| 摘要 |
PURPOSE:To omit limit switches and to improve durability by providing a position resistor which emits a stop signal to a control mechanism and stops a variable speed motor when a movable part arrives at a prescribed position. CONSTITUTION:When a slide table 1 retreats to an origin and abuts on a stopper 32, excessive electric current is supplied from a power amplifier 16 to a DC motor 4. The excess current is detected with a shunt resistor 33 and when the current exceeds a set value, an origin signal is fed to an AND circuit 20 and a load limiter 35, and the signal thereof is held for a specified time. When the signal from the circuit 20 is inputted to a position resistor 13, the contents of storage are set at zero or at a certain absolute value. |
