| 摘要 |
PROBLEM TO BE SOLVED: To provide a dew-point meter for continuously measuring dew point temperatures even when a dew-point meter is under control of automatic cleaning.SOLUTION: A first dew-point meter whose measurement value of dew-point temperature is always used as a valid measurement value is handled as a primary dew-point meter, and a second dew-point meter whose measurement value of dew-point temperature is used as a valid measurement value of dew-point temperature while the first dew-meter is under control of automatic cleaning is handled as an auxiliary dew-point meter. Based on the state of a mirror surface of the auxiliary dew-point meter, it is determined whether the state of a mirror surface of the primary dew-point meter is at a stage prior to an abnormality. If determined as the prior stage, the control of the auxiliary dew-point meter for measuring a dew-point temperature is interrupted to shift to automatic cleaning control and then is returned to dew-point temperature measurement control. |
