JP4743539B2 - Process data recording apparatus and process data recording method - Google Patents

Description

  The present invention relates to a process data recording apparatus and a process data recording method for recording process data of a field device.

  FIG. 4 is a diagram illustrating an arrangement example of field devices in a plant. In the example of FIG. 4, a pump 91, 93, a valve 94, a transmitter 95 for measuring pressure, temperature, flow rate, etc., a differential pressure for measuring a flow rate using an orifice plate 96 a and an orifice plate 96 a are provided in a plant pipe 91. A transmitter 96b (see Patent Document 1) and the like are connected.

  Each field device is connected to a transmission path 99 for a 4-20 mA signal transmitted from the field device, a digital signal superimposed thereon, or a digital signal such as fieldbus communication. Each field device is connected to a central control device 97 for controlling and monitoring the plant via a transmission line 99, and transmission / reception of measured values and control amounts and process values are performed between the field device and the central control device 97. Alarm information indicating a malfunction or device malfunction is transmitted. The central control device 97 can collect and store data transmitted from the field device via the transmission path 99 as a history.

Furthermore, a device management terminal 98 for managing field devices is connected to the transmission path 99, and setting processing for the measurement ranges, tags, etc. for the field devices is performed. Also, the device management terminal 98 can intermittently collect and store field device measurement values and alarm information.
US Pat. No. 5,754,596

  As described above, the process value and alarm information transmitted from the field device can be collected and stored in the central controller 97 or the device management terminal 98. However, due to the load on the field device, the central control device 97, the device management terminal 98, or the transmission path 99, the monitoring period of process values and the like is limited to about several hundred milliseconds to several seconds or less.

  On the other hand, an excessive pressure or water hammer phenomenon due to plant operating conditions or fluid conditions, or a cavitation phenomenon occurring in a pump, valve, or orifice plate may occur inside the pipe 91. Generation | occurrence | production of these phenomena and the generated pressure by the repetition may cause damage to the piping 91 or a field apparatus. However, since the time of the differential pressure generated by such a water hammer or cavitation phenomenon is a minute time of several hundred milliseconds or less, it is difficult to detect these phenomena in the central controller 97 or the equipment management terminal 98 having a long monitoring cycle. It is.

  In addition, it is difficult to continuously collect data for a long time using a recorder oscilloscope or the like in order to capture a minute time phenomenon that cannot be predicted when it occurs. On the other hand, the capacity of memory mounted in field devices such as differential pressure transmitters is generally smaller than that of recorders, etc., and continuous data is recorded and held in field devices for a long time at minute time intervals. It is even more difficult to do.

  In addition, when field devices are damaged due to high temperatures based on fluids or the surrounding environment, detailed data directly related to damage is often not stored, and the cause of device damage cannot be confirmed. There is a case where it must be estimated from the above.

  An object of the present invention is to provide a process data recording apparatus and a process data recording method capable of efficiently recording process data necessary for analyzing a phenomenon occurring in a plant.

The process data recording apparatus of the present invention is a process data recording apparatus for recording process data of a field device, a recording means for updating and storing the process data by sequentially overwriting a memory provided in the field device, and a predetermined data Detecting means for detecting the event, and prohibiting means for prohibiting overwriting in the recording means triggered by the detection of the event by the detecting means, and the process data updated and stored in the recording means is monitored The process data is sometimes more detailed than the process data transferred to the host device of the field device, and the process data left in the memory due to prohibition of overwriting by the prohibiting unit is It can be acquired .
According to this process data recording apparatus, since the process data of the field device is recorded with the detection of the event as a trigger, the process data necessary for analyzing the phenomenon occurring in the plant can be efficiently recorded.

The recording means may update and store the process data in a shorter cycle than the transfer cycle of the process data transferred to the host device of the field device during monitoring.

The process data may be pressure.

The process data recording method of the present invention is a process data recording method for recording process data of a field device, a recording step of updating and storing the process data by sequentially overwriting a memory provided in the field device; A detection step for detecting the event, and a prohibition step for prohibiting overwriting in the recording step triggered by the detection of the event in the detection step, and the process data updated and stored by the recording step is monitored. The process data is sometimes more detailed than the process data transferred to the host device of the field device, and the process data left in the memory due to the prohibition of overwriting by the prohibit step is transferred by the host device. Can be obtained It is characterized in.
According to this process data recording method, since the process data of the field device is recorded with the detection of the event as a trigger, the process data necessary for analyzing the phenomenon occurring in the plant can be efficiently recorded.

In the recording step, the process data may be updated and stored in a cycle shorter than a transfer cycle of the process data transferred to the host device of the field device during monitoring.

  According to the process data recording apparatus of the present invention, since the process data of the field device is recorded with the detection of the event as a trigger, the process data necessary for analyzing the phenomenon occurring in the plant can be efficiently recorded.

  According to the process data recording method of the present invention, since the process data of the field device is recorded with the detection of the event as a trigger, the process data necessary for analyzing the phenomenon occurring in the plant can be efficiently recorded.

  Hereinafter, an embodiment of a process data recording apparatus according to the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram showing the configuration of an embodiment in which the process data recording apparatus of the present invention is applied to a differential pressure / pressure transmitter.

  As shown in FIG. 1, the differential pressure / pressure transmitter 100 includes a sensor unit 1A and a sensor unit 1B that output pulse signals having frequencies corresponding to process pressures, and pulse signals from the sensor unit 1A and the sensor unit 1B. A frequency counter 2 that counts the frequency (number of pulses), an information processing unit 3 that receives an output signal from the frequency counter 2, and an oscillation circuit such as a crystal oscillator are provided, and the frequency counter 2 and the information processing unit 3 are used as reference clocks. Including a clock generator 4 to be supplied to a digital signal processor, a D / A converter 5 for converting a digital signal from the information processing unit 3 into a 4-20 mA signal, a RAM 61 and an EEPROM 62 as recording means, a liquid crystal display panel, and the like. And a display device 7 that periodically displays a pressure and an alarm.

  As shown in FIG. 1, the sensor unit 1A includes an “H” -shaped silicon resonant sensor 11A, a driver 12A that amplifies the signal of the silicon resonant sensor 11A and continues self-oscillation at a natural frequency by positive feedback. . The tribar 12A amplifies and shapes the oscillation waveform to output a pulse signal having the natural frequency.

  Similarly, the sensor unit 1B includes an “H” -shaped silicon resonant sensor 11B, and a driver 12B that amplifies the signal of the silicon resonant sensor 11B and continues self-oscillation at a natural frequency by positive feedback. The tribar 12B amplifies and shapes the oscillation waveform to output a pulse signal having the natural frequency.

  The silicon resonant sensor 11A and the silicon resonant sensor 11B are attached to a common sensor chip (not shown) that receives the process pressure, and the natural frequency of the self-excited oscillation depends on the amount of deformation of the sensor chip due to the process pressure. Each changes.

  The frequency counter 2 counts the number of pulses of signals from the sensor unit 1 </ b> A and the sensor unit 1 </ b> B and supplies the counted number to the information processing unit 3.

  As shown in FIG. 1, the information processing unit 3 includes a detection unit 31 that detects the occurrence of an event, which will be described later, and an overwrite that prohibits a new overwrite on the RAM 61 as a temporary memory, triggered by the detection of the event by the detection unit 31. And prohibiting means 32. The operations of the detection unit 31 and the overwrite prohibition unit 32 will be described later.

  The information processing unit 3 calculates the natural frequency of the sensor unit 1A and the sensor unit 1B based on the number of pulses counted by the counter 2. Further, the process pressure is calculated based on the calculated natural frequency. The process pressure is defined as a function of the natural frequency of the sensor unit 1A and the natural frequency of the sensor unit 1B, and the information processing unit 3 calculates the process pressure based on this function.

  The calculated process pressure is converted into a 4-20 mA signal by the D / A converter 5 and given to a host device such as a central controller at a constant cycle (for example, a cycle of several hundred milliseconds to several seconds). Further, the D / A converter 5 has a modem function, and superimposes information from the information processing unit 3 such as numerical values of process pressure and alarm information on a 4-20 mA signal as a digital signal such as BRAIN / HART communication, It can be transferred to the host device. The transferred information is stored as normal process data. This function corresponds to the function of the normal data storage means.

  Furthermore, when the field device 100 is a fieldbus communication device such as a foundation fieldbus or a profibus, a digital signal conforming to IEC 61158-2 can be transmitted to the bus line.

  In addition, the field device 100 periodically performs self-diagnosis determined in advance as device specifications, and when abnormality detection is repeated a predetermined number of times or more, a current (out of the 4-20 mA range) is detected as a burnout signal. For example, a current of 3.6 mA or less or 21.6 mA or more) is output. The contents of the self-diagnosis include, for example, whether or not the sensor unit 1A or the sensor unit 1B has failed or whether or not the process pressure is abnormal.

  Also, when performing communication in which a digital signal is superimposed on 4-20 mA, such as BRAIN / HART communication, or when performing fieldbus communication, alarm information can be transmitted by a digital signal.

  FIG. 2 is a flowchart showing the operation procedure of the process data recording apparatus of this embodiment. This procedure is executed based on the control of the information processing unit 3.

  The process shown in FIG. 2 is started by turning on or resetting the differential pressure / pressure transmitter 100. When the power is turned on or reset, each part of the differential pressure / pressure transmitter 100 becomes operable.

  In step S1 of FIG. 2, an initialization process is executed. In the initialization process, a coefficient and a set value that define the function for pressure calculation stored in advance in the EEPROM 62 are read. Further, the event contents to be detected by the detecting means 31 are read from the EEPROM 62. The contents of the event stored in the EEPROM 62 can be set or changed by the manufacturer or user of the differential pressure / pressure transmitter 100.

  In step S1, a flag value for determining whether to acquire and hold continuous data, which will be described later, is set to “1”. Also, a count value to be described later is reset to “0”.

  Next, in step S2, the information processing unit 3 calculates a process value. The process value includes the process pressure calculated by the above-described procedure. Further, the process value includes an internal calculation value other than the process pressure, for example, the natural frequency of the silicon resonant sensor 11A and the silicon resonant sensor 11B. Further, the calculation cycle in step S2 is shorter than the transmission cycle of the process pressure to the host device, for example, about several tens of milliseconds. As described above, in step S2, detailed process values having higher resolution and more types than the process values transmitted to the host device are obtained.

  In step S <b> 2, the calculated process pressure is displayed on the display device 7.

  Further, in step S2, the information processing unit 3 executes the above self-diagnosis, and when an abnormality is detected, a signal notifying the abnormality is output via the D / A converter 5 and also displayed on the display device 7. Displays the occurrence of an abnormality.

  Next, in step S3, the value of the flag is read. If the flag value is "1", the process proceeds to step S4. If the flag value is "0", the process returns to step S2.

  In step S4, the detailed process values calculated in step S2 are sequentially stored in designated addresses in the RAM 61.

  FIG. 3 shows a procedure for storing detailed process values in the RAM 61.

  In the example of FIG. 3, the memory capacity for n sets is prepared in the RAM 61. For example, in step S4, the internal calculation values are initially set to fa0 and fb0, the process pressure is set to PV0, and the RAM 61 is set for one set. Stores the process value of. The next set of process values is stored with the internal calculation values as fa1 and fb1 and the process pressure as PV1, respectively. In this way, when n sets of memory areas are consumed by n times of writing, the next (n + 1) time of writing will again overwrite process values as fa0, fb0, and PV0. . In this way, by cyclically overwriting and using the memory area, the process values stored in the RAM 61 are sequentially updated, and the old process values are deleted in order.

Next, in step S5, it is determined whether or not the occurrence of a predetermined event has been detected by the detection means 31, and if the determination is affirmed, the process proceeds to step S6, and if the determination is negative, the process returns to step S2. Here, for example, an abnormal process pressure value can be set as the predetermined event. For example, when the process pressure value is PV,
MIN ≦ PV ≦ MAX
Not satisfying can be set as the predetermined event. In this case, MIN and MAX are the minimum and maximum values of the process pressure, and are stored in the EEPROM 62 as those that can be set by the user.

  The event can be arbitrarily set. For example, it may be defined as the predetermined event that the natural frequency of the silicon resonant sensor exceeds a specified value, or the predetermined event that the sensor failure is detected. You may define it as an event. An event defined by a combination of various events may be the predetermined event.

  In step S6, one count value is added. This count value is a parameter for controlling the number of times of overwriting to the RAM 61 based on the time of occurrence of the event. As described above, the count value is reset to “0” in the initialization process (step S1).

  Next, in step S7, it is determined whether or not the count value exceeds the offset value. If the determination is affirmative, the process proceeds to step S8, and if the determination is negative, the process returns to step S2. Here, the offset value is a value for defining the set number of process values stored after the occurrence of the event, is designated by the user, and is stored in the EEPROM 62 in advance. The offset value can be specified to a value of n or less corresponding to the memory capacity of the RAM 61 or the number of addresses prepared.

  In accordance with the offset value, a time zone in which a detailed process value is stored based on the event occurrence time is defined. For example, if the offset value is small, many process values before the event occurrence are stored, and if the offset value is large, many process values after the event occurrence are saved.

  In step S <b> 8, the process value as continuous data stored in the RAM 61 is transferred to the EEPROM 62. As described above, by storing the process value in the EEPROM 62 which is a nonvolatile memory, for example, even if the device is removed after a failure, an analysis based on the detailed process value stored in the EEPROM 62 becomes possible.

  Next, in step S9, the value of the flag is set to “0” by the overwrite prohibiting means 32, thereby prohibiting overwriting of a new process value in the RAM 61 (step S4), and the process returns to step S2. The user can also reset the value of the flag to “1”. In this case, the writing of detailed process data to the RAM 61 is resumed.

  The detailed process value stored in the RAM 61 or the EEPROM 62 can be acquired externally by a digital communication via the D / A converter 5, and the analysis based on the detailed process value is performed. Can do.

  As described above, according to the process data recording apparatus of the present embodiment, when an event such as a process abnormality occurs, process data that is continuous data at a minute time interval is stored using the event as a trigger. For this reason, it is possible to grasp the danger inherent in the plant by continuous data, such as an abnormal state such as an overpressure caused by a water hammer phenomenon or cavitation, or an air column vibration of a distillation column, which occurs in a short time inside the process. . Further, by storing process data triggered by an event such as a transmitter failure, it is possible to obtain continuous data such as process data before and after the transmitter failure and operation results of the device. For this reason, the factor of failure etc. can be considered based on continuous data.

  Further, according to the process data recording apparatus of the present embodiment, only process data before and after the event is stored in the transmitter. For this reason, the internal memory of the transmitter can be used effectively, and continuous data for capturing a sudden phenomenon can be collected easily and inexpensively.

  An event serving as a trigger for recording process data is not limited to the above embodiment. For example, an arbitrary alarm in the plant system may be used as a trigger, and detailed process data may be recorded using information transmitted from another field device as a trigger.

  Process data recorded with an event as a trigger can be more detailed in terms of time or data type than normal process data stored by the normal data storage means. For example, even if the number of types of process data recorded with an event as a trigger is smaller than that of normal process data, data having a short time interval corresponds to more detailed data. In addition, even if the time interval of process data recorded with an event as a trigger is not short, if process data other than data stored at normal time is included, it corresponds to more detailed data.

  The scope of application of the present invention is not limited to the above embodiment. The present invention can be widely applied to a process data recording apparatus and a process data recording method for recording process data of field devices.

The block diagram which shows the structure of embodiment which applied the process data recording apparatus of this invention to the differential pressure / pressure transmitter. The flowchart which shows the operation | movement procedure of a process data recording device. The figure which shows the procedure which stores a detailed process value with respect to RAM. The figure which shows the example of arrangement | positioning of the field apparatus in a plant.

Explanation of symbols

31 Detection means 32 Overwrite prohibition means 61 RAM (temporary memory, recording means)
62 EEPROM (Recording means)

Claims (5)

In a process data recording device for recording process data of field devices,
Recording means for updating and storing the process data by sequentially overwriting a memory provided in the field device;
Detection means for detecting a predetermined event;
Prohibiting means for prohibiting overwriting in the recording means triggered by the detection of the event by the detecting means;
Equipped with a,
The process data updated and stored in the recording means is more detailed than the process data transferred to the host device of the field device at the time of monitoring,
2. The process data recording apparatus according to claim 1, wherein the process data remaining in the memory due to prohibition of overwriting by the prohibiting means can be acquired by the host apparatus. 2. The process data recording according to claim 1, wherein the recording means updates and stores the process data in a cycle shorter than a transfer cycle of the process data transferred to a host device of the field device during monitoring. apparatus. The process data recording apparatus according to claim 1 , wherein the process data is pressure . In a process data recording method for recording process data of field devices,
A recording step of updating and storing the process data by sequentially overwriting a memory provided in the field device, and
A detecting step for detecting a predetermined event;
A prohibiting step for prohibiting overwriting in the recording step triggered by the detection of the event by the detecting step;
Equipped with a,
The process data updated and stored by the recording step is more detailed than the process data transferred to the host device of the field device at the time of monitoring,
The process data recording method , wherein the process data remaining in the memory due to prohibition of overwriting by the prohibiting step can be acquired by the host device . 5. The process data according to claim 4, wherein in the recording step, the process data is updated and stored in a shorter cycle than a transfer cycle of the process data transferred to a host device of the field device during monitoring. Recording method.

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