| CPC G01N 27/4163 (2013.01) [G01N 27/4166 (2013.01)] | 8 Claims |
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1. A measuring device, comprising:
a first electrode immersed in sample water stored in a measuring tank;
a second electrode immersed in the sample water;
a controller that causes a power source to flow a current through the sample water between the first electrode and the second electrode;
a slip ring disposed between the first electrode and the power source;
a brush disposed to contact the slip ring;
a converter that converts the current into an analog signal; and
an AD converter that converts the analog signal into a digital signal by sampling the analog signal with a sampling period during a measuring mode in which a concentration of a measurement target in the sample water is calculated, wherein
the controller during the measuring mode:
detects, based on the digital signal, that one or more changes in the analog signal are equal to or greater than a predetermined value, wherein the one or more changes in the analog signal are each caused by a change in contact between the slip ring and the brush;
extracts a part of samples of the digital signal; and
calculates the concentration based on the extracted part of samples,
the measuring device further comprising:
a motor that rotates the first electrode at a rotational velocity that is changed by the controller,
the controller operates in a standby mode where the concentration is not calculated, and
when the controller operates in the standby mode, the controller controls the motor such that a first absolute value of the rotational velocity when operating in the standby mode is larger than zero and smaller than a second absolute value of the rotational velocity when operating in the measuring mode.
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