JP2002008178A - Variable measuring period type measurement control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable measuring period type measurement control system facilitating change of a change judgement reference value of a measuring period of field equipment 2 and change of a value of a measurement and communication period. SOLUTION: This system is provided with the field equipment 2, high-order control equipment 1A, and an electric transmission path 5 and is provided with a normal operation period register 36 recording a first measuring period T1 of the field equipment 2, a change operation period register 37 recording a second measuring period T2 of the field equipment 2, reference value registers 32 to 35 storing values set in advance, and a comparison means 30 comparing values measured by the field equipment 2 with reference values stored in the reference value registers 32 and 35 to switch the first measuring cycle T1 recorded in the normal operation period register 36 and the second measuring period T2 recorded in the change operation period register 37 based on the results of comparison by the comparison means 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital type in which, for example, a primary battery is installed in a field as a power supply for equipment, a measured amount such as a water level and a temperature is measured, and data processing and control are collectively performed in a remote control room. The present invention relates to a variable measurement cycle type measurement control system.

[0002]

2. Description of the Related Art FIG. 9 is a diagram for explaining an example of the system configuration of the present invention and the prior art in a measurement control system using optical fiber transmission. In FIG. 9, the optical fiber transmission type measurement control system includes a host control device 1A placed in the control room 1.
, An optical field device 2 (2A, 2B, 2C,...), A trunk optical fiber 51, an optical star coupler 52, and the like in the illustrated example that forms a transmission path 5 between the upper control device 1A and the optical field device 2.
And a branch optical fiber 53.

FIG. 10 shows a conventional optical field device 2.
10A is an explanatory diagram of the measurement cycle T0 and the communication cycle with the upper control device 1A, the transmission output TX11 to TA13 of the upper control device 1A is shown in (A) of FIG. 10 in the upper row, and (B) of FIG. The response outputs TX21 to TA23 of the optical field device 2 and the timing of the measurement operation (measured values mes1 to mes4) of the sensor unit 26 of the optical field device 2 are illustrated. In FIG. 10, when the higher-level control device 1A transmits the measurement value request TX11 at time t11, the optical field device 2 receives the measurement value request TX11 and notifies the time t12 that the measurement value request TX11 is addressed to its own station. , The previous measurement value mes1 of the sensor unit 26 is responded with the communication data TX21, and the sensor unit 26 starts measurement (mes2) for the next response from time t13 after the response is completed with the communication data TX21, Times of Day
At t14, the measured value mes2 is detected. At time t14, the optical field device 2 enters the operation pause state and enters the low power consumption state. The communication cycle TO between the higher-level control device 1A and the optical field device 2 and the measurement period T0 during which the sensor unit 26 of the optical field device 2 measures a measurement value are varied in the illustrated example, and the period T0 is extended. An example of the optical field device 2 at the time is shown.

[0004] In addition, there is an optical field device 2 that measures a measurement amount at a fixed period preset to the device 2, for example, 200 ms, and communicates with the host control device 11 at a fixed period of 200 ms. . Japanese Patent Laid-Open No. 9-2166 discloses a method of extending the battery life by changing the measurement cycle of the sensor unit 26 and performing measurement.
7 Disclosed in "Flow Measurement Devices". In the present invention,
A flow rate calculating means for calculating a flow rate from a signal propagation time difference between the ultrasonic transducers using an ultrasonic flow meter, a measurement ending means for notifying the completion of the flow measurement by the flow rate calculating means, a measurement ending means or a measurement start Means for controlling the supply voltage of the measurement circuit by the means, and a cycle variable means for changing the cycle of the measurement start means based on the value of the flow rate calculation means. In addition, during the measurement cycle, the power supply voltage is lowered to reduce the power consumption and prolong the battery life.

According to the disclosed contents, as a method of extending the measurement cycle while maintaining the accuracy of the flow rate, for example, an average cycle variable which changes the average value of the cycle of the measurement means based on the value of the flow rate calculation means Means and random value generating means for generating a random value are added to constitute a cycle variable means. Alternatively, for example, for gas flow rates,
As a usage state of gas, there is a case where the period during which the gas flow rate is zero is relatively large. In such a case, as a method of increasing the cycle of the measurement start means according to the number of times of zero value detection of the flow rate calculation means, or further improving the accuracy of the integrated value of the gas flow rate, the zero value detection of the flow rate calculation means When a flow rate value equal to or greater than a predetermined value is detected later, specifically, the flow rate measurement cycle is lengthened, and it is not known at what point in time when the flow rate was increased and at what rate the flow rate changed. Such a correction method is disclosed.

[0006]

In an optical field device, it is difficult to supply sufficient energy to an optical fiber, so a primary battery is used as a power source, and the energy amount of the primary battery is reduced once every several years. When the alarm is lowered and the alarm is notified, the battery is appropriately replaced. The energy of the battery is
It is mainly consumed when the optical field device performs the measurement operation and the communication operation.However, in the measurement control system using the conventional optical fiber transmission, the measurement period and the communication period are fixed, and the short period (200 ms) is used. ), The measurement operation and the communication operation are performed. For this reason, measurement and communication operations are always performed at a fixed high-speed cycle, even when the measurement amount such as water level and temperature does not change so rapidly, or when it is used only for detecting the alarm amount. As a result, it has been difficult to reduce power consumption.

[0007] Further, in Japanese Patent Application Laid-Open No. 9-21667 "Flow measurement device" according to the prior art, the measurement cycle of a field device driven by a battery is increased to reduce the power consumption of the battery and to improve the accuracy of the integrated flow value. A method for improving is disclosed. The integrated value of the flow rate related to the transaction conditions of the flow rate needs to ensure the accuracy that can be agreed between the consumer and the supplier.
Of course, from the viewpoint of general process control, it is sometimes necessary to ensure the accuracy related to the transaction conditions.However, from the viewpoint of stable monitoring and control of the process, the upper and lower limits of the measured values, Equipped with cycle change judgment means for judging the optimal measurement cycle based on the allowable range of the upper limit value, lower limit value, or upper and lower limit value of the time change rate of the measured value, and easily in the central control monitoring room etc. It is desired to develop a measurement cycle variable type measurement control system which can change the reference value of the cycle change determination means and change the measurement / communication cycle.

Further, according to the prior art, when the measurement cycle is changed, the field device receives a communication request from the host control device, and when the communication request is addressed to its own station, activates the central processing unit and returns a response. Then, the next measurement value is measured and the central processing unit is stopped. Therefore, in such a case, for example, when performing feedback control on the higher-level control device side, the dead time until the higher-level control device secures this measurement value at the next communication request when the field device measures the measurement value. There is a problem that L becomes longer in proportion to the change time of the measurement cycle. In general, in the feedback control system, when the dead time L is longer than the process time constant T, a problem occurs that largely changes PID control parameters and greatly affects control stability.

The present invention facilitates the change of the reference value for changing the measurement cycle of the field device and the change of the value of the measurement / communication cycle, and also changes the measurement cycle in which real-time performance of a feedback control system or the like is emphasized. It is an object of the present invention to provide a measurement cycle variable measurement control system in which the dead time L is substantially constant.

[0010]

According to the present invention, there is provided a field device for measuring a measured amount by using a battery as a device power source, and a host device for performing a predetermined process by receiving a measurement result from the field device. In a system including a control device, a transmission path connecting the field device and a higher-level control device, a normal operation cycle register for recording a first measurement cycle of the field device, and a second measurement of the field device A change operation cycle register for recording the cycle,
A reference value register for storing a preset value; and comparing means for comparing a measured value measured by the field device with a reference value stored in the reference value register, and a normal operation based on a comparison result of the comparing means. It is assumed that the first measurement cycle recorded in the cycle register and the second measurement cycle recorded in the changed operation cycle register are switched.

With this configuration, the measured value measured by the field device is compared with the reference value stored in the reference value register, and based on the comparison result, the field device records the measured amount and records the measured operation cycle in the normal operation cycle register. The first
The operation can be switched to the second measurement cycle recorded in the measurement cycle or the changed operation cycle register. Also, the reference value for the comparison means to determine the change of the measurement cycle of the field device is a predetermined upper limit value, lower limit value, upper / lower limit value of the measured value, or an upper limit value, a lower limit value which determines the time change rate of the measured value. Values, upper and lower limits.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a main part of a measurement cycle variable type measurement control system according to one embodiment of the present invention, and FIG. 2 is an application of the variable measurement cycle type measurement control system according to one embodiment to optical field devices. FIG. 3 is an explanatory diagram of a reference value register for judging a change in the measurement cycle of the field device and a control register for controlling the measurement cycle, and FIG. 4 is a diagram showing an increase in the measured value of the water level meter per unit time. Explanatory diagram of cycle change,
FIG. 5 is a configuration diagram of additional communication data used for communication between a higher-level control device and a field device, FIG. 6 is an operation timing explanatory diagram of a field device that has received a communication request, and FIG. 7 is a first embodiment.
FIG. 8 is a flowchart of the second embodiment, and the same members corresponding to FIGS. 9 and 10 are denoted by the same reference numerals. (Embodiment 1) In FIGS. 1 and 2, a measurement cycle variable type measurement control system according to the present invention is a field device 2 (2A, 2B, 2C) that measures a measurement amount using a battery 27 as a device power supply.
..), a higher-level control device 1A that receives a measurement result from the field device 2 and performs a predetermined process, and a predetermined value each time the field device 2 measures a measurement amount (mes1, mes2...). Change of the cycle (T1, T2) measured by the field device (for example, 2A, hereinafter referred to as 2A as the field device) by comparing with the reference value (32A to 35A) or (32B to 35B) And determination means 3A or 3B.

The upper control device 1A includes a central processing unit 13, a memory 14, a communication means 15 for communicating with the field device 2, and a reference value register (32A) for determining a change in the measurement cycle (T1, T2) of the field device 2. To 35A), a status register 31A for holding the result determined by the cycle change determining means 3A or 3B, a normal operation cycle register 36A for recording the first measurement cycle T1 of the field device 2, and a second register for the field device 2. A change operation cycle register 37A for recording the measurement cycle T2, and a control register for controlling the measurement cycle (T1, T2) of the field device 2 comprising
3C.

The field device 2 is a central processing unit.
Communication means between (CPU) 23, memory 24, and host controller 1A
25 and a sensor unit 26 that measures the measured amount such as water level and temperature
The reference value registers (32B to 35B) transmitted by the communication means 15 of the higher-level control device 1A and judging a change in the measurement cycle (T1, T2) of itself (for example, 2A), and the cycle change judgment means 3B or 3A A state register 31B that holds the result of the operation, a normal operation cycle register 36B that records the first measurement cycle T1 of the field device 2, and a change operation cycle register 37B that records the second measurement cycle T2 of the field device 2. , Which is provided in the central processing unit 23 or the memory 24 and has its own measurement cycle (T1,
T2), and a control register 3D for controlling T2).

The cycle change determining means 3A, 3B includes a reference value register (32A to 35A) or (32B to 35B) for determining the measurement cycle (T1, T2) of the field device (for example, 2A). Comparing means 30A or 30B for comparing the measured values (mes1, mes2 ...) with the reference values stored in the reference value registers (32A to 35A) or (32B to 35B). The comparing means 30A or 30B can be provided in one or both of the host control device 1A and the field device 2.

With this configuration, the reference value register (32A to 35A) for judging the measurement cycle in the upper control device 1A, the normal operation cycle register 36A, and the changed operation cycle register 37A
By changing the data of the field device 2A and transmitting the data to the field device 2A, the data of the corresponding reference value register (32B to 35B) of the field device 2A or the data of the normal operation cycle register 36B and the changed operation cycle register 37B can be easily changed. be able to.

Further, when the criterion of the cycle change judging means 3A or 3B or the cycle change judging means 3A or 3B judges that the operation is the normal operation or the changed operation, the subsequent operation cycle is changed to the cycle designated by the upper control device 1A. You can drive with The upper control device 1A is provided with a cycle change determination unit.
Communication request TX1 (N) to the field device (2A) at the specified measurement cycle (T1, T2) based on the result determined by 3A or 3B.
When the communication request TX1 (N) from the higher-level control device 1A is addressed to the own station (2A), the field device (2A) starts the central processing unit 23 and includes the measurement amount mesN measured last time. After responding to the request data TX2 (N) and subsequently measuring the next measurement amount mes (N + 1), the central processing unit 23 can be stopped.

With this configuration, when receiving the communication request TX1 (N) addressed to the own station 2A from the higher-level control device 1A, the field device 2A can immediately respond to the request data TX2 (N). The device 1A can minimize the response waiting time from the field device 2A, and can immediately send a communication request to the next field device (for example, 2B) after receiving the response from the field device 2A, The field device 2 can be used without deteriorating the communication efficiency of the host control device 1A.
Easily change the operation cycle (T1, T2) of the host controller 1A.
Can be controlled. (Embodiment 2) Further, the higher-level control device 1A issues a communication request to the field device (2A) at the specified measurement cycle T1 or T2 based on the result determined by the cycle change determination means 3A or 3B.
TX1 (N) is transmitted, and the field device 2A determines the timing at which the host control device 1A previously transmitted the communication request TX1 (N-1) to the field device 2A and the status register 31A determined by the cycle change determination means 3A or 3B. Or the timing T at which the local station 2A requests communication from the measurement cycle T1 or T2 corresponding to 31B
At this timing time T, the sensor unit 26
The central processing unit is started in advance by a time τ1 required to measure mes (N), the measured amount mes (N) is measured, and a communication request TX1 ( When N) is received, the central processing unit 23 can be stopped in response to the measured value mes (N).

With such a configuration, in particular, the host control device 1A
Can be made substantially constant regardless of whether the measurement operation cycle (T1, T2) is changed or not, and the feedback control system Can be made constant, so that control can be easily stabilized even if a PID control loop is configured on the host control device 1A side. Further, when receiving the communication request addressed to the own station 2A from the above-described higher-level control device 1A, the field device 2A can immediately respond to the request data (for example, the status register 31B).
1A can minimize the response waiting time from the field device 2A, and can immediately send a communication request to the next field device 2B after receiving the response TX2 (N) from the field device 2A, The operation cycle of the field device 2A can be easily changed and controlled from the host control device 1A without deteriorating the communication efficiency of the control device 1A.

[0020]

(Embodiment 1) In FIG. 2, an optical field device 2 of an optical fiber transmission type measurement and control system according to the present invention is shown.
Will be described. The optical field device 2 (2
(A, 2B) is a power circuit 28 using a battery 27 as an energy source.
Logic power supply VCC etc. is supplied. The measured amount mes (N) measured by the sensor unit 26 is subjected to predetermined arithmetic processing by a central processing unit (CPU) 23, and a modem 22, an optical / electrical (O / E) converter and an electric / optical (E / O) ) It is transmitted as optical digital signal data from the transmission line (branch optical fiber) 5 via the optical unit 21 composed of a converter.

Conversely, the optical digital signal input from the transmission line 5 is input to the central processing unit (CPU) 23 via the optical unit 21 and the modem 22, and can perform predetermined processing.
The non-volatile memory 24A illustrated in a part of the memory 24 includes:
It is provided for saving data. FIG. 3 shows an example of a group of registers 31 to 38 for controlling the measurement and communication cycle provided in the central processing unit (CPU) 23 in two stages of (T1, T2). The case where the measurement cycle and the communication cycle can be changed with the lower limit value 33, the unit time increase value 34, and the unit time decrease value 35 is illustrated.

In FIG. 3, a register a indicates a control state of a measurement cycle and a communication cycle. When 1 is present in each corresponding bit position, it means that the control operation indicated by the following reference is permitted. That is, EN: measurement / communication control is permitted. HL: Period change by the upper limit is permitted. LL: Period change by the lower limit is permitted. dtH: Cycle change by increase in measured value per unit time is permitted. dtL: Period change due to decrease in measured value per unit time is permitted.

Each of the registers b to g stores each set value data and the normal / change period data for which the measured amounts are compared, and the higher-level control device and the field device transmit information to each other to transmit information. Can be transmitted. That is, the register b is the set upper limit value 32 of the measured amount, the register c is the set lower limit value 33 of the measured amount, the register d is the set value 34 of the increase rate per unit time, and the register e is the set value of the decrease rate per unit time. The register f stores 8-bit data of the normal measurement cycle and the register g stores the measurement cycle at the time of change. The register g2 is
For example, data of another change measurement cycle is stored, and although not shown, for example, an upper limit value or a lower limit value is set in the register b1 or the register c1, and when the data is detected with these set values, the register g2 is stored. Measurement and communication can be performed frequently in a cycle.

The number of bits of these registers 31 to 38 may be appropriately increased by a register having a large number of bits according to the required resolution, condition, change determination method, and the like. In addition, the change of the measurement cycle and the communication cycle can be performed with another register as necessary.
For example, although not shown, the upper / lower limit value, the lower / lower limit value, or a register g2 (38) of the change measurement cycle 2 in relation to these values.
By preparing such a method, the measurement cycle and communication cycle can be changed in three or four steps. The registers 31 to 38 shown in FIG. 3 can be provided in the nonvolatile memory 24A in addition to the central processing unit (CPU) 23A.

The rewriting of these registers (31B to 38B) can be performed from the control room 1 by the host controller 1A or the handheld communicator. The upper control device 1A also has registers (31A to 38A) similar to those in FIG.
But it can be detected at the same time. Since the normal measurement cycle and the changed measurement cycle are set in the registers f and g, E of the position of bit 0 of the measurement / communication control register is set.
When N is not permitted or when none of the conditions of bit1 to bit4 is satisfied, the operation is performed in the normal measurement period set in the register f, and the EN of bit0 is permitted and bit1 to bit4 When at least one of the conditions is satisfied, the operation is performed at the changed measurement cycle set in the register g.

FIG. 4 shows, as an embodiment, an example of changing the cycle by increasing the measured value per unit time in the water level meter.
When there is no significant change in the water level, the operation is performed at a long interval of the normal cycle T1, and when the water level starts to change rapidly, the measurement / communication operation is performed at a high speed in the change cycle T2. The duration of the change period T2 can be set as necessary, such that the change in the water level lasts several cycles after stabilization.

The operation when the water level exceeds the set upper limit value 32 is almost the same, and the description is omitted. Here, for example, if the normal cycle is set to 60 seconds and the change cycle is set to 1 second, and if the standby operation in which the current consumption is reduced during a period other than during the measurement / communication operation of the field device 2 is performed, the current consumption in the normal cycle T1 is increased. Compared to the current consumption in the change cycle T2
Can be reduced to nearly 60.

FIG. 5 shows an example of additional communication data according to the present invention used for communication between the optical field device 2 and the host control device 1A. CH: During measurement / communication cycle change operation HLD: Cycle change by upper limit value LLD: Cycle change by lower limit value dtHD: Cycle change by increase of measured value of unit time dtLD: Cycle change by decrease of measured value of unit time WR: Rewrite of device register The position of bit 7 indicates that the contents of any of the registers 31 to 37 in FIG. 3 have been changed. Therefore, even when the register is rewritten by the handheld communicator or the like, both the optical field device 2 and the host control device 1A can recognize whether or not the register has been rewritten.

Also, since the status of the cycle change and the detected condition can be confirmed by bit0 to bit4, the optical field device 2 and the higher-level control device 1A immediately change the communication cycle immediately after the measurement cycle change without any delay. can do. (Embodiment 2) FIG. 7 shows a flowchart of an embodiment of the field device 2 of the measurement cycle variable measurement control system described in Embodiment 1, which is used in combination with FIGS. 6 (A) and 6 (B). Will be explained. In FIG. 7, in step S1, the field device 2 (hereinafter, represented by 2A) measures the next measurement amount by the N-th communication request TX1 (N) from the higher-level control device 1A or the time-up of the measurement timer in the device 2A. Waiting for an event such as start. In the illustrated example, the communication request TX1 (N)
Will be described below by taking a second communication request TX12 corresponding to N = 2 as an example. At time t21, the upper control device 1A transmits a communication request TX12 to the field device 2 (2A, 2b,...)
When each field device 2 (2A, 2b,...) Detects the occurrence of the event of the communication request TX12 from the higher-level control device 1A, the process proceeds to step S2, where the central processing unit (CPU) 23 is started, and In S3, it is determined whether or not the communication request TX12 is a communication request addressed to the own station. When the communication request TX12 is No addressed to the own station (for example, 2A), the process proceeds to step S13, and the central processing unit (CPU Pause 23).

In step S3, the communication request TX12 is addressed to the own station (2A).
The field device 2A that has detected the communication request addressed to
In step S4, the contents of the communication request TX12 are analyzed, and the register is rewritten? If Yes, the process proceeds to step S5, where the reference value registers b to e, the normal cycle register f, and the normal cycle register g
Of the corresponding register, and then executes step S6.
Move to Also, in step S4, the content of the communication request TX12 is the register rewrite? If No, the process directly proceeds to step S6.

Next, when the content of the communication request TX12 is a request for the measurement value mes2, the process shifts to step S7, and returns the measurement value mes2 to the host control device 1A. Subsequently, in step S8, the field device 2A sets mes3, which is the next measurement amount (N + 1), to the time
Measurement starts at t23, ends at time t24, and the measured value mes
Get three. The measured value mes3 is compared with the reference value registers b to e in step S9, and it is determined in step S10 whether the measurement / communication cycle has been changed. Has measurement / communication cycle changed in step S10? If Yes, the process proceeds to step S11, where the data of the other measurement cycle register different from the current operation cycle is selected from the normal cycle register f or the normal cycle register g, which is the measurement cycle register, and the next reply data is returned in step S12. Set the measured value of mes3 in the memory for reply, and
The measurement cycle selected in S11 is set in the measurement timer, and the process proceeds to step S13 to suspend the central processing unit (CPU) 23.

In step S10, has the measurement / communication cycle changed? If No, the process proceeds to step S12 without any processing. Also, is a measurement value request in step S6? When No, in such a case, for example, it is conceivable that a transmission abnormality occurs due to superimposition of noise or the like on the transmission line 5, so that no processing is performed in step S13.
Then, the central processing unit (CPU) 23 is stopped. The above is
The case where the event of the Nth communication request TX1 (N) has occurred from the upper control device 1A has been described.Similarly, for example, when a communication error with the higher control device 1A occurs and the communication request is not received, the field The time-up of the measurement timer in the device 2A allows the field device 2 to start measuring the next measurement amount.

In this step, when the occurrence of an event is detected in step S1, the process proceeds to step S2 and the central processing unit (C
PU) 23, and since it is addressed to itself in step S3, the process proceeds to step S4, and since there is no register rewriting, step S6
Then, the measurement amount mes3 is measured in step S8, the processes in steps S8 to S12 are performed, and the central processing unit (CPU) 23 is stopped in step S13.

The above description is a flowchart on the assumption that the communication control of the field device 2 is simultaneously controlled by the central processing unit (CPU) 23. However, the field control provided with the integrated circuit IC dedicated to the communication control is performed. When the device 2 is used, activation of the central processing unit (CPU) 23 in step S2 and communication to the own station in step S3 due to software modification? When,
Can be replaced.

With this configuration, the field device 2
It is possible to configure so as not to be activated one by one in response to a communication request addressed to another station from the host controller 1A, but to be activated only in response to a communication request addressed to the own station. (Embodiment 3) FIG. 8 shows a flowchart of an embodiment of the field device 2 of the measurement cycle variable type measurement control system described in Embodiment 2, which is used in combination with FIGS. 6 (A) and 6 (C). Will be explained. In FIG. 8, in step S21, the field device 2 (hereinafter represented by 2A) is
It waits for the occurrence of an event such as the next communication request TX1 (N) or the start of measurement of the next measurement amount due to the expiration of the measurement timer in the device 2A. In the illustrated example, the communication request TX1
A description will be given below of an example of the second communication request TX12 in which (N) corresponds to N = 2. At time t21, the higher-level control device 1A transmits a communication request TX12 to the field device 2 (2A, 2b,...)
When each field device 2 (2A, 2b,...) Detects the occurrence of the event of the communication request TX12 from the higher-level control device 1A, the process proceeds to step S22, where the central processing unit (CPU) 23 is activated. In step S23, the central processing unit (CPU) 23 determines whether or not a reception interrupt is to be processed. If yes,
The flow shifts to step S33, where it is determined whether or not the communication request TX12 is a communication request addressed to the own station. When the communication request TX12 is No for the own station (for example, 2A), the process shifts to step S32 to suspend the central processing unit (CPU).

In step S33, the communication request TX12 is addressed to the own station (2A).
Field device 2A that detected a communication request addressed to its own station in Yes
Analyzes the contents of the communication request TX12 in step S34 and rewrites the register? If Yes, the flow shifts to step S35 to rewrite the corresponding one of the reference value registers b to e, the normal cycle register f, and the normal cycle register g, and shifts to step S36. In step S4, the communication request TX
Is the content of 12 rewriting the register? If No, the process directly proceeds to step S36.

Next, when the content of the communication request TX12 is a request for the measured value mes2, the process shifts to step S36, and the process proceeds to step S37.
To reset the measurement timer. The time for resetting the measurement timer is determined by the information in the register a and the registers f and f.
The time (T-τ1) obtained by subtracting the time τ1 required for measuring the next measurement quantity mes3 from the measurement cycle T selected from the normal or changed measurement cycle by the register g is reset as a predetermined time in the measurement timer. I do. Subsequently, the process proceeds to step S38, in which the measured value mes2 measured immediately before the transmission of the communication request TX12 is returned to the host control device 1A, and the process proceeds to step S32 to suspend the central processing unit (CPU) 23.

In step S23, the central processing unit (CPU) 2
3 judges whether or not it is reception interrupt processing.
If No, the process proceeds to step S24, and the time (T-τ1) reset to the above-mentioned measurement timer is subtracted with the passage of time, and it is determined whether or not the measurement timer has expired. Measurement timer time up? If No, the process proceeds to step S32, in which the central processing unit (CPU) 23 is stopped and the measurement timer expires. If Yes, the flow shifts to step S25, and the time (T-τ1) is reset as a predetermined time in the measurement timer, and the flow shifts to step S26, as described above in step S37. In step S26, the field device 2A
Starts measurement of mes3, which is the next measured amount (N + 1), at time t15, ends measurement at time t16, and obtains measurement value mes3. In step S27, the measured value mes3 measured in step S26
Is compared with the reference value registers b to e described in step S35, and it is determined in step S29 whether or not the measurement / communication cycle has been changed. Has measurement / communication cycle changed in step S29? Yes
In step S30, the process goes to step S30 to select the data of the other measurement cycle register, which is different from the current operation cycle, from the normal cycle register f or the normal cycle register g, which is the measurement cycle register. The measurement value mes3 is set in the memory for reply, and the measurement cycle selected in step S30 is set in the timer for measurement.
The process goes to step 2 to suspend the central processing unit (CPU) 23.

Is there a change in the measurement / communication cycle in step S29? If No, the process proceeds to step S32 without any processing. Also, is the measurement value request in step S36? In the case of No, in such a case, for example, it is conceivable that noise or the like is superimposed on the transmission line 5 and a transmission error occurs, so that the process is performed without any processing in step S3.
The process goes to step 2 to suspend the central processing unit (CPU) 23. According to the flowchart of the variable measurement cycle type measurement control system, the higher-level control device 1A sets the cycle change determination unit 3A or 3B
The measurement period T1 specified based on the result determined by
At T2, a communication request TX1 (N) is transmitted to the field device (2A), and the field device 2A changes the timing when the host controller 1A previously transmitted the communication request TX1 (N-1) to the field device 2A and changes the period. From the measurement period T1 or T2 corresponding to the status register 31A or 31B determined by the determination means 3A or 3B, a timing time T at which the own station 2A is requested to communicate is predicted,
At this timing time T, the central processing unit is started in advance of the time τ1 required for the sensor unit 26 to measure the measured amount mes (N), and the measured amount mes (N) is measured.
When receiving the communication request TX1 (N) addressed to the own station 2A from 1A, the central processing unit 23 can be suspended in response to the measured value mes (N).

As described above, the water level is obtained by using the battery 27 as a power source,
An optical fiber 5 connects a field device 2 for measuring temperature and the like and a higher-level control device 1A for executing a predetermined process in response to a measurement result from the field device 2 (2A, 2B, 2C...)
In an optical fiber transmission type measurement cycle variable measurement control system that communicates using an optical signal as a transmission medium, the field device 2 and the upper control device 1A change the measurement cycle and the communication cycle according to the measurement amount mes (N). The normal measurement / communication cycle T can be lengthened in a water level meter, thermometer, etc., where the change in the value mes (N) is not so rapid, and the measurement cycle can be increased only when the measured quantity mes becomes a value that warns. In addition, the battery life can be significantly extended without impairing the original function of the measuring instrument.

As described above, according to the present invention, the trunk optical fiber 51 and the optical star coupler 52
And the branch optical fiber 53 and the field device 2
Are optical / electrical converters (O / E converters) and electrical / optical converters (E
/ O converter), and an optical unit 21 consisting of
By providing communication means 25 with the higher-level control device 1A.
Since the optical fiber transmission lines 51, 52, and 53 are used as transmission media, they can communicate with the host controller 1A by transmitting and receiving optical signals connected to the transmission media, so that data transmission is hindered by electrical noise and the like. And stable communication can be performed.

The reference value by which the cycle change determining means 3A, 3B determines whether to change the measurement cycle of the field device (2A) is:
If necessary, predetermined upper limit value, lower limit value, upper and lower limit value of the measured value, or upper limit value, lower limit value, upper and lower limit value that determines the time change rate of the measured value can be set, and these settings can be made. Since the value can be easily changed from a control room or the like, the control target can be controlled and monitored in an optimum state at all times.

When a field device having a single-loop control function having a sensor function and a PID control function is used as the field device 2, for example, a signal from the higher-level control device 1A described in the first embodiment or FIG. Communication request TX1
The problem of the dead time of the reply data from the field device 2 for (N) can also be solved by performing the arithmetic processing of the control operation immediately after the measurement by the field device 2.

Further, as described in the second embodiment or the flowchart of FIG. 8, in a system in which the latest measurement data can always be transmitted to the host control device 1A even if the measurement cycle and the communication cycle are changed, the dead time L Is substantially constant, stable PID control can be performed even if the higher-level control device 1A has a distributed control function.

[0045]

According to the present invention, it is possible to easily change the reference value for changing the measurement cycle of the field device and to change the value of the measurement / communication cycle, and also attach importance to the real-time property of the feedback control system and the like. In addition, it is possible to provide a measurement cycle variable measurement control system in which the dead time L takes a substantially constant value even when the measurement cycle is changed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of a measurement cycle variable measurement control system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of an optical field device of a measurement control system with a variable measurement cycle.

FIG. 3 is an explanatory diagram of a reference value register for judging a change in a measurement cycle of a field device and a control register for controlling the measurement cycle.

FIG. 4 is an explanatory diagram of a cycle change due to an increase in a measured value per unit time with a water level gauge.

FIG. 5 is a configuration diagram of additional communication data used for communication between a host control device and a field device.

FIG. 6 is a diagram illustrating the operation timing of a field device that has received a communication request.

FIG. 7 is a flowchart of the first embodiment.

FIG. 8 is a flowchart of a second embodiment.

FIG. 9 is an explanatory diagram of a measurement control system using optical fiber transmission.

FIG. 10 is an explanatory diagram of a measurement cycle and a communication cycle of an optical field device according to the related art.

[Explanation of symbols]

1 Control room 1A Host control equipment 13,23 Central processing unit 14,24 Memory 15,25 Communication means 2,2A, 2B, 2C Field equipment 21 Optical unit 21a, 22b, 23a, 26b Signal 22 Modem 23A, 24A Control register 23B Internal bus 26 Sensor 27 Battery 28 Power supply circuit 29 Measurement timer 3A, 3B Period change judgment means 30A Comparison means 31-38 Register 31A Status register 32A-35A, 32B-35B Reference value register 36A, 36B Normal operation cycle register 37A, 37B Change operation cycle register 5 Transmission line 51 Main line optical fiber 52 Optical star coupler 53 Branch line optical fiber EN Measurement / communication control enable bit HL Cycle change enable bit by upper limit LL Cycle change enable bit by lower limit dtH Due to increase in measured value per time Cycle change enable bit dtL Cycle change enable bit due to decrease in measured value per time CH Measurement / communication cycle change operation notification bit HLD Cycle change notification bit by upper limit value LLD Cycle by lower limit value Change notification bit dtHD Period change notification bit due to increase in unit time measurement value dtLD Period change notification bit due to decrease in unit time measurement value WR Device register rewrite notification bit TX11 to TX13 Communication request TX21 to TX23 Reply response mes1 to mes4 Measurement value T1 Normal cycle T2 change cycle

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H04B 10/02 H04B 9/00 X F term (Reference) 2F014 GA10 2F073 AA11 AB01 BB06 BC04 CC03 CC07 CC11 DD02 DE11 EE11 EF09 FG01 FG02 FG14 FH01 FH07 GG01 GG08 5K002 AA05 FA01 GA03 5K048 AA16 BA30 CA08 DA02 DC08 EA11 EB02 EB10 EB13 FB09 FC01 HA01 HA02 HA05 HA07 HA31

Claims (2)

[Claims] 1. A field device for measuring an amount of measurement using a battery as a device power source, a higher-level control device for receiving a measurement result from the field device and performing a predetermined process, and the field device and the higher-level control device. A transmission path to connect,
A normal operation cycle register for recording a first measurement cycle of a field device, a changed operation cycle register for recording a second measurement cycle of a field device, and a reference value for storing a preset value. Register, comparing means for comparing the measured value measured by the field device with the reference value stored in the reference value register, and based on the comparison result of the comparing means, Switching between a first measurement cycle and a second measurement cycle recorded in the changed operation cycle register. 2. The variable measurement cycle measurement control system according to claim 1, wherein the reference value used by the comparing means to determine a change in the measurement cycle of the field device is an upper limit value, a lower limit value, and a predetermined measurement value. A measurement cycle variable measurement control system, wherein upper and lower limits, or an upper limit, a lower limit, and an upper and lower limit that determine a time change rate of a measured value are set.