The OPB350 series liquid sensor is designed to work with 1/16” [1.6mm] 1/8” [3.2mm], 3/16” [4.8 mm] and 1/4” [6.3 mm] outside diameter clear tubes. When output reference circuitry is added, multiple output states such as “fluid present,” “no fluid present” and “no tube present” can be recognized.
Clear liquid present causes the phototransistor to sink the maximum current, while dark liquid present causes it to sink the minimum current. As bubbles pass through the tube, the signal will vary between the “liquid present” and “no liquid” states. If no tube is present, the phototransistor sinks current between the dark fluid and clear Fluid states. The customer will have to identify the typical current values for each situation. The ratio between the different stated allows acknowledgment of different conditions.