| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a flowmeter, etc. capable of knowing existence of influence of magnetism from the outside without increasing size and weight and without increasing cost and restrictions of substrate design. <P>SOLUTION: The flow meter includes: magnetic sensors (70A, 70B) for detecting magnetic changes caused by rotation of a magnetic body attached on a rotor and generating magnetic detection signals (207A+, 207A-, 207B+, 207B-) corresponding to the magnetic changes; and a period detection control part 2 for determining whether or not the flow meter is in an abnormal state that accurate flow rate cannot be measured due to influence of magnetism from the outside of the flow meter based on the magnetic detection signals. The period detection control part 2 detects first and second periods which are two periodical change periods of the magnetic detection signals included in one-rotation period of the rotor, compares the first period with the second period, and when a difference between both the periods is deviated from a predetermined value, determines an abnormal state. <P>COPYRIGHT: (C)2013,JPO&INPIT |
