OPTEK OCB350L125Z Auto-calibration design kit Datasheet

OCB100-KIT
The OCB100 Series
Auto-Calibrating
Boards take the
guesswork out of
tuning the sensor
for your unique
applications.
Auto-Calibration Design Kit
Content
Page
Kit Description
3
Included in your OCB100-KIT
4
OCB100CZ
Theory of operation
5
Powering up the OCB100CZ
7
Package Drawing
9
Calibration Circuit Drawing
8
OPB732WZ
2
Theory of operation
10
Using the OPB732CZ with the OCB100CZ
11
Package Drawing
13
OPB885Z
Theory of operation
14
Using the OPB885Z with the OCB100CZ
16
Package Drawing
18
OPB350 Series & OCB350 Series
Theory of operation
19
Using the OPB350C125Z with the OCB100CZ
21
Package Drawing
22
OCB100-KIT
KIT DESCRIPTION
The OCB100-KIT design kit provides engineers an opportunity to
become familiar with the capabilities of a variety of basic optoelectronic sensor types: transmissive, reflective, and fluid. The kit includes
an automatic calibration circuit card that interfaces with each sensor
to make evaluation of the sensor much easier. In addition, the calibration PCB can be interfaced to almost any optoelectronic sensor via
the onboard Molex 70553-0038 four pin header. The circuit provides
automatic calibration and therefore provides an easy way to utilize the
full range of production devices that may be provided on any type of
sensor. The circuit allows the engineer to compensate for manufacturing variations, temperature changes, and device aging present in
optoelectronic systems.
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3
INCLUDED IN YOUR OCB100-KIT DESIGN KIT
•
OCB100CZ — PCBoard Calibration Circuit (includes
OCB100 - MC24 mating cable)
•
OPB350C125Z — Fluid Sensor for 0.125” [3.18mm] O.D.
tubing
•
OPB732CZ — Medium distance reflective object sensor.
•
OPB885CZ — Slotted Switch 0.375” [9.53mm] slot width.
•
Sample of 0.125” tubing
•
Label / Liner sample
CZ
00
1
CB
4
O
OC
B10
0A
Z
OPB732WZ
*
OPB885Z *
OPB350W125Z *
* Denotes OPTEK part number of non-connectorized standard part
OCB100-KIT
THEORY OF OPERATION OCB100
The OCB100 series is designed to minimize the change of optical devices due to manufacturing variance, temperature change, and device
aging. This system can be used to calibrate either reflective or interruptive devices to provide a consistent output, thus eliminating the
need to confirm either the LED drive resistance or the phototransistor
load resistance. With the OCB100, the design engineer can reduce
the sensor to sensor variation present in many systems. By providing a
pre-calibrated sensor to the system design, the engineer can enhance
the reliability and consistency. 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 OCB100 series is designed to maintain the
calibrated setting even if power is lost, thus allowing 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, and 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 on pg. 9) you can change the load resistance from approximately 2.5K to 27K ohms. Increasing the load
resistor increases the device sensitivity.
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 3 times when the
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5
preset phototransistor output level is reached.
At this time, the LED drive current is locked and maintained until
the calibration pin is grounded. If for some reason the LED drive current reaches the maximum allowable value, a RED warning light will
turn on. During the calibration process, remote monitoring of J1-Pin
5 allows the designer to ensure the system is calibrated (this output
should be at the preset calibrated output level of 1/2 Vcc when the
calibration procedure is completed). Adjusting the phototransistor
load resistor may allow the system to calibrate properly.
6
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).
Connection of the analog ouput to additional circuitry allows the
design engineer to set any reference point to recognize an optical
change for the device being monitored. The Analog Output can be
used with reflective devices to monitor small changes in the distance
from the device.
The Logical Output will change state once the preset optical light
condition is reached. Logic Out A” (mating connector orange wire)
switches when the optical output signal decreases below approximately 1/3 of Vcc while “Logic Out B” (mating connector blue wire)
switches when the optical output signal increases above approximately 2/3 of Vcc.
As with all optical devices with logic outputs, the switching condition
is consistent with the phototransistor receiving a preset light level.
OCB100-KIT
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)
The OCB100 PCBoard can be wired directly to any optical device
with an LED and Phototransistor such as:
• Interruptive devices / slotted switches / interruptive encoders
• Reflective devices / reflective switches / reflective encoders
• Specialty devices / fluid sensors
POWERING UP THE OCB100CZ
The OCB100CZ should be powered by a 5.0V ± 0.5V, 50mA minimum regulated power supply.
You can also use three 1.5V AA batteries connected in series in a
battery holder such as P/N SBH331AS available from batteryholders.
com. Connect +5 volts to pin #1 of connector J1 (red wire of the
supplied mating connector) and ground to pin #6 of J1 (black wire of
the mating connector).
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7
OCB100-KIT
Vcc
Logic Out A
Red - 1
Orange - 2
Color - Pin # Function
OCB100 Circuit Schematic
Green - 4
Blue - 3
Color - Pin #
Calibrate
Logic Out B
Function
J-1
8
Black - 6
White - 5
Color - Pin #
Ground
Analog Out
Function
Calibration Circuit
9
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THEORY OF OPERATION OPB732 / OPB732WZ
The OPB732 (PCB mount, no mounting tabs) and OPB732WZ
(mounting tabs and wires) are non-focused analog output reflective
sensors designed to operate from .05” [1.27mm] to 2”[50.8mm] or
greater with an output signal significantly above the typical background signal in a dark environment. These sensors are tested against
a white 90% reflectance white card at a distance of 1.0” to guarantee a minimum Ic(ON) collector current of 0.25mA @ VCE = 0.4V and
IF = 30mA. Other surfaces will give different signal levels.
Infrared light with a center wavelength of about 850nm is emitted
from an LED with a total half power angle (ØHP, Beam Angle) around
10 18°. When the light strikes an object, it is reflected back toward
the phototransistor. The amount of current Ic(ON) generated from the
phototransistor is dependent upon the amount of light striking it. The
following graph shows the effect of target distance on the output
current of the OPB732.
OCB100-KIT
USING THE OPB732CZ WITH THE OCB100CZ
Connect the OCB100CZ to a power source as described on page 7
“Powering up the OCB100CZ”.
Plug the OPB732CZ connector into the 4 pin Molex mating connector on the OCB100CZ , and then apply power to the circuit. Adjust the
phototransistor emitter load resistor to equal approximately 10Kohms
(RL @10K) by placing the shorting bar on the board betweens pins 2 &
3 (see table on pg. 9) of the header. Point the OPB732CZ at a sheet of
white paper and position its front surface about ½ ” from the paper.
While holding the sensor in this position, momentarily ground the pin
4 of connector J1 by touching the green wire of the mating connector
to the black wire (ground) of the 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
at the distance it is held from the paper. If the unit calibrated correctly,
and you have not allowed the sensor to move from the position it was
calibrated at, there will be no LEDs lit on the calibration PCB. This
means that the LED drive has ramped up to a current level sufficient to
generate an output voltage level (VOUT ) @ to ½ Vcc.
Now slowly move the sensor away from the sheet of paper until a
green LED lights on the PCB. This light indicates that VOUT has dropped
to 1/3 Vcc or less. As you move the sensor closer to the paper, this
green LED will go out and then come back on at a distance very close to
the surface of the paper. At some distance between the two distances
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11
12
where the green light comes on, a blue LED may come on for some
range of distance. The blue light indicates that VOUT has risen to
a level of 2/3 Vcc or greater. You can experiment with calibrating
the sensor at various distances to see how this changes the distances at which the green and blue LEDs come on. Monitor the
VOUT voltage directly by connecting a volt meter or an oscilloscope
between the white and black wires of the mating connector. If you
move the sensor too far or too close to the paper, the circuit will be
unable to calibrate because the VOUT cannot reach ½ Vcc even when
the LED has ramped to it’s maximum value allowed by the calibration circuit (@ 14mA). When this happens, a red LED indicator will
flash multiple times and then remain lit to notify the user that the
circuit could not calibrate. In practice, the OPB732 family LEDs can
be driven at DC current levels up to 50mA (maximum rating at room
temperature).
See the device data sheet at www.optekinc.com for more details.
Applicable part numbers: OPB732, OPB732CZ, OPB732WZ
OCB100-KIT
OPB732WZ package drawing
15.49 ±0.25
.610 ±.01
1
2 3
4
Anode - 1
Collector - 3
2.16 ±0.25
.085 ±.01
4.32 ±0.25
.170 ±.01
Cathode - 2
Emitter - 4
2X
2.44 ±0.25
Ø .096 ±.01
12.19 ±0.25
.480 ±.01
13
12.70 ±0.25
.500 ±.01
5.08 ±0.25
.200 ±.01
19.81 ±0.25
.780 ±.01
DIMENSIONS ARE IN INCHES AND [MILLIMETERS].
Color-Pin # Function
Color-Pin #
Function
Red - 1
Anode
White - 3
Collector
Black - 2
Cathode
Green - 4
Emitter
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24
MIN
THEORY OF OPERATION OPB885Z / OPB885CZ
The OPB885Z is a wide gap slotted (transmissive) switch with a
single mounting tab on the phototransistor side of the assembly.
Current forced through the LED provides a light signal with a center
wavelength of 890nm directed across the open gap of the switch
toward the phototransistor sensor. The Ic(ON) collector current of the
phototransistor is dependent on the amount of light striking it. When
a non-transparent target passes through the gap, the amount of collector current is lowered significantly. The three graphs on the following page show the effect of an opaque target passing next to the LED
tower, next to the phototransistor tower, and in the center of the slot.
Analysis of these graphs shows a narrower signal area next to both
14
towers. This effect is due to the beam angle and acceptance angle
of the LED and phototransistor of about 40° and the presence of a
.05”[1.27mm] wide aperture in front of each component.
OCB100-KIT
OPB885 Switching Graphcs
OPB885 - Flag Next to Emitter
1.2
Top to Bottom
Typical IC(ON) Response
1.0
0.8
Left to Right
Right to Left
0.6
0.4
0.2
0.0
0.00
0.05
0.10
Distance (inches)
0.15
0.20
0.25
OPB885 - Flag Next to Sensor
1.2
Top to Bottom
15
Typical IC(ON) Response
1.0
0.8
Left to Right
Right to Left
0.6
0.4
0.2
0.0
0.00
0.05
0.10
0.15
0.20
0.25
0.20
0.25
Distance (inches)
OPB885 - Flag in Middle of Slot
1.2
Top to Bottom
Typical IC(ON) Response
1.0
0.8
Left to Right
Right to Left
0.6
0.4
0.2
0.0
0.00
0.05
0.10
0.15
Distance (inches)
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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 connector 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 betweens 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 indicates that the LED drive has ramped up to a current level sufficient to
generate an output voltage level (VOUT ) @ to ½ Vcc. If Vcc = 5V and
RL = 1K, then the sensor VOUT 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
to a higher load resistor value in those cases. Place the shorting bar
between pins 2 & 3 and try calibrating again. In this case the OPB885CZ only needs to reach an Ic(ON) value of 2.5V / 10K = 0.25mA
to calibrate. We could have suggested the 10K load resistor to begin
with, but this exercise can show the importance of matching the
phototransistor load resistance to data sheet specifications of the particular sensor being interfaced to the OCB100CZ.
An example of an application where the OPB885Z could be used
in combination with the OCB100CZ would be where a semi-opaque
or semi-transmissive material needs to be sensed. Since the material
does not block all of the light, the sensor might see through the material and not be able to detect its presence. The OCB100CZ solves this
problem by calibrating the sensor output at a level slightly higher than
the detection trip point. If the material to sense is 50% transmissive
or less, it will be sensed.
Another example would be when the difference in two semitransmissive materials needs to be detected, such as in a label
printer where a sensor is required to see through the liner of a roll of
labels, but detect the label. A sample label / liner is included in this
OCB100-KIT. Try the following experiment:
Insure that the shorting bar is placed between pins 2 & 3 to set
the load resistor at approximately 10K ohms. Place the gap between
the two labels in the center of the optical path. Calibrate the sensor.
Now move the labels back and forth in the gap to see that the green
LED lights when the labels are present, but does not light when the
label is present. Remove the label / liner from the gap completely.
The blue light of the OCB100CZ should now be lit.
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17
OPB885 Package Drawing
24.82 ±0.25
.977 ±.01
22.03 ±0.25
.868 ±.01
3.18 ±0.25
Ø .125 ±.01
3.18 ±0.25
.125 ±.01
18.67 ±0.25
.735 ±.01
OPTICAL
9.53 ±0.25
.375 ±.01
15.11 ±0.25
.595 ±.01
2.54 ±0.25
.100 ±.01
18
1.14 ±0.25
.045 ±.01
4.83 ±0.25
.190 ±.01
24
MIN.
CL
2.79
.110
NOM
2.03 ±0.25
.080 ±.01
#26 AWG
3
2
6.35 ±0.25
.250 ±.01
5.08 ±0.25
.200 ±.01
1
Anode - 1
16.38 ±0.25
.645 ±.01
4
DIMENSIONS ARE IN INCHES
AND [MILLIMETERS].
Emitter - 4
Color-Pin # Function
Cathode - 2
Collector - 3
Red - 1
Anode
Black - 2
Cathode
White - 3
Collector
Green - 4
Emitter
OCB100-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 diameter 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 phototransistor 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.
The OPB350L Series have leads that are designed to mount directly
to PCBs. The OPB350W Series with 26 AWG wires are remote mountable.
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 sensor 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 optical 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 presence of either a clear fluid (blue LED indicator), a dark fluid (green LED
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19
indicator), or no fluid (no indicators will be lit). If the sensor is unable
to calibrate, a red LED will flash multiple times and then remain lit.
This is an indication that there is an insufficient infrared light reaching
the phototransistor, such as when a dark object or dark fluid is in the
optical path, or when the OCB100 circuit just needs higher gain.
The onboard jumper can be configured to set the gain at three different levels. See the OCB350 Series data sheet www.optekinc.com for
more details.
COMPLETE PART NUMBERS OF OPB350 AND OPB350 SERIES
20
OPB350
PCB mount for 1/8” tubing
OPB350L062
PCB mount for 1/16” tubing
OPB350W062Z
Wired assembly for 1/16” tubing, with mounting tabs
OPB350L125
PCB mount for 1/8” tubing
OPB350C125Z
Wired assembly for 1/8” tubing, mounting tabs & Molex connector 50-57-9404
OPB350W125Z
Wired assembly for 1/8” tubing, with mounting tabs
OPB350L187
PCB mount for 3/16” tubing
OPB350W187Z
Wired assembly for 3/16” tubing, with mounting tabs
OPB350L250
PCB mount for 1/4” tubing
OPB350W250Z
Wired assembly for 1/4” tubing, with mounting tabs
OCB350L062Z
OPB350L062Z mounted on OCB100AZ calibration circuit board
OCB350L125Z
OPB350L125Z mounted on OCB100AZ calibration circuit board
OCB350L187Z
OPB350L187Z mounted on OCB100AZ calibration circuit board
OCB350L250Z
OPB350L250Z mounted on OCB100AZ calibration circuit board
OCB100-KIT
USING THE OPB350C125Z WITH THE OCB100CZ
Note: The above discussion of the OCB350 series also applies to
using the wired OPB350W series and the OPB350C125Z with the
OCB100Z.
Connect the OCB100CZ to a power source as described on page 7
“Powering up the OCB100CZ”.
Plug the OPB350C125Z connector into the 4 pin Molex mating
connector 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
betweens pins 1 & 2 (see table on pg. 9) of the header. Calibrate the
sensor by momentarily grounding pin 4 of connector J1 by touching
the green wire of the mating connector to the black wire (ground) of
the mating connector.
A short length of 1/8” clear tubing is included in the OCB100-KIT.
Try the following experiment. Snap the tubing into place in the
optical path of the OPB350C125Z. Calibrate the sensor. Insert water
into the tubing sample. The blue light on the OCB100CZ should
light when water is present in the optical path, and no LED should be
lit when water is not present.
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21
OPB350 Package Drawing
22
OCB100-KIT
For any additional information or questions please feel free to contact
us via our applications hotline at 972.323.2488
23
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OPTEK Technology
1645 Wallace Drive
Carrollton, TX 75006 USA
Telephone: 972.323.2200
Fax: 972.323.2396
[email protected]
www.optekinc.com
OCB100-KIT
OPTEK reserves the right to make changes at any time in order
to improve design and to supply the best product possible.
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