Abstract: A neural network control based on a general multi-variable nonlinear dynamic model incorporating time delays is disclosed. The inverse dynamics of the process being controlled is learned represented by a multi-layer neural network which is used as a feedforward control to achieve a specified closed loop response under varying conditions. The weights between the layers in the neural network are adjusted during the learning process. The learning process is based on minimizing the combined error between the desired process value and the actual process output and the error between the desired process value and the inverse process neural network output.

Abstract: A method and apparatus for controlling the delignification process by monitoring and minimizing variations in the Kappa Number and the digester residual chemical concentration. A parameter representative of the H factor for the delignification process and a measurement of the initial chemical concentration are utilized to produce signals representative of the actual Kappa Number and the residual acid concentration in the digester. The expected perturbations in Kappa Number and the residual chemical concentration are compared with target values for same to produce estimated errors due to mismatch which are compared with actual measured errors for these parameters to produce compensated control errors for same.

Abstract: A method and apparatus for controlling the delignification process by monitoring and minimizing variations in the Kappa Number and the digester residual chemical concentration. A parameter representative of the H factor for the delignification process and a measurement of the initial chemical concentration are utilized ot produce signals representative of the actual Kappa Number and the residual acid concentration in the digerter. The expected perturbations in Kappa Number and the residual chemical concentration are compared with target values for same to produce estimated errors due to mismatch which are compared with actual measured errors for these parameters to produce compensated control errors for same.

Abstract: A method and apparatus for controlling the delignification process by monitoring and minimizing variations in the Kappa Number and the digester residual chemical concentration. A parameter representative of the H factor for the delignification process and a measurement of the initial chemical concentration are utilized to produce signals representative of the actual Kappa Number and the residual acid concentration in the digester. The expected perturbations in Kappa Number and the residual chemical concentration are compared with target values for same to produce estimated errors due to mismatch which are compared with actual measured errors for these parameters to produce compensated control errors for same.

Abstract: A method and apparatus for controlling the delignification process by monitoring and minimizing variations in the Kappa Number and the digester residual chemical concentration. A parameter representative of the H factor for the delignification process and a measurement of the initial chemical concentration are utilized to produce signals representative of the actual Kappa Number and the residual acid concentration in the digester. The expected perturbations in Kappa Number and the residue chemical concentration are compared with target values for same to produce estimated errors due to mismatch which are compared with actual measured errors for these parameters to produce compensated control errors for same.

Abstract: A method and apparatus for controlling the delignification process by monitoring and minimizing variations in the Kappa Number and the digester residual chemical concentration. A parameter representative of the H factor for the delignification process and a measurement of the initial chemical concentration are utilized to produce signals representative of the actual Kappa Number and the residual acid concentration in the digester. The expected perturbations in Kappa Number and the residual chemical concentration are compared with target values for same to produce estimated errors due to mismatch which are compared with actual measured errors for these parameters to produce compensated control errors for same.

Abstract: A performance monitor generates a fouling factor which indicates the level of fouling of a heat exchanger having a heat exchange surface area and through which a heat exchange medium passes having a known specific heat. Temperature transmitters are utilized to obtain values for the input and output temperatures of the heat exchange medium as well as the temperature in the heat exchanger of a heat exchange fluid used to transfer heat to or from the heat exchange medium. Modules are used to generate a value for an actual heat transfer coefficient in the heat exchanger as a function of the temperatures, flow rate and constant parameters such as area and specific heat, for the heat exchanger. The actual heat transfer coefficient is compared with a nominal or original heat transfer coefficient to determine if any deterioration in the coefficients has occurred which reflects the fouling of the heat exchanger.

Abstract: Supervisory control system including an arrangement and process for controlling the operation of a dryer for the continuous adiabatic drying of a moist solid product with heated air for achieving the desired final product moisture content which would not exceed scorch level.

Abstract: A system for the automatic and continuous determination of the efficiency of a fossil fuel-fired vapor generator for utilization by an automatic load control (88) to control the distribution of the system load among a plurality of generators, wherein various heat losses from various combustion sources are separately determined, the individual losses summed (80) and subtracted (86) from 100 percent to obtain a measure of the vapor generator efficiency.

Abstract: A system for optimizing the performance of a plurality of energy conversion devices is disclosed. Measurements of fluid flow into and out of the energy conversion devices, the efficiencies of the conversion devices and the power produced by the conversion devices are used as inputs to function blocks in a logic arrangements. The function blocks cause a decrease in load demand to be applied to the energy conversion device having the lowest efficiency and an increase in load demand to be applied to the energy conversion device having the highest efficiency.

Abstract: An enthalpy measuring arrangement for measuring the heat content of a substance which may in the liquid phase, vapor phase or a mixed phase of liquid and vapor, comprises a first enthalpy calculating module for calculating the enthalpy of the substance when in a two-phase condition utilizing a plurality of discrete function blocks. The specific volumes of the overall mixture is calculated using a density transmitter which measures the density of the substance. Tables are utilized to obtain the specific volumes of the gas and vapor part of the substance on the basis of a measured temperature for the substance. These values are in turn used to obtain a quality value which is multiplied by a value representing the difference between the enthalpys of the vapor and liquid components of the substance to obtain the overall enthalpy of the mixture. Another module with a plurality of function blocks generates the enthalpy of the substance when it is superheated or entirely in the vapor phase.

Abstract: An integrated control system for both the output and surge protection of a centrifugal compressor in a chilled, water system is provided by biasing the output of a feed forward and cascade centrifugal compressor output control logic module with the output of a coordinating control logic module, which utilized a surge control logic module output to establish the biasing signal.

Abstract: A cooling tower monitor for determining the performance of a cooling tower includes temperature transmitters for determining the input water temperature, the output water temperature and the surrounding temperature of the tower. A flow transmitter measures the output flow of water and a speed transmitter determines the flow of air through the tower. A relative humidity transmitter is also utilized to measure the surrounding relative humidity. The transmitters are connected to function blocks to generate a value corresponding to the performance of the cooling tower as a function of the parameters measured. A first set of function blocks utilizes the surrounding temperature and relative humidity to calculate the wet bulb temperature of the air outside the tower. This measurement is utilized in conjunction with the input and output temperatures as well as the air flow value to calculate a nominal or available water flow rate for the tower.

Abstract: An adaptive control for a process is disclosed which utilizes a process parameter calculator made up of simple function blocks which generate a plurality of process parameters, and a tuning parameter calculator, also made up of simple function blocks, for calculating tuning parameters from the process parameters.The process parameter calculator is provided with values for various disturbances, a set point, a control output from a process controller and process structure data including process sensitivity and nominal operating data. From these values, the process parameters are determined. The tuning parameter calculator is provided in addition to the process parameters, with performance parameters and design function for generating tuning parameters that are applied to the controller for modifying the control output in response thereto.

Abstract: A system for optimizing the control of the water temperature within a cooling tower is disclosed. The temperature and the relative humidity of the air outside the cooling tower are measured and are selectively utilized as inputs to a plurality of modules containing function blocks in a logic arrangement. The function blocks produce an output signal indicative of the wet bulb temperature of the outside air which is compared to the cooling tower water temperature causing the speed of the cooling tower fans to be adjusted in response to the temperature difference therebetween.

Abstract: An arrangement and method of controlling optimum chilled water temperature supplied to a process by a pump, the water being chilled by coolant in a coolant cycle having a compressor and a load valve, comprises first and second sensors for sensing a supply and a return temperature to and from the process. A value is obtained for the amount of work done by the pump and the compressor with that value as well as the supply and return temperature values being supplied to a supervisory control. The supervisory control operates to generate a reference temperature which is a function of the supply temperature but which is either above or below the supply temperature depending on a ratio between the difference in work and a change in the difference between the supply and return temperatures. When the ratio is about zero this indicates the difference between supply and return temperature is at an optimum and the reference temperature is the same as the supply temperature.

Abstract: A load control for a system comprised of a plurality of energy converters wherein a System Control Signal proportional to system load is developed and utilized to simultaneously adjust the rate of energy conversion of each of the converters in parallel in accordance with changes in system load. The rate of energy conversion for each converter, while operating under stead-state conditions for a predetermined period of time, is readjusted until its actual incremental cost of production is equal to a desired incremental cost.

Abstract: A load control for a system comprised of a plurality of energy converters wherein increases in total energy demand from the system is compensated by increasing only the rate of energy conversion of that converter producing energy conversion at least cost and decreases in total energy demand from the system is compensated by decreasing only the rate of energy conversion of that converter producing energy conversion at highest cost.

Abstract: A load control for a system comprised of a plurality of energy converters wherein the energy output of all converters is adjusted in parallel to maintain the total rate of energy output from the system equal to demand and wherein during steady-state conditions the rate of energy conversion for that converter having the lowest incremental cost is increased and simultaneously the rate of energy conversion for that converter having the highest incremental cost is decreased a like amount.

Abstract: A system for the measurement and control of the rate of BTU input to a gas burner wherein a signal is generated corresponding to the square root of the product of the burner inlet pressure multiplied by the in-situ density olf the gas, which, multiplied by a signal of constant value, corresponds to the mass flow of gas to the burner. This signal is then multiplied by a second signal of constant value to generate a signal corresponding to the rate of BTU input to the burner and which is compared with a set point signal to regulate the mass flow of gas to the burner as required to maintain the rate of BTU input to the burner at set point.