EP3114439A1

EP3114439A1 - Method for checking a measuring device

Info

Publication number: EP3114439A1
Application number: EP15705620.1A
Authority: EP
Inventors: Matthias Brenzinger; Dominik Brand; Toni Jehle; Emilio Schiavi; Michael Moellgaard
Original assignee: Endress and Hauser Process Solutions AG
Current assignee: Endress and Hauser Process Solutions AG
Priority date: 2014-03-03
Filing date: 2015-02-23
Publication date: 2017-01-11
Also published as: WO2015132088A1; US20170059390A1; DE102014102797A1

Abstract

The invention relates to a method for checking a measuring device (FG) using a reference measuring device (RG). The measuring device (FG) is incorporated into a field bus system (F1) in a system (A), said field bus system (F1) being connected to a field bus access unit (G1, G2). The measuring device (FG) remains incorporated in the field bus system (F1) during the check of the measuring device (FG), and the measurement values transmitted from the measuring device (FG) via the field bus system (F1) during the check are transmitted to an analyzing unit (X) by means of the field bus access unit (G1, G2), said analyzing unit (X) being connected to the reference device (RG) in order to compare the measurement values of the measuring device (FG) with reference measurement values of the reference measuring device (FG).

Description

Method for checking a measuring device

The invention relates to a method for checking a

Measuring device, the use of the method, a fieldbus access unit and an arrangement comprising a measuring device, a reference measuring device, an evaluation unit and a fieldbus access unit.

Usually, gauges must be calibrated or periodically inspected for proper operation and proper and accurate signal conversion.

The publication US 71 17122 discloses for this purpose a device for diagnosing a fieldbus by means of a fieldbus communicator. The fieldbus communicator can be operated with two different fieldbus protocols. As a result, a signal with a known measured value is fed into the input of a measuring device, and the fed-in signal is read back at the output of the device. By comparing these two signals it can be confirmed whether the transmitter is operating correctly, i. whether the meter correctly converts the injected signal. However, this is only a software-based calibration, which does not actually check the function of a sensor of the meter.

From the prior art, a similar to US 71 17122 functioning calibrator is known from the publication WO 20131 17818 A1.

From the patent application DE 102013105412 also a calibration system comprising an open fluid circuit and a closed

Fluid circulation has become known. For this purpose, a measuring device to be checked is installed in the calibration insert. In the

Calibration is at least one reference measuring device which the same process medium, preferably also to the same

Process conditions, is exposed. In the case of a flow meter, therefore, both the meter to be tested and the

Flowed through the reference meter from the same flow rate. The of The measured values output from the measuring devices can be compared and thus a statement about the function of the measuring device can be made. For this purpose, an evaluation unit is provided which, for example, adjusts the flow rate, for example by controlling pumps, and / or that of the

Meter and the reference meter

compared with each other.

However, such calibration systems have the disadvantage that the measuring device that is to be checked must be removed from the system in which the field device is used, and / or that the measuring device that is to be checked is disconnected from the fieldbus system for controlling the system and must be connected to the evaluation unit. It is necessary that the communication related settings of the meter from those for the control of the system towards those of the

Evaluation unit used to control the calibration can be used to change. This not only increases the effort required for calibration, but also results in additional sources of error in the

Adjustment of the measuring device. The invention has for its object to provide a simpler and safer way to check a meter.

The object is achieved by methods for checking a measuring device, the use of the method, a fieldbus access unit and an arrangement comprising a measuring device, a reference measuring device, an evaluation unit and a fieldbus access unit.

With regard to the method, the object is achieved by a method for

Checking a measuring device solved by a reference measuring device, wherein the measuring device is integrated into a fieldbus system in a system, to which fieldbus system a fieldbus access unit is connected, wherein during the review of the field device, the field device in the

Fieldbus system remains involved and the transmitted during the review of the field device via the fieldbus system measured values by means of Fieldbus access unit are transmitted to an evaluation unit, which evaluation unit is in communication with the reference measuring device to the measured values of the measuring device with reference measured values of the

Compare reference meter.

A fieldbus access unit, for example, from the published patent DE

102009045055 A1 has become known and is referred to there as a field bus interface, and there serves for retrieving diagnostic data of a field device from the parent bus system, is in the

Communication architecture of a process plant hierarchically arranged usually parallel to a control system. The

Control system serves to control the running in a plant processes.

As a rule, measuring instruments are used in modern systems

Process automation technology via a fieldbus (such as Profibus, Foundation Fieldbus, etc.) interconnected. In this case, the measuring devices are also connected to higher-order units (for example a control system or a control unit), which superordinate units are likewise often connected to one another by a bus system having a higher-level bus system. These superordinate units serve among other things to

Process control, process visualization, process monitoring and commissioning of field devices.

In particular, the data exchange of the measuring device via the fieldbus is carried out according to a protocol (Profibus DP, Profibus PA, Foundation Fieldbus, etc.), which via a variety of individual parameter settings, for example. Regarding the addressing of the individual stations on the fieldbus, the control of access to the Meter, etc. has. Data containing measured values and parameter settings are displayed in the form of

Telegrams transmitted according to the protocol used via the fieldbus. The fieldbus access unit can, for example, be physically connected to the fieldbus. A data exchange on the field bus can then be intercepted by the fieldbus access unit via the connection. The data which are exchanged in the form of telegrams in the case of the commonly used protocols can be measured values as well as a wide variety of parameters and / or parameter values which serve to control and / or regulate and / or monitor the process taking place in the system.

The measured values generated by the meter during the check are also transmitted during the check via the fieldbus to which the control unit also controls the process taking place in the system. At this time, the measuring device transmits the measured values that are generated by a medium used for checking. The control unit queries these measured values over the fieldbus according to a predetermined schedule. To compare these readings with those of

Reference device to compare, which reference meter is used to capture the same process size of the medium, as the meter is checked, an evaluation is provided. The measuring device is connected to the evaluation unit via the fieldbus and the fieldbus access unit, which in turn is connected to the fieldbus and the evaluation unit. The fieldbus access unit is configured in such a way that it forwards the measured values acquired by the measuring device to be checked to the evaluation unit. In one embodiment of the method, the measured values during the checking of the measuring device in the cyclic data traffic over the

Transmitted fieldbus system. This means that at least two users of the fieldbus exchange process data, such as, for example, measured values in accordance with a defined message cycle. In particular

compared to the acyclic data exchange the advantage that measured values can be retrieved from the meter faster and more reliable.

In a further embodiment of the method, by means of the Feldbuszugnffseinheit during the review of the measuring device over the fieldbus system transmitted measured values. The

Fieldbus access unit is, for example, configured such that only the measured values of the measuring device or of the field bus subscriber are detected and / or relayed, which is to be checked, while the remaining data transmitted via the fieldbus is discarded.

In a further embodiment of the method, one of the

Measured signal recorded measured signal converted into a measured value, and this measured value is transmitted via the fieldbus system. The measuring signal corresponds to the measured variable or process variable of the medium used for the calibration. In the case of a flow meter, this is, for example, the flow rate of the medium. The reference meter also measures or is used to determine the flow rate. In which

In such a case, for example, the reference measuring device may likewise be a flow meter or else a balance, by means of which balance the flow rate is determined.

In a further embodiment of the method, the over the

Fieldbus transmitted measuring value of the measuring device by means of a first functional block, which serves to process the measurement signal (TB), and a second function block (AI), which serves to that of the first

Function block processed processing signal processed further generated. This ensures that the meter outputs a correct reading even while it is being used in the system. Because today, for example, gem. The Foundation Fieldbus protocol uses several function blocks to process a measurement signal into a measured value. During a conventional calibration, however, only a first functional block may possibly be used to generate a measurement signal by means of a

Sensor of the measuring device was detected to transmit to an evaluation unit, while added during measurement operation for monitoring and / or control of a system, a further functional block which also serves to generate the measured value. This second function block contains, for example, a linearization curve or the like. In a further embodiment of the method, the measuring device remains during the check in a communication connection via the fieldbus system with a control unit of the system in which the measuring device is installed. For example. can be a piping system in front of and behind the

Open the meter so that the fluid being used in the test is inserted into the tubing in front of the meter, pass through the meter and exit behind the meter or into the reference meter. In a further embodiment of the method, the measuring device is removed for checking out of the system, but still remains in a communication connection with the control unit, in particular without the communication connection being interrupted via the fieldbus system. For example. Thus, the existing wiring can remain on the field device, while it is removed and in a calibration system such as. A

Fluid circuit is installed.

In a further embodiment of the method, the measuring device is operated during the check with the same communication schedule (link schedule) as during a previous and / or subsequent operation in a system, through which communication flowchart determines the communication behavior of the measuring device. The measuring device is therefore operated with the same communication flowchart as during the measuring operation in the system.

In a further embodiment of the method, one of the

Meter generated during the check acc. the

Communication schedule (deterministic) provides,

in particular transmitted via the fieldbus system and this measured value in the evaluation unit used for comparison with the reference device.

In a further embodiment of the method, at least one

Identification date of the measuring instrument during the inspection, preferably automatically with reference data of the calibration and

Evaluation unit compared, eg. To avoid errors.

In a further embodiment of the method is the

Fieldbus access unit on the one hand with the fieldbus system and on the other hand with the evaluation, for example. Via an Ethernet connection, connected. The connection between the fieldbus access unit and the evaluation unit can therefore be an Ethernet connection. In a further embodiment of the method, the reference device and / or the evaluation unit is part of a calibration device. The

Reference device may be part of a mobile calibration facility that can be brought close to the instrument being calibrated. The calibration system can also include, for example, a fluid circuit, a fluid reservoir and / or the evaluation unit.

In a further embodiment of the method, the reference device is not connected to the fieldbus system to which the measuring device is connected. That The reference measuring device is not a participant of the fieldbus to which the measuring device is connected. Rather, the fieldbus access unit is connected to the fieldbus and also participants of the fieldbus.

In a further embodiment of the method, the measuring device is a flow meter.

In a further embodiment of the method is by means of

Evaluation unit created a log of the verification of the meter.

In a further embodiment of the method, both the

Meter as well as the reference meter to detect a

Process variable of a medium. The medium is, for example, a medium to be used for the calibration, for example a certain amount of water. With regard to use, the object is achieved by the use of the method according to one of the preceding claims for calibration,

Adjustment, validation or calibration of the measuring device solved. With regard to the fieldbus access unit, the object is achieved by a

Field bus access unit for use in the method according to one of the previous embodiments solved. For this purpose, the fieldbus access unit has a corresponding configuration in which data of a field bus subscriber are forwarded to an evaluation unit for comparing measured values with those of a reference measuring device.

With regard to the arrangement, the object is achieved by an arrangement comprising a measuring device, a reference measuring device, an evaluation unit and a fieldbus access unit for carrying out the method according to one of the preceding embodiments.

The invention will be explained in more detail with reference to the following drawings. FIG. 1 shows a schematic illustration of an embodiment of the invention. FIG

proposed invention, with a test device to be tested, a first and a second fieldbus access unit, and a calibration,

Fig. 2 is another schematic representation of an embodiment of the invention

Figure 1 shows a schematic representation of a fieldbus F1 to which a measuring device FG is connected. The measuring device FG is, for example, part of a distributed control and / or control system, in English: DCS. It is also a central control unit D1, the example. Visualization and / or operating means has provided. In order to calibrate or otherwise check the measuring device FG, it has hitherto been necessary to remove the measuring device FG from the system A and to install it in a calibration system K. Alternatively, it has also become known to provide an influence and an outflow in front of or behind the measuring instrument FG, so that it can remain at its installation location in the system A.

Subsequently, a medium F is used to determine a process variable of the medium F by means of the measuring device FG and a reference measuring device RG.

According to one embodiment of the invention, however, the measuring device FG is no longer disconnected from the fieldbus F1 in order to compare it with the evaluation unit X, which is used to compare the means of measurement FG and of the

Reference meter RG measured values is used to connect.

Rather, a field bus access unit G1 or G2, also referred to as a gateway, is used, which is connected to the fieldbus F1, to which the measuring device FG is connected to the fieldbus F1 and also connected to the evaluation unit X.

The measured values determined by the measuring device FG during the calibration and transmitted via the fieldbus F1 are then determined by means of the

Fieldbus access unit G1 or G2 detected and forwarded to the evaluation unit X.

For calibration, the measuring device FG can remain installed in the system A or be installed in a calibration system, although the fieldbus connection of the measuring device FG is not disconnected. The fieldbus access unit G1 or G2 can acc. a first

Embodiment already be installed in Appendix A and to

Verification purposes are connected to the evaluation unit X.

On the other hand, the evaluation unit X can also be part of the calibration system K and be connected to the fieldbus F1 for checking purposes. If the fieldbus access unit G1 is permanently connected to the fieldbus F1 of the installation, the fieldbus access unit G1 can not only be connected to a first fieldbus F1, but also to at least one further fieldbus F2, F3, F4. Thus, measuring devices connected to these other fieldbuses F2-F4, as proposed, can be calibrated in a simple manner. The field buses F2, F3, F4 may, for example, in each case have its own control unit D2-D4, that is to say be both physically and logically independent of each other.

The evaluation unit X can be part of the calibration system, as shown in FIG. 1, and only needs to be connected to the one fieldbus access unit G1 which is connected to the field bus F1 or the field buses F1-F4, for example via an Ethernet connection ET become.

Alternatively, the fieldbus access unit G2 can also be arranged on the calibration system K and then connected to the fieldbus F1, to which the measuring device FG, which is to be checked, is connected. This fieldbus access unit G2 can then alternatively be connected to at least one other of the other field buses F2-F4.

The fieldbus access unit G2 thus establishes a connection between the evaluation unit X and the measuring device FG, which is to be checked. In this case, however, the measuring device FG does not communicate directly with the fieldbus access unit G1 or G2, but according to a communication flowchart also otherwise used in Appendix A with the control unit D1 and / or other measuring devices connected to the fieldbus F1, not shown. The fieldbus access unit G1 or G2 serves, for example, at least during the calibration for monitoring the of the

Measuring device FG via the fieldbus F1 transmitted measured values.

These measurements can then be compared to the ones from the

Reference meter RG generated measured values. The comparison can then be used to calibrate, validate, adjust the meter. The calibration system K may comprise one or more reference measuring devices which are installed in a calibration circuit through which a medium F passes. The medium F can be conveyed, for example, by means of a pump P from a reservoir R in which the medium F is located. For controlling the calibration system K, it is likewise possible to use a control unit S which is installed in the calibration installation K and which, for example, is connected to the pump P. In addition, the

Calibration K include the evaluation unit X, which with the

Reference meter RG is connected.

Claims

claims

1 . Procedure for checking a measuring instrument (FG) by means of

Reference measuring device (RG), wherein the measuring device (FG) is integrated in a fieldbus system (F1) in a system (A) to which fieldbus system (F1) a fieldbus access unit (G1, G2) is connected,

wherein during the checking of the measuring device (FG) the measuring device (FG) remains integrated in the fieldbus system (F1) and which during the

Checking transmitted by the measuring device (FG) via the fieldbus system (F1) measured values by means of the fieldbus access unit (G1, G2) to an evaluation unit (X),

which evaluation unit (X) is in connection with the reference device (RG) in order to compare the measured values of the measuring device (FG) with reference measured values of the reference measuring device (FG).

2. Method according to the preceding claim,

whereby the measured values are transmitted during the checking of the measuring device (FG) in cyclic data traffic via the fieldbus system (F1).

3. The method according to any one of the preceding claims,

wherein by means of the field bus access unit (G1, G2) during the review of the measuring device (FG) transmitted via the fieldbus system (F1)

Measured values are recorded.

4. Method according to one of the preceding claims,

wherein a measuring signal recorded by the measuring device (FG) is converted into a measured value, and that this measured value is transmitted via the fieldbus system (F1).

5. Method according to one of the preceding claims,

wherein the transmitted over the fieldbus system (F1) measured value of

Measuring device (FG) by means of a first functional block, the

Processing of the measurement signal is used (TB), and a second function block (AI), which is used to further process the processed by the first function block measurement signal is generated.

6. The method according to any one of the preceding claims,

the meter (FG) during the review in one

Communication connection via the fieldbus system (F1) with a

Control unit (D1) of the system (A) in which the measuring device (FG) is installed remains.

7. The method according to any one of the preceding claims,

the meter (FG) being removed from the system (A) for inspection, but still in communication with the

Control unit (D1) remains, in particular without the

Communication connection via the fieldbus system (F1) is interrupted.

8. The method according to any one of the preceding claims,

wherein the measuring device (FG) is operated during the check with the same communication flowchart, for example a so-called Macro Cycle Schedule, such as during a previous and / or subsequent operation in a system (A), through which communication flowchart the communication behavior of the measuring device ( FG) determined.

9. Method according to one of the preceding claims,

wherein the fieldbus access unit (G1, G2) on the one hand to the fieldbus system (F1) and on the other hand to the evaluation unit (X), for example. Via an Ethernet connection (ET) is connected.

10. The method according to any one of the preceding claims,

wherein the reference device (RG) and / or the evaluation unit (X) is part of a calibration device (K).

1 1. Method according to one of the preceding claims,

wherein the reference device (RG) is not connected to the fieldbus system (F1) to which the meter (FG) is connected.

12. The method according to any one of the preceding claims,

wherein the meter (FG) is a flow meter.

13. The method according to any one of the preceding claims,

wherein by means of the evaluation unit (X) a protocol of the verification of the measuring device (FG) is created.

14. Use of the method according to one of the preceding claims for calibration, adjustment, validation or calibration of the measuring device (FG).

A fieldbus access unit (G1, G2) for use in the method of any of claims 1-12.

16. Arrangement comprising a measuring device (FG), a reference measuring device (RG), an evaluation unit (X) and a fieldbus access unit (G1, G2) for carrying out the method according to one of claims 1 -12.