JP6132097B2 - Measuring system and measuring method - Google Patents

Description

  The present invention relates to a measurement system including a measurement processing module that acquires a sensor value and converts it into a measurement value, and an arithmetic processing module that performs an operation using the measurement value, and a measurement method in such a measurement system.

  Various field devices are used in plants and the like, and representative field devices include measurement systems that measure and output physical quantities such as temperature, pressure, and flow rate.

  In a measurement system, calculation is often performed based on measurement data acquired from a sensor or the like, and the calculation result is output as a measurement result. In general, these series of processes are performed by a single processing device. In recent years, modules have been modularized for each function in order to share the equipment, and even in the measurement system, the acquisition processing unit for acquiring the measurement data and the arithmetic processing unit for performing the calculation can be modularized. By proceeding, it is expected that each module will be generalized and the degree of freedom of combination will be improved.

  FIG. 5 is a block diagram showing a configuration example of a measurement system assumed when modularization is performed. As shown in the figure, the measurement system 300 includes a measurement processing module 310 and an arithmetic processing module 320. The measurement processing module 310 and the arithmetic processing module 320 are configured independently, and information is exchanged using a communication protocol such as Modbus.

  The measurement processing module 310 includes a changeover switch 311, an AD converter 312, and a measurement management unit 313. The changeover switch 311 sequentially switches signals of a plurality of input channels input from sensors or the like under the control of the measurement management unit 313 and guides them to the AD converter 312. As the sensor, a device corresponding to the measurement target is used. For example, if the measurement object is temperature, a thermocouple, a resistance temperature detector, or the like is used.

  Here, the input signals are classified into two types: main input signals and sub input signals. The main input signal is, for example, a signal corresponding to the physical quantity to be measured output from the sensor. On the other hand, the sub input signal is a signal used for compensation or normalization of a main input signal such as a wiring resistance value and a zero point measurement value, a signal for failure diagnosis such as detection of disconnection of the wiring, and the like. The main input signal has a characteristic that requires as high a response as possible, and the sub input signal has a characteristic that the priority is lower than that of the main input signal, and the immediate response is not necessarily questioned. Here, the number of channels of the main input signal is n, and the number of channels of the sub input signal is m.

  The AD converter 312 digitally converts the main input signal and the sub input signal of the analog signal input via the changeover switch 311 and outputs the converted data to the measurement management unit 313 as measurement data.

  The measurement management unit 313 includes a microcontroller including a CPU, a memory, an input / output circuit, and the like, and stores measurement data sequentially acquired from input signals in the measurement data memory 314 by controlling the changeover switch 311.

  As shown in FIG. 6, for one input signal, the measurement management unit 313 first controls the changeover switch 311 so that the input signal is input to the AD converter 312 (timing t0). Then, it waits until complete measurement data corresponding to the input signal is output from the AD converter 312 (timing t1), acquires the measurement data, and stores it in the measurement data memory 314. Let Tin be the time required for measurement processing performed on one input signal.

  The measurement data memory 314 is a memory area in the measurement management unit 313, and stores measurement data of n main input signals and measurement data of m sub input signals, as shown in FIG. Each measurement data is overwritten and updated every time it is input.

  Each measurement data stored in the measurement data memory 314 is collectively delivered to the arithmetic processing module 320 in response to an acquisition request from the arithmetic processing module 320. This is because the arithmetic processing module 320 needs to acquire measurement data voluntarily in time for the output rate of the measurement result required by the specification, and the arithmetic processing module 320 operates as a master from the request of the communication protocol. This is because the measurement processing module 310 is operated as a slave.

  As shown in FIG. 5, the arithmetic processing module 320 includes an arithmetic processing unit 321 and a display 322. The arithmetic processing unit 321 is configured by a microcontroller having a CPU, a memory, an input / output circuit, and the like, sends a measurement data acquisition request to the measurement management unit 313 at a predetermined period Treq, and is stored in the measurement data memory 314. Acquire each measurement data at once. Then, the acquired measurement data of the main input signal is corrected using the measurement data of the sub input signal, predetermined adjustment values, etc., and necessary calculations such as unit conversion and scale conversion are performed, and the calculation result is displayed. The data is displayed on the device 322 or transmitted to the host device.

  The measurement management unit 313 of the measurement processing module 310 continuously measures the input signal sequentially. FIG. 8 is a diagram illustrating an input signal measurement cycle in the measurement management unit 313. As shown in the figure, the measurement management unit 313 measures all n of the main input signals in one cycle, but the immediate input responsiveness is not questioned for the sub input signals. k (1 ≦ k <m) are measured. Then, the sub input signal acquired for each measurement cycle is changed.

  Here, as shown in FIG. 9, in the measurement management unit 313, the time required to measure n main input signal measurement data is Tma (= n × Tin), and the time required for one cycle is Tcy (= (n + k). ) × Tin). Tin is the time required for measuring one piece of measurement data as described above.

  The measurement data storage timing of the measurement management unit 313 and the measurement data acquisition timing of the arithmetic processing unit 321 are asynchronous, and data processing is performed at independent cycles. However, it is assumed that the acquisition request cycle Treq of the arithmetic processing unit 321 satisfies (n + 1) × Tin ≦ Treq <(n + m) × Tin.

JP 2013-160505 A

  Since the arithmetic processing unit 321 collectively acquires the measurement data stored in the measurement data memory 314 as a response to the acquisition request, only the value of the measurement data stored after the previous acquisition request is updated. The measurement data that has not been overwritten from the acquisition request is acquired with the same value as the previous time.

  In general, in the measurement system, in order to satisfy the requirements on the specification of the measurement rate, all the n pieces of measurement data need to be updated with one acquisition request for the main input signal. For this reason, the acquisition request interval Treq of the arithmetic processing unit 321 is made longer than the time Tcy of one cycle of the measurement management unit 313.

  However, in addition to the measurement management unit 313 and the arithmetic processing unit 321 operating asynchronously, the time Tcy of one cycle of the measurement management unit 313 and the acquisition request interval Treq of the arithmetic processing unit 321 have real-time characteristics. It may change due to deterioration or the influence of noise. If the times including the fluctuation are Tcy ′ and Treq ′, respectively, as shown in FIG. 10, Tcy ′> Treq ′, and there is a possibility that some measurement data of the main input signal is not updated.

  Therefore, the present invention sequentially switches and measures an input signal including a main input signal and a sub input signal, stores the measurement data in a memory, sends a measurement data acquisition request to the measurement processing module, In the measurement system including an arithmetic processing module that acquires each measurement data stored in the measurement data, the measurement data of the main input signal is updated every time the measurement data is acquired.

In order to solve the above-described problem, a measurement system according to a first aspect of the present invention is a measurement processing module that sequentially switches and measures an input signal including a main input signal and a sub input signal, and stores measurement data in a memory. And an arithmetic processing module that sends measurement data acquisition requests to the measurement processing module at predetermined intervals and acquires each measurement data stored in the memory, and the measurement processing module includes the main input signal after the main input signal. The measurement is performed according to the acquisition pattern in which the measurement order is determined so as to measure the sub input signal, and when the measurement data acquisition request is received, the measurement according to the acquisition pattern is interrupted and the head returns to the top of the acquisition pattern. And restarting the measurement.
Here, a plurality of types of acquisition patterns may be prepared, and the measurement processing module may start measurement according to another acquisition pattern when the measurement according to the acquisition pattern is completed.
In addition, when the measurement processing module accepts the current measurement data acquisition request before the completion of the measurement according to the acquisition pattern after accepting the previous measurement data acquisition request, the measurement processing module notifies the arithmetic processing module to that effect. You may make it do.
At this time, when the arithmetic processing module receives the notification, the arithmetic processing module can make the interval for sending the next measurement data acquisition request longer than the predetermined interval.
In order to solve the above-described problem, a measurement method according to a second aspect of the present invention is a measurement processing module that measures by sequentially switching an input signal including a main input signal and a sub input signal, and stores the measurement data in a memory. A measurement data acquisition request to the measurement processing module and an arithmetic processing module for acquiring each measurement data stored in the memory, wherein the measurement processing module includes the measurement processing module, Performing the measurement according to the acquisition pattern in which the measurement order is determined to measure the sub input signal after the main input signal, and receiving the measurement data acquisition request, interrupting the measurement according to the acquisition pattern, The measurement is resumed by returning to the top of the acquisition pattern.

  According to the present invention, a measurement processing module that sequentially switches and measures an input signal including a main input signal and a sub input signal, stores the measurement data in a memory, and sends a measurement data acquisition request to the measurement processing module. In the measurement system including an arithmetic processing module that acquires each measurement data stored in the measurement data, the measurement data of the main input signal is updated every time measurement data is acquired.

It is a block diagram which shows the structural example of the measurement system of this embodiment. It is a figure explaining the acquisition pattern of a measurement cycle. It is a flowchart explaining operation | movement of the measurement management part of this embodiment. It is a timing diagram explaining operation when there is an acquisition request. It is a block diagram which shows the structural example of the measurement system assumed when modularization is performed. It is a figure explaining the timing which acquires measurement data from one input signal. It is a figure which shows the structure of a measurement data memory. It is a figure explaining the measurement cycle of the input signal in a measurement management part. It is a figure explaining the time of 1 cycle, and the space | interval of an acquisition request. It is a figure explaining that there is a possibility that some measurement data of a main input signal may not be updated.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a measurement system according to this embodiment. As shown in the figure, the measurement system 100 includes a measurement processing module 110 and an arithmetic processing module 120. It is assumed that the measurement processing module 110 and the arithmetic processing module 120 are configured independently and exchange information using a communication protocol such as Modbus.

  The measurement processing module 110 includes a changeover switch 111, an AD converter 112, and a measurement management unit 113. The changeover switch 111 sequentially switches n main input signals and m sub input signals input from a sensor or the like under the control of the measurement management unit 113 and guides them to the AD converter 112. As the sensor, a device corresponding to the measurement target is used. For example, if the measurement object is temperature, a thermocouple, a resistance temperature detector, or the like is used.

  The AD converter 112 digitally converts the main input signal and the sub input signal of the analog signal input via the changeover switch 111 and outputs them as measurement data to the measurement management unit 113.

  The measurement management unit 113 includes a microcontroller including a CPU, a memory, an input / output circuit, and the like, and stores the measurement data sequentially acquired from the input signal in the measurement data memory 114 by controlling the changeover switch 111.

  The measurement data memory 114 has the configuration shown in FIG. That is, the measurement data of n main input signals and the measurement data of m sub input signals are stored. Each measurement data is overwritten and updated every time it is input. Each measurement data stored in the measurement data memory 114 is collectively delivered to the arithmetic processing module 120 in response to an acquisition request from the arithmetic processing module 120.

  The measurement management unit 113 of the measurement processing module 110 sequentially acquires input signals sequentially. The measurement management unit 113 acquires all n of the main input signals during one cycle, but acquires k (1 ≦ k <m) of the m input signals. Then, the sub input signal acquired for each measurement cycle is changed.

  Here, it is assumed that the auxiliary input signal acquired for each measurement cycle is defined as an acquisition pattern as shown in FIG. As shown in the figure, the acquisition pattern defines the acquisition order of input signals in one cycle, and the measurement management unit 113 controls the changeover switch 111 according to the acquisition pattern.

  The acquisition pattern is determined such that k sub-input signals are acquired after all n main input signals are acquired first. That is, in each measurement cycle, all n main input signals are always measured before the sub input signals.

  The k sub input signals defined by each acquisition pattern are extracted from the m sub input signals. The k sub input signals may be determined so that each sub input signal is acquired at the same frequency when the acquisition pattern is changed, or the acquisition frequency is determined according to the nature of the sub input signal. May be. For example, the acquisition frequency of the sub input signal whose value changes relatively frequently may be increased, and the acquisition frequency of the sub input signal whose value hardly changes may be decreased. Note that all n main input signals are acquired prior to the sub input signal in each acquisition pattern, but the acquisition order may be changed.

  Returning to the description of FIG. 1, the measurement management unit 113 includes a measurement cycle synchronization processing unit 115. When the measurement management unit 113 receives a measurement data acquisition request from the arithmetic processing module 120, the measurement management unit 113 collectively transfers the measurement data stored in the measurement data memory 114 to the arithmetic processing module 120. The measurement cycle synchronization processing unit 115 interrupts the currently executed measurement cycle and starts the acquisition pattern of the measurement cycle again from the top.

  The arithmetic processing module 120 includes an arithmetic processing unit 121 and a display 122. The arithmetic processing unit 121 includes a microcontroller including a CPU, a memory, an input / output circuit, and the like, sends a measurement data acquisition request to the measurement management unit 113 at a predetermined cycle Treq, and is stored in the measurement data memory 114. Acquire each measurement data at once. Then, the acquired measurement data of the main input signal is corrected using the measurement data of the sub input signal, predetermined adjustment values, etc., and necessary calculations such as unit conversion and scale conversion are performed, and the calculation result is displayed. The data is displayed on the device 122 or transmitted to the host device.

  Next, the operation of the measurement management unit 113 of the measurement system 100 of this embodiment will be described with reference to the flowchart of FIG.

  When the operation is started, an acquisition pattern is first set (S101). The acquisition pattern can be set according to a predetermined order. Then, a measurement cycle is started with the set acquisition pattern (S102). In the measurement cycle, an input signal to be measured is specified (S103), and the changeover switch 111 is controlled so that the input signal is guided to the AD converter 112 (S104).

  When the measurement data output for the input signal to be measured is completed (S106: Yes), the measurement data is stored in the measurement data memory 114 (S107). The above processing is repeated until the measurement cycle is completed while switching the measurement target according to the acquisition pattern. When the measurement cycle is completed (S108: Yes), the next acquisition pattern is set (S101), and the measurement cycle is started with the set acquisition pattern (S102).

  If there is a measurement data acquisition request from the arithmetic processing unit 121 during the measurement cycle (S105: Yes), the measurement data stored in the measurement data memory 114 is collectively transferred to the arithmetic processing unit 121 (S109). . At this time, information for specifying measurement data updated from the previous batch delivery may be added to the arithmetic processing unit 121. The acquisition request determination process (S105) from the arithmetic processing unit 121 is performed between the process (S104) and the process (S106) for convenience, but the acquisition request is an external interrupt. The timing is not limited to this.

  Then, the measurement cycle synchronization processing unit 115 interrupts the measurement cycle being executed (S110), and starts the acquisition pattern that is currently set again from the top (S102). However, the next acquisition pattern may be set to start from the beginning.

  In each acquisition pattern, it is determined that all n main input signals are measured first, and then k sub input signals are measured. When the measurement data is transferred based on the acquisition request, the acquisition pattern starts again from the beginning, so that n main input signals are always measured first in each measurement cycle. For this reason, all the main input signals are updated at the time when the acquisition request is received even if the time variation occurs and the time Tcy ′ of the measurement cycle> the interval Treq ′ of the acquisition request. Of course, the design is performed so that the measurement time Tma ′ ≦ Treq ′ of the n main input signals is guaranteed even when the maximum time fluctuation occurs.

  On the other hand, the measurement of the secondary input signal after the acquisition request is not performed in that cycle, but since the measurement cycle is started again with the same acquisition pattern, the secondary input signal is acquired as scheduled when the fluctuation is eliminated. .

  For example, if Tcy ′ <Treq ′ is in a normal state, as shown in FIG. 4A, the acquisition pattern A is acquired after the measurement cycle of the acquisition pattern A is completed and the measurement cycle of the next acquisition pattern B is started. The request will be accepted. In this case, the measurement cycle of the acquisition pattern B is interrupted, and the measurement cycle of the acquisition pattern B is started again from the beginning. At this time, measurement data in which all of the n main input signals and the k sub input signals are updated (including two or more updates) is delivered to the arithmetic processing unit 121.

  On the other hand, when time fluctuation occurs and Tcy ′> Treq ′ is established, an acquisition request is received before the measurement cycle of the acquisition pattern A is completed, as shown in FIG. In this case, the measurement cycle of the acquisition pattern A is interrupted, and the measurement cycle of the acquisition pattern A is started again from the beginning. At this time, measurement data in which all of the n main input signals and a part of the k sub input signals are updated is delivered to the arithmetic processing unit 121.

  Note that the calculation processing unit 113 determines that Tcy ′> Treq ′ has occurred, that is, that the current measurement data acquisition request has been received before the completion of the measurement cycle after the previous measurement data acquisition request has been received. 121 may be notified. In this case, in order to ensure the state of Tcy ′ <Treq ′ in the next measurement cycle, the arithmetic processing unit 121 may finely adjust the timing of the next acquisition request in response to this notification. Good. Although the amount of adjustment can be set arbitrarily, it can be set to an extent that does not exceed the maximum time fluctuation range of Treq, for example.

100 measurement system 110 measurement processing module 111 changeover switch 112 AD converter 113 measurement management unit 114 measurement data memory 115 measurement cycle synchronization processing unit 120 arithmetic processing module 121 arithmetic processing unit 122 display

Claims (5)

A measurement processing module that sequentially switches and measures an input signal including a main input signal and a sub input signal, and stores measurement data in a memory;
A measurement data acquisition request is sent to the measurement processing module at a predetermined interval, and an arithmetic processing module that acquires each measurement data stored in the memory is provided.
The measurement processing module performs the measurement according to an acquisition pattern in which a measurement order is determined to measure the sub input signal after the main input signal,
When the measurement data acquisition request is received, the measurement according to the acquisition pattern is interrupted, and the measurement system is resumed by returning to the top of the acquisition pattern.   The acquisition pattern according to claim 1, wherein a plurality of types of the acquisition patterns are prepared, and the measurement processing module starts measurement according to another acquisition pattern when the measurement according to the acquisition pattern is completed. Measuring system.   When the measurement processing module receives a current measurement data acquisition request after completion of measurement according to the acquisition pattern after receiving a previous measurement data acquisition request, the measurement processing module notifies the arithmetic processing module to that effect. The measurement system according to claim 1 or 2.   4. The measurement system according to claim 3, wherein upon receiving the notification, the arithmetic processing module makes an interval for sending a next measurement data acquisition request longer than the predetermined interval. A measurement processing module that sequentially switches and measures an input signal including a main input signal and a sub input signal, stores the measurement data in a memory, sends a measurement data acquisition request to the measurement processing module, and is stored in the memory A measurement method in a measurement system comprising an arithmetic processing module for acquiring each measurement data,
The measurement processing module performs the measurement according to an acquisition pattern in which a measurement order is determined so as to measure the sub input signal after the main input signal;
When the measurement data acquisition request is received, the measurement according to the acquisition pattern is interrupted, and the measurement is resumed by returning to the top of the acquisition pattern.