Patent Description:
In the plants having a variety of equipment, a plurality of field devices such as flowmeters, transmitters, scientific devices (pH meters) and actuators such as valves are installed for the purpose of measurement of the state of fluid inside a variety of equipment installed in the plant and control of fluid and the like. Some of such field devices have a self-diagnosis function to diagnose whether a field device itself normally operates or not (see, for example, Patent Literature <NUM> (PTL <NUM>)).

In a self-diagnosis of a field device, when a self-diagnosis is hierarchically made by a plurality of diagnostic processes as in the case where a diagnostic result of one diagnostic process is used by a subsequent diagnostic process, the diagnostic result of a previous diagnostic process affects a subsequent diagnostic result. PTL <NUM> relates to automatic process diagnostics and relates particularly to reliability, validation, and conditioning of the measurement data. PTL <NUM> relates to a method for automatically registering a topology of a fieldbus network from a device access software.

A field device is used in a variety of environments and applications. Under a specific use condition, there are some cases where the operating state of the field device may be treated as normal assuming that the condition is known. However, in this case, there are some cases where the diagnostic result of a specific diagnostic process is "Fail", and the diagnostic result of a process after the specific diagnostic process is also "Fail", which may cause the diagnostic result of the operating state of the field device to be "Fail". For example, when the field device is an electromagnetic flowmeter, a noise generated depending on the state of a wetted surface between an electrode and a fluid is increased under a certain condition and affects a fluid signal. Even in the case where the operating state of the field device may be treated as normal assuming that the noise is known, the diagnostic result of a specific diagnostic process will be "Fail" due to the noise, and the diagnostic result of the operating state of the field device will be "Fail". Thus there is room for improving the adaptability of a diagnosis of the operating state of a field device under a specific use condition.

It is therefore an object of the present disclosure in view of the above-described problem to provide a field device, a method of diagnosing a field device and a diagnostic apparatus that can improve the adaptability of diagnosis of the operating state of the field device.

The invention is defined according to the independent claims.

Aspects of the present disclosure will be described below with reference to the drawings. In each drawing, the same reference signs indicate the identical or similar components.

<FIG> is a block diagram illustrating a configuration example of a field device <NUM> according to Aspect <NUM> of the present disclosure. The field device <NUM> according to this aspect is installed in a plant, and performs measurement of a state of fluid and the like in the equipment installed in a plant and control of fluid and the like. Further, the field device <NUM> according to this aspect has a self-diagnosis function that diagnoses, by itself, if the field device <NUM> itself operates normally. The field device <NUM> is, for example, a sensor device such as a pressure gauge, a flowmeter and a temperature sensor, a valve device such as a flow control valve and an on-off valve, an actuator device such as a fun and a motor, an image capturing device such as a camera and a video camera that captures an image of a state and an object in a plant, an audio device such as a microphone and a speaker that collects abnormal noise in a plant and outputs alarm, a position detection device that outputs position information of each device and the like. The plants where field devices are installed include industrial plants such as chemical plants, plants that manage and control well site such as gas field and oil field or the periphery of such well site, plants that manage and control power generation such as hydro, thermal and nuclear powers, plants that manage and control environmental power generation such as photovoltaic or wind power and plants that manage and control water and sewage, dams and the like.

The field device <NUM> illustrated in <FIG> has a sensor <NUM>, an A/D conversion circuit <NUM>, a display <NUM>, a memory <NUM>, an output circuit <NUM> and an operation circuit <NUM>.

The sensor <NUM> measures the state of fluid and the like (e.g. flow rate, pressure, temperature, level and the like) in equipment in which the field device <NUM> is installed, and outputs the measurement result (analog measurement signal) to the A/D conversion circuit <NUM>. Configuration of the sensor <NUM> differs depending on an object to be measured by the sensor <NUM>. Configuration of the sensor <NUM> for measuring the above described each object to be measured is not directly related to the present disclosure, and thus the description thereof is omitted.

The A/D conversion circuit <NUM> converts a measurement result (analog measurement signal) output from the sensor <NUM> into a digital value corresponding to a size of a signal measured by the sensor <NUM> through analog/digital conversion and outputs it to the operation circuit <NUM>.

The display <NUM> is a display device such as a Liquid Crystal Display (LCD), for example. The display <NUM> displays, according to the control of the operation circuit <NUM>, a variety of information such as, for example, the state of fluid and the like in the equipment in which the field device <NUM> is installed, the diagnostic result of the operating state of the field device <NUM> and the like. The display <NUM> may be what is called a touch panel, which is formed by integrating the display <NUM> and a touch sensor and by disposing a touch face of the touch sensor on the surface of the display <NUM>. When the display <NUM> is a touch panel, touch operation to the touch panel enables operation input to the field device <NUM>.

The memory <NUM> stores application program to be implemented by the operation circuit <NUM>, the running data and the like. Examples of the memory <NUM> include a variety of memories such as, for example, Read Only Memory (ROM), Random Access Memory (RAM) and a flash memory. According to the control of the operation circuit <NUM>, the memory <NUM> stores (writes) and outputs (readouts) data.

According to the control by the operation circuit <NUM>, the output circuit <NUM> outputs the measurement result of the sensor <NUM> to an external device of the field device <NUM> such as, for example, a control device that controls operation of equipment in a plant. Specifically, the output circuit <NUM> converts a digital value that is output from the operation circuit <NUM> and that corresponds to the size of the measurement signal of the sensor <NUM> into a DC analog signal in a range from <NUM> mA to <NUM> mA and outputs to an external device. The output circuit <NUM> can communicate with an external device by using a communication protocol specified in HART®, BRAIN, Foundation Field Bus®, ISA100.11a and the like.

The operation circuit <NUM> controls each component included in the field device <NUM>. The operation circuit <NUM> is a Central Processing Unit (CPU), for example, and controls each component included in the field device <NUM> according to the application program and data for realizing a function of the field device <NUM>. For example, the operation circuit <NUM> allows the output circuit <NUM> to convert a digital value corresponding to the size of the measurement signal of the sensor <NUM> into a DC analog signal in a range from <NUM> mA to <NUM> mA and to output to an external device. Further, the operation circuit <NUM> allows the display <NUM> to display a state of fluid in equipment in which the field device <NUM> is installed.

The operation circuit <NUM> includes a diagnoser <NUM>. The diagnoser <NUM> diagnoses the operating state of the field instrument <NUM> (whether the field device <NUM> operates normally or not). The diagnoser <NUM> diagnoses the operating state of the field device <NUM> by hierarchically implementing a plurality of diagnostic processes. The operation circuit <NUM> allows the display <NUM> to display the diagnostic result of the diagnoser <NUM> or allows the output circuit <NUM> to output the result to an external device.

Next, a method of diagnosing the operating state of the field device <NUM> by the diagnoser <NUM> will be described. First, as a comparative example, a conventional method of diagnosing the operating state of a field device will be described.

In a field device with a self-diagnosis function, diagnosis of an operating state of the field device is generally made by a plurality of diagnostic processes. Further, in a field device with a complex structure, a plurality of diagnostic processes are implemented comprehensively or in stages to determine whether the operating state of the field device is normal or abnormal. As illustrated in <FIG>, a diagnosis is made by dividing into an upper layer, a middle layer and a lower layer, for example.

In the example illustrated in <FIG>, the upper layer includes diagnostic processes A to E. In each of the diagnostic processes A to E, an operating state of a predetermined object to be diagnosed is diagnosed and whether the operating state of the object to be diagnosed is normal ("Pass") or defective ("Fail") is determined. The object to be diagnosed in the diagnostic processes A to E is a component included in the field device <NUM>. For example, examples of components include an exciting circuit configured to drive the sensor <NUM>, a signal detection circuit configured to detect a signal generated at an electrode provided in the sensor <NUM>, the A/D conversion circuit <NUM> and the like, and the object to be diagnosed in the diagnostic processes A to E may be values (variables) being different from each other and treated inside the identical component.

The middle layer includes diagnostic processes F and G. In diagnostic process F, a diagnosis is made on the basis of the diagnostic results of diagnostic processes A, B and C. Specifically, if the diagnostic results of diagnostic processes A, B and C are all "Pass", the diagnostic result of diagnostic process F is "Pass". Further, if at least one of the diagnostic results of diagnostic processes A, B and C is "Fail", the diagnostic result of diagnostic process F is "Fail". In the example of <FIG>, since the diagnostic result of diagnostic process B is "Fail", the diagnostic result of diagnostic process F is "Fail".

Further, in diagnostic process G, a diagnosis is made on the basis of the diagnostic results of diagnostic processes D and E. Specifically, if the diagnostic results of diagnostic processes D and E are all "Pass", the diagnostic result of diagnostic process G is "Pass". Further, if at least one of the diagnostic results of diagnostic processes D and E is "Fail", the diagnostic result of diagnostic process G is "Fail". In the example of <FIG>, since the diagnostic results of diagnostic processes D and E are "Pass", the diagnostic result of diagnostic process G is "Pass".

The lower layer includes diagnostic process H. In diagnostic process H, a diagnosis is made on the basis of the diagnostic results of diagnostic processes F and G. Specifically, if the diagnostic results of diagnostic processes F and G are all "Pass", the diagnostic result of diagnostic process H is "Pass". Further, if at least one of the diagnostic results of diagnostic processes F and G is "Fail", the diagnostic result of diagnostic process H is "Fail". In the example of <FIG>, since the diagnostic result of diagnostic process F is "Fail", the diagnostic result of diagnostic process H is "Fail".

The diagnostic result of each diagnostic process illustrated in <FIG> is as indicated in Table <NUM> below.

As illustrated in <FIG> and Table <NUM>, when the diagnostic result of diagnostic process B is "Fail", the diagnostic results of diagnostic processes F and H after diagnostic process B are also "Fail". In other words, in the conventional diagnostic method, the diagnostic result of one diagnostic process affects the diagnostic result of a diagnostic process after the one diagnostic process.

Depending on the use condition of a field device, there are some cases where the operating state of the field device may be treated as normal assuming that the condition is known. However, in this case, the diagnostic result of a specific diagnostic process is determined as "Fail", and the diagnostic result of a diagnostic process after the specific diagnostic process is also determined as "Fail", and as a result the operating state of the field device is determined as "Fail". In other words, in the conventional diagnostic method, the diagnostic result of one diagnostic process affects the diagnostic result of a diagnostic process after the one diagnostic process. Thus, under a specific condition, the condition is not adapted, and as a result the operating state of the field device cannot be diagnosed correctly.

Next, the method of diagnosing the operating state of the field device <NUM> by the diagnoser <NUM> according to Aspect <NUM> will be described with reference to <FIG>. As with <FIG>, the diagnoser <NUM> diagnoses the operating state of the field device <NUM> by hierarchically implementing a plurality of diagnostic processes (diagnostic processes A to H).

The diagnostic method according to this aspect includes a diagnostic step of diagnosing the operating state of the field device <NUM> by hierarchically implementing a plurality of diagnostic processes by the diagnoser <NUM>. The diagnoser <NUM> can, in the diagnostic step, select whether to enable or disable the diagnostic result of at least one diagnostic process of a plurality of diagnostic processes that diagnose the operating state of the field device <NUM> in a diagnostic process after the one diagnostic process. Specifically, the diagnoser <NUM> holds parameter X that indicates whether to enable or disable the diagnostic result of at least one diagnostic process X of a plurality of diagnostic processes. Further, the diagnoser <NUM> selects whether to enable or disable the diagnostic result of one diagnostic process on the basis of the parameter. For example, when parameter X corresponding to diagnostic process X is "Enable," the diagnoser <NUM> enables the diagnostic result of diagnostic process X in a diagnostic process after diagnostic process X. Further, when parameter X corresponding to diagnostic process X is "Disable," the diagnoser <NUM> disables the diagnostic result of diagnostic process X in a diagnostic process after diagnostic process X.

When disabling the diagnostic result of one diagnostic process, the diagnoser <NUM> diagnoses by not using the disabled diagnostic result of one diagnostic process in a diagnostic process after the one diagnostic process, for example, but by using an enabled diagnostic result in the other diagnostic process. In this case, processing is required for diagnosing by not using the disabled diagnostic result of one diagnostic process but by using only enabled diagnostic result of the other diagnostic process. Thus, when disabling the diagnostic result of one diagnostic process, the diagnoser <NUM> may, regardless of the diagnostic result of the one diagnostic process, diagnose assuming that the diagnostic result of the one diagnostic process is normal ("Pass") in a diagnostic process after the one diagnostic process. In this manner, even in the case where the diagnostic result of one diagnostic process is disabled, in a subsequent diagnostic process, a diagnosis can be made by the same processing as in the case where the diagnostic result of one diagnostic process is enabled. As a result configuration can be simplified.

<FIG> illustrates an example where the diagnoser <NUM> holds parameters X (X: A to G) corresponding to diagnostic processes A to G, respectively. Further, <FIG> illustrates an example where "Enable" is set as parameters A, C, D, E and F and "Disable" is set as parameters B and G. In other words, in diagnostic processes B and G, although the diagnostic result is "Fail" according to a specific use condition of the field device <NUM>, it may be treated as "Pass". Further, <FIG> illustrates an example where the diagnostic results of diagnostic processes A, C and E included in the upper layer are "Pass" and the diagnostic results of diagnostic processes B and D are "Fail".

In diagnostic process F of the middle layer, the diagnoser <NUM> diagnoses on the basis of the diagnostic results of diagnostic processes A, B and C. In this case, although the actual diagnostic result of diagnostic process B is "Fail", since "Disable" is set as parameter B, the diagnoser <NUM> diagnoses, regardless of the diagnostic result, that is, without using the actual diagnostic result, assuming that the diagnostic result of diagnostic process B is "Pass". Since "Enable" is set as parameters A and C and the diagnostic results of diagnostic processes A and C are "Pass", the diagnoser <NUM> determines that the diagnostic result of diagnostic process F is "Pass".

In diagnostic process G of the middle layer, the diagnoser <NUM> diagnoses on the basis of the diagnostic results of diagnostic processes D and E. In this case, the diagnoser <NUM> determines that the diagnostic result of diagnostic process G is "Fail" on the basis that "Enable" is set as parameters D and E, the diagnostic result of diagnostic process D is "Fail", and the diagnostic result of diagnostic process is "Pass".

The diagnoser <NUM> diagnoses on the basis of diagnostic results of diagnostic processes F and G in diagnostic process H of the lower layer. In this case, although the actual diagnostic result of diagnostic process G is "Fail", since "Disable" is set as parameter G, the diagnoser <NUM> diagnoses, regardless of the diagnostic result, that is, without using the actual diagnostic result, assuming that the diagnostic result of diagnostic process G is "Pass". Since "Enable" is set as parameter F and the diagnostic result of diagnostic process F is "Pass", the diagnoser <NUM> determines that the diagnostic result of diagnostic process H is "Pass".

As illustrated in <FIG> and Table <NUM>, even if the diagnostic result of diagnostic process B is "Fail", "Disable" is set as parameter B. Thus, in the subsequent diagnostic process F, a diagnosis is made by disabling the diagnostic result of diagnostic process B (without using the actual diagnostic result of diagnostic process B or by determining that the diagnostic result of diagnostic process B is "Pass"). Further, even if the diagnostic result of diagnostic process G is "Fail", since "Disable" is set as parameter G, in the subsequent diagnostic process H, a diagnosis is made by disabling the diagnostic result of diagnostic process G (without using the actual diagnostic result of diagnostic process G or by determining that the diagnostic result of diagnostic process G is "Pass"). Thus, even if the diagnostic result may be treated as normal due to a known specific use condition of the field device <NUM>, the diagnoser <NUM> can prevent the diagnostic result of the subsequent diagnostic process from being also "Fail" when the diagnostic result is determined to be "Fail". As a result the adaptability of diagnosis of the operating state of the field device <NUM> can be improved. Further, whether to enable or disable the diagnostic result of one diagnostic process can be easily selected on the basis of parameter X.

The parameter X is set by an operator by using, for example, a hand held terminal, which is a mobile information terminal configured to set a variety of parameters of the field device <NUM>. The operator can set parameter X corresponding to each diagnostic process by monitoring the diagnostic result of each diagnostic process in an installation site of the field device <NUM> during installation of the field device <NUM> and considering a specific condition and the like. Further, in the case where the display <NUM> of the field device <NUM> is provided with a depression type switch button, an infrared type switch button and the like, or where the display <NUM> is a touch panel, if a variety of parameters of the field device <NUM> can be set through a switch button or a touch panel, parameter X corresponding to each diagnostic process may be set by an operation input through the touch panel.

Once installed, the position where the field device <NUM> is installed may not be rarely changed. Thus the diagnoser <NUM> may preferably hold parameter X corresponding to each diagnostic process in a non-volatile manner, that is, hold parameter X in a non-volatile memory provided in the field device <NUM>. In this manner, if parameter X is set once depending on the installation environment and usage of the field device <NUM>, there is no need to set parameter X again unless the use condition is changed after installation of the field device <NUM>, and thus a diagnosis can be continuously made. Further, after parameter X is set, parameter X is held even if the power supply of the field device <NUM> is turned on/off. Thus there is no need to set parameter X again, and in this manner a diagnosis can be continuously made.

In this aspect, although an explanation was given by using an example where parameters X (parameters A to G) are set respectively to all diagnostic processes (diagnostic processes A to G) of the upper layer and the middle layer, setting of parameter X is not limited thereto. For example, the default values of parameters X corresponding to all diagnostic processes in the upper layer and the middle layer may be set to "Enable," and "Disable" may be set to parameters X only for the diagnostic processes (only parameters B and G in <FIG>) except those require the diagnostic result in the subsequent diagnostic process. In this manner, the labor of setting parameters X can be reduced and the diagnostic result of the diagnostic process required for diagnosing the operating state of the field device <NUM> can always be enabled. Thus default values are remained and as a result no error in setting may occur.

Further, in this aspect, although an explanation was given by using an example where the diagnostic result of the diagnostic process in which "Disable" is set as parameter X is treated as "Pass" in the subsequent diagnostic process, it is not limited thereto. For example, in a diagnostic process where a diagnosis is performed by using the diagnostic results of the previous diagnostic processes, a diagnosis may be made by using only the diagnostic results of the diagnostic processes in which parameters X corresponding to the previous diagnostic processes are "Enable" (the diagnostic results of the diagnostic processes in which parameters X are "Disable" are not used).

In this manner, the field device <NUM> according to this aspect has the diagnoser <NUM> configured to diagnose the operating state of the field device <NUM> by hierarchically implementing a plurality of diagnostic processes. The diagnoser <NUM> can select whether to enable or disable the diagnostic result of at least one diagnostic process of a plurality of diagnostic processes in a diagnostic process after the one diagnostic process.

In this manner, with respect to a diagnostic process in which the diagnostic result may be treated as "Pass" due to a known specific condition and the like, a diagnostic result of the diagnostic process can be disabled by making it possible to select whether to enable or disable a diagnostic result of at least one diagnostic process. Thus, even though the diagnostic result may be treated as normal due to a known specific use condition, it is possible to prevent the diagnostic result of the subsequent diagnosis from also becoming "Fail" when a diagnostic result of the process is "Fail", and as a result the adaptability of diagnosis of the operating state of the field device <NUM> can be improved.

In Aspect <NUM>, an explanation was given by using an example where the field device <NUM> itself diagnoses the operating state. In Aspect <NUM> according to the present disclosure, an explanation is given by using an example where a diagnostic apparatus such as a hand held terminal, which is an external device of the field device <NUM>, diagnoses the operating state of the field device <NUM>.

<FIG> is a block diagram illustrating a configuration example of a diagnostic apparatus <NUM> according to this aspect. The diagnostic apparatus <NUM> according to this aspect is an external device of the field device <NUM>, such as a hand held terminal.

The diagnostic apparatus <NUM> illustrated in <FIG> has an acquirer <NUM> and a diagnoser <NUM>.

The acquirer <NUM> transmits/receives data to/from the field device <NUM> wired or wirelessly. The acquirer <NUM> acquires diagnostic results of a plurality of diagnostic processes (first diagnostic processes) performed in the field device <NUM> to diagnose the operating state of the field device <NUM>. It is to be noted that, in this aspect, only a part of the diagnostic processes (e.g. the diagnostic processes A to E of the upper layer) of a plurality of diagnostic processes (e.g. diagnostic processes A to H in the example in <FIG>) to diagnose the operating state of the field device <NUM> are performed in the field device <NUM> (diagnoser <NUM>). The acquirer <NUM> outputs the diagnostic results of a plurality of the first diagnostic processes acquired from the field device <NUM> to the diagnoser <NUM>.

The diagnoser <NUM> diagnoses the operating state of the field device <NUM> by one or more second diagnostic processes (e.g. diagnostic processes F, G and H in the example illustrated in <FIG>) by using the diagnostic results of a plurality of first diagnostic processes output from the acquirer <NUM>. In this case, the diagnoser <NUM> can select whether to enable or disable the diagnostic result of at least one diagnostic process of a plurality of first diagnostic processes or one or more second diagnostic processes in a diagnostic process after the one diagnostic process. It is to be noted that selecting whether to enable or disable the diagnostic result of the diagnostic process and processing such as a diagnosis in a diagnostic process by using a plurality of diagnostic results by the diagnoser <NUM> are the same as those of the diagnoser <NUM>, and thus explanation thereof will be omitted.

In this manner, in this aspect, the diagnostic apparatus <NUM> has an acquirer <NUM> configured to acquire diagnostic results by a plurality of first diagnostic processes performed in the field device <NUM> to diagnose the operating state of the field device <NUM>, and a diagnoser <NUM> configured to diagnose the operating state of the field device <NUM> by one or more second diagnostic processes by using the diagnostic results of a plurality of first diagnostic processes. The diagnoser <NUM> can select whether to enable or disable a diagnostic result of at least one diagnostic process of a plurality of first diagnostic processes and one or more second diagnostic processes in a diagnostic process after the one diagnostic process.

Claim 1:
A field device (<NUM>) comprising a diagnoser (<NUM>) configured to diagnose an operating state of the field device (<NUM>) by hierarchically implementing a plurality of diagnostic processes, wherein the diagnoser (<NUM>) is configured to select whether to enable or disable a upper layer diagnostic result of at least one upper layer diagnostic process of the diagnostic processes in a diagnostic process of a lower layer of the one diagnostic process,
wherein the diagnoser (<NUM>) is configured to perform a diagnostic process of a lower layer of the one diagnostic process based on the diagnostic result of one or a plurality of upper layer diagnostic processes, wherein, when disabling a upper layer diagnostic result of one upper layer diagnostic process,
the diagnoser (<NUM>) is configured to assume that the diagnostic result of the one upper layer diagnostic process is normal in the diagnostic process of a lower layer of the one diagnostic process, and
wherein the diagnoser (<NUM>) is configured to hold a parameter that indicates whether disabling a upper layer diagnostic result of a upper layer diagnostic process is being implemented or not, and is configured to select whether or not to assume that the upper layer diagnostic result of the one upper layer diagnostic process is normal on the basis of the parameter.