DE102017012081A1 - Field device with monitoring function - Google Patents

Abstract

A field device (100) comprises: a measuring transducer (20) for detecting a process variable and for providing at least one primary signal dependent on a current value of the process variable, an operating and evaluation circuit (30, 32, 34) for processing the primary signal and outputting a A measured value of the process variable which depends on the signal; a display unit (40) for displaying the measured value and / or status information of the field device, the display unit being connected to the operation and evaluation circuit; a housing (10) in which the operating and Evaluation circuit and the display unit are arranged, wherein the housing has a viewing window (14) with a window pane, which provides a view of the display unit (40); andan optical monitoring sensor for monitoring the environment of the field device (10) through the viewing window, wherein the monitoring sensor (50) is disposed in the housing, an objective for imaging a monitored area of the surroundings of the field device onto the optical monitoring sensor; characterized in that the viewing window is a Lens (16) of the lens has.

Description

The present invention relates to a field device with a monitoring function for the environment of the field device.

Generic field devices include: a transducer for detecting a process variable and for providing at least one of a current value of the process variable dependent primary signal; an operation and evaluation circuit for processing the primary signal and outputting a measurement value of the process variable which depends on the signal; a display unit for displaying the measured value and / or status information of the field device, wherein the display unit is connected to the operating and evaluation circuit; a housing in which the operation and evaluation circuit and the display unit are arranged, wherein the housing has a viewing window with a window pane, which provides a view of the display unit. Generic field devices are further adapted to perform the monitoring of the environment of the field device in a process plant in addition to the measurement and / or influencing a process variable. The still unpublished patent application with the file number DE 10 2017 116 167.8 discloses a method for monitoring an automation system with such field devices. As secondary environmental information to be monitored by the respective field device, temperature parameters, a gas composition, an image information, or a vibration quantity are mentioned there. The publication DE 10 2016 207 058 A1 discloses an additional module for environmental monitoring, which is connectable via a communication interface with a field device. This is disadvantageous in that a separate housing for the additional module and an additional interface are required. It is therefore the object of the present invention to provide a field device with the least possible effort with an optical monitoring function. The object is achieved by the field device according to claim 1.

The field device according to the invention comprises: a measuring transducer for detecting a process variable and for providing at least one of a current value of the process variable dependent primary signal; an operation and evaluation circuit for processing the primary signal and outputting a measurement value of the process variable which depends on the signal; a display unit for displaying the measured value and / or status information of the field device, wherein the display unit is connected to the operating and evaluation circuit; a housing in which the operation and evaluation circuit and the display unit are arranged, wherein the housing has a viewing window with a window pane, which provides a view of the display unit; and an optical monitoring sensor for monitoring the environment of the field device through the viewing window, wherein the monitoring sensor is disposed in the housing, an objective for imaging a monitored area of the order of the field device onto the optical monitoring sensor; wherein the viewing window has a lens of the lens.

A field device in the sense of the invention is in particular a field device of automation technology, in particular of process automation technology. It is used to detect and / or influence at least one process variable, such as level, flow, density, viscosity, gas loading of a liquid pressure, temperature, pH, redox potential, conductivity, humidity, dielectric properties, analytical sum parameters such as TOC, turbidity, the Concentration of dissolved gases in liquids, quality parameters of fuels such as natural gas or biogas, or the composition of mixtures. To influence process variables, temperature control devices are used for heating or cooling, and actuators, such as valves or pumps, can be used to change the flow rate of a fluid in a pipeline section or the fill level in a vessel. In principle, field devices are all devices that are used close to the process and that provide or process process-relevant information. A large number of such field devices are manufactured and distributed by the Endress + Hauser Group.

In one development of the invention, the field device comprises a communication interface for wired and / or wireless communication. Wired communication can be used, for example, in accordance with classic fieldbuses such as Foundation Fieldbus, Profibus PA, Profibus DP, HART, Modbus, CANbus, ControlNet, WorldFIP, INTERBUS, CC-Link, TCnet and SERCOS, as well as Ethernet-based fieldbuses such as Profinet, HART-IP , Ethernet-IP, EtherCAT, VNET / IP and Ethernet POWERLINK. Wireless communication can be done over Wi-Fi, Bluetooth, Low Energy, ZigBee, ANT, Wireless-HART or cellular networks such as GPRS (2G), EDGE (2G), UMTS (3G), HSPA (3G ), LTE (3G), LTE-Advanced (4G), 5G, or satellite access.

In a development of the invention, the optical sensor comprises a spectrophotometer. By detecting selective absorption of characteristic wavelengths, it is thus possible, for example, to detect the escape of a gas from the process plant compared to reference data, in particular historical data at the location of the field device.

In one development of the invention, the field device is set up to emit light in a monitored area lying in front of the viewing window. The light signal may in particular comprise a modulated light signal according to an embodiment of the invention.

In one development of the invention, the optical sensor is set up to receive backscattered light from the monitored area. By analyzing the backscattered light, for example, dust, aerolols can be detected.

In one development of the invention, the optical sensor has a camera, in particular a camera.

In one development of the invention, the optical sensor comprises a motion sensor, in particular a proximity sensor.

In one development of the invention, the operating and evaluation circuit is set up to activate the optical sensor in an event-controlled manner.

In one development of the invention, an event for activating the optical sensor comprises a change in the noise or the ratio of signal to noise of the primary signal or of a variable derived therefrom.

In a further development of the invention, the field device further comprises acceleration and / or sound sensors, wherein the operating and evaluation circuit is adapted to activate the optical sensor when sensor signals of the acceleration and / or sound sensors indicate an event.

In a development of the invention, the operating and evaluation circuit is set up to monitor the process variable and the signals of the optical sensor with regard to a correlation.

The measuring arrangement according to the invention comprises a first field device according to the invention and a second field device according to the invention, wherein the field devices are set up to communicate with each other, wherein at least one operating and evaluation circuit of one of the field devices is set up, a correlation between the signals of the optical sensor of the first field device and to monitor the optical sensor of the second field device.

• 1: Einen schematischen Längsschnitt durch ein Ausführungsbeispiel eines erfindungsgemäßen Feldgerätes;
• 2: Einen schematischen Längsschnitt durch eine Modifikation des Ausführungsbeispiels aus 1; und
• 3: Einen schematische Darstellung einer erfindungsgemäßen Messanordnung.

The invention will now be explained in more detail with reference to the embodiments illustrated in the drawings. It shows:

• 1 : A schematic longitudinal section through an embodiment of a field device according to the invention;
• 2 : A schematic longitudinal section through a modification of the embodiment 1 ; and
• 3 : A schematic representation of a measuring arrangement according to the invention.

This in 1 illustrated embodiment of a field device according to the invention 100 includes a metallic housing 10 , and a transducer 20 Here's a pressure transducer inside the case 10 arranged and can be acted upon via a housing opening with a media pressure. Of course, the field device instead of the pressure transducer may have any other transducer that are to be coupled with the housing accordingly and in particular can be arranged outside the housing. The field device 100 also includes an operating and evaluation circuit 30 here's a home electronics 32 and a transducer circuit 34 comprising, the latter primary signals of the transducer 20 recycled and the main electronics 32 provides a digital presentation of the metric. The main electronics 32 is configured to provide the components of the field device with energy and, if necessary, to exchange data with them and to implement the digital presentation of the measured value in a measured value signal and this according to a protocol used in a respective process plant, for example via a bus 200 to communicate. About the bus 200 the power supply of the field device also takes place 100 , The field device further comprises a display unit 40 , which with the main electronics 32 coupled to be supplied by the latter with data and energy to be displayed. The of the display unit 40 Information displayed is through a viewing window 14 , which has a glass pane, in a wall of the housing 10 read. The information may relate in particular to the measured value and / or status information of the field device.

The field device further comprises an optical monitoring sensor 50 , the here in the display unit 40 is integrated but basically can be realized independently of it. In spite of the cramped conditions prevailing in the field device housing at a given focal length of the objective, a good luminous efficiency for the monitoring sensor 50 to realize, has the viewing window 14 a lens 16 a lens of the monitoring sensor 50 on. The Lens 16 can be monolithic with the pane of the viewing window 14 be formed, or be connected to it by joining methods, in particular gluing or soldering. Instead of the convex lens shown here may also be provided a concave lens.

The optical sensor 50 includes, for example, a spectrophotometer comprising monitoring intensities of at least two wavelengths or wavelength ranges. The main electronics 32 is adapted to form a ratio between the intensities and to signal this deviation in case of deviations from a reference intensity ratio between the two wavelengths. This can be, for example, an indication of a leaked gas from a process plant in the vicinity of the field device. A prerequisite for this mode of operation is that the lighting conditions in the environment of the field device are constant. Otherwise, an assignment of changed intensities to a disturbance such as leaked gas is not readily possible.

The modified embodiment in 2 largely corresponds to the embodiment 1 , The field device shown here 100 ' additionally has a light source 60 ' on that in the display unit 40 ' is integrated and light through the window of the viewing window into the environment of the field device 100 ' radiates. The light is thereby emitted modulated, being excluded that light from the light source 60 ' or by reflections on the window of the viewing window 14 to the optical monitoring sensor 50 arrives. Only backscatter of objects 500 outside the detector allows the emitted light with the signature of the temporal modulation to the optical monitoring sensor 50 arrives. In this way, dust, aerosols or people approaching can be detected.

The monitoring sensor 50 can be used in continuous operation, but with an increased energy requirement of the field device 100 . 100 ' accompanied. Alternatively, the monitoring sensor may be activated periodically, for example once per minute or hour. In another alternative, the activation of the monitoring sensor takes place 50 and possibly the light source event-driven. Such events may be due to the measured variable-dependent primary signals of the field device 100 . 100 ' For example, it can be controlled by an unusual history in a batch process, or by values outside of a tolerance range or by a greatly changed ratio of signal to noise with respect to a reference value. Furthermore, the triggering event via the fieldbus 200 be signaled. This can directly a trigger signal to activate the optical sensor 50 or a reading from another field device that should be correlated. If the operation and evaluation circuit 30 determines a deviation from the expected correlation, becomes the monitoring sensor 50 activated. Finally, additional acceleration or vibration sensors that are in the field device 100 integrated are a trigger signal for event-driven activation of the optical monitoring sensor send.

The optical monitoring sensor 50 may also include a camera, which is caused in particular by an event-driven activation, an image of the environment of the field device 100 to record, with that in a memory of the main electronics 32 stored and / or over the bus 200 to a higher-level unit 300 is transmitted. Insofar as this is associated with comparatively large amounts of data, it is advantageous to generate and transmit image data only in an event-controlled manner.

In the 3 illustrated measuring arrangement according to the invention comprises a first field device according to the invention 101 and a second field device according to the invention 102 that over a bus 200 with each other and with a control system 300 communicate. At least one of the field devices is autonomous insofar as it monitors its own measurement data for expected correlations with the measurement data of the other field device. In the case of deviations, it activates its optical monitoring sensor activated in order to disrupt the process, for example, using a cloud of dust 500 to be able to detect. Preferably, both field devices are configured as described. Otherwise, the control system can 300 send corresponding trigger signals to field devices without the autonomous function.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102017116167 [0002]
• DE 102016207058 A1 [0002]

Claims (12)

A field device (100) comprising: a transducer (20) for detecting a process variable and for providing at least one primary signal dependent on a current value of the process variable; an operation and evaluation circuit (30, 32, 34) for processing the primary signal and for outputting a measurement value of the process variable which depends on the signal; a display unit (40) for displaying the measured value and / or status information of the field device, wherein the display unit is connected to the operating and evaluation circuit; a housing (10) in which the operation and evaluation circuit and the display unit are arranged, wherein the housing has a viewing window (14) with a window pane, which provides a view of the display unit (40); and an optical monitor sensor for monitoring the environment of the field device (10) through the viewing window, wherein the monitor sensor (50) is disposed in the housing, an objective for imaging a monitored area of the surroundings of the field device onto the optical monitor sensor; characterized in that the viewing window has a lens (16) of the lens. Field device after Claim 1 , further comprising: a communication interface for wired and / or wireless communication. Field device, after Claim 1 or 2 wherein the optical sensor comprises a spectrophotometer. Field device, according to one of Claims 1 to 3 wherein the field device comprises a light source which is adapted to emit light in a monitored area lying in front of the viewing window. Field device, after Claim 4 wherein the optical sensor is adapted to receive backscattered light from the monitored area. Field device according to one of the preceding claims, wherein the optical sensor comprises a camera, in particular a camera. Field device according to one of the preceding claims, wherein the optical sensor comprises a motion sensor, in particular a proximity sensor. Field device according to one of the preceding claims, wherein the operating and evaluation circuit is adapted to activate the optical sensor event-controlled. Field device after Claim 8 wherein an event for activating the optical sensor comprises a change in the signal-to-noise ratio of the primary signal or a quantity derived therefrom. Field device after Claim 8 which further comprises acceleration and / or sound sensors, wherein the operation and evaluation circuit is adapted to activate the optical sensor when sensor signals of the acceleration and / or sound sensors indicate an event. Field device according to one of the preceding claims, wherein the operation and evaluation circuit is adapted to monitor the process variable and the signals of the optical sensor with respect to a correlation. Measuring arrangement comprising a first and a second field device according to Claim 2 or one of Claim 2 dependent claim, wherein the field devices are adapted to communicate with each other, wherein at least one operation and evaluation circuit of the field devices is adapted to monitor a correlation between the signals of the optical sensor of the first field device and the optical sensor of the second field device.

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