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CS2 Color Scanner
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.
Delta Computer Systems, Inc., 11719 NE 95th Street, Vancouver, Washington 98682-2444 (360) 254-8688
email@deltacompsys.com http://www.deltacompsys.com
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.
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