| 摘要 |
PURPOSE:To improve the operationability while to automate the evacuating operation, by producing the starting pulse with predetermined period only when a drive signal is inputed while detecting the ion pump state after each pulse and stopping the drive signal when it is under blocked state. CONSTITUTION:Upon input of a start signal to a block circuit 7 of a high voltage generating circuit 6, an ion pump 1 will start but if excessive current IC will flow due to insufficient preliminary exhaust, the voltage across a detection resistor 2 is detected by a detector 3 and a comparator 5 to provide a blocking signal to the blocking circuit 7 thus to stop the pump 1. On the other hand, the starting signal will constitute a logical sum by passing the output signal from an operating circuit 10 and a pulse from a pulse generator 9 through gate 8 thereby even if the pump 1 has stopped, the starting pulse is produced again through pulse synchronization thus to start the ion pump. A counter circuit 11 will count the starting pulse, and if the block circuit 7 is under blocked state at predetermined count the gate 12 will block the operating circuit 10. |
