Title:
PID CONTROLLER FOR DDC CONTROL
Document Type and Number:
Japanese Patent JPS5829001
Kind Code:
A
Abstract:
PURPOSE:To perform switching from a local instrument mode to a DDC operation with bumpless operation at manual operation, by monitoring a manipulated variable when a backup instrument is at the local instrument mode at a DDC control PID controller. CONSTITUTION:A mode switch SW13 which changes over a DDC operation mode C and a local instrument mode L is provided between a mode changeover switch (SW)5 and an output circuit 6 of a DDC control PID controller 8. Further, an output terminal of an output manipulated variable MV of a backup instrument 12 is connected to an L terminal of the SW13 and the SW is changed over to the L with the switching signal of a mode changeover SW9. Thus, the output of the circuit 6 and that of the instrument 12 are always made coincident and the controller 8 can monitor the output value of the instrument 12. Even at the manual M position of the SW5 of the controller 8, a switching signal of the SW9 and the manupulated variable MV are inputted to a bumpless circuit 4, and the SW13 is changed over from the L to the C. Since the output of the circuit 6 is changed from a value at the L mode, the changeover is performed without bumping.
Inventors:
SHIRAGAKI TAKAMICHI
Application Number:
JP12675881A
Publication Date:
February 21, 1983
Filing Date:
August 14, 1981
Export Citation:
Assignee:
HITACHI LTD
International Classes:
G05B7/02; (IPC1-7): G05B7/02
Attorney, Agent or Firm:
Akio Takahashi