Method and automatic control apparatus for controlling a technological process

An automatic control apparatus for automatically controlling a technological process, comprising:

• an automatic controller for maintaining an output parameter of said process at a predetermined level;
• a control quality signal generating device for generating a signal representative of an index of control quality;
• a control signal generating circuit for generating a control signal depending on variation of said signal representative of the index of control quality;
• a parameter adjusting device connected to the output of said control signal generating circuit for adjusting a parameter of said automatic controller;
• a controlled storage device having a data input connected to the output of said control quality signal generating device and a control input;
• a direction signal generating circuit having an input connected to the output of said control quality signal generating device for generating a signal indicative of the direction of variation of the index of control quality and an output connected to the input of said control signal generating circuit for changing the signal at said output of said control signal generating circuit immediately after the direction of variation of the index of control quality changes from increasing to decreasing control quality;
• a comparison circuit having a first input connected to the output of said controlled storage device and a second input connected to the output of said control quality signal generating device;
• and
• a control circuit having inputs respectively connected to the output of said direction signal generating circuit and to the output of said comparison circuit for generating a binary signal having a first value when the magnitude of the difference between the current value of the index of control quality and its value stored in said controlled storage device exceeds a preselected value, and having a second value after the direction of variation of the index of control quality changes from increasing to decreasing control quality if the magnitude of the difference between the current value of the index of control quality and its value stored in said controlled storage device is smaller than said preselected value, said control circuit having an output connected to said control input of said control storage device to enable said controlled storage device to store the value of the index of control quality occurring just before said binary signal assumes said second value, said parameter adjusting device being connected to the output of said control circuit to abruptly change said parameter of the automatic controller, when said parameter attains a first predetermined value and said binary signal has said first value, to a limit value beyond the range of variation of said parameter during the period that said binary signal has said second value;
• said automatic control apparatus further comprising
• setting means for setting said parameter adjusting device to a second predetermined value a predetermined time after said parameter achieves said first value, said second predetermined value being less than said first predetermined value.