| 摘要 |
PURPOSE: To detect a desired r.p.m. quickly and accurately without causing any erroneous function even in the low r.p.m. region. CONSTITUTION: The r.p.m. measuring circuit 20 determines the r.p.m. based on an r.p.m. signal received from a rotation detector 11 and, when a predetermined r.p.m. is reached, operates a relay drive circuit 39 to delivery a relay contact output to the outside. In the r.p.m. measuring circuit 20, a counter circuit 27 is preset with an initial count based on an r.p.m. signal and the count of the counter circuit 27 is down counted in synchronism with a clock signal. When the initial count is reached, the relay drive circuit 39 is actuated. |
