a communication unit K2 and is connected to the radio module FM via the FS interface. Data such as that required to supply the field device F1 with electrical energy, the necessary voltage, or the required current can be transmitted via the FS interface.

[0031] For this purpose, the FM radio module has a power supply unit EV, which is, for example, a battery.

[0032] Furthermore, the FM radio module has operating electronics, for example in the form of a microprocessor µC1. In addition, a process flow plan AP is stored in or available in the FM radio module, according to which the FM radio module transmits radio signals to a higher-level unit, such as an operator panel, to contain process-relevant data, which originate, for example, from the field device.

[0033] Depending on the schedule AP, the FM radio module not only sends process-relevant data, but also controls the power consumption of the connected field device F1 by means of control signals transmitted via the FS interface using the FM radio module or the AP schedule.

[0034] These control signals can be used to put the field device F1 into certain operating states corresponding to the control signals.

[0035] To receive the control signals, the field device F1 can contain a corresponding power module M1, which serves to control the power consumption of the field device F1. The radio module FM controls this power module M1. The power module M1 can then, for example, control the power consumption of the field device F1 via a transistor and / or communicate with the operating electronics BE of the field device F1 in order to initiate a specific operating mode defined by the control signals.

[0036] Fig. Figure 2 shows a schematic representation of the FS interface between the field device F1 and the FM radio module. The FS interface can consist of one or more signal lines, which are used for transmitting digital data between the field device F1 and the FM radio module, for transmitting electrical energy, and / or for transmitting a control signal from the FM radio module to the field device F1.

[0037] For example, the FS interface can be used to connect the communication unit K2 of the field device F1 with the communication unit K1 of the radio module FM. Furthermore, the FS interface can be used to transmit the control signals, which are used to control the power consumption of the field device F1, from the communication unit S0 of the radio module to a corresponding control unit S1 of the field device F1, which then controls the power consumption of the field device F1. Additionally, the FS interface can be used to connect a power module M0 of the radio module FM with a power module M1 of the field device F1. This can be done as described in Fig. 2 shown via separate signal lines.

[0038] Furthermore, as can be seen, for example, in Fig.Figure 2 shows the communication for data transmission between the field device F1 and the radio module FM as well as the reception and processing of the control signals by means of a microprocessor µC2 of the field device F1.

[0039] According to the invention, a radio module FM is proposed that can be arranged separately from the field device F1 and connected to the field device F1, for example, via a wired connection through the interface FS. Thus, even though the radio module FM is not a standard component of the field device F1, the power consumption of the field device F1 can be controlled by means of the radio module FM. This extends the operating time of the field device F1 and / or the radio module FM. Furthermore, it allows for easy replacement of the power supply EV, such as a battery, within the radio module FM.

[0040] For the data transmission of process-relevant data between the field device and the radio module, for example a 4-20mA signal and / or the HART protocol can be used.

Claims

[1] Radio module (FM) for a field device (F1), wherein the radio module (FM) contains a schedule (AP) according to which process data, in particular measurement data, are retrieved from the field device (F1) by means of the radio module (FM) and transmitted wirelessly to a higher-level unit, wherein the radio module (FM) comprises an interface (FS) with several signal lines, wherein the communication between the radio module (FM) and the field device (F1) takes place via a first signal line, wherein the radio module (FM) transmits control signals to the field device (F1) based on the schedule (AP), which serve to control the power consumption of the field device (F1), wherein the field device (F1) has different operating modes, and the control signals serve to switch the field device (F1) from a first operating mode to a second operating mode, wherein the power consumption of the field device (F1) differs from one another in the respective operating mode, wherein the control signals are transmitted via a second signal line which serves to transmit data between the field device (F1) and the radio module (FM), wherein energy is transmitted from the radio module (FM) to the field device (F1) via a third signal line, and wherein the signal lines are designed separately from each other. [2] Radio module (FM) according to claim 1, wherein the radio module (FM) has an energy source (EV) by means of which the field device (F1) and the radio module (FM) are supplied with electrical energy. [3] Radio module (FM) according to one of the preceding claims, wherein the first operating mode is a power saving mode, such as a sleep mode, a hibernate mode or a standby mode. [4] Radio module (FM) according to one of the preceding claims, wherein the second operating mode serves to determine a process variable and to wirelessly transmit corresponding process data by means of the radio module (FM). [5] Radio module (FM) according to one of the preceding claims, wherein the schedule (AP) determines at which times a process value is transmitted via the radio module (FM) or at which time a process value is retrieved from the field device (F1). [6] Radio module (FM) according to one of the preceding claims, wherein the radio module can be connected to a field device-internal bus via the interface. [7] Radio module (FM) according to one of the preceding claims, wherein the radio module (FM) is designed as an adapter for retrofitting the field device (F1) with a wireless communication interface (RF, A). [8] Radio module (FM) according to one of the preceding claims, wherein the interface (FS) between the field device (F1) and the radio module (FM) is an inductive interface (FS). [9] Radio module (FM) according to one of the preceding claims, wherein the radio module (FM) and the field device (F1) can be connected to one another via a power control bus, ie power management bus. [10] Field device (F1) with an interface for data transmission, wherein the interface (FS) comprises several signal lines, wherein the communication between a radio module (FM) according to one of the preceding claims and the field device (F1) takes place via a first signal line, wherein a control device (S1) is provided for controlling the power consumption of the field device (F1), which controls the power consumption of the field device (F1) by means of the control signals transmitted by the radio module (FM) via a second signal line, wherein energy is transmitted from the radio module (FM) to the field device (F1) via a third signal line, and wherein the signal lines are designed separately from each other. [11] Field device (F1) according to the preceding claim, wherein the field device is a measuring device. [12] Field device (F1) according to one of claims 10 or 11, wherein the field device (F1) is supplied with electrical energy transmitted via the interface by means of the radio module (FM). [13] Method for operating a field device (F1) according to claim 10, wherein, based on a flow chart (AP) contained in a radio module (FM) according to one of claims 1 to 9, process data, in particular measurement data, are retrieved from the field device (F1) by means of the radio module (FM) and transmitted wirelessly to a higher-level unit, wherein the radio module (FM) transmits control signals to the field device (F1) based on the schedule (AP), and wherein the power consumption of the field device (F1) is controlled by these control signals.

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