OCB100-KIT Datasheet, PDF (19/24 Pages) OPTEK Technologies – Auto-Calibration Design Kit

THEORY OF OPERATION OPB350 SERIES AND OCB350 SERIES
The OPB350 Liquid Sensor Series are designed to work with 1/16”
[1.6mm], 1/8”[3.2mm], 3/16” [4.8mm], and 1/4” [6.3mm] outside di-
ameter clear tubes. When custom 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 a dark liquid present causes it to sink the least 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 pho-
totransistor sinks current between the dark fluid and clear fluid states.
The designer must identify the typical current values for each situation
and design the output reference circuitry to match.
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The OPB350L Series have leads that are designed to mount directly
to PCBs. The OPB350W Series with 26 AWG wires are remote mount-
able.
The OCB350 Series incorporate the OPB350L Series directly onto
the OCB100AZ (ref page 2) calibration circuit board. This series is
configured to minimize the design effort needed to use a fluid sen-
sor by utilizing the onboard calibration circuitry. Four visible LED
lights are provided on the board to indicate whether the sensor has
been calibrated and what its output state is. The user will normally
want to calibrate the sensor after placing empty tubing in the op-
tical path. At the end of the calibration process, a green light will
flash 3 times and then turn off to indicate that the sensor is properly
calibrated. The OCB350 is now ready to be used to sense the pres-
ence of either a clear fluid (blue LED indicator), a dark fluid (green LED
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