Delta CS2 Manual

11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] Fax [phone]
[e-mail] http://www.deltacompsys.com
CS2 Color Scanner
A Self-Contained, Easy-To-Use Scanning/Lighting System in a
Compact Package For Production Line Automation Applications
The CS2 Color Scanner analyzes
reflected light captured by a silicon
cell.
It determines color by turning on only
the desired color at a given time using
its patented, solid-state lighting
system.
The CS2 then activates data outputs
based on the relative magnitude of the
Base color and the ratio of the Base
color and the Sense color.
Primary features
•Fast response rate: 500
microseconds, 50 uS optional.
•100,000 hour life LED lighting
system
•Automatic adjustment to changing
ambient
•Optically isolated outputs for Base
limit and Ratio limit. Analog
outputs for Base and Sense colors
•Easy set-up using integrated bar
graph display
•Compact size: 6 x 6.4 x 1.25"
•Low power requirements: 24Vdc @
250 mA maximum
•Color range options: blue to near-
infrared
•Versatility: Other options include
optimizing computer interface. Use
with rotary pulse generator to check
product or defect length, too.
Use the CS2 Color Scanner to:
•Sort objects and compare
peeled vs. unpeeled
organic vs. non-organic
ripe vs. green
over-ripe/rotten vs. normal
•Detect product defects such as
stains
spills
knots
over or undercooked product
•Align
materials
labels
packages
•Read paint markings
where bar coding or inkjet
printing is impractical or
impossible
The CS2 detects deviations from
normal or average color, based on the
Sense/Base ratio.
It can be configured to detect either a
high or low ratio. whether that's a
feature needed to be recognized or a
product defect.
Using the narrow-line scanning area
option, a wide area up to 1.25" can be
scanned for defects or features.
Detecting green areas on carrots, knots
on wood, and burned cookies are
applications that typically use the Low
Ratio setting. Detecting white ends on
asparagus is an example of a High
Ratio setting.
Setup is a simple, three-step
process
1. Mount scanner(s)
2. Wire power & outputs
3. Adjust gains & thresholds and
you're your way to the benefits of
improved product quality. Fast!
Where to find more information:
Free Sample Testing 2
How The CS2 Works 2
Using the Displays 3
Bar Graph Display 3
Status Indicators 3
Inputs and Outputs 3
Scan Cycle 3
Base & Sense Limit Outputs 4
Data Ready Output 4
External Trigger Input 4
Threshold Analog Inputs 4
Analog Outputs 4
Mounting the CS2 5
Wiring 6
Configuration 8
Adjustments 9
Color Tolerances 10
Pencil Sorting Example 10
Putting It To Work 11
Comparing Colors 11
Application Guidelines 12
Power Supplies 12
Electrical noise 12
Data Skew 12
Color Errors 12
Background Errors 12
Reflections 12
Intensity Variations 12
Using Multiple CS2s 12
Technical Information 14
Ordering Information 14
Company Profile 14
General Application Information 15

CS2 Color Scanner
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] 2
[e-mail] http://www.deltacompsys.com
Free Sample Testing
Delta will test your samples and tell you if your application
is a candidate for the CS2 color scanner (or another Delta
color scanning product).
This service is available to anyone with a potential
application. Simply send the samples, along with a business
card (se we can call and get a brief description of the
application) to:
Delta Computer Systems, Inc.
11719 NE 95th Streed, Suite D
Vancouver, WA 98682
Attn: Steve Nylund
If this brochure is more than a year old, please call and
cornfirm our address before sending. Please call (360)254-
8688.
After receiving your samples and discussing the application,
we will test your samples using a CS2 scanner and/or a
spectrometer. Will will then recommend a praticular
configuration for online testing.
Take advantage of the offer today. It's easy!
How The CS2 Works
The CS2 measures the difference in reflected light between
two light sources. In its standard configuration, the
reference color is 880-940nm (near-infrared) which is
referred to as the Base color. The second light source is
660nm (red) which is referred to as the Sense color. The
reflected color is measured by turning on the Base and Sense
high intensity LEDs, one color at a time, and reading a
silicon photocell. The amplified information is stored so
that the measured color information will still be present
when the LEDs are off. The LEDs are on for only about 20
microseconds out of the 500 microsecond cycle in order to
reduce power and maximize life.
Once the reflected Base and Sense color amplitudes are
stored, the current or real time-time values are subtracted
from the running averages (running averages are derived
from the minimum color amplitudes) for each color. The
running averages change over time, allowing the CS2 to
automatically adjust to changes in temperature, ambient
lighting, etc., and making periodic recalibration to
compensate for these changes unnecessary.
By comparing the ratio of the Base and Sense colors, a
determination can be made as to when and where a color
deviation occurs. The CS2 can be configured to detect either
a Low or High Ratio deviation. Example applications where
the Low Ratio setting is used include detecting green areas
on carrots, knots on wood and burned cookies, while the
High Ratio setting would be used to detect white ends on
asparagus, some paint applications, eand so on. The default
setting is Low Ratio.
When more sophisticated filtering, thresholds, or limit
algorithms are needed, the CS2 provides an easy interface to
an optimizing computer. In addition to analog inputs to
permit control of the Base and Sense Thresholds, analog
outputs are provided for Base and Sense colors. The outputs
do not provide absolute color information, but provide
relative values that can be processed by an optimizing
computer.

CS2 Color Scanner
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] 3
[e-mail] http://www.deltacompsys.com
Using the Displays
TB2
TB1
Bar Graph
Status
Indicators
LED's
LED's
Tri
g
In
Bar Graph Display
In order to make adjustment easy, the CS2 contains its own
voltmeter with a bar graph display which is visible through
the top. This display uses a "moving dot" technique where
the segment position represents the amplitude of the
reflected light.
Output Bar Graph Displa
y
Red
Green
Yellow
Less intense bar indicates Base Color
Bri
g
ht bar indicates Sense Color
The lowest voltage segments are yellow, the center green,
and the highest are red. Usually, once the Gains are
adjusted, the background intensity will be no higher than the
yellow segments and normal objects will be in the green
range. The 10th (red) segment indicates an overrange
condition; at this point the readings are invalid. The Gains
need to be set such that the highest intensity is not higher
than the 9th segment.
Both the Base color and the Sense color are simultaneously
displayed using a different intensity for each color. The
brighter LED represents the Sense color.
Status Indicators
Four indicators provide status of the digital inputs and
outputs. Indicators are lit when the condition they represent
is true (Output NPN transistor ON).
Tri
g
In
Data Read
y
Base Limit
Sense Limit
Inputs and Outputs
The CS2 provides two analog and three digital outputs and
two analog inputs. The digital outputs are: Data Ready,
Base Limit and Sense Limit. All three are optically isolated
uncommitted NPN open-collector outputs.
The two analog outputs provide voltages proportional to the
real time Base color and Sense color. Updated every scan
cycle, the outputs range from 0-10V and will drive high
impedance inputs (2 kohms or higher). These outputs are
not temperature compensated and must be used with the
appropriate software algorithms.
Scan Cycle
Bus
y
Data Read
y
Data
Read
y
Sense
Base
S
B
Limit &
Outputs Outputs Stable
Scan C
y
cle
Internal
Tri
gg
er Tri
gg
er Dela
y
Time
External
Tri
gg
er RPG Phase See
Note 1
OR
Analo
g
Measure
Measure
Output
Input
(
NPN output ON
)
(
NPN output ON
)
(
Limits NPN output ON when
limits exceed setpoint
)
Trigger Delay Time
(Determines Scan
Cycle Time when
using internal Data B & S Auto Restart
Jumpers
trigger) Ready 2 4 8
(default) 500us 110us 22us
435us 110us 22us Yes
380us 110us 22us Yes
330us 110us 22us Yes Yes
275us 110us 22us Yes
220us 110us 22us Yes Yes
164us 110us 22us Yes Yes
110us 55us 22us Yes Yes Yes
*50us 25us 12us Yes Yes Yes
*Special order, must
be set by factory
Note 1. When using an external trigger, the Scan Cycle Time is
determined by the time between RPG transitions ( RPG NPN output
changes from OFF to ON). If the time between transitions is less
than the Trigger Delay Time, scan data will be lost.

CS2 Color Scanner
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] 4
[e-mail] http://www.deltacompsys.com
Base & Sense Limit Outputs
Limit outputs provide the means to control an external
device when the setpoints are exceeded. Each is an isolated
open collector NPN output. When the limit setpoint is met
(Base color above setpoint and Sense limit below setpoint),
the NPN output is turned ON. ON current is 1.6 mA
minimum, 8 mA typical. The maximum open collector
voltage is 30VDC.
Note: If the limit outputs are connected to a high speed
input, they may need to be qualified with the Data Ready
output.
Data Ready Output
The Data Ready output should be used when the CS2 is
connected to a fast Analog-to-Digital converter. Inaccurate
readings can result if the A-D tries to read the analog color
voltages at the same time that the CS2 is updating them. By
synchronizing the external A-D converter to the CS2's
scanning cycle, this problem is eliminated.
The Data Ready output varies with the scan time. When
scanning with the internal trigger, Data is valid (Data Ready
line OFF) for approximately 110 microseconds each scan.
For high scan rates, the Data Ready NPN open collector
load resistor may need to be lowered (below 2.7k). It is a
good idea to allow 20-50% margin for gain degradation of
the opto-coupler. The ON current is 1.6 mA minimum, 8
mA typical. The maximum open collector voltage is 30Vdc.
External Trigger Input
This input allows a scanning cycle to be started by an
external signal. It is particularly useful when the scanner is
connected up to an optimizing computer. When the
scanning cycle is initiated by a signal from a rotary pulse
generator (RPG) connected to a belt or other conveying
system, the length of objects and features detected can be
determined by counting the number of RPG counts that
occur while the object or feature is within view of the
scanner. In this way, dimensional information can be
obtained.
To use this option, jumper the scanner for external triggered
operation, and wire the output of the RPG (or other trigger
source) to the Trig In terminals. The trigger input of the
CS2 requires 5 mA and will work with signal sources
between 3.5 and 24V, ensuring compatibility with most TTL
and open-collector encoders.
Threshold Analog Inputs
The CS2 provides two analog inputs to control the Base and
Sense limit setpoints. For applications using these inputs,
please contact Delta for assistance.
Analog Outputs
The CS2 provides two analog outputs proportional to the
real time Base color and Sense color. These outputs are
updated every scan cycle. The outputs are 0-10V and will
drive high impedance inputs (2 kohms or higher).
When using the analog outjputs with a PLC or other
computer, the Sense reading is divided by the Base reading
to get the Sense/Base ratio. This ratio is then compared with
a threshold value as is done within the CS2.
However, using the analog outputs allows additional
flexibility, such as multiple thresholds, thresholds that can
be stored and set remotely.
Note that is is often advantageous to subtract the
background readings before calculating ratios in cases where
the object being viewed does not completely fill the viewing
area.
Contact Delta for help with specific applications.

CS2 Color Scanner
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] 5
[e-mail] http://www.deltacompsys.com
Mounting the CS2
The CS2 scanner is contained in a enclosure which has
mounting tabs on the bottom. The lighting LEDs shine
through the clear bottom and the optics pick up the
reflected light through the bottom also. The bar graph
display and status indicators can be viewed through the
clear top.
Mount the CS2 so that the object to be scanned is within
the scanning area. In the default configuration, the center
of the scanning range is 1.75" from the bottom of the
scanner. Although the CS2 can see to some extent from
about 1" to about 4", best performance is from 1.5 to 2".
The CS2 will operate in any position. However, in dirty
environments, it is best to have the CS2 looking straight
down, and worst to be looking straight up. If the scanner
must be placed such that it is looking up, a stream of air
may be adequate to keep the window clean.
It is also advantageous to be able to see the indicators
through the clear top of the unit when it is in operation.
Scannin
g
Ran
g
e
Ob
j
ect
Various scannin
g
areas and shapes are possible.
Please contact Delta for further information.
Nominal Distance
from Scanner to
ob
j
ect
Top View of Scanned Area
Object
Scannin
g
Area Line Orientation
P/N CS2-NR-A1X8-00
Bottom View of CS2
Scanning Area
Background
LEDs LEDs
Viewer
CS2

CS2 Color Scanner
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] 6
[e-mail] http://www.deltacompsys.com
Wiring
The CS2 is designed to be wired using watertight flexible plastic conduit. In applications where sealed operation is
unnecessary, the wires can be run out through a strain relief connector. The conduit can also be used to pressurize the CS2
with low pressure, dry air for additional protection.
The number and type of wires required depend on the mode of operation. Only two wires, for 24Vdc power, are required to
operate the device. In simple applications, two more wires are used for the output. A four wire cable with an overall shield is
fine.
If analog threshold inputs or color outputs are used they need to be run through individually twisted, shielded pairs.
General Wiring Guidelines
1. The CS2 has sensitive circuitry which can be affected by electrical noise generated by loads. Its power supply should not
be used to power other loads.
2. The output of the 24Vdc sensor power supply must be isolated from earth ground. The CS2's common is connected to
earth ground through its case.
Application using Sense and Base Limits Outputs for Sorting or Rejecting Objects
Sense Threshold
Base Threshold
Sense Color
Base Color
Common
Data Read
y
+
Data Read
y
-
Common
Sense Limit -
Sense Limit +
Base Limit +
Common
24V +
External Tri
gg
er +
External Tri
gg
er -
Base Limit -
CS2
+
- Sensor
Power
24Vdc
+
- Output
Power
24Vdc
CM 90-PS-110 AC/24
Order No. 2943408
or equiv.
Phoenix
CM 90-PS-110 AC/24
Order No. 2943408
or equiv.
Phoenix
SSR Load
+
-
Case
In this application, the
CS2 is used in its
default configuration
(internal trigger, darker
areas to be sorted or
rejected, object scanned
every 500uS). In order
to activate the solid-
state-relay (SSR), the
object in the scanning
area must cause the
Base color to exceed
the Base Threshold
(object present) and the
Sense color must be
below the Sense
Threshold (Low Ratio).

CS2 Color Scanner
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] 7
[e-mail] http://www.deltacompsys.com
Using the CS2 With a Rotary-Pulse-Encoder (RPG) for Counting Objects and Defects
Sense Threshold
Base Threshold
Sense Color
Base Color
Common
Data Read
y
+
Data Read
y
-
Common
Sense Limit -
Sense Limit +
Base Limit +
Common
24V +
External Tri
gg
er +
External Tri
gg
er -
Base Limit -
CS2
+
- Sensor
Power
24Vdc
+Output
Power
24Vdc
CM 90-PS-110 AC/24
Order No. 2943408
or equiv.
Phoenix
CM 90-PS-110 AC/24
Order No. 2943408
or equiv.
Phoenix
Case
Object Counter
-
-RPG
Phase A
Open Collector
NPN
+
Defect Counter To synchronize CS2's
scan with an external
event, use the external
trigger input. In this
example, a new scan is
started every time a
pulse is received from
the RPG. The Sense
Limit output is used to
count the number of
dark areas (defects)
seen, while the Base
Limit output is used to
count the number of
objects.
Example Using the CS2 with an Optimizing Computer
Sense Threshold
Base Threshold
Sense Color
Base Color
Common
Data Read
y
+
Data Read
y
-
Common
Sense Limit -
Sense Limit +
Base Limit +
Common
24V +
External Tri
gg
er +
External Tri
gg
er -
Base Limit -
CS2
+
- Sensor
Power
24Vdc
+Output
Power
24Vdc
CM 90-PS-110 AC/24
Order No. 2943408
or e
q
uiv.
Phoenix
CM 90-PS-110 AC/24
Order No. 2943408
or e
q
uiv.
Phoenix
Case
-
-RPG
Phase A
Open Collector
NPN
+
-
+
Optimizing Computer
Isolated Differential
Analo
g
Inputs 0-10Vdc
2.7K
5V
TTL or CMOS
+
-
+
-
-
+
A/D
Tri
gg
er
+
-
+
-
In applications that require more sophisticated
filtering, thresholds, or limit algorithms, CS2's
analog outputs and inputs provide an easy interface
to an optimizing computer. As shown, the analog
outputs are read each time the Data Ready isolated
NPN output goes from ON to OFF. The
optimizing computer then processes the analog
information. Remember, the analog data provided
by the CS2 is not absolute color information, but
relative values.
In this example the Base and Sense Threshold
analog inputs are not used. If desired, these can be
used to control of the Base and Sense Limits
setpoints. By controlling the setpoints, the
optimizing computer can use the CS2's two
isolated NPN outputs for control. Contact Delta
for additional information.

CS2 Color Scanner
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] 8
[e-mail] http://www.deltacompsys.com
Configuration
2
4
8
Internal Tri
gg
er
External Tri
gg
er
Hi
g
h Ratio
Low Ratio
2
4
8
Internal Tri
gg
er
External Tri
gg
er
Hi
g
h Ratio
Low Ratio
Default Jumper Confi
g
uration
Confi
g
uration
Jumpers
TB2
TB1
Bar Graph
Status
Indicators
LED's
LED's
Sense Low/High Ratio
The Sense Limit is jumper configurable to respond to
either Sense/Base ratios that are lower than normal (Low)
or Sense/Base ratios that are higher than normal (High).
Example applications where the Dark setting (default) is
used including detecting green areas on carrots, knots on
wood and burnt cookies, while the High setting would be
used to detect white ends on asparagus, some paint
applications, etc.
External and Internal Triggers
When using the Internal trigger (default), every 500
microseconds the CS2 automatically takes new Sense and
Base color readings, calculates averages and Sense/Base
ratio and updates the outputs and indicators.
If an external trigger is desired, move the jumper from the
internal trigger position to the external trigger position and
wire the output of the RPG (or other trigger source) to the
Trig In terminals located on TB1.

CS2 Color Scanner
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] 9
[e-mail] http://www.deltacompsys.com
Adjustments
The CS2 has five potentiometers (pots): LED Time, Overall Gain, Sense Match, Base Threshold, and Sense Threshold. The
LED time adjustment is not used for basic operation; contact Delta for more information
TB2
TB1
Bar Graph
Status
Indicators
LED's
LED's
Trim Pots
Output
Tri
g
In
Data Read
y
Base Limit
Sense Limit
Led Time
Overall Gain
Sense Match
Base Limit Threshold
Sense Limit Threshold Output Bar Graph
Displa
y
Red
Green
Yellow
Status Indicators
The procedure below is for applications where the background (with no object present) is dark compared to the objects to be
viewed and the features to be identified are relatively dark (in the Sense color spectrum) compared to the object. Examples
include green areas on carrots, knots on wood and burned cookies.
Gains and Thresholds
1. Mount and wire the unit and connect power. The lighting LEDs on the bottom of the CS2 and the Data Ready indicator
should come on when power is applied. The output bar graph display may or may not be lit.
2. Find a sample object with the greatest reflectance (biggest and lightest). Put it in the viewing area and adjust the Overall
Gain until the less intense bar graph indicator is in the 8th or 9th position (red).
Output Bar Graph Displa
y
Red
Green
Yellow
Less intense bar indicates Base Color
Bri
g
ht bar indicates Sense Color
3. Adjust the Sense Match pot until the bright bar graph indicator is on top of the less intense bar graph indicator (8th or 9th
position).
4. Put an average object in the viewing area. Both base color and sense color bar graph indicators should be within the
center of the display (green).
5. Remove all objects. Reflected light from background should display no higher than the second bar graph indicator
(yellow).
6. Place an average size and color object in the viewing area for about ten seconds. Remove all objects and then
immediately put a minimum size, normal color object in the viewing area. Adjust the Base Threshold pot such that the
Base Limit indicator is just activated.
7. Put a marginally nominal object in the viewing area (make sure the low/high ratio limit configuration jumper setting is
correct). Adjust the Sense Threshold pot such that the sense limit indicator is just activated.
8. Fine tune both threshold adjustments while observing on-line operations.

CS2 Color Scanner
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 [phone] 10
[e-mail] http://www.deltacompsys.com
Color Tolerances
You want a bunch of paperweights in the shape of our logo.
You sketch the thing, add dimensions, and send it off to a
turn-key manufacturing shop with these instructions:
Dimensions: ±0.035"
Weight 1 LB, ±1 oz.
Color: Red; just like the sample.
To keep costs down, you've given generous tolerances on
dimensions and weights, but what is your color tolerance?
The manufacturer might think he's got an excellent match,
and you might think it clashes terribly. It gets worse. If you
are matching items that are not colored the same way, such
as plastic and metal, you have to take into account the
lighting as well.
Most colors are made up of a mixture of pigments and can
look very different under varied lighting. Different
pigments are used for paints, plastics, inks, dyes, etc.
Perfect matches of different materials under varied lighting
conditions is virtually impossible.
So how do you express color tolerances? Color can be
expressed in mathematical terms; intensity, hue, etc., and
can have mathematical tolerances, but this will seldom
produce optimum results.
Why is that? In order to keep manufacturing costs down,
tolerances should be as wide as possible. But color
tolerances are based on perception, and are not evenly
distributed. In most cases, larger variations in intensity are
permissible than in hue.
Tolerances in hue are often not even. Butter, for example
can be quite orange without cause for concern, but even
slightly green butter is likely to be repulsive.
Creating a multidimensional tolerance color model is
possible, but would take a lot of time. Even if you went to
this expense, on line, high speed testing against this model
would be very expensive.
In short, color is a perception issue, and is still more of an
art than a science. Fortunately, in many real-world
situations, a one dimension test for color is all that is
required; green areas on carrots, white ends on asparagus,
dark knots on wood, paint either there or not there, etc.
These types of applications are suited to the CS2 scanner.
Pencil Sorting Example
In this hypothetical application, red pencils are being
examined for missing erasers and missing paint. The CS2 is
used with an optimizing computer in order to make length as
well as color decisions on the product.
The pencils travel lengthwise, erasers first, under the CS2
which is configured for a viewing area of 1/32" by 1/2". A
rotary pulse generator (RPG) provides a pulse for every
1/32" of pencil travel so that the entire top side of pencil is
examined. The CS2 is triggered from this RPG.
The optimizing computer reads the raw analog color
information, subtracts the average background intensity, and
determines when a pencil is in the viewing area -- Base color
amplitude 15% or more than average Base amplitude, pencil
length -- counts RPG pulses while Base amplitude is high,
eraser present -- counts RPG pulses while Sense/Base ratio
is 110% or more than average Sense/Base ratio at the
beginning of the pencil, paint present -- checks that
Sense/Base ratio does not go high again during remainder of
the pencil length.
The system was set up, adjusted and it ran great. Except,
after maintenance shutdowns. Sometimes it would just
ignore the pencils.
A little troubleshooting pinpointed the problem. During
maintenance, the machine was cleaned using air nozzles.
The fine sawdust settled everywhere, including on the pencil
conveying belt. The sawdust was light colored and highly
reflective, making the background intensity readings as high
as the pencils!
A simple continuous belt cleaning system took care of the
problem.