JPS6195405A - Plant control device - Google Patents

Abstract

PURPOSE:To attain continuous control even if transmission is temporally disconnected and to secure high accuracy and high reliability of control by generating an objective value of integration on the component controller side independently on the basis of an objective value of integration obtained from a master controller. CONSTITUTION:Each of component controllers C1-Cn generates objective flow rate value DSSVc through its integrator ACCG by using an independent timer on the basis of an objective flow rate value transmitted from the master controller M. A comparator CMP compares the objective flow rate value DSSVc with a value DSSVm (alpha) obtained by multiplying the master integration objective value DSSVm transmitted from the controller M by a ratio alphaj, and if the compared result is included within a limit value DELTASSVc, an integration PID controller SPID generates an operation output MV corresponding to the deviation between the compared result and a process value integrated value SPVc. If said value exceeds the SSVc, the comparator CMP outputs a correction value DELTASSVc and an alarm NG. Consequently, a corrector AUX is actuated to compensate the objective value so as to be DSSVc=DSSVmalpha and applies the compensated value to the controller SPID to generate similar output MV.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a plant control device.

[Technical background of the invention and its problems] In a plant that mixes multiple types of liquids to make one product, each liquid is sent at a predetermined ratio and mixed to obtain the product.

For example, taking gasoline as an example, gasoline consists of several components such as naphtha and kerosene, and each of these is sent through a pipe at a specified flow rate, and each pipe is connected to a main pipe where they join together to produce gasoline as a product. get.

Therefore, accurate flow control is important to maintain the quality of gasoline, and since gasoline plants use the integrated value of flow rate control as the shipping amount, for example, when loading into tankers, the accuracy of the integrated value is important. is also a problem.

Conventionally, a device as shown in FIG. 2 has been used as a device for performing such control.

That is, in the figure, P is a pattern setter, OP is an operation controller, PG is a pulse generator, PS is a pulse transmitter, and the pattern setter P is used to set the flow rate value of each raw material set in advance. . These setting values may be set by preparing a plurality of values depending on the component ratio of the product, and reading the optimum value as necessary, or by manual setting. In addition, the operation controller OP gives various operation commands, such as giving a start command, changing the setting value of the pattern setting device P, and setting the production amount, and also
Various setting statuses, etc. are displayed on the display unit of P. The pulse generator PG generates a pulse that becomes the flow l reference value at predetermined time intervals based on the setting value of the pattern setting device P in response to commands from the operation device OP. The flow rate per unit pulse is determined in advance, and the pulse generator PG generates a number of pulses corresponding to the target flow rate at predetermined time intervals based on the set value of the pattern setting device P.

The pulse transmitter PS transmits the pulses output from the pulse generator PG, and these constitute a master-side controller M.

This master controller M is provided with component controllers C1° to Cn, the number of which corresponds to the type of raw material. Each component controller C1, ~C
n is a pulse receiver PR, a master pulse integrator PSM,
Ratio setter αJ, component totalizer SP■, totalizer P
The ID controller consists of 5 PIDs. Among these, the pulse receiver PR receives pulses sent from the pulse transmitter PS of the master component, and the master pulse integrator PSM integrates the received pulses and calculates the ratio given by the ratio setter αj. The product is multiplied and used as a reference flow rate value, which is then output. In addition, the component load control device SPv is the detected value of the raw material flow rate in the pipe of the system controlled by the component controller.
Process value) PV is received and integrated.

Further, the integration PID controller 5PID compares the output of the component integrator SPV with reference to the output of the master pulse integrator PSM, and outputs an output according to the deviation as an operation IMV.
is used to control the opening degree adjustment of the valve of the pipe in the system controlled by the component controller.

Each component controller also has a pulse transmitter P.
S and dedicated transmission lines 1aLs and ~1n are individually connected to each other, and a switch SW is connected to these transmission lines l, ~1n.
1. ~SWn are connected and these switches SW
1. A transmission line Ls that transmits pulses by selectively turning on SWn.

~In can be selected.

A conventional device with such a configuration has an operation controller O.
When a starting command is given from P, the pulse generator PG is started and generates a pulse serving as a flow rate reference value at predetermined time intervals based on the setting value of the pattern setting device P. The flow rate value of each raw material is set in the pattern setting device P.

The flow rate per unit pulse is determined in advance, and on the other hand, as described above, the pulse generator PG sequentially calculates the number of minutes corresponding to the desired flow rate for each raw material at predetermined time intervals based on the set value of the pattern setting device P. Generates a pulse. This pulse is applied to the pulse transmitter PS, which transmits the pulse output from the pulse generator PG to the transmission line L1. -Send to n.

Each component controller C1, ~Cn is individually connected to a pulse transmitter PS and a dedicated transmission line ~1n, respectively, and these transmission lines Li.

Switches SWI and ~SWn are connected to ~1n, and these switches SW1. By selectively turning on SWn, the transmission line L1.~SWn transmits pulses. -n can be selected.

Therefore, on the master component side, the switches SW1 to SWn of the component controllers are selectively turned on in order to give the corresponding component controllers the number of pulses corresponding to the target flow rate of each raw material that are sequentially generated.

As a result, a transmission pulse is input to the pulse receiver PR of the selected component controller, and this pulse is applied to the master pulse integrator PSM, where the number of pulses is integrated.

The master pulse integrator PSM multiplies this pulse integrated value by the ratio given by the ratio setter αj and outputs the result to the integrated PID controller 5PIO as a reference value for the integrated flow rate. Further, the component integrator SPV receives the detected value (process value) PV of the raw material flow rate in the vibrator of the system controlled by this component controller, integrates it, and inputs it to the product 11PID controller 0-5PID.

Then, the integration PID controller 5PID compares the output of the component integrator SP with reference to the output of the master pulse integrator PSM, and outputs an output according to the deviation as the operation IMV, and this operation amount MV is used as the input signal to the component controller. is applied to the valve drive unit of the pipe in the system to be controlled, the opening is adjusted, and the opening is controlled to 1M, which corresponds to the reference value. That is, at every predetermined timing, the flow rate cumulative value up to the next timing is given as a pulse, and this is integrated and controlled to reach the target value based on comparison with the actual flow rate cumulative value.

In this way, in order to give pulses for each raw material 11[flow rate] given by the master controller at predetermined time intervals to each component controller to which the pulses are input, a dedicated transmission is connected to each component controller. Line 11, ~Ln switch SWI
, ~swn is selected, and the component controller selected by this integrates the sent pulses and outputs a reference value according to this integrated value, and combines this with the process value integrated by the component integrator SPV. The operation IMV was calculated according to the deviation, and the valve opening degree was adjusted to achieve the target integrated amount. Note that the flow rate of the main pipe is detected and given to the master component side, and fed back as the actual value of the product flow rate, and the target flow rate value is corrected to maintain the accuracy of the production amount.

As described above, the conventional apparatus requires a flow rate detector for each of the raw material supply pipe and the main pipe. Furthermore, transmission lines as many as the number of component controllers are required between the master controller and the component controllers, and a switch is also required on the transmission line for pulse distribution, and a switch is required for selecting the switch. Wiring was required. Therefore, not only the wiring becomes complicated, but also the device becomes complicated. Furthermore, the only information transmitted between the master controller and the component controller is a pulse for specifying the flow rate on the master component side, and no other information can be transmitted.

An even bigger problem is that the detected values of each raw material flow rate are not fed back to the master component side, so the mixing ratio of each raw material is not the same as the set value! It is not possible to confirm whether IIIH is being carried out, and therefore, it is difficult to maintain product quality with high precision unless the flow rate of each raw material is controlled with sufficient accuracy.

Therefore, in order to simplify the system and maintain product quality by feeding back each raw material flow rate information from the component controller side to the master controller, a digital bus type device as shown in Figure 3 was proposed. It was done.

That is, in the figure, M is a master controller, and this master controller M includes a pattern setter P that sets the lll1llll parameter, an integrated target value generator SSvm that generates an integrated target value based on the parameters given by this pattern setter P, and this integrated target value generator SSvm. It consists of a data transmitter S that transmits information such as generated cumulative target values.

Although not shown, the cumulative target value generator SSvm is equipped with an internal or external timer, and this timer generates a cumulative target value for each raw material at predetermined time intervals. Furthermore, control can be started, stopped, reset, etc. from the operation device OP of the master controller M.

The master controller M and the component controllers C1, -Cn are connected on a common transmission line (serial or parallel) L, and the above-mentioned integrated target value data is transmitted using this transmission line.

Therefore, each component controller C1, to Cn inputs target flow rate data for each raw material output from the master controller M at predetermined time intervals.
The data transmitter S sends the data to the transmission line with the designation codes of the component controllers C1, to Cn added thereto.

Each of the component controllers C1, to Cn receives the data of the integrated value set value transmitted from the master controller M at the data receiver R, sends it to the target value integrator 5SVc, and integrates it there.

This cumulative target value is provided to a multiplier X, where it is multiplied by a ratio αj set by a ratio setter (not shown) and is provided as a reference cumulative target value to the cumulative PID controller 5PIO. On the other hand, the component integrator SP2 receives the detected value (process value) PV of the raw material flow rate in the vibrator of the system controlled by this component controller, integrates it, and inputs it to the integration PID control O-puller ID.

Then, the integration PID controller 5PID compares the output of the component integrator SP with reference to the standard integration target value, and outputs an output according to the deviation as the operation JiMV, and this operation IMV indicates that the component controller is the target of t+IIII. The valve is applied to the drive section of the vibrator of the system in question, and the opening is adjusted, and the flow rate is adjusted to a flow rate corresponding to the reference value.

In this way, each component controller Cs inputs target flow rate data for each raw material given at predetermined time intervals by the master controller M,
~Cn, each component controller C
Both the specification codes 1 and ~Cn are sent to the transmission line, and on the component controller side, the data receiver R receives the transmitted data on the path line, judges whether the data is for itself, and determines whether the data is for itself. If so, send this data to the integration target value unit 5SVc, integrate it there, further multiply it by the ratio αj, and give it to the controller 5PID as the reference integration port 41111i, and then use the component integrator based on this reference integration target value. Compare the SPv outputs and output the output according to the deviation as the operation IMV,
The component controller applies this manipulated variable MV to the drive section of the valve of the pipe in the system to be controlled, adjusts the opening, and controls the flow rate to correspond to the reference value, thereby giving a target integrated value moment by moment. The flow rate is controlled to follow the flow rate. Therefore, only one system of transmission lines is required, and the amount of wiring is reduced accordingly. In addition, since it is transmitted in the form of digital data, information can be sent as data more quickly than the above-mentioned devices, and other information can also be transmitted, and since it is controlled by a computer, software It is possible to easily change the control contents by making changes.

In addition, since it becomes possible to return information from the component controllers C1 to Cn to the master controller M via the transmission line, high-precision, high-quality products can be produced using the flow rate of each raw material and its integrated value information. can be manufactured.

However, in this method, data transmission to each of the component controllers Cs, ~cn relies on the timer of the master controller M (llII).
Even if the timing of data transmission to the component controllers C1, .about.Cn deviates due to some reason, the timing of data transmission to the component controllers C1, .about.Cn will not be noticed on the side of the component controllers C1, .about.Cn, and there is a risk that the control will be out of order. That is, the master controller M sends out 1111 minutes of data that should be achieved by the next timing at regular intervals based on the set pattern, but if a timing deviation occurs at this time, the component controller C1 that received this data
, ~Cn, the component integrator SP
The integrated value (2) becomes large (or small), and the integrated PID controller 5PID outputs a correction amount to correct it, resulting in disordered control. In addition, it is necessary to always transmit the integrated target value at predetermined timings, and there is a lot of waste in transmission. Furthermore, if the transmission is temporarily interrupted or the processing of data taken in by the component controller is delayed, this may lead to control disturbances or stoppages. Therefore, it lacks reliability.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to reduce the amount of information transmitted between the master controller and the component controllers,
In addition, even if there is a timing lag between sending and receiving information during information transmission, it will not be affected by it, and control will be maintained even if there is a temporary loss of transmission between the master controller and the component controller. The object of the present invention is to provide a process control device that makes it possible.

[Summary of the Invention] In other words, in order to achieve the above object, the present invention uses a component controller provided for each raw material to track multiple types of raw materials to an integrated target value for each raw material sent from a master controller at a predetermined timing. In a device that mixes at a desired ratio by controlling the flow rate so that A means for generating an integrated target value at a predetermined timing, a process value integrating means for integrating the detected raw material flow rate, and a comparison between the obtained integrated target value on the component controller side and an integrator tMM from the master controller side, A means for generating a predetermined correction amount when the difference exceeds a predetermined value, and a means for comparing the process value integrated value based on the integrated target value obtained by the component controller side, and generating an operating device according to the deviation. The device comprises means for controlling the raw material flow rate, and means for correcting the integrated target value on the component controller side by the correction amount when the correction amount is obtained, and the component controller side adjusts the target flow rate given from the master controller side. Based on the value, we independently obtain the raw material integration target value at each predetermined timing, compare the process value integration value based on this value, perform flow control according to the deviation, and also calculate the integration target value on the master component side. By correcting this, the amount of information transmitted from the master controller side can be reduced, and even if information timing shifts or interruptions occur, it is possible to continue normally and control with high precision.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to FIG.

In the figure, M is a master controller, and this master controller M has a pattern setter P that sets control parameters, and a new one that is sequentially set at predetermined intervals by an integration timer on the master controller M side based on the parameters given from this pattern setter P. It consists of an integrated target value generator ssvmA that generates an integrated target value, and a flow rate setting generator SVm that generates a flow rate (flow 1) target value (amount of change is also acceptable). Further, OP is an operation device of the master controller M, and from this operation device OP, control can be started, stopped, reset, parameters can be changed, etc. DSRm is master controller M
This data transmitter/receiver DSRm is a data transmitter/receiver provided on the side, and this data transmitter/receiver DSRm transmits the flow rate target value only at the time of transmitting and changing the cumulative target value at a relatively low frequency (at the time of break port), and also transmits the flow rate target value at a relatively low frequency. - Receive process value integrated value 5PVC from Cn.

SUMm is the received process value integration (ISPVc) from each component controller C1, ~Cn.
This is an adder that calculates the amount of product by adding the

Each component controller CI, ~Cn is a pattern generator that generates a target flow velocity (flow I) value on the component controller side based on the flow velocity set value DSVm transmitted from the master controller M and the ratio αj set by a ratio setting device (not shown). Based on the PTG and the integration timer provided on the component controllers C1° to Cn, the flow velocity target value generated by the pattern generator PTG is integrated at predetermined time intervals, and the flow velocity target value is calculated on the component controller side based on the flow velocity target value. A multiplier ACCG that generates a cumulative target value 1i1DssVC of 1i1DssVC, a multiplier X1 that calculates a multiplication value 1iDssVm (α) by multiplying the cumulative target value DSSVm received from the master controller M by the ratio αj; Target value DSSVc
, and the limit value Δ5SVc of the target integrated difference, and if the former exceeds the latter, an alarm (error) signal is issued.
The comparator CMP generates the limit value ΔSS■ to the integration PID controller 5PID, receives the process value PV, integrates it, and produces the process value integrated value 5PVc.
Combo that outputs -°Nent totalizer SP■, totalizer AC
This process value integrated value 5PVc is compared with the integrated target value DSSVc output by the CG as a reference, and in order to correct the deviation, a manipulated output value MV corresponding to the deviation is outputted, and when an error signal NG occurs, this error signal NG is used. By the action of the corrector ALJX, the process value integrated value 5PVc is compared with the new integrated target value obtained by adding the limit value ΔSS■ output from the comparator CMP to the integrated target value DSSVc, and the operation output corresponding to the deviation is made. It consists of a product IPIO controller 5PID that generates MV.

Next, the operation of this device having the above configuration will be explained.

The master controller M generates a target flow velocity value by the flow velocity setting generator SVm based on the parameters of the pattern setting device P in response to a start signal from the operation controller OP, and transmits the target flow velocity value to the component controller C1 corresponding to each raw material through the data transmitter DSRry+. ,~Cn
have it sent to In addition, on the master controller M side, the integrated count 1 for each raw material is calculated every predetermined time based on its internal timer.
1i1 is generated by the integrated target value generator ssvm and transmitted to each corresponding component controller via the data transmitter/receiver DSRm.

The component controllers Cs, to Cn calculate the target integrated value of the component controller based on the target flow velocity value sent from the master controller M, and based on the component controller's own timer, separately from the integrated target value sent from the master controller M. DS
SVC is generated through an accumulator ACCG. This and the value DSSVm (α) obtained by multiplying the master integrated target value DSSVm sent from the master controller M by the ratio αj
is compared with the comparator CPM, and if it is within the above ΔSSVmu, the target integration on the component controller side is 11Ds.
Based on sVc, the difference from the integrated value 5PVc of the process value @PV is given to the integrated PID controller 5PID to generate a manipulated output MV according to the deviation from the process value integrated value 5PVc.

If it exceeds Δssvm, the comparator CMP
ΔSSV, which is equal to svm, is output as a correction amount, and
Outputs alarm NG. Then the corrector ALJX works,
DSSVc is corrected by adding ΔSS■ so that the integration target value given to the integration PID controller 5PID is as close to DSSVc-DSSVm (α) as possible.

Then, this is given to the integration PID controller 5PID to generate a manipulated output MV according to the deviation from the process value integration 1st shift 5pvc.

As a result, the raw material flow to be controlled by the component controller is controlled by the operation output MV! The opening degree of the adjustment valve is controlled to reach the target value. Process value integrated value 5PV of each component controller C1, ~Cn
c is sent to the master controller side via the data transmitter/receiver DSRc, and added by an adder StJMm to determine the product quantity.

According to this device, (1) Unlike conventional systems, the integration target value on the component controller side is not directly given from the master controller side, but is the Nagareyama target value first given by the master controller. Based on this, this is generated independently by the pattern generation setter PTG and the integrator ACCG at predetermined intervals based on the component controller's own timer. can get.

In other words, in the conventional system, the timing of updating the cumulative target value was shifted due to a sampling difference between the transmission on the master controller side and the reception on the component controller side, or a transmission delay, which caused υHill to be disturbed, but in this system, the component Since the controller side generates the integrated target value independently, there is no such influence at all.

In addition, by comparing the cumulative target value sent from the master controller at predetermined intervals with the unique cumulative target value on the component controller side for reference, the cumulative target value sent from the master controller side and the component controller side Mutual diagnosis of timer abnormalities, i.e.
can be detected (with conventional methods, the timer deviation on the master controller side is completely unknown).

Furthermore, if the transmission between the master controller and the component controller is temporarily interrupted, control will be disrupted in the conventional method, but with this system, the component controller generates its own integrated target value, so such problems can be prevented. There is no problem, and control can be continued.

Therefore, high precision and high reliability can be ensured.

(2) Furthermore, in the digital bus system, the amount of transmission between the master controller and the component controllers can be reduced compared to the conventional method.

In other words, conventionally, the component controller side is directly controlled by the integrated target value sent from the master controller, so there is a constraint that it must be as accurate as possible. Previously, the integrated target value had to be sent, but in this system, basically only the target flow velocity value can be transmitted between the master controller and the component controller, and moreover, only at breakpoints (when changing).

Of course, it is necessary to send the integrated target value from the master controller, but since it is not used directly to control the master controller and is only for reference, it is transmitted at a low speed (about 1/10 of the conventional value). It is enough. Therefore, the amount of transmission is much smaller than in the past, and the transmission line can be used for other purposes, allowing for more leeway.

(3) If the difference between the integrated target value from the master controller side and the integrated target value from the component controller side exceeds a predetermined value, this can be detected, and an alarm will be output in case of significant transmission deviation, timer deviation, or transmission line stoppage. is possible.

(4) When the cumulative target value deviates by more than a predetermined value between the master and component controller, it should be adjusted to the master component side, and when the timer deviates, an alarm output is issued and the component controller side is adjusted. A correction function has been added to the master controller side for cooperation.

This notifies the operator of abnormalities and also
It is possible to prevent the component controller from running on its own.

(5) Furthermore, the conventional method requires a master process input value for the master controller, but this system does not require it because the component controller target value is generated, compared with the process amount, and PIDtlJ'm. Additionally, this system can be applied to conventional plants as is.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, and can of course be implemented with appropriate modifications within the scope of the gist. Find the integrated target value and find the flow velocity according to the integrated target value,
A possible method is to integrate this at predetermined time intervals and use it as an integrated target value on the component controller side.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to reduce information transmission noise between a master controller and a component controller, and control is possible even if a timing shift or interruption occurs in information transmission. Therefore, it is possible to provide a plant system U device having features such as high precision and high reliability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2 and 3 are block diagrams showing a conventional example. M... Master controller, P... Pattern setter, SSVm... Total target value generator, SVm... Flow rate setting generator, OP... Operation controller, DS
Rm, DSRc...data transmitter/receiver, C1~Cn...
・Component controller, PTG...pattern generator, ACCG...integrator, X...multiplier, CM
P... Comparator, SPV... Process value integrator, 5P
ID...product 111PID controller, AIJX...
・Corrector. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a device that mixes multiple types of raw materials at a desired ratio by controlling the flow rate to follow the integrated target value for each raw material sent at a predetermined timing from the master controller side by a component controller provided for each raw material, the master means for generating flow velocity target values for each raw material provided on the controller side; means provided on the component controller side for receiving these corresponding flow velocity target values and generating an integrated target value at a predetermined timing;
A process value integrating means that integrates the detected raw material flow rate compares the obtained integration target value from the component controller side and the integration target value from the master controller side, and when the difference exceeds a predetermined value, a predetermined correction amount is applied. means for controlling the raw material flow rate by comparing the process value integrated value with reference to the integrated target value obtained by the component controller side and generating a manipulated variable according to the deviation; and means for correcting the cumulative target value on the component controller side by the correction amount when the component controller side has received the correction amount.