JP2010003043A - Field device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To refine the type of a failure and reliably notify the failure. <P>SOLUTION: A burn-out H signal and a burn-out L signal corresponding to a type of abnormality are set and registered in a memory 7 for each type of abnormalities. For example, a burn-out H signal is set and registered in accordance with a failure of a sensor part 1, a failure of an A/D converter 2, and a failure of a CPU 3, and a burn-out L signal is set and registered in accordance with failures of a D/A converter 4, a communication part 5, and a power source part 6. The burn-out signals are output to a transmission line L according to the contents set and registered in the memory 7 (Table TB1). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a field device that adjusts the value of a current flowing through a two-wire transmission line according to a measurement value with a predetermined current range (for example, 4 to 20 mA) as a normal adjustment range.

  Conventionally, field devices that use two-wire transmission lines such as differential pressure / pressure transmitters, electromagnetic flow meters, and positioners are equipped with a CPU, and in addition to the instrument's original measurement and control functions, There are those having an abnormality diagnosis function for diagnosing abnormalities occurring in

  For example, a differential pressure / pressure transmitter includes a sensor unit that generates an analog signal corresponding to a magnitude of a pressure or a differential pressure, and an A / D converter that converts the analog signal from the sensor unit into a digital signal. A CPU that samples the digital signal output from the A / D converter and obtains a measured value of pressure and differential pressure, and a predetermined current range (4 to 20 mA) corresponding to the measured value of the digital obtained by the CPU A D / A converter for converting the analog signal to the analog signal, a communication unit for outputting the analog signal output from the D / A converter to a two-wire transmission line, and 4 to 4 obtained from the two-wire transmission line It has a power supply unit that generates an operation power supply to each unit in its own device based on a current of 20 mA.

  This differential pressure / pressure transmitter has a function of detecting various abnormalities occurring in its own device, and the detection of this abnormality is performed by a CPU or an abnormality diagnosis circuit built in the device. When an abnormality is detected by this function, the CPU outputs a signal of a level different from the current range of 4 to 20 mA (normal adjustment range) when outputting the measured value as a burnout signal to the two-wire transmission line. To do. As a result, the host device (monitoring device) that monitors the current flowing through the two-wire transmission path is notified that an abnormality has occurred in its own device.

  Note that the level burnout H signal exceeds the upper limit value of the normal range of adjustment to the burnout signal, there is a level burnout L signal is below the lower limit value of the normal regulating range, either in advance for each device on the other hand Is selected and set as an output signal to the transmission line when an abnormality is detected (see, for example, Patent Documents 1 and 2).

  FIG. 7 shows a flowchart of a general processing operation when outputting a burnout signal. In this case, when the CPU detects an abnormality occurring in its own device (step S101), it checks whether the burnout H signal is set as the burnout signal or the burnout L signal is set. (Step S102).

  The selection setting of the burnout signal is performed by a dip switch or the like, for example, at the factory shipment stage. In the field, it is possible to select and set by operating a dip switch or the like.

If the burnout H signal is set, the set burnout H signal is output to the transmission line (step S103 (see FIG. 8)). If the burnout L signal is set, the set burnout L signal is output to the transmission line (step S104 (see FIG. 9)).
Japanese Utility Model Publication No. 6-25073 JP-A-8-247881

  However, in a field device that performs such an operation, it is possible to select and set one of the burnout L signal and the burnout H signal, but only one burnout signal can be set. Therefore, it can be seen that an abnormality has occurred, but the type of abnormality is unknown.

  In addition, some abnormalities that occur in the device itself cannot output more than 20 mA due to the abnormalities that have occurred. For example, when an abnormality occurs in the D / A converter or the power supply unit, an output exceeding 20 mA may not be output to the transmission line.

  That is, when a burnout H signal is set as an output signal to the transmission line when an abnormality is detected, a burnout H signal exceeding 20 mA is output even if an abnormality in the D / A converter or the power supply unit is detected. And the value of the current flowing through the transmission line may drift within a normal adjustment range of 4 to 20 mA (see FIG. 10). For this reason, a case where an abnormality in its own device cannot be notified to a higher-level monitoring device occurs, and the abnormality notification cannot be reliably performed.

  The present invention has been made to solve such problems, and the object of the present invention is to provide a field device capable of narrowing down the types of abnormalities and capable of reliably performing abnormality notifications. It is to provide.

  In order to achieve such an object, the present invention relates to a field device that adjusts a value of a current flowing through a two-wire transmission line according to a measurement value with a predetermined current range as a normal adjustment range. An abnormality detecting means for detecting various abnormalities occurring in the first level, a signal having a level exceeding the upper limit value of the normal adjustment range, a first burnout signal (burnout H signal), A memory means for storing first and second burnout signals set and registered in correspondence with the type of abnormality for each type of abnormality, and a second burnout signal (burnout L signal) as a signal; When an abnormality is detected by the detecting means, the type of the detected abnormality is determined, and the burnout signal set and registered corresponding to the determined abnormality type is read from the memory means. It is obtained by providing a burnout signal output means for outputting a burnout signal readout to the transmission path.

  In the present invention, a burnout H signal and a burnout L signal corresponding to the type of abnormality are set and registered in the memory means for each type of abnormality. For example, a burnout H signal is set and registered for sensor unit abnormalities, A / D converter abnormalities, CPU abnormalities, and burnouts for D / A converter abnormalities, communication unit abnormalities, and power supply unit abnormalities. The L signal is set and registered. When an abnormality is detected, the burnout signal output means discriminates the type of the detected abnormality, reads out the burnout signal set and registered corresponding to the determined abnormality type from the memory means, The read burnout signal is output to the transmission line. For example, when an abnormality of the sensor unit is detected, the burnout H signal registered corresponding to the abnormality of the sensor unit is read from the memory means and output to the transmission path.

  Here, as described above, the burnout H signal is used for the sensor unit abnormality, the A / D converter abnormality, and the CPU abnormality, the D / A converter abnormality, the communication unit abnormality, and the power supply unit abnormality. If the burnout L signal is set and registered in the memory means, a plurality of types of abnormalities occurring in its own device are distributed and output to the burnout H signal or the burnout L signal. . As a result, it is possible to narrow down the types of abnormality in the host device, and it is easy to take measures against the abnormality.

  Moreover, in a differential pressure / pressure transmitter or the like, if an abnormality occurs in a D / A converter, a communication unit, a power supply unit, or the like, it becomes difficult to output a burnout H signal. If a burnout L signal is set and registered for an abnormality of a type that may not be able to output such a burnout H signal, the burnout L signal is always output for that abnormality. As a result, it is possible to reliably notify the abnormality.

  Further, either one of the burnout H signal and the burnout L signal is set and registered in the memory means for one predetermined type of abnormality corresponding to the type of the abnormality, and a burnout is performed for other abnormalities except for the predetermined one type. The other of the out H signal and the burnout L signal may be set and registered. For example, the burnout H signal is set and registered for the abnormality of the sensor unit, and other abnormalities except the abnormality of the sensor unit (A / D converter abnormality, CPU abnormality, D / A converter abnormality, communication part) In this case, the burnout L signal is set and registered. In this way, when an abnormality occurs in the sensor unit, the host device can uniquely identify the abnormality type by eliminating the possibility of other abnormality types. This makes it possible to take appropriate measures promptly when an abnormality requiring the most alert is generated.

  In the present invention, when the burnout signal read from the memory means is a burnout H signal, it is checked whether the burnout H signal can actually be output, and the burnout H signal is actually output. If this is not possible, a burnout L signal may be output instead. In this case, if an abnormality set and registered to output the burnout H signal occurs, even if the burnout H signal cannot be output due to power shortage or the like, the burnout L signal is output instead. Thus, it is possible to notify the host device that an abnormality has occurred in at least the device itself.

  According to the present invention, for each abnormality type, the burnout H signal and the burnout L signal are set and registered in the memory means corresponding to the abnormality type, and when an abnormality is detected, the detected abnormality is detected. The burnout signal set and registered corresponding to the determined abnormality type is read from the memory means, and the read burnout signal is output to the transmission line. It is possible to narrow down the types of abnormalities by distributing a plurality of types of abnormalities occurring in the output to two types of burnout H signals and burnout L signals.

  Further, according to the present invention, by setting and registering the burnout L signal for the type of abnormality that may not be able to output the burnout H signal, the burnout is always performed for the abnormality. By outputting the L signal, it is possible to reliably notify the abnormality.

Hereinafter, the present invention will be described in detail with reference to the drawings.
[Embodiment 1]
FIG. 1 is a block diagram showing an outline of an embodiment of a field device according to the present invention.
In the figure, 100 is a field device according to the present invention, and 200 is a host device (monitoring device) connected to the field device 100 via a two-wire transmission line L (L1, L2). In this example, the field device 100 is a differential pressure / pressure transmitter.

  The field device 100 includes a sensor unit 1 that generates an analog signal corresponding to the magnitude of pressure or differential pressure, an A / D converter 2 that converts the analog signal from the sensor unit 1 into a digital signal, A CPU 3 that samples a digital signal output from the A / D converter 2 to obtain a measurement value of pressure / differential pressure, and a predetermined current range (4 to 20 mA) corresponding to the digital measurement value obtained by the CPU 3. From a D / A converter 4 for converting to an analog signal, a communication unit 5 for outputting an analog signal output from the D / A converter 4 to a two-wire transmission line L, and a two-wire transmission line L A power supply unit 6 that generates an operating power supply Vcc for each unit in its own device based on the obtained current of 4 to 20 mA, and a burnout H signal that is set and registered corresponding to the type of abnormality for each type of abnormality And bar A memory 7 for storing the out L signal, the ROM 8, and a RAM 9.

  In the configuration of the field device 100, the memory 7 may be in the ROM 8 or the RAM 9. Here, in order to make the explanation easy to understand, an example in which the memory 7 is provided independently of the ROM 8 and the RAM 9 is shown.

  In this embodiment, it is assumed that the burnout H signal and the burnout L signal that are set and registered for each abnormality type corresponding to the abnormality type are stored in the memory 7 as the table TB1.

  Further, in this embodiment, the burnout H signal is set and registered in the table TB1 corresponding to the abnormality of the sensor unit 1, the abnormality of the A / D converter 2, and the abnormality of the CPU 3, and the D / A converter 4 Assume that the burnout L signal is set and registered in response to an abnormality in the communication unit 5 and the power supply unit 6. The contents set and registered in this table TB1 can be freely changed. The memory 7 for storing the table TB1 corresponds to the memory means in the present invention.

  In this field device 100, the CPU 3 operates in accordance with a program stored in the ROM 8 while accessing the memory 7 and the RAM 9. In ROM8, in addition to the measurement value processing program for sampling the digital signal from the A / D converter 2 to obtain the measurement value of the pressure / differential pressure and notifying the monitoring device 200, the program specific to this embodiment is as follows: An abnormality diagnosis program for detecting various abnormalities occurring in its own device and notifying the monitoring apparatus 200 is stored.

  In FIG. 1, the measurement value calculation unit 3-1, the transmission control unit 3-2, and the abnormality detection unit 3-3 are shown as functional blocks in the CPU 3. The control unit 3-2 and the abnormality detection unit 3-3 are realized as a processing function according to a program in the CPU 3.

  In the functional block in the CPU 3, the measured value calculation unit 3-1 samples the digital signal from the A / D converter 2 to obtain the measured value of pressure / differential pressure, and performs D / A conversion as the digital measured value. To the device 4.

  The abnormality detection unit 3-3 monitors the outputs of the sensor unit 1, the A / D converter 2, the CPU 3, the D / A converter 4, the communication unit 5 and the power supply unit 6, and detects abnormalities in these units in its own device. Are detected as various abnormalities. In addition, about CPU3, abnormality of CPU3 itself is diagnosed by monitoring the output from the measured value calculating part 3-1. This abnormality detection unit 3-3 corresponds to the abnormality detection means in the present invention.

  According to the contents of the table TB1 stored in the memory 7, the transmission control unit 3-2 determines whether the output signal to the transmission line L when the abnormality is detected by the abnormality detection unit 3-3 is the burnout H signal. Decide whether to use the L signal and instruct the communication unit 5. This transmission control unit 3-2 corresponds to the burnout signal output means in the present invention.

  FIG. 2 shows processing operations executed in the transmission control unit 3-2. In this processing operation, when an abnormality is detected by the abnormality detection unit 3-3 (step S201), the transmission control unit 3-2 determines the type of abnormality (step S202).

  Then, the table TB1 stored in the memory 7 is accessed, and a burnout signal corresponding to the type of abnormality determined in step S202 is read from the table TB1 (step S203).

  For example, when the abnormality type is an abnormality of the sensor unit 1, the burnout H signal set and registered corresponding to the abnormality of the sensor unit 1 is read from the table TB1, and the abnormality type is the D / A converter 4 Is read out, the burnout L signal set and registered corresponding to the abnormality of the D / A converter 4 is read from the table TB1.

  Then, it is checked whether the read burnout signal is a burnout L signal or a burnout H signal (step S204). If the burnout signal is a burnout L signal, an output signal to the transmission line L for the abnormality is output. The burnout L signal is set (step S205). If it is a burnout H signal, an output signal to the transmission line L for the abnormality is set as a burnout H signal (step S206).

  A time chart of the output state of the burnout signal in this processing operation is shown in FIG. As can be seen from this time chart, if an abnormality of the sensor unit 1, an abnormality of the A / D converter 2, or an abnormality of the CPU 3 occurs in this processing operation, the burn is performed according to the contents of the table TB1 stored in the memory 7. When an out H signal is output and a D / A converter 4 abnormality, a communication unit 5 abnormality, or a power supply unit 6 abnormality occurs, a burnout L signal is output according to the contents of the table TB1 stored in the memory 7 Is done.

  As described above, in the present embodiment, a plurality of types of abnormalities that occur in the device itself are distributed and output to two types of burnout H signals or burnout L signals. As a result, the host device 200 can narrow down the types of abnormalities and can easily take measures against the abnormalities.

  In the present embodiment, when an abnormality of the D / A converter 4, an abnormality of the communication unit 5, or an abnormality of the power supply unit 6 occurs, a burnout L signal is output. That is, when a type of abnormality that may not be able to output the burnout H signal occurs, the burnout L signal is always output according to the contents of the table TB1 stored in the memory 7. As a result, even when there is a type of abnormality that may not be able to output the burnout H signal, the abnormality can be reliably notified to the host device 200.

[Embodiment 2]
In the first embodiment described above, the transmission control unit 3-2 burns the output signal to the transmission line L when an abnormality is detected in the abnormality detection unit 3-3 according to the contents of the table TB1 stored in the memory 7. It is determined whether the signal is an out H signal or a burnout L signal, and the communication unit 5 is instructed.

  In contrast, in the second embodiment, when the burnout signal is determined when the burnout signal read from the table TB1 is the burnout H signal, whether or not this burnout H signal can actually be output. If the burnout H signal cannot be actually output, the burnout L signal is output instead.

  FIG. 4 shows processing operations executed in the transmission control unit 3-2 in this case. In this processing operation, when an abnormality is detected by the abnormality detection unit 3-3 (step S301), the transmission control unit 3-2 determines the type of the abnormality (step S302).

  Then, the table TB1 stored in the memory 7 is accessed, and a burnout signal corresponding to the type of abnormality determined in step S302 is read from the table TB1 (step S303).

  Then, it is checked whether the read burnout signal is a burnout L signal or a burnout H signal (step S304). If the burnout signal is a burnout L signal, an output signal to the transmission line L for the abnormality is output. The burnout L signal is set (step S305).

  On the other hand, if the burnout signal in step S304 is a burnout H signal, it is checked whether the burnout H signal can actually be output (step S306). In this case, the communication unit 5 is prohibited from outputting a signal to the transmission line L, and the measurement value calculation unit 3-1 is instructed to output a current value corresponding to the burnout H signal. By observing the output value of the / A converter 4, it is checked whether or not the burnout H signal can actually be output.

  If the burnout H signal cannot be actually output in step S306, the transmission control unit 3-2 sets the output signal to the transmission line L for the abnormality as the burnout L signal (step S305). That is, an instruction is given to the communication unit 5 and a burnout L signal is output to the transmission line L.

  If the burnout H signal can be actually output in step S306, the transmission control unit 3-2 outputs the output signal to the transmission line L as the burnout H as described in the setting registration of the burnout signal in the table TB1. A signal is set (step S307).

  A time chart of the output state of the burnout signal in this processing operation is shown in FIG. As can be seen from this time chart, in this processing operation, when an abnormality that cannot actually output the burnout H signal occurs, the burnout L signal is output.

  In the second embodiment, by checking whether or not the burnout H signal can actually be output, for example, even when the burnout H signal cannot be output due to power shortage, the burnout is performed instead. An out L signal is output. As a result, it is possible to notify the host device 200 that an abnormality has occurred at least in its own device, and the reliability of the abnormality notification is increased.

[Embodiment 3]
In the first and second embodiments described above, the burnout H signal is set and registered in the table TB1 in the memory 7 corresponding to the abnormality of the sensor unit 1, the abnormality of the A / D converter 2, and the abnormality of the CPU 3. The burnout L signal is set and registered in response to an abnormality in the A / A converter 4, the communication unit 5, and the power supply unit 6. However, as shown in FIG. As for the H signal, the burnout L signal may be set and registered for other abnormalities except the abnormality of the sensor unit 1.

  In this way, when an abnormality of the sensor unit 1 occurs, the host device 200 can uniquely identify the abnormality type by eliminating the possibility of other abnormality types. This makes it possible to take appropriate measures promptly when an abnormality requiring the most alert is generated.

  In the example shown in FIG. 6, the burnout H signal is set and registered only for the abnormality of the sensor unit 1. However, for example, the burnout L signal may be set and registered only for the abnormality of the power supply unit 6. Good. In this case, the burnout H signal is set and registered for other abnormalities except the abnormality of the power supply unit 6.

  In the above-described embodiment, the processing in the transmission control unit 3-2 and the abnormality detection unit 3-3 is realized as a processing function according to the program in the CPU 3, but the transmission control unit 3-2 and the abnormality detection unit 3 Alternatively, an abnormality diagnosis circuit having the same processing function as that of -3 may be provided.

It is a block diagram which shows the outline of one Embodiment (Embodiment 1) of the field device which concerns on this invention. It is a flowchart which shows the processing operation of the transmission control part in this field apparatus. It is a time chart which shows the output state of the burnout signal in the processing operation of this transmission control part. It is a flowchart which shows another example (Embodiment 2) of the processing operation of this transmission control part. It is a time chart which shows the output state of the burnout signal in the processing operation of this transmission control part. It is a block diagram which shows the outline of the field apparatus (Embodiment 3) set and registered as a burnout H signal only about abnormality of a sensor part. It is a flowchart of the general processing operation at the time of outputting the burnout signal in the conventional field device. It is a time chart which shows the output state of the burnout signal at the time of the burnout H setting in this general processing operation. It is a time chart which shows the output state of the burnout signal at the time of the burnout L setting in this general processing operation. It is a time chart for demonstrating the problem at the time of the burnout H setting in the conventional field device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sensor part, 2 ... A / D converter, 3 ... CPU, 3-1 ... Measurement value calculating part, 3-2 ... Transmission control part, 3-3 ... Abnormality detection part, 4 ... D / A converter, DESCRIPTION OF SYMBOLS 5 ... Communication part, 6 ... Power supply part, 7 ... Memory, TB1 ... Table, 8 ... ROM, 9 ... RAM, 100 ... Field device (differential pressure / pressure transmitter), 200 ... Host device (monitoring device), L ( L1, L2) ... 2-wire transmission line.

Claims (4)

In a field device that adjusts a value of a current flowing through a two-wire transmission line according to a measurement value using a predetermined current range as a normal adjustment range,
Anomaly detection means for detecting various anomalies that occur in the device itself;
A signal having a level exceeding the upper limit value of the normal adjustment range is defined as a first burnout signal, and a signal having a level lower than the lower limit value of the normal adjustment range is defined as a second burnout signal. Memory means for storing the first and second burnout signals set and registered corresponding to the type of abnormality;
When an abnormality is detected by the abnormality detection means, the type of the detected abnormality is determined, and a burnout signal set and registered corresponding to the determined abnormality type is read from the memory means, and this reading is performed. And a burnout signal output means for outputting the burnout signal to the transmission line. The field device according to claim 1,
The memory means includes
A field device that stores the second burnout signal that is set and registered in accordance with the type of abnormality that may not be able to output the first burnout signal. . The field device according to claim 1,
The memory means includes
One of the first and second burnout signals set and registered corresponding to the type of abnormality for one predetermined type of abnormality is stored, and the other types of abnormality other than the predetermined one type are stored as described above. A field device characterized by storing the other of the first and second burnout signals. In the field device according to any one of claims 1 to 3,
The burnout signal output means includes
If the burnout signal read from the memory means is the first burnout signal, it is checked whether the first burnout signal can actually be output, and the first burnout signal is checked. If the signal cannot be actually output, the field burner outputs the second burnout signal instead.

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