| 摘要 |
Automatic Process Control Device having input transistors to receive process and set point signals; a subtractive amplifier to compare the process and set point signals and produce one of two amplified deviation signals which are limited to maximum values by zener diodes; capacitors to receive, time-integrate and store the amplified and limited deviation signals, and produce a neutral output if the time-integration of the amplified and limited deviation signals is in balance, and one of two trigger signals if the time-integration of the amplified and limited deviation signals is positive or negative; and relay switches connected to discharging circuits and in series with zener diodes to receive the trigger signals and operate a controlling device upon the process to urge the process toward its desired set point, and simultaneously produce a corresponding tripping signal which urges the capacitors toward a status to produce the neutral output, such that as the controlling device is operating upon the process the Automatic Control Device is simultaneously being urged toward its neutral position, and the response of the controlling device is time-integrated to the accumulative deviation of the process. In use, the disclosed Automatic Control Device virtually eliminates "hunting", and it can also accomodate and control extreme and sudden changes ("bumping") in either the process variable or the set point without damage to the Automatic Process Control Device or its operation.
|
