OCB100-KIT Datasheet, PDF (16/24 Pages) OPTEK Technologies – Auto-Calibration Design Kit

USING THE OPB885CZ WITH THE OCB100CZ
Connect the OCB100CZ to a power source as described on page 7
“Powering up the OCB100CZ”.
Plug the OPB885CZ connector into the 4 pin Molex mating connec-
tor on the OCB100CZ , and then apply power to the circuit. Adjust
the phototransistor emitter load resistor to equal approximately
2.5Kohm (RL @ 2.5K) by placing the shorting bar on the board be-
tweens pins 1 & 2 (see table on pg. 9) of the header. Insure that no
object is blocking the gap of the OPB885CZ, and then calibrate the
sensor momentarily grounding pin 4 of connector J1 by touching the
green wire of the mating connector to the black wire (ground) of the
16 ^{mating connector.}
After approximately 2-3 seconds you should see an onboard green LED
flash three times to indicate that the sensor has been calibrated. There
should now be no LEDs lit on the calibration PCB. If instead the red LED
is lit on your calibration board, change the load resistor to a larger value
and repeat the calibration process. If your board is calibrated, this indi-
cates that the LED drive has ramped up to a current level sufficient to
generate an output voltage level (V_OUT ) @ to ½ Vcc. If Vcc = 5V and
RL = 1K, then the sensor V_OUT will be approximately 2.5 volts. Therefore
the present Ic_(ON) current of the OPB885CZ is 2.5V / 1K = 2.5mA. The
OPB885Z data sheet available at www.optekinc.com shows that the
device has a specified minimum Ic_(ON) guarantee of 1.3mA minimum @
IF=20mA, Vce = 5V. Since the calibration circuit is designed to ramp the
LED drive up to a maximum of IF = 14mA, it may become apparent to you
that this specification does not guarantee every OPB885CZ can reach an
Ic_(ON) of 1.0mA @ IF=14mA, and therefore it may be necessary to change
OCB100-KIT