| 摘要 |
A process control method comprises the steps of generating a first electrical signal representing a measured value of a process variable, generating a second electrical signal representing a desired value of said process variable, generating a third electrical signal, which changes at a prechosen rate corresponding to a desired rate of change of said measured value of said process variable, comparing said second electrical signal with said third electrical signal to generate a fourth electrical signal, applying said fourth electrical signal to cause said third electrical signal to tend towards equality with said second electrical signal, and comparing said first electrical signal with said third electrical signal to produce a process control signal therefrom. Apparatus for carrying out the method is also described as well as the application of the method to the control of the temperature of dyebath liquor.
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