| 摘要 |
PURPOSE:To hold a diaphragm stably at a specified position by changing the ratio of intermittent conduction in consideration of the difference of diaphragming-position holding torque by frictional force different according to the location of diaphragming and generating holding torque required at each position of diaphragming while reducing excessively flowing currents. CONSTITUTION:When a diaphragm value is determined, a micro-computer 101 outputs 0 from an output port P6, outputs 1 after a fixed time passes and resets binary counters DFFs 105-107 and frequency dividing circuits DFFs 128-130. 1 is output from output ports P3-P5, and an output from an AND gate 140 is brought to 1, thus making currents in the direction A flow through a coil 13, then stopping a diaphragm. When an output from an output port P1 is brought to 0 and one pulse is output from an output port P2, the count values of the binary counters are brought to 1, thus conducting the coil 13 in the direction A and a coil 12 in the direction B and operating a stepping motor, then diaphragming the diaphragm by a one eighth stage. |
