OPB350W187Z Optek Technology (TT electronics), OPB350W187Z Datasheet - Page 6

• Manufacturer Part Number: OPB350W187Z
• Manufacturer: Optek Technology (TT electronics)
• Type: Transmissiver

Specifications of OPB350W187Z

• Number Of Elements: 1
• Output Device: Phototransistor
• Reverse Breakdown Voltage: 2V
• Collector-emitter Voltage: 30V
• Forward Current: 50mA
• Collector Current (dc) (max): 50mA
• Power Dissipation: 100mW
• Pin Count: 4
• Mounting: Screw
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Compliant

Tube Liquid Sensor
OPB350 / OCB350 Series
(Calibration Circuit Available)
Issue C.1
Page 6 of 8
Calibration Circuit theory of operation:
The OCB350 series is designed to minimize the change of optical devices due to manufacturing variance. With the calibration
circuit, the design engineer can narrow the initial output state providing a device that will operate the same for years with the
same startup state thus enhancing the reliability and consistence of the system. Degradation of the LED or phototransistor is
compensated for each time the system is calibrated allowing the system to provide a known, consistent output level resulting
in years of consistent quality. The OCB350 series are designed to maintain the calibrated setting even if power is lost. This
allows faster startup without the need for calibration every time the device is initiated. The designer can initiate the calibration
procedure at any time by momentarily grounding J1-Pin-4 (green wire). This allows the device to be remotely calibrated then
mounted in the equipment.
The PCBoard has a set of shorting pins allowing the user to change the phototransistor load resistor. By arranging the
shorting bar to the appropriate location (see table), the load resistance can be changed from approximately 2.5K to 27 K Ω.
Increasing the load resistor increases the sensitivity of the device.
When the “Calibrate” pin (#4) is momentarily grounded, the system begins its calibration process and raises the current
through the LED, from 0 mA to 14 mA, until the phototransistor reaches the preset calibration point. A green calibration light
will blink during the initiation and will stop when the preset phototransistor output level is reached. At this time, the LED
drive current is locked and maintained until Reset/Clear pin is momentarily grounded. If for some reason, the LED drive
current reaches the maximum allowable value, a RED warning light will be turned on. During the calibration process, remote
monitoring of J1-Pin3 allows the designer to ensure the system is calibrated (this output should be at the preset calibrated
output level when the calibration procedure is completed). The phototransistor load resistor may need to be adjusted to allow
the system to calibrate properly.
After the calibration process is complete, the device is ready for acknowledgement of a change in the signal. The design
engineer can monitor either the Analog Output (J1-Pin 5) or Logical Output (J1-Pin 2 or J1-Pin 3).
The Logical output will change state once the preset optical light condition is reached. The “Logic Out A” switches when the
optical signal increases above approximately 2/3 of V
below approximately 1/3 of V
As with all optical devices, the switching condition is consistent with the phototransistor receiving a preset light level. This
switching position and light level may vary dependent on several possible factors such as:
•
•
•
•
•
Ambient light variation ((reduced or eliminated with periodic recalibration)
LED and phototransistor pair degradation (eliminated with periodic recalibration)
Contamination in front of either the LED or phototransistor (reduced or eliminated with periodic cleaning)
System power variation (reduced or eliminated with periodic recalibration)
Temperature changes (reduced or eliminated with periodic recalibration)
03/09
OPTEK reserves the right to make changes at any time in order to improve design and to supply the best product possible.
CC
.
Phone: [phone] or [phone]
CC
while “Logic Out B” switches when the optical signal decreases
OPTEK Technology Inc. — 1645 Wallace Drive, Carrollton, Texas 75006
FAX: [phone] [e-mail] www.optekinc.com