Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Akira Sugano

Atsushi Takita

Hiroshi Matsumoto

Masayuki Fukai

Masahide Nomura

Hisanori Miyagaki

Eiji Toyama

Haruya Tobita

Seiitsu Nigawara

Katsuhito Shimizu

Tooru Kimura

Makoto Shimoda

Sachio Yamanobe

Hiroshi Yamada

Yoshio Sato

Hiroshi Miyadera

Tadayoshi Saito

Akira Kaji

Masayuki Kikuchi

Naganobu Honda

Nobuyuki Yokokawa

Yukihiro Oda

Eiji Tooyama

Michihiro Iioka

Masakazu Kondoh

Yataro Suzuki

Shinya Kikuchi

Masato Okano

Takayuki Yosioka

Tadashi Komada

Takafumi Fukumaru

Masayuki Kumazaki

Masaru Muramatsu

An energy supply system operates to supply heat energies, such as cooling water, steam, heating water, etc. to a community, and the system has a function for predicting a future energy demand of the community and to correct it. In a system having an energy plant to store energy and an energy supply pipeline network for connecting the energy plant to the community, the system includes an energy demand plan making section for predicting an energy demand of the community on the basis of past cases of energy supply and for formulating an energy demand plan with respect to time, and an energy demand variation detecting section for determining a variation of the energy demand from the energy demand plan by using a personnel flow measured value measured by personnel flow measuring apparatuses provided at paths to or positions of the community as a parameter. The variation of the future energy demand of the community is predicted and energy which accomodates the determined variation can be prepared.

Urban energy system for controlling an energy plant supplying energy to

A method and apparatus for displaying on a display screen the controlling circuit in a plant controlling system for controlling a plant by a controller using a microcomputer. The display screen is segmented into a software region and a hardware region. The software circuit which is realized by software is displayed in the software region, and the hardware circuit related to the software circuit is displayed in the hardware region. The information, which is plotted during the interactive process and is displayed in the software regions, is automatically translated into a program for controlling the controller. Operation data of the plant is also given on the display screen. Desired circuit elements of the software circuit may be selected to change parameters of the circuit elements. Maintenance work can be carried out while observing the indication on the display screen without any aid of documents such as the maintenance manual or the like.

Plant control system and method for displaying control circuit thereof

A method for controlling a controlled system by a controller such that a controlled variable can be brought into conformity with a desired value. With respect to at least one of input/output variables for a combined controlling-controlled system, which includes in combination the controller and the controlled system, and input/output variables for the controlled system, information containing its characteristics is taken out from the combined controlling-controlled system. The information with the characteristics contained therein is inputted to a neural network which has been caused beforehand to learn a correlation between the information containing the characteristics and control parameters. From the neural network, one or more of the control parameters, said one or more control parameters corresponding to a corresponding number of inputs to the neural network, are outputted to the controller.

Process control method and system for performing control of a controlled

A process controller having a setting section for giving a target value for a fixed period of time, a control section including a predicting section for predicting a process response for the fixed time period in accordance with a current value of a process control amount and a virtual value of an operation amount; a quantitating section for quantitating a difference between the target value and the result by the predicting section; a calculating section for calculating a basic signal of the operation amount in accordance with the quantitated result, and an optimizing section including a predicting section for predicting a process response for the fixed time period with a control amount and an initial operation amount of the process; another quantitating section for quantitating a difference between the prediction and the target value, a calculating section for calculating the operation amount in accordance with the second quantitated result; and a section for performing control in such a way that the quantitating result and a predetermined evaluation criterion are compared with each other to perform an evaluation. The calculated result of the operation amount is repeatedly applied to the predicting section until the evaluation criterion is satisfied, a correcting signal used for optimizing the operation amount is obtained from a value of the operation amount when the quantitated result satisfies the criterion, and the correcting signal is added to a basic signal of the control section, and the adding result is output to the process.

Process controller for controlling a process to a target state

A distributed control system for a plant includes an electric equipment room for supplying electric power to a plurality of field apparatuses constituting parts of the plant by way of a plurality of operation terminals. Apparatuses for controlling the function units are provided distributively in the field in which the field apparatuses to be controlled are installed. Operation terminals to be controlled by the control apparatus are installed in the field.

Distributed plant control system

A system and a method of monitoring and displaying in which control screen indicating a control data of a control device for process control displayed on the display screen of a display unit by a touch operation on a diagram of the control device, the control data being further selected by another touch operation. The display condition of the control data display area thus changes, the operator being permitted to visually check whether the operation has been selected correctly. After visual confirmation, a switch disposed outside of the display screen and corresponding to the called control screen is operated to start the operation of the control device determined for control for the first time at this time point. In case of a combined display of a control device and a control screen, on the other hand, a first display unit is utilized such that the called control screen is displayed at a position far from the control device to be controlled, thereby not hiding the control device display. The control screen may be moved to a given position on the system diagram. A second display unit is utilized such that the original system diagram is displayed in a reduced form in combination with and not superimposed on the called control screen. The control screen and the control-related screen are called repeatedly so that when the reduction rate of the original system diagram exceeds a critical value, the reduction rate is fixed to a predetermined value and the control screens are displayed in scroll.

Process monitoring and control system and method of process monitoring

A digital controlling device in which arithmetic operations are executed under control of a predetermined program on the basis of an input signal obtained from at least one detector in a section to be controlled to generate a driving signal, said driving signal being sent to actuating means in said controlling section. Said digital controlling device comprises a plurality of calculation specification tables for respectively describing therein an operation type for each arithmetic element, storage addresses of input/output data for said each arithmetic element, and storage addresses of operation parameters for the each arithmetic element; a calculation sequence table for describing therein the number of arithmetic blocks and addresses used for reading-out of associated said calculation specification tables corresponding to said arithmetic elements in an order that arithmetic operations are to be executed in said digital controlling device, said calculation sequence also being a total arithmetic element number at its leading address; data tables for respectively describing therein data in the corresponding address zones specified in said calculation specification tables; and a processing program section for executing said operation elements in said order described in said calculation sequence table and reading data necessary for said execution from said data tables on the basis of associated said calculation specification tables.

Digital controlling device

A master controller receives a load demand and a plurality of plant data from a heat power plant and outputs command signals on at least two of an electric power, a feed water flow rate, a fuel flow rate, an air flow rate and a recirculation gas flow rate of the plant required to achieve the load demand. A plurality of sub-loop controllers independently provided one for each of the command signals provide control quantities for controlling respective control ends in accordance with the command signals. A transmission loop is arranged between the sub-loop controllers and the master controller. Drive means drive the control terminals provided one for each of the control quantities supplied from the sub-loop controllers. An I/O bus is arranged between one of the sub-loop controllers and the drive means driven by the command signal for the one sub-loop controller. Detection means detect the plant data to be delivered to the master controller or the sub-loop controllers.

Controller for heat power plant

An automatic control system for a thermal power plant comprises a master controller controlling a turbine in response to an externally applied load command signal, and producing a boiler input command signal by correcting the load command signal on the basis of the detected pressure of main steam generated from a boiler, and a water/steam process controller, a fuel process controller, a combustion process controller and a draft process controller to all of which the boiler input command signal is applied from the master controller. The process controllers apply control signals to equipments controlling a water/steam process, a fuel process, a combustion process and a draft process respectively among the terminal actuating equipments of the various parts of the boiler.

Automatic control system for thermal power plant

An apparatus for controlling the drum water level of a drum boiler prevents the boiler system from being tripped off which would otherwise be caused by an excessive fall in the drum water level immediately after the start of load runback, by increasing the real feed water flow rate in such a manner that a feed water flow rate demand signal obtained from the drum water level deviation is corrected by a feed water flow rate increment signal obtained from the amount of load reduction (load demand--load reference after load runback) at the time of load runback. In addition, the fact that the drum water level stops falling and starts to rise is detected, and the feed water flow rate demand signal is adjusted so as to take a medium value between the real feed water flow rate and the real main steam flow rate, thereby preventing the boiler system from being tripped off which would otherwise be caused by an excessive rise in the drum water level.

Apparatus for controlling drum water level of drum type boiler

A method of controlling an air heater of a coal-fired boiler system comprising an air heater for heating a primary air used to dry a pulverized coal and convey it into the boiler and a secondary air to combust the pulverized coal by a heat exchange utilizing the exhaust gas discharged from the boiler as a heat source. The air heater includes a primary air heater and a secondary air heater arranged in parallel and the exhaust gas is introduced therein from the boiler by an induced draft fan with the flow rate of the exhaust gas being introduced into each of the air heaters being controlled by a respective gas damper. The heater primary air is mixed with a cold air to have a suitable temperature to dry and convey the pulverized coal, wherein the opening of the damper for the cold air is maintained at a low value of approximate 0% for maintaining the flow rate of the cold air low, while the suitable temperature is obtained by controlling the gas damper for the primary air heater.

Method of controlling an air heater of a coal-fired boiler

Disclosed is an automatic anticipatory control system for controlling, by one common control quantity, a plurality of points of operation that can be changed over individually and arbitrarily between start and stop operations and between an automatic operation mode and a manual operation mode. The system includes a master controller for obtaining a control signal for each of the points of operation that are operating in the automatic operation mode, on the basis of the sum of biases of the points of operation that are operating in the automatic operation mode, the sum of loads to be borne by the points of operation that are operating in the automatic operation mode on the basis of the common control quantity and the number of the points of operation that are operating in the automatic operation mode; a plurality of sub-loop controllers each disposed for each of the points of operation and generating a driving control instruction for each point of operation on the basis of the control signal; and driving means for practically driving the corresponding points of operation on the basis of the driving control instruction of each sub-loop controller.

Feed-forward type automatic control system

A plant model is constructed with a mathematical procedure known as the Kalman filter. The presumed value or predictive value of a certain parameter of a plant is compared with the actually-measured value of the parameter, and the state transition matrix and drive matrix of the Kalman filter are corrected. When a parameter which is a direct controlled object is difficult of actual measurement, the model is corrected by utilizing another parameter whose actual measurement value is easily obtained. When the plant has a feedback control system based on the proportional-plus-integral control, the gain of the system is corrected in correspondence with the corrections of the elements of the matrices.

Plant control method

Sub-loop controllers arranged around a microprocessor are assigned to operation terminals to be controlled, and connected to a master controller and a host computer through a system bus to be supplied with a control command therefrom. Analog memories for manual control of the operation terminals are connected to the host computer through a special, common wiring. If one of the sub-loop controllers breaks down, the host computer directly controls the operation terminal by use of this analog memory thereby to back up the sub-loop controller.

Hierarchical-structure plant control system

A proportional-integral circuit comprising a proportional element, an integrator and an adder. In an automatic mode, the proportional element delivers an output signal V.sub.P which is proportional to an input signal V.sub.i, the integrator delivers an output signal V.sub.I by integrating the input signal V.sub.i, and the adder delivers an output signal V.sub.PI which is the sum of the output V.sub.P of the proportional element and the output V.sub.I of the integrator. In a handling mode, the input signal V.sub.i is not applied to the integrator, and the output V.sub.P of the proportional element and an output V.sub.H of a manual handling source are applied to the integrator. A resistor is connected in parallel with a feedback capacitor in the integrator so that the integrator possesses an adding function. The adder adds up the output V.sub.P of the proportional element and the output V.sub.I of the integrator. Further, in this circuit, the gain of the integrator output V.sub.I relative to V.sub.P and V.sub.H is selected to be l/n, and the gain of the adder output V.sub.PI relative to V.sub.I is selected to be n.

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Katsuta, Japan

Akira Sugano