초록 ▼

A variable limit is utilized to prevent a position controller which requires a velocity set point signal from overdriving a stuck control valve. Control based on a comparison of the actual position to desired position is utilized unless the valve is stuck. If the valve is stuck, the variable limit c

A variable limit is utilized to prevent a position controller which requires a velocity set point signal from overdriving a stuck control valve. Control based on a comparison of the actual position to desired position is utilized unless the valve is stuck. If the valve is stuck, the variable limit controls the velocity set point provided to the position controller until such time as the valve becomes unstuck.

대표청구항 ▼

Apparatus comprising: a first control valve means for manipulating the flow of a fluid; means for establishing a first signal representative of the desired position of said first control valve means; means for establishing a second signal representative of the actual position (P) of said first contr

Apparatus comprising: a first control valve means for manipulating the flow of a fluid; means for establishing a first signal representative of the desired position of said first control valve means; means for establishing a second signal representative of the actual position (P) of said first control valve means; a velocity controller for comparing said first signal and said second signal and for establishing a third signal which is representative of any change (Dn) generated by said position controller in response to said velocity set point; means for establishing a fifth signal which is representative of a driving force limit (R); means for establishing a sixth signal representative of the value of said fourth signal one time period earlier (An-1); means for calculating said velocity set point (D