Patent ID: 7668606

Claim:
A control device for controlling a control object at a ratio of ON-time to OFF-time for a time-proportional output, said control device comprising: a PID computation unit executing PID computation of deviation between a set value and a measured value from the control object, an integrator sequentially adding up control output values each representing the result of the PID computation executed by the PID computation unit, wherein an input of said integrator is directly connected to an output of said PID computation unit; an ON/OFF determination unit determining whether the time-proportional output is turned ON or OFF on the basis of an integrated value of the integrator, wherein an input of said ON/OFF determination unit is directly connected to an output of the integrator, wherein the integrator integrates the control output value renewed for every control cycle by adding the latest control output value thereto for every resolution cycle, and wherein the resolution cycle corresponds to one half of a commercial rower supply cycle delivered to the control object; and a time-proportional output unit turning the time-proportional output ON/OFF on the basis of a determination value of the ON/OFF determination unit; and wherein an input of the time-proportional output unit is directly connected to an output of the ON/OFF determination unit.