PURPOSE: To remove the influence of resonation which may be exerted upon an instrumenting wire and to obtain a true pressure signal by finding out a resonance amplifier ratio from a relational expression to resonance frequency, extracting a resonance component from a pressure signal, dividing the extracted component by the resonance amplification ratio, and synthesizing the pressure signal again.
CONSTITUTION: A pressure detecting signal (p) outputted from a pressure trans mitter of the instrumentation piping is inputted to a band-pass filter 1 to obtain a pressure signal Δp1 corresponding to a resonance peak of a frequency spectram. The pressure signal Δp1 of the resonance frequency component is multiplied by a factor C1 equal to the reciprocal of the resonance amplification factor by a factor unit 2 to obtain a pressure signal Δp2. The pressure signal Δp1 of the resonance frequency component is subtracted from the pressure detecting signal (p) to obtain the pressure signal p1 excluding the resonance frequency component and the pressure signal p1 is added to the pressure signal Δp2 to obtain a corrected pressure signal p*. Consequently, the processor can be prevented from the change of control characteristics based upon the reso nance characteristics or the generation of an unnecessary plant tripping signal.
FUKUNISHI HIROARI
OMORI TAKU
KINOSHITA MITSUO
