Initial Confocal Displacement Sensor User`s Manual

Initial
Confocal Displacement Sensor
User’s Manual
Manual p/n LLL122010 – Rev. 1.0
For use with Acuity products
January 6, 2012
Acuity
A product line of Schmitt Industries, Inc.
2765 NW Nicolai St.
Portland, OR 97210
www.acuitylaser.com
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A Product Line of Schmitt Industries, Inc.
Limited Use License Agreement
CAREFULLY READ THE FOLLOWING TERMS AND CONDITIONS BEFORE OPENING THE
PACKAGE CONTAINING THE PRODUCT AND THE COMPUTER SOFTWARE LICENSED
HEREUNDER. CONNECTING POWER TO THE MICROPROCESSOR CONTROL UNIT
INDICATES YOUR ACCEPTANCE OF THESE TERMS AND CONDITIONS. IF YOU DO NOT
AGREE WITH THE TERMS AND CONDITIONS, PROMPTLY RETURN THE UNIT TO THE
DEALER FROM WHOM YOU PURCHASED THE PRODUCT WITHIN FIFTEEN DAYS FROM
DATE OF PURCHASE AND YOUR PURCHASE PRICE WILL BE REFUNDED BY THE
DEALER. IF THE DEALER FAILS TO REFUND YOUR PURCHASE PRICE, CONTACT
SCHMITT INDUSTRIES, INC. IMMEDIATELY AT THE ADDRESS FOLLOWING
CONCERNING RETURN ARRANGEMENTS.
Schmitt Industries, Inc. provides the hardware and computer software program contained in the
microprocessor control unit. Schmitt Industries, Inc. has a valuable proprietary interest in such
software and related documentation ("Software), and licenses the use of the Software to you
pursuant to the following terms and conditions. You assume responsibility for the selection of
the product suited to achieve your intended results, and for the installation, use and results
obtained.
License Terms And Conditions
a.
b.
c.
d.
e.
You are granted a non-exclusive, perpetual license to use the Software solely on and in
conjunction with the product. You agree that the Software title remains with Schmitt
Industries, Inc. at all times.
You and your employees and agents agree to protect the confidentiality of the Software.
You may not distribute, disclose, or otherwise make the Software available to any third
party, except for a transferee who agrees to be bound by these license terms and
conditions. In the event of termination or expiration of this license for any reason
whatsoever, the obligation of confidentiality shall survive.
You may not disassemble, decode, translate, copy, reproduce, or modify the Software,
except only that a copy may be made for archival or back-up purposes as necessary for
use with the product.
You agree to maintain all proprietary notices and marks on the Software.
You may transfer this license if also transferring the product, provided the transferee agrees
to comply with all terms and conditions of this license. Upon such transfer, your license will
terminate and you agree to destroy all copies of the Software in your possession.
Procedures for Obtaining Warranty Service
1. Contact your Acuity distributor or call Schmitt Industries, Inc. to obtain a return
merchandise authorization (RMA) number within the applicable warranty period.
Schmitt Industries will not accept any returned product without an RMA number.
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2. Ship the product to Schmitt Industries, postage prepaid, together with your bill of
sale or other proof of purchase, your name, address, description of the problem(s).
Print the RMA number you have obtained on the outside of the package.
This device complies with:
EN 50 081-1
Spurious emission
EN 61000-6-2
Resistance to disturbance
Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation.
Note: This equipment has been tested and found to comply with the limits for a Class
A digital device, pursuant to part 15 of the FCC rules. These limits are designed to
provide reasonable protection against harmful interference when the equipment is
operated in a commercial environment. This equipment generates, uses, and can
radiate radio frequency energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio communications.
Operation of this device in a residential area is likely to cause harmful interference in
which case the user will be required to correct the interference at his own expense.
This manual copyright © 2012, Schmitt Industries, Inc.
Acuity Initial Confocal Sensor
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Table of Contents
Procedures for Obtaining Warranty Service ...................................................................................... i Table of Contents ............................................................................................................................. ii Table of Figures ............................................................................................................................... vi 1. 0BIntroduction to the Acuity Initial ............................................................................................... 1 1.1 Acuity Initial Controller ..................................................................................................... 1 1.1.1 Description ............................................................................................................... 1 1.1.2 Specifications ........................................................................................................... 2 1.1.3 LED indicators ......................................................................................................... 2 1.2 Optical pen ....................................................................................................................... 3 1.3 Fiber optics cable............................................................................................................. 4 1.4 Light source ..................................................................................................................... 4 1.5 Accessories ..................................................................................................................... 4 1.5.1 2. 3. 105BMetrology standards ................................................................................................ 5 1BSafety ...................................................................................................................................... 6 2.1 23BElectrical hazards ............................................................................................................ 6 2.2 24BOptical hazards ................................................................................................................ 6 2.3 25BGeneral recommendations .............................................................................................. 6 2.4 26BCompliance with the EC regulation 89/336/EEC « Electromagnetic Compatibility » ...... 6 2.5 27BCompliance with the RoHS Regulation ........................................................................... 6 2BInstallation and startup ............................................................................................................ 7 3.1 28BElectrical Connections ..................................................................................................... 7 3.1.1 106BPower ....................................................................................................................... 7 3.1.2 107BRS232 connector ..................................................................................................... 7 3.1.3 108BUSB connector......................................................................................................... 7 3.1.4 10BSynchronization signals ........................................................................................... 7 1B ................................................................................................................................................ 7 3.2 29BFiber optics connections .................................................................................................. 8 3.3 30BInstalling the USB driver and “CCS Manager” software .................................................. 8 3.3.1 12BInstalling the USB driver: ......................................................................................... 8 3.3.2 13BInstalling the software ............................................................................................ 10 3.4 4. 31BSensor Startup ............................................................................................................... 10 3BBasic System Characteristics ............................................................................................... 11 4.1 32BChromatic Confocal Imaging (CCI)................................................................................ 11 Acuity Initial Confocal Sensor
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5. 6. 4.2 3BApplications ................................................................................................................... 12 4.3 34BMeasuring modes .......................................................................................................... 12 4.3.1 14B“Distance” measuring mode .................................................................................. 13 4.3.2 15B“Thickness” measuring mode ................................................................................ 13 4.4 35BMeasured data ............................................................................................................... 13 4.5 36BExternal scanning .......................................................................................................... 13 4BCommunication with the Initial .............................................................................................. 15 5.1 37BVia the CCS Manager .................................................................................................... 15 5.2 38BVia DLL .......................................................................................................................... 15 5.3 39BVia direct digital I/O........................................................................................................ 15 5BGetting started ...................................................................................................................... 16 6.1 40BConnecting to the Initial ................................................................................................. 16 6.2 41BConfiguring the sensor................................................................................................... 17 6.3 42BSaving the configuration ................................................................................................ 18 6.4 43BSelecting the output data ............................................................................................... 19 6.5 4BViewing and saving the measured data......................................................................... 20 6.6 45BAcquiring the Dark signal ............................................................................................... 22 6.6.1 6.7 46BAdjusting the LED brightness ........................................................................................ 23 6.7.1 7. 16BRelated topics ........................................................................................................ 23 17BMinimal brightness level ........................................................................................ 24 6.8 47BPlacing the sample within the measurement range of the optical pen .......................... 24 6.9 48BSample Rate adjustment ............................................................................................... 25 6.10 49B
Intensity data ............................................................................................................. 26 6.10.1 18BIntensity as a quality indicator ............................................................................... 26 6.10.2 19BIntensity images ..................................................................................................... 27 6BAdvanced Configuration........................................................................................................ 27 7.1 50BSynchronizing the sensor with other devices ................................................................ 28 7.1.1 120BThe “Start” trigger mode ........................................................................................ 28 7.1.2 12BTraining .................................................................................................................. 29 7.2 51BCCS Manager software ................................................................................................. 30 7.2.1 12BHelp utility .............................................................................................................. 30 7.2.2 123BCommand Terminal ............................................................................................... 30 7.2.3 124BTools Menu ............................................................................................................ 31 7.3 52BSerial communications................................................................................................... 31 7.4 53BMeasuring thickness ...................................................................................................... 32 7.4.1 125BThe “Thickness” measuring mode ......................................................................... 32 Acuity Initial Confocal Sensor
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8. 7.4.2 126BMinimum measurable thickness ............................................................................ 32 7.4.3 127BSingle surface in “Thickness” mode ...................................................................... 32 7.4.4 128BThickness calibration (refractive index file generation) ......................................... 33 7.4.5 129BMeasuring the Thickness of opaque samples ....................................................... 33 7.4.6 130BTeach functions for thickness measurement ......................................................... 34 7BMain functions of the CCS Initial ........................................................................................... 35 8.1 8.1.1 134BAcquiring and saving the Dark signal .................................................................... 35 8.1.2 135BMinimal rate authorized after Dark acquisition ...................................................... 35 8.1.3 136B“Fast” Dark ............................................................................................................. 35 8.2 9. 5BDark signal ..................................................................................................................... 35 56BSampling rate................................................................................................................. 36 8.2.1 137BSelecting a preset sampling rate ........................................................................... 36 8.2.2 138B“Free” sampling rate .............................................................................................. 37 8.2.3 139BExposure time ........................................................................................................ 37 8.2.4 140BExamples ............................................................................................................... 37 8.3 57BMeasuring modes .......................................................................................................... 38 8.4 58BRefractive index ............................................................................................................. 39 8.4.1 14BSetting a constant refractive index ........................................................................ 39 8.4.2 142BSe........................................................................................................................... 39 8.4.3 143BSelecting a Refractive index file ............................................................................ 39 8.5 59BAdjustment of the LED brightness ................................................................................. 40 8.6 60BAveraging ....................................................................................................................... 40 8.7 61BHolding the last valid value ............................................................................................ 41 8.8 63BGetting the serial number and the firmware version...................................................... 41 8.9 64BSaving the current configuration .................................................................................... 41 8.10 65BResetting the sensor ...................................................................................................... 42 8BDigital Outputs ...................................................................................................................... 43 9.1 6BSelection of the data to be transmitted .......................................................................... 43 9.1.1 14BAvailable data ........................................................................................................ 43 9.1.2 145BMeaning of the data ............................................................................................... 44 9.1.3 146BData Selection ....................................................................................................... 44 9.2 67BSpecific features of the RS232 link................................................................................ 45 9.2.1 147BConfiguring of the COM port of the host computer ................................................ 45 9.2.2 148BLimits of simultaneous data transmissible ............................................................. 46 9.3 68BSpecific features of the USB link ................................................................................... 47 9.3.1 149BUSB driver ............................................................................................................. 47 Acuity Initial Confocal Sensor
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9.3.2 10. 150BUsing the USB link ................................................................................................. 47 10BAuto-adaptive modes ......................................................................................................... 48 10.1 71B “Auto-adaptive Dark” mode .......................................................................................... 48 10.2 72B“Auto-adaptive LED” mode ............................................................................................ 48 10.3 73B“Double Frequency” mode ............................................................................................. 49 11. 10.3.1 15BActivation ............................................................................................................... 49 10.3.2 152BFrequencies ........................................................................................................... 50 10.3.3 153BIntensity ................................................................................................................. 50 10.3.4 154BSelected frequency bit ........................................................................................... 50 10.3.5 15BCompatibility with other commands/modes ........................................................... 51 10.3.6 156BIntensity LED indicator in “Double Frequency” mode ............................................ 51 10.3.7 157BSynchronization in “double frequency” mode ........................................................ 51 1BSynchronization ................................................................................................................. 53 11.1 74B“Sync out” signals .......................................................................................................... 53 11.2 75B“Sync in” signals ............................................................................................................ 53 11.3 The “Start on edge” trigger mode .................................................................................. 54 11.4 Training .......................................................................................................................... 54 11.5 Additional Trigger modes ............................................................................................... 55 11.6 Identification of the first point measured after trigger .................................................... 55 11.7 7BTrigger configuration ...................................................................................................... 56 11.7.1 158B“Start” (“TRG”) trigger ............................................................................................ 56 11.7.2 159B“Start/stop on state” trigger (“TRN”)....................................................................... 56 11.7.3 160B “Start/stop on edge” (“TRS”) trigger...................................................................... 57 11.7.4 16B“Burst” (“TRE”) trigger ............................................................................................ 57 11.7.5 162BSelecting the active edge/active state ................................................................... 57 11.7.6 163BSoftware trigger ..................................................................................................... 57 11.8 12. 79BMaximum rate of “Sync in” pulses ................................................................................. 58 d
BA13 Advanced
topics............................................................................................................... 59 12.1 86BDetection threshold ........................................................................................................ 59 12.2 87B Light source test .......................................................................................................... 59 12.2.1 167BEnabling/Disabling the test .................................................................................... 60 12.3 8B “First peak” mode......................................................................................................... 60 12.4 89B“Altitude” mode .............................................................................................................. 60 12.5 90BHandling of unmeasured peak in Thickness mode ....................................................... 61 12.6 91BWatchdog ....................................................................................................................... 61 12.7 92B “Counter”, “State” and “Auto-adaptive mode” data ....................................................... 62 Acuity Initial Confocal Sensor
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12.7.1 168BThe “Counter” data ................................................................................................ 62 12.7.2 169BThe “State” data ..................................................................................................... 62 12.7.3 170BThe “Auto-adaptive mode” data ............................................................................. 63 12.8 13. 14BLow-level Commands ........................................................................................................ 64 13.1 17BCommand syntax ................................................................................................... 64 13.1.2 172BSensor response.................................................................................................... 64 95BCommand List for the CCS Initial .................................................................................. 65 15BDATA FORMAT AND DATA ENCODING ......................................................................... 67 14.1 96BData transmission formats ............................................................................................. 67 14.1.1 173BAscii Format ........................................................................................................... 67 14.1.2 174BBinary format ......................................................................................................... 68 14.2 15. 94BCommand Language ..................................................................................................... 64 13.1.1 13.2 14. 93BSynchronization mode ................................................................................................... 63 97BDecoding the data.......................................................................................................... 68 14.2.1 175BData decoding for the Distance measuring mode ................................................. 68 14.2.2 176BData decoding in Thickness measuring mode ...................................................... 69 16BMaintenance ...................................................................................................................... 70 15.1 98BHandling the fiber optics ................................................................................................ 70 15.2 9BHigh Dark signals........................................................................................................... 70 15.3 10B Diagnostics File ............................................................................................................ 72 15.4 10BFirmware update ............................................................................................................ 72 15.5 102BTechnical support .......................................................................................................... 72 16. 17BAppendix: Chronograms .................................................................................................... 73 Table of Figures
Figure 3 - A modular optical pen with its fiber optic cable..................................... 4 Figure 4 Connection of the fiber optics lead ........................................................ 8 Figure 5 Description of Chromatic Confocal Imaging ...........................................11 Figure 6 Connection Wizard to CCS Manager Program ........................................16 Figure 7 ” image (left) and “Intensity” image (right) of a micro lens .....................27 Figure 8 “Distance” Image (left) and “Intensity” image (right) of a scratch on the
neck of a glass bottle.....................................................................................27 Figure 9 Trigger Settings Dialog Box in CCS Manager .........................................29 Figure 10 Built-in terminal program in CCS Manager ..........................................30 Acuity Initial Confocal Sensor
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1. Introduction to the Acuity Initial
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The Acuity Initial sensor consists of an opto-electronic unit (controller) and a chromatic
objective (“optical pen”). The optical pen is connected to the controller using a fiber
optics cable.
A CD with the software drivers, the “CCS Manager” program and this User Manual is
delivered with each sensor.
The sensor is available in three models with measuring ranges of 400 µm, 4 mm and 12
mm, respectively. The difference between the three models resides in the sizes of the
optical pens; the controller is identical for the three models.
1.1
Acuity Initial Controller
The Acuity Initial controller controls signal acquisition, performs signal processing,
computes the distance and thickness data and transmits the data on the digital
outputs (RS232 or USB).
1.1.1 Description
The front panel of the controller features:
Fiber optic socket for connecting the optical pen
USB 2.0 connector
3 LED indicators entitled “POWER”, “INTENSITY” and “MEASURE”
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The rear panel of the controller features:
Power connector (male IEC),
On/Off switch
Two BNC connectors for “Sync In” and “Sync Out” signals
RS232 Socket
On/Off Switch
Sync IN
Sync OUT
RS232 Port
Power Supply
1.1.2 Specifications
Measuring modes
- Distance mode
- Thickness mode
100 Hz – 2000 Hz
RS232 (up to 460800 baud)
USB 2.0
In “Distance” mode: 30 bits
In “Thickness” mode: 15 bits
Input and output TTL 0V – 5V
Extensive trigger capabilities
100V to 240 V Ac / 25 W
Measuring rate
Digital outputs
Digital resolution
Synchronization
Power
supply/Consumption
Weight
Dimensions W x H x D
1920 g
199 mm x 123.5 mm x 277 mm
1.1.3 LED indicators
1.1.3.1 Power LED indicator
Green when power is on
Off otherwise
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1.1.3.2 “Intensity” LED Indicator
Off
if no signal is detected
Red in case of signal saturation
Green
if signal intensity is comfortable (> 5% of the maximum level),
Orange if signal intensity is low ( < 5% of the maximum level)
1.1.3.3 “Measure” LED Indicator
Off
if no object is detected in the measuring range.
Green
scale)
at the center of the measuring range (between 15% and 85% of full
Orange near the limit of measuring range (between 0% and 15% of full scale or
between 85% and 100% of full scale)
1.2
Optical pen
The optical pen is totally passive, since it incorporates neither heat sources nor
moving parts, thus avoiding any thermal expansion which could affect the accuracy of
the sensor measuring process.
The optical pen determines the metrological characteristics of the sensor.
The following table reviews the basic optical characteristics of the three Acuity Initial
models.
Sensor Model
Optical Pen Model
Distance Measuring range
Working distance
Spot size
Max measurable slope angle
(1)(2)
Distance Mode Specifications
Accuracy
(3)(4)
Static noise (3)(5)
with no averaging
with averaging 10
Thickness mode Specifications
Min. measurable Thickness
(6)(7)
Max. measurable Thickness
(6)(7)
Acuity Initial 0.4
Acuity Initial 4
Acuity Initial 12
mm
mm
µm
deg
CL2-MG140
0.4
11
3.4
±28°
CL4-MG35
4.0
16.4
7.2
±21°
CL5-MG35
12
29
16.5
±14°
nm
80
300
600
nm
22
8
160
55
400
180
µm
15
75
420
µm
580
5800
17400
Notes:
(1) The maximum angular slope applies to samples with a specular (mirror-like) surface. For diffusing
surfaces the maximal slope angle is higher (up to 87° for perfect diffusers).
(2) Measured on a mirror at 100 Hz, with no averaging. At high slope angle the intensity of the signal is
low.
(3)
Measured in “Distance” measuring mode
(4) Accuracy is the max error inside the entire measuring range, measured immediately after calibration
at the following conditions:
“Auto-adaptive Led” mode, optimal rate, averaging factor= measuring rate / 10, slope angle=0°
(5)
RMS noise measured on a static sample at the center of the measuring range at optimal rate.
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(6)
These values are for a refractive index of 1.5
(7)
Measured at the center of the measuring range at optimal rate, with no averaging
Recommendation:
Metallic samples should be measured with the Acuity Initial 0.4, in particular in
applications requiring high resolution, such as roughness measurement.
When measuring metallic samples with the Acuity Initial 4 or Acuity Initial 12,
performances may fall short of the above specifications.
The following table resumes the mechanical properties of the optical pen.
Optical Pen Model
Length (with no fiber)
Diameter
mm
mm
Weight
g
1.3
CL2MG140
208.9
 27
190
CL4MG35
145.5
 27
155
CL5MG35
145.5
 27
175
Fiber optics cable
The fiber optics cable is of type multimode 50/125. It is 3 m long.
When handling the fiber optics lead take care to avoid bending the fiber to a radius of
curvature of less than 20 mm.
Dust particles or dirt on the fiber optics tip or inside the fiber connector can result in
significant malfunctioning. When no optical fiber is connected, the socket must at all
times be fitted with its protection cap to avoid contamination.
Figure 1 - A modular optical pen with its fiber optic cable
1.4
Light source
The Acuity Initial is equipped with an internal light source (white LED).
The light source brightness may be set by command to any desired value between 0%
and 100% of the max brightness. Alternatively, the sensor may be configured to an
“auto-adaptive” mode in which the source brightness is automatically adjusted to the
sample reflectivity.
The sensor features an automatic test of the light source. A bit in the “State” data is
set in case the LED should be replaced. The Light source test may be enabled or
disabled and is operational under some conditions.
1.5
Accessories
The following accessories are supplied with the sensor:
•
USB cable
•
RS232 cable
•
A CD comprising the Use Manual (this document) and the Software
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1.5.1 Metrology standards
105B
As optional equipment, Acuity can supply the following metrology standards:
10 µm depth groove
Roughness standard Ra = 0.8 µm
Optical flats (diameter 140 mm or 300 mm)
Reference sphere
Metrology standards may be ordered with or without a certificate. For more
information please contact sales@acuitylaser.com.
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2. Safety
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The CCS Initial is an opto-electronic instrument. It is safe in normal operating conditions
described in this User’s Manual. Unlike other Acuity sensors products, the CCS Initial
displacement sensor system does not use lasers and is not governed by the same safety
considerations.
2.1
Electrical hazards
23B
The CCS Initial controller box should be opened by qualified technicians only. If
opened, electrical hazards may exist, especially during an inappropriate tampering of
the instrument.
Unplug the instrument from the power outlet before changing accessories,
maintenance, cleaning, or changing the lamp.
2.2
Optical hazards
24B
The optical pen emits a beam of visible light with wavelengths ranging from 400 to
750 nm.
The flux contained in this beam is smaller than the MPE (Maximum Permissible
Exposure). However it is recommended to avoid looking directly into the optical pen.
2.3
General recommendations
25B
Do not use the instrument if it has been dropped and shows signs of damage or
functions improperly, or if the fan does not operate properly. In this case do not open
the instrument and contact our helpline: sales@acuitylaser.com.
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Repairs should only be carried out by qualified technicians using original replacement
parts.
In case of inappropriate use or failure to comply with the instructions, the
manufacturer disclaims all liability and the guarantee will not apply. See the Acuity
Warranty at the beginning of this document
2.4
Compliance with the EC regulation 89/336/EEC
« Electromagnetic Compatibility »
26B
The CCS Initial sensor complies with the generic or specific requirements of the
following harmonized standards:
EN 50 081-1
Spurious emission
EN 61000-6-2
Resistance to disturbance
2.5
Compliance with the RoHS Regulation
27B
The CCS Initial is RoHS compliant.
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3. Installation and startup
2B
3.1
Electrical Connections
28B
The following paragraphs explain how to:
Connect the sensor to a power supply
Connect the sensor to a host computer using either the RS232 port or the USB 2.0
port (the two ports may be connected simultaneously),
Connect the synchronization signals,
Connect encoders for synchronous reading of position and sensor data
3.1.1 Power
106B
Connect a power cable to the main input socket (100-240 Vac – 50/60Hz) of the
Initial controller (rear panel).
Electrical power: 40W.
Fuse rating : 5x20mm 1A (it is located at the rear panel).
3.1.2 RS232 connector
107B
A 9-pin female D-Sub socket is at the rear panel of the Initial controller.
The RS232 pin-out is described below:
Pin
3
5
2
Pin Name
Rx
Gnd
Tx
Description
Receiver (input)
Ground
Transceiver (output
3.1.3 USB connector
108B
The USB 2.0 connector is a standard B-type connector. An USB 2.0 (High-speed)
compliant cable is required. (Note: A USB cable may be ordered from the other
vendors).
3.1.4 Synchronization signals
10B
Two BNC female socket are located on the rear panel dedicated to synchronization
signals:
“Sync In” :
0-5V dc TTL trigger signal from an external device.
“Sync out” : 0-5V dcTTL output signal at the measuring rate.
1B
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3.2
Fiber optics connections
29B
Insert the lead of the optical pen fiber optics into the “Sensor Input” fiber socket on
the controller front panel, taking care to comply with the correct orientation of the
connector.
Connection and disconnection of the fiber optics lead
Figure 2 Connection of the fiber optics lead
To connect the fiber optics, insert the plug into the fiber socket as shown in Figure 4
until a “click” is heard as it locks into position. To remove the fiber optics from its
socket, first press on the locking lever, then pull the lead out of the socket.
If your sensor is equipped with an external light source, connect the light box to the
“external source“ socket located on the controller front panel using the light source
fiber optics.
3.3
Installing the USB driver and “CCS Manager” software
30B
3.3.1 Installing the USB driver:
12B
If you wish to communicate with the sensor using the USB port, you should install
the dedicated USB driver on the host computer. The driver should be installed for
each USB port of the PC to which a CCS sensor is connected.
The driver may be installed from the CD delivered with the sensor. Connect your
sensor to the USB 2.0 port and switch it off. Insert the CD, and start the driver
installation. Do not restart the sensor until prompted to do so by the
installation program.
Use a host computer equipped with XP operating system with SP2, or more recent
Insert the “CCS Manager” Utility CD into the CDROM drive.
The Autorun screen appears:
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After the driver’s installation from the CD, the Windows “Add new Hardware
wizard” starts. Select in the first window “Not this time” and in the following one
“install automatically”. If the Windows wizard starts before or during Acuity driver
installation, leave it beside and come back to it when Acuity driver installation is
done.
3.3.2 Installing the software
13B
From the Autorun screen, install the “CCS Manager” program. This program is used
in the tutorial and the training sections.
If you intend to develop your own program for controlling the sensor, install the
DLL SDK (Software Developer’s Kit).
3.4
Sensor Startup
31B
If your sensor is equipped with an external light source, switch on the light source first,
then the controller, by operating their On/Off switches.
Startup procedure lasts about 10 seconds. The LED indicators on the sensor front
panel go on and off, and the startup message indicating the firmware version is sent
on the digital output channels, e.g.:
High Speed VART – COM Initiate<
Acuity Initial V1.3.1
FPGA : 011081
Booting sequence
At the end of the startup, the sensor starts measuring.
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4. Basic System Characteristics
3B
The CCS Initial is a high-resolution distance point-sensor. It is based on Chromatic
Confocal Imaging (CSI). This chapter gives some basic notions concerning the technology,
the applications and the measuring modes of the sensor.
4.1
Chromatic Confocal Imaging (CCI)
32B
Chromatic Confocal Imaging is based on 2 principles:
Confocal imaging
Chromatic coding of the optical axis.
The Confocal setup is an optical setup in which an optical system generates the image
S’ of a point source S on the surface of the object. The backscattered light is collected
by the same optical system, which images the light spot on a pinhole S”. The pinhole
is placed in front of a photodetector. It filters the light rays that can reach the
photodetector and for this reason it is also called “spatial filter”. Confocal setups are
characterized by an exceptional Signal-to-Noise ratio. In the case of CCI, the optical
system is the chromatic optical pen and the photodetector is a spectrometer.
Chromatic coding of the optical axis means that the optical system has axial
chromatism: each wavelength is focalized at a different point along this axis. Suppose
now that a sample is present inside the chromatically-coded range so that the
wavelength 0 is focalized on its surface. When the reflected (or backscattered) beam
reaches the plane of the pinhole, the rays at wavelength are focalized on the pinhole
so they can pass through the pinhole and reach the sensitive area of the spectrometer.
Other wavelengths are imaged as large spots so they are blocked by the pinhole. The
spectrometer “decoding” the sample position by identifying the wavelength 0.
The spectrometer signal corresponds to the spectral repartition of the collected light.
It presents a spectral peak. When the object moves inside the measuring range, the
spectral peak on the spectrometer shifts.
Figure 3 Description of Chromatic Confocal Imaging
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The relation between the position of the spectral
peak (“barycenter” in pixels) and the axial position of
the object (“distance” in µm) is called “calibration
lookup table” (LUT).
The calibration LUT, characterizing a specific
spectrometer and a specific optical pen, is measured
by the fabricant and loaded into the controller.
4.2
Applications
3B
Chromatic confocal sensors are used both in industrial environments for in-line
inspection during production process, and in laboratory environments as high precision
instruments. Their principal applications are:
Microtopography (measuring the shape of the sample)
Dimensional control (testing whether the size of certain features of manufactured
products complies with specifications),
Quality control: (identification and characterization of defects on manufactured
products)
Roughness measurement (measuring the statistical characteristics of the sample
surface)
Tribology (characterization of mechanical or chemical erosion)
Thickness measurement
Chromatic confocal sensors are fully compatible with the ISO 25178 standard
concerning the measurement and analysis of 3D a real surface texture. Moreover, Part
601 of this standard, dedicated to non-contact surface measurement, cites CCI as the
first reference technology.
Chromatic confocal sensors can measure samples made of practically any type of
material (glass, ceramic, plastic, semiconductor, metal, fabric, paper, leather…). They
can measure polished surfaces (mirrors, lenses, wafers) as well as rough ones.
The optical characteristics of the optical pen, and in particular the spot size, the axial
resolution and the maximal slope angle, should be suited to the size and slope of the
features present on the sample to be measured.
Metallic objects should be measured with the CL1 or the CL2 optical pens, in particular
when measuring roughness or in applications requiring high resolution.
When measuring metallic objects with optical pens whose spot size is larger,
performances may fall short of specifications. The amount of degradation depends on
microstructure of the metallic surface.
4.3
Measuring modes
34B
Chromatic confocal sensors have two measuring modes: “Distance” and “Thickness”.
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The principal measuring mode of the CCS Initial is the “Distance” mode. The
sensor is calibrated and tested in this mode. Acuity can furnish a calibration
certificate attesting to these test results.
4.3.1 “Distance” measuring mode
14B
The “Distance” measuring mode is dedicated to measuring the altitude of points
located on the surface of a sample. The distance data is transmitted with 30-bit
digital resolution.
When measuring height profiles on an opaque sample (metal, paper, ceramics…),
the use of the “Distance mode” is straightforward.
When measuring thin transparent samples or coated samples, it is possible that the
sensor “sees” two signals at the same time: the coating surface reflects one signal
and the substrate reflects a second one. By default the sensor selects the strongest
signal and ignores all other detected signals, regardless of the relative positions of
the spectral peaks. In some applications this behavior is not optimal: in the above
example, the substrate reflectivity is often stronger than that of the coating, while
one may wish to measure the coating surface. The “First peak” mode, described in
the “Advanced Topics” chapter, gives a solution to such applications.
4.3.2 “Thickness” measuring mode
15B
The “Thickness” mode is an additional measuring mode dedicated to measuring the
thickness of transparent samples. In this mode the sensor measures
simultaneously the positions of the two faces of the transparent sample, and
computes the thickness as the difference between these two positions.
Measuring thickness is more difficult than measuring distance and is less precise. It
is also subject to some limitations. In order to obtain metrological performances in
this mode, a special procedure called “thickness calibration” should be carried out.
Thickness calibration is performed by the user. This process requires a thickness
standard. The “Thickness” measuring mode is described in section 7.4.
4.4
Measured data
35B
At each point of the sample, the sensor measures simultaneously several data points.
In the “Distance“ measuring mode the measured data are:
the distance of the measured sample point
the intensity of the retro-diffused light beam.
In the thickness measuring mode the measured data are:
the distance and intensity of the first sample face,
the distance an intensity of the second sample face,
the thickness.
In addition to measured data the sensor may deliver some additional data (counter,
state…). The sensor system may be configured to transmit some or all of these data.
4.5
External scanning
36B
An important characteristics of the CCS Initial sensor, is the fact that it is a “point”
sensor; in other words, at any given instant the sensor measures a single point
located on its optical axis. In order to obtain a profile or measure an entire surface, it
is necessary to scan the sample along one or two axes with the aid of some external
scanning device. Generally the scanning device is motorized; in some cases it
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comprises an encoder for determining the precise position of the sample at any given
instant.
For some applications the synchronization between the sensor and the external
scanning device is an important issue. The CCS Initial may be synchronized both as a
“slave” and as a “master”. This topic is discussed further in section 12.
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5. Communication with the Initial
4B
There are two options for communicating with the CCS Initial sensor: The CCS Manager
program, a DLL, direct serial communications via RS232 or USB.
5.1
Via the CCS Manager
37B
The “CCS Manager” application may be used to configure the sensor very easily and to
view, save and print the measured data. It is supplied on a CD with the sensor. It
features a “Command Terminal” for low-level communication with the sensor, and
allows uploading new firmware versions. The application comprises special procedures
for in-situ calibration and for generating refractive index files. In case you have a
problem with the sensor, this software can generate with a single mouse click a
diagnostics data file with all sensor parameters. Please join the diagnostics file to any
technical question addressed to your vendor.
5.2
Via DLL
38B
DLL may be used to interface the sensor with a general-purpose user program.
The « CHR DLL » is intended for user programs in “classic” C or C++ language. The
operating manual of the DLL includes a large number of code samples. The “Acuity
Sensor DLL” is intended for all .NET compatible languages (Labview, VB, C# C++/CLI,
etc.) This DLL features an internal help utility. The DLL for the sensor are provided on
a CD.
5.3
Via direct digital I/O
39B
The RS232 serial link and the USB link enable sensor configuration using a specific
control language and acquisition of the measured data. As an example, the Windows™
« Hyper Terminal »™ utility can be used to send the commands and receive the
measurements back from the sensor via the RS232 link. The Command Terminal of
the “CCS Manager” software can be used with either RS or USB link. For
communication using the USB port, a dedicated USB driver should be installed on the
host device.
The serial link allows baud rates up to 460800. For this link there exist some
limitations on the amount of data transmissible simultaneously (see section 9.2). USB
allows unlimited data transmission at all rates.
Recommendation: All software applications use the same COM port or USB port to
communicate with the sensor. Remember to always free the port by quitting one
application before attempting to connect it to another application.
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6. Getting started
5B
This chapter is a tutorial intended for new users to familiarize themselves with the main
characteristics of the Acuity Initial sensor. For simplification purposes, this tutorial only
introduces one measuring mode (« Distance » mode) and one communication option (the
«CCS Manager» software and the USB digital output). We recommend that new users
follow this tutorial even if they wish subsequently to use a different measuring mode or
another communication option.
6.1
Connecting to the Initial
40B
Connect the sensor to a power supply as described in section 3.1.1. Connect it to a
free USB 2.0 port of your computer as described in section 3.1.3. Make sure the
dedicated USB driver has been previously installed on the computer.
Switch the sensor ON and start the “CCS Manager” program. This program has four
access levels.
The “Operator” level requires no password. This level allows configuring the sensor,
launching a measurement, viewing and saving the data as time-profiles.
The “User” level requires a password – please contact your vendor to receive it. The
“User” level allows, in addition to the above operations, viewing the photodetector
signal.
The two other levels are reserved. For this tutorial you can enter either in the
“Operator” level or in the “User” level.
The “Connection wizard” window opens.
Figure 4 Connection Wizard to CCS Manager Program
The program’s default configuration connects to the CCS device via the USB link. (If
you wish to connect to the serial link, click on “Parameters” and check the “Serial link”
option, and then click on “Connect”). The program will scan all available USB ports on
the host computer until it finds the sensor and will start the connection process,
including download of the entire sensor configuration.
The “CCS Manager” Main Window appears: It comprises a menu and two data frames
on the top, a status bar at the bottom, page-selection buttons and a “Dark” button on
the left, a central zone for displaying the current page, and two data bar graphs.
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Data 2 Frame
Data 1 Frame
Data 1 Selection
Data 2 Selection
Menu
Pageselection
Buttons
Data 1 Bar
graph
Dark
Button
Status Bar
Current Page (here « Measurement »
Page)
Data 2 Bar
graph
Note: the “Signal” page-selection button does not appear in the “Operator” level.
6.2
Configuring the sensor
41B
Click on the « Configuration » button on the left side of the Main
Window to develop the arborescence of configuration pages (1
“Basic” page, 5 “Advanced” pages and 1 “Expert” page)
Select the “Basic” configuration page.
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Set the measuring mode to “Distance” and then select a Preset Rate of 100 Hz.
6.3
Saving the configuration
42B
The configuration is the ensemble of settings of all sensor parameters (measuring
mode, rate, sensor id, Led brightness level, etc). The sensor has two configurations:
a temporary configuration, kept in the sensor RAM,
a permanent configuration, kept in the non-volatile memory (FLASH memory).
Each time the sensor is switched off, the temporary configuration is lost; on startup
the sensor recovers permanent configuration. This allows the user to test different
settings, or to adapt the sensor to a particular application, without modifying its
permanent configuration. When you wish that the temporary configuration become
permanent, you must save it on the FLASH memory. Below are instructions for saving
to FLASH memory:
Select a preset rate of 100 Hz
Quit CCS Manger
Switch the sensor off, then restart it.
Connect to “CCS manger” again, open the “Basic” page and observe the rate: the last
setting was lost.
Set the rate to 100 Hz again.
Save the configuration to the FLASH memory: in the “File” menu, select “Save the
current configuration”. The program asks for confirmation: click on “OK”.
Quit the “CCS Manager” program; switch the sensor off and on.
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Connect to “CCS manager” again, open the ”basic” page and observe the rate: the last
setting was conserved.
Recommendation:
When you find the optimal settings which suit your application, save the
configuration on the sensor FLASH Memory so that the sensor always starts
with this “nominal” configuration.
6.4
Selecting the output data
43B
The CCS transmits several data items for each measured point.
Before launching a measurement, you should check that the data item/s you wish to
measure are directed to the right output port (the USB port or the Serial port), and
that the other data items are not transmitted. On the left side of the Main Window,
select the “Digital Output” page.
First, observe the list of available data items in the “Distance” measuring mode. In
this mode you can measure the Distance and the Intensity of the reflected signal.
The other data items in the list will be described later so for the moment we shall
content ourselves with a brief presentation:
The “Distance LSB” data comprises additional 15-bit resolution to the “Distance” data.
This topic is described in §9.1.2. For the moment, each time you select the “Distance”
data, select this data as well.
The “Barycenter” data is the position (pixel number) of the spectral peak on the
photodetector.
The “Counter” data is a 15-bit cyclic counter incremented at each measured point: this
data is supplied as a tool for software developers. This data is particularly useful in the
case of “trigger modes”.
The “Adaptive mode” data and the “State” data are described in the “Advanced
Topics” chapter.
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Next, set the measuring mode to “Thickness”. In this mode you measure the two faces
of a transparent sample, so you have 2 Distances, 2 Intensities and 2 Barycenters:
In the screen copy above, the thickness and the intensities are directed to the RS232,
while the 2 distances are directed to USB. In this way one can connect the sensor to
two applications simultaneously (e.g. HyperTerminal on the serial port and CCS
manager on the USB port).
Note: Encoder data may be transmitted simultaneously with other data regardless of
measuring mode. Transmission is enables and disabled from the “Encoder” page.
To finish, return to the “Distance” measuring mode which is the principal measuring
mode of the sensor. Set the “Distance”, “Intensity” and “Counter” data to “USB”, and
the other data to “Not Transmitted”. On the left side of the Main Window, select the
“Measurement” page.
6.5
Viewing and saving the measured data
4B
Note that each of data1 and data2 is displayed in 3 ways:
Digitally, in the “Data frame”
As a barograph (to the left and to the right of the graphic window, respectively)
Graphically, in the graphic window of the Measurement page.
The buttons at the top of the “Measurement” give access to the following functions:
Start and stop the measurement
Print, Save and Clear the graphics window
Find the curve at high zoom values
See the statistics of the last measurement
Modify the number of displayed points
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In the “Data 1 frame” on the top of the Main Window the list shows the transmitted
data items (Distance, Intensity, and Counter). Select data1 as “Distance”; In the
“Data 2” frame Select “Intensity”.
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Note that each data has its own scale, zoom factor and
slide. To access the zoom, click on the point at the upper
end of the scale. You may also zoom with the mouse
button.
To save the measured data, use the “save graph” icon.
Data may be saved either as a screen-copy (bitmap) or
as digital data (text file).
6.6
Acquiring the Dark signal
45B
The dark signal of the sensor is generated by undesirable back-reflections on the
optical surfaces inside the sensor. This signal must be measured and saved to the
non-volatile memory so that it can be subtracted from the measured signal. The level
of the Dark signal depends on the sampling rate and on the LED brightness.
A dark signal acquisition is performed during adjustment by the manufacturer, but
must be repeated at regular intervals.
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Recommendation: The dark signal acquisition procedure should preferably be
performed at least a quarter of an hour after switching on the sensor, in order to
ensure that sensor has reached thermal equilibrium.
Dark signal measurement may be launched either by pressing the “Dark” button on
the sensor front panel, or by clicking on the “Dark” button on the “CCS Manager”
software, or, more generally, by sending the “$DRK” command to the sensor.
This operation may take a few dozens of seconds, as the sensor measures and saves
the “Dark” signal at all pre-set frequencies successively.
In order to perform a dark signal acquisition, it is essential to have no object within
the measurement field, or even better, to blank off the light beam by applying a piece
of paper over the tip of the optical pen.
Press the “Dark” button on the front panel of the sensor. The “Intensity” and
“Measure” Led indicators on the front panel blink on and off in green alternatively, to
indicate that the operation is in progress. Keep the optical pen tip blanked off. When
measurement is done, the 3 LED indicators blink on and off simultaneously, and their
color indicates the result of the operation:
Green: if the level of the acquired dark signal is satisfactory at all rates
Orange: if the dark signal level is too high at low rates, but it is still possible to
measure at higher rates
Red: if the dark signal level is too high at all rates.
The piece of paper can now be removed and the sensor can be used in the normal way.
6.6.1 Related topics
16B
High Dark signal - If after completion of the dark acquisition sequence, the color
of the blinking LED indicators is orange or red, this means that the acquired dark
signal is too high. In this case it is not possible to configure the sensor to the
lowest measuring rate (or rates).
If the problem persists, see instructions in the “Maintenance” section 17.2.
Auto adaptive Dark - The CCS features an operation mode (“auto adaptive dark”
mode) in which the dark signal is permanently updated. This mode is described in
the “Advanced Topics” chapter.
“Fast” Dark – see section 8.2
Measuring the Dark of a Multiplexed sensor – see section 13.2
6.7
Adjusting the LED brightness
46B
Select the light source type corresponding to your model: “Internal LED” or “External
source”.
If your sensor is equipped with an external light source, please skip this paragraph.
Internal LEDS brightness may be controlled by command. There are two modes for
doing this: “Manual” and “Automatic”. This section describes the Manual mode. The
“Automatic” LED mode is described in the “Advanced Topics” chapter.
The LED emission is modulated at a high rate (100 kHz). The effective brightness is
determined by the cycle ratio (percentage of the exposure time for which the LED is
on).
Set the level control to “Manual” and move the Brightness slide to the right until the
brightness level is 100%.
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Place a piece of white paper in front of the optical pen and observe the spot of light
emitted by the sensor. Move the paper forward and backward to find the focus plane
where the spot brightness is maximal.
Move the brightness slide to the left to get a brightness level of 0%. The light spot
disappears.
Try intermediate values
To finish, set the LED to maximal brightness again.
6.7.1 Minimal brightness level
17B
For each frequency there exists a minimal brightness level below which the LED
cannot go:
Measuring Rate
Up to 500 Hz
500 Hz – 2000 Hz
Minimal brightness
level
10%
25%
The operator sets the LED
to level X
X = 0%
X ≤ Minimal level
X > Minimal level
6.8
Maximal brightness
level
100%
100%
The sensor behavior:
The LED goes off
The LED is practically set to the minimal level
The LED is set to level X
Placing the sample within the measurement range of the
optical pen
47B
Mount the optical pen on a suitable support (for example, a « V » shape block).
Position the sample to be measured in front of the pen, and move it forward or
backward until the optical pen working distance is reached.
For pens with a millimetric measurement range, the positioning of the sample within
the measurement range of the optical pen is easy to achieve, simply observe on the
sample surface or on a piece of white paper the luminous spot emitted by the optical
pen: as the measuring range is approached, the spot becomes smaller and smaller
and its intensity increases.
For optical pens with a micrometric measurement range, the operation is more difficult:
position the sample on a stable support on a small manually translating bed, with a
suitable pitch lead screw.
Optical axis
Optical pen
Working
distance
Measurement
range
The sample to be measured must be
located in front of the optical pen, within
the measurement range of the pen. Its
distance from the optical pen should be
approximately equal to the working
distance of the pen.
As soon as the sample is located inside the measuring range of the optical pen, the
“Measurement” LED indicator on the sensor front panel lights on. Once the sample is
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inside the measuring range, use the “Measurement” LED indicator color to adjust its
position at the center of the measuring range: This indicator is:
Off - If no object is detected in the measuring range.
Green - At the center of the measuring range (between 15% and 85% of full scale)
Orange - Near the limits of the measuring range (between 0% and 15% of full scale
or between 85 and 100% of full scale).
Troubleshooting:
If the “Measurement” LED indicator on the sensor front panel never turns on even though the
sample is within the measuring field of the sensor, check the following points:








6.9
The fiber optics cable connector is fully plugged into the socket on the front panel.
A light beam is emitted from the optical pen and the spot is focused on the sample.
The distance between the extremity of the optical pen and the surface of the
sample is equal to the working distance of the optical pen.
The sample surface is normal to the optical axis. The local slope must be less than
the maximal slope angle of the optical pen.
The sampling rate selected is the lowest shown in the list (100 Hz), the measuring
mode selected is “Distance” mode.
The displacement pitch of the translation bed carrying the sample is suitable for the
measurement (for example, for pen model OP 020, the pitch must be  5 µm).
The Dark signal has been correctly acquired.
If your sensor’s light source is internal, check that the LED brightness is adjusted to
the
maximum level (100).
Sample Rate adjustment
48B
There are three options for setting the sampling rate:
The “Single Frequency” is the simplest option for adjusting the rate is by selecting
one of the preset rates in the list.
A second option consists of selecting a “free” rate: this option is described in section
8.3.
The “Double Frequency” option is described in the “Auto-adaptive modes” in section
11 .
In this tutorial we shall use preset rates only.
When the sample is within the central part of the measurement range of the optical
pen, select the optimal preset rate in the list: the signal should be strong but not
saturated. You can know if the signal is too strong or too weak by watching the
“Intensity” LED indicator. This indicator is:
Off - if no signal is detected
Red- in case of signal saturation
Green - if signal intensity is comfortable (> 5% of the maximum level),
Orange - if signal intensity is low (< 5% of the maximum level)
If the indicator is red, you should increase the sampling rate or decrease the LED
brightness. If it is orange you should lower the sampling rate or increase the LED
brightness.
Recommendation: Always set the Rate and the LED Brightness so that the “Intensity” LED
Indicator is green. When the signal is low (yellow “Intensity” LED Indicator) or saturated (red
“Intensity” LED Indicator) the sensor still measures, but measurement quality may be
deteriorated.
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6.10
49B
Intensity data
The Intensity data has a dual roles:
it often serves as a quality indicator, for validating that the measurement is performed
at optimal conditions
it may be used for generating a “grey level” 2D image of the sample
6.10.1 Intensity as a quality indicator
18B
The « Intensity » data measured by the sensor is an indication of the level of the
signal reflected back off the sample, as a percentage of the dynamic response of
the sensor. Its value depends on several parameters:
The sampling rate of the sensor
The local slope on the sample (angle between the optical axis and the normal to the
surface at the point of impact)
The reflectivity of the sample at the detection wavelength o
The brightness of the LED at wavelength o
The response of the photodetector at wavelength o
The detection wavelength,  varies within the measurement range. Thus it is not
surprising that the intensity measured at a given point on the sample varies when
the latter is moved within the measurement range of the optical pen.
For each point in the measurement range, the value of the intensity varies between
0% and a maximum value Isat. Beyond that, the sensor is saturated. The state of
saturation is indicated by an intensity value of 100% as shown in the graph below,
and by the red color of the “Intensity” LED indicator.
Intensity measured by the sensor
100
Isat
0
0%
Amplitude of the signal returned from the sample
100%
The value of Isat depends on the detection wavelength o, and may vary slowly
within the measurement range of the sensor. For some wavelengths Isat equals
99%. For others it is lower.
Example: If Isat is 60% and the sensor is on the limit of saturation, the measured
intensity will oscillate between 60% and 100% and the “Intensity” LED indicator
will oscillate between GREEN and RED.
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Recommendation: Measurement quality is good when the “Intensity" LED–indicator
is Green. If the indicator colour is Red, you must increase the rate or lower the LED
brightness. If it is Orange, lower the sampling rate or increase the LED brightness.
6.10.2 Intensity images
19B
In many applications it is desirable to obtain, in addition to the 3D measurement, a
2D image of the sample which resembles a microscope image. This can be done by
scanning the sample and displaying the Intensity data. In fact the Intensity data
gives exactly the same information as one pixel of a camera; by scanning one
reconstructs the entire “image”.
“Distance” images and “Intensity” images provide complementary information on
the sample: the “Distance” image gives information on the altitude of each sample
point, while the “Intensity” image gives information on the reflectivity of each
sample point. “Distance” images are often displayed in false color or as 3D images,
while “Intensity” images are usually displayed in grey-level or as “rendered” images
simulating shadow effects. As an example, consider the following pairs of
“Distance” and “Intensity” images.
Figure 5 ” image (left) and “Intensity” image (right) of a micro lens
Figure 6 “Distance” Image (left) and “Intensity” image (right)
of a scratch on the neck of a glass bottle.
All measured data are available simultaneously, so the “distance” and “intensity”
images may be obtained in a single scan.
7. Advanced Configuration
6B
This chapter is a tutorial intended for users having acquired some initial experience with
the CCS Initial sensor in the « Distance » measuring mode and using the « CCS Manager
» application. This tutorial covers the following topics:
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Synchronizing the sensor with external devices:
Synchronizing the sensor with digital encoders
Synchronization signals and « Trigger » modes
More about the “CCS Manger” program
Help Utility
Communication with the sensor via the “CCS Manager” Command Terminal
The “Tools” menu
Communication with the sensor via RS232 serial link using the Windows « Hyper
Terminal »™ utility.
The “Thickness” measuring mode
7.1
Synchronizing the sensor with other devices
50B
It is often necessary to synchronize the sensor with an external device, such as an
encoder, a motion controller or a photocell indicating the approach of an object
traveling on a conveyor belt.
When the external device to be synchronized with the sensor is a digital encoder, this
task is particularly easy, as it is performed automatically by the CCS Initial (refer to
section 12)
For other types of devices (analog encoders, motion controllers) synchronization may
be achieved using synchronization signals and Trigger modes. The CCS Initial may be
synchronized with an external device as “master” (using the “Sync out” TTL signals),
as a “slave” (using the “Sync in” TTL signals), or in a mixed mode (using both types of
signals).
“Trigger modes” specify the way the sensor should respond to rising or falling edges
of the “Sync in” signals. The common feature to all trigger modes is that the sensor
stops measuring and stands by for an “active” edge on “Sync in” connector. Trigger
modes may be enabled and disabled from the “Trigger” page of the “CCS manager”
program, by the DLL or by low-level commands. By default, all trigger modes are
disabled, and the sensor transmits data without interruption immediately after startup.
When no trigger mode is enabled, rising and falling edges of the “Sync in” signal are
simply ignored.
7.1.1 The “Start” trigger mode
120B
The simplest trigger mode is the “Start on edge” trigger. It is enabled by sending
the “$TRG” command, either from the Command Terminal or from the “Trigger”
page of the “CCS Manager” program.
On receipt of the command, the sensor stands by for the trigger signal.
Measurement starts as soon as an “active” edge is detected at the "Sync in" input,
with repeatability (jitter) better than 1 µs.
Once the first "Sync in" pulse is received, the sensor exits the “Start on edge”
Trigger mode and resumes normal operation. Additional "Sync in" pulses are simply
ignored.
A typical application for this trigger mode is for starting successive scan lines during
a 2D scan of a sample: the excellent repeatability ensures that there is no jitter on
the beginning of successive scan lines.
Additional trigger modes are described in Section 12.
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7.1.2 Training
12B
To train the system to trigger on the desired signal, connect an optical pen to the
sensor; configure the sensor to the right optical pen and to « Distance» measuring
mode as described in section 6. Launch a « Dark » signal measurement.
Place a sample in the measurement range of the pen and adjust the sampling rate
and/or the LED intensity.
Connect the « Sync in » pins on the Interface connector to an adjustable external
signal (for example, a TTL 0-5V pulse generator) as described in section 3.1.5.
Check that the signal is on 0V.
Select the “Trigger” page of the “CCS Manager” software. Select the “Start” trigger
type and rising edge as the “active” edge. Click on the “Enable the selected mode”
button to enable the mode.
Figure 7 Trigger Settings Dialog Box in CCS Manager
Select the “Measurement” page. Set Data 1 to “Distance” and the number of points
to 100, and click several times on the “Start” button.. If previous steps have been
carried out correctly, nothing happens: no data is displayed in the Graphic window
as the sensor is in standby for a “Sync in” signal. Check that the measurement is not
stopped: the “Start/stop” button should look as following:
Send a TTL pulse to the “Sync In” input in order to trigger the measurement: data
transmission starts immediately.
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7.2
CCS Manager software
51B
7.2.1 Help utility
12B
To learn more about the“CCS Manager” features, click on the “?” icon in the Menu
and open the “Help” utility. In particular, we recommend reading the sections
concerning the “Maintenance”, the Configuration “Other Settings” page and the
“Analog Data” page, which are not described in this tutorial.
7.2.2 Command Terminal
123B
Within the CCS Manager is a terminal emulator program with direct, command line
communications to the Initial sensor. To access the built-in terminal program,
open the “Expert” configuration page.
Type $AVR25 (6 characters:$ sign, 3 upper case letters, and 2 digits) in the
“Command” line, and click on the “Send” button. This command sets the temporal
averaging to 25. As a result, for each 25 successive points the sensor sends a
single value. As a result data transmission is 25 times slower and the signal to
noise ratio is improved by a factor of 5 (5 = square root of 25). Watch the sensor
reply in the “Sensor response” line.
Type $MOD0 ($ sign, 3 upper case letters and 1 digit), and click on the “Send”
button. This command selects the “Distance” measuring mode. Watch the sensor
reply in the “Sensor response” line.
Type $BAU115200 , and click on the “Send” button. This command sets the baud
rate to 115200. Watch the sensor reply in the “Sensor response” line.

Type $ASC, and click on the “Send” button. This command
configures the sensor in « ASCII » mode.
Figure 8 Built-in terminal program in CCS Manager
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The Terminal allows communicating with the sensor using the specific CCS
command language. Commands are described in detail later on in this manual. For
the moment, note that commands begin by a $ sign, comprise 3 upper case letters,
and end with the numerical value of the parameter.
The sensor echoes the command and then sends “ready”.
Note the button “Reload sensor parameters” below the command terminal. This
button uploads the configuration again, so that the “CCS Manager” program will
refresh its parameter list in order to take the modifications following the commands
into account. This button has no effect on the sensor, it effects only the “CCS
Manger” user interface.
7.2.3 Tools Menu
124B
The « Tools » menu gives access to the « Preferences » page, which allows
personalizing the program, and to two additional dedicated calibration procedures:
In-Situ Distance Calibration
Refractive index file generation (Thickness
calibration).
Please consult the “Help” pages for more details
concerning these features.
7.3
Serial communications
52B
The easiest means to send commands to the Initial is the Command Terminal of the
“CCS Manager” software. This Terminal is user friendly, for example it converts lower
case characters to upper case and adds missing $ characters. However if you wish to
write your own software using low-level communication, it is useful to get some
training in using a standard RS232 utility such as “HyperTerminal” ™ for
communicating directly with the sensor.
In the “CCS program”, select the “Digital Output” page and Send Data n° 0 (Distance)
to the serial port, the other data items to “Not Transmitted”.
If the “CCS Manager” application is connected to the sensor RS232 port, you must quit
it to release the sensor serial port. If it is connected to the sensor USB port, you may
leave it connected as the two channels are independent.
Connect your sensor to a free COM port of the host computer as described in section
3.1.2. Most computers have at least one RS232 port available (COM1). Otherwise, use
a USB to RS232 converter and follow the instructions included with that hardware for
its installation. Note the assigned serial port.
Most PC computer running Microsoft Windows™ has Hyperterminal installed. In the
« Start » menu of your PC, select Programs » Accessories » Communication » Hyper
Terminal™ utility. If your PC does not have Hyperterminal, visit the Acuity website for
an alternate terminal emulator
Name your session, and then click on « OK ».
In the « Connect using » field, select the COM port of your computer which is
physically connected to the sensor.
In the « Port parameters » window, configure the link as follows :
bits per second : 115200
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data bits : 8
parity : none
stop bits : 1
flow control : none
Select the “File/Properties” menu, then, in the window which opens, the “parameters”
tab. Click on the “ASCII configuration” button. In the “ASCII Configuration” window,
check the first and third boxes of the “ASCII reception” frame. This will add <LF>
after each <CR> received. No box should be checked in the “ASCII transmission”
frame. Click twice on OK to return to the main window. The utility is now ready for
communication with the sensor.
Using the PC's keyboard enter $AVR33 then press « Enter ». This command
configures the averaging factor at 33. Data output is 3 times faster, as averaging
changed from 99 to 33.
Enter $AVR? then press « Enter » to interrogate the sensor on the averaging value.
Observe the sensor response ($AVR ? 33 ready) displayed on PC screen.
Enter $MOD? then press « Enter » to interrogate the sensor on the current measuring
mode. Observe the response.
Enter $SCA then press « Enter » to interrogate the sensor on the measurement
range of the current optical pen. Observe the response.
Enter $SRA? then press « Enter » to interrogate the sensor on the current sampling
rate. Observe the response.
Quit the « HyperTerminal »™ utility to release the sensor serial port.
7.4
Measuring thickness
53B
7.4.1 The “Thickness” measuring mode
125B
In the “Thickness” measuring mode the sensor searches for 2 signals, reflected
from the 2 faces of a transparent sample. If they are found, it calculates the
intensity and distance of face 1 (front face, i.e. the nearest face), the distance and
intensity of face 2 (rear face), and the thickness. All these data are available
simultaneously.
Important: To obtain a valid measurement in « Thickness » mode, the sensor should
be configured to the correct refractive index. Refractive index may be specified either as
a constant value or as a file.
7.4.2 Minimum measurable thickness
126B
The thickness of the sample to be measured must be greater or equal to the
“Minimum Measured Thickness” of the optical pen. The « Minimum thickness » limit
is specified in the data sheet of each optical pen, and may be found on our
website www.acuitylaser.com.
4H
If the sample thickness is less than the specified « Minimum thickness » limit, the
sensor is unable to resolve the two spectral peaks produced by reflections from the
two faces of the sample and considers them as a single peak.
7.4.3 Single surface in “Thickness” mode
127B
Sometimes, a single surface is detected while the sensor is configured to
“Thickness” mode. This may occur if one or the other of the sample faces is outside
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the measuring range, if one of the signals is too weak, or if the thickness is smaller
than the “Minimal measurable thickness” of the optical pen. In the latter case the
sensor fails to resolve the two surfaces and considers them as a single one.
The “Unmeasured peak handling” (see section 12.5) command determines the
behavior of the sensor in such a case. The default behavior is: the data relative to
face 2 is set equal to the data of face 1, and the thickness is set to zero.
Recommendation: In « Thickness » mode, place the sample in the center of the
measuring range to avoid having either one of the faces close to the limits of the range.
7.4.4 Thickness calibration (refractive index file generation)
128B
Thickness measurement is less precise than Distance measurement, due to several
reasons:
By definition, the thickness is computed as a difference so that the noise is doubled,
The refractive index varies with wavelength and as a result, it varies inside the
measuring range
The sample itself reduces the quality of the optical beam which passes through its
volume
Thickness measurement is more sensitive to errors in angular alignment
The thickness computation is based on paraxial approximation.
For some application relative thickness measurement is sufficient. In this case, the
“refractive index” parameter can be set to an approximate value. This is a rapid
method but it does not yield precise results.
In order to get metrological precision the sensor should be calibrated in thickness
mode. Thickness calibration is a procedure requiring a standard with known
thickness. This procedure generates a “refractive index” file which specifies an
effective refractive index value for each position in the measuring range. The file is
specific to a given sample type (e.g. a 3 mm BK7 glass) and a given sensor. The
“CCS manager” software comprises a utility for generating refractive index files
(accessible from the “Tools” menu). Please refer to the “Help” utility of this
software for a detailed description of this procedure.
The sensor can hold up to 8 refractive index files in its non volatile memory.
Existing files may be selected in the “Basic” configuration file of “CCS manager” or
by command.
7.4.5 Measuring the Thickness of opaque samples
129B
The “Thickness” mode can only be used for transparent thickness whose thickness
is compatible with the min and max measurable thickness of the optical pen.
For measuring the thickness of opaque samples, the most frequently used method
consists of using two sensors looking at each other and located on both sides of the
sample with collinear optical axes.
Both sensor are configured to “Distance” mode. The Thickness of the sample is
given by:
Thickness = K – (D1 + D2)
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Where D1 and D2 are the distances measured by the two sensors and the constant
K is determined using a standard with known thickness.
7.4.6 Teach functions for thickness measurement
130B
In the “Basic” page, set the measuring mode to Thickness. Set the “refractive
index” parameter value to the average refractive index of the sample in the visible
range. (If you do not know the precise value, leave it at its default value). In the
“Digital output” page, select Data n° 0 (Thickness). Set the other data to “Not
Transmitted”.
Place a thickness sample in the measurement range of the optical pen, such as a
glass slide, a piece of cellophane, a transparent plastic film or any other flat
transparent sample. If it is a sheet or a film, ensure it is pulled tight. Also check
that the axis of the optical pen is normal to the surface of the sample. The sample
thickness must be compatible with the thickness measuring range of the
optical pen.
In the “Measurement” page set the number of points to 3000, and click on “Start”.
Move the optical pen slowly backward and forward to bring the two faces of the
sample inside the measuring range. As soon as the sample is inside the measuring
range, non-zero thickness values appear in the Graphic window.
Note that of the “Measure” LED-indicator depends only on the presence and
position of the first peak, it does not tell if a second peak has been detected.
Note that the displayed thickness values are proportional to the refractive index
value.
Troubleshooting: If you succeed to obtain a measurement in “Distance” measuring
mode, but in “Thickness” measuring mode the measured thickness is zero, check the
following points:

The thickness of the sample must be compatible with the measurement range
limits

The sample must be sufficiently transparent.

The sample must be pulled tight.

The optical axis must be normal to the surface of the sample.

The sampling rate selected must be the lowest in the list

The two faces of the sample must be inside the measuring range
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8. Main functions of the CCS Initial
7B
8.1
Dark signal
5B
The Function of the « Dark » signal is explained in the « Getting started » chapter.
Dark acquisition may be launched using the “Dark” button on the sensor front panel,
from the “CCS Manger” Main Window, or by sending a ‘Dark’ command.
8.1.1 Acquiring and saving the Dark signal
134B
The ‘Dark’ command records and saves of the dark signal in the FLASH memory of
the CCS Initial for all sampling rates in succession. If the level of the dark signal is
too high for low rates, the CCS Initial returns the index of the lowest sampling rate
which is usable (see ‘Set Sampling rate’ command), and lower sampling rates are
inhibited.
When done, the sensor returns to the last sampling rate that was before Dark
acquisition.
Function
Command
Value returned
Dark
Acquire and save the dark signal
$DRK
Index of the lowest sampling rate usable
Note: in case the rate or the LED brightness are modified after a “Dark” command,
there is no need to refresh the dark signal.
8.1.2 Minimal rate authorized after Dark acquisition
135B
The ‘Minimal rate’ command may be used to get to get the minimal sampling rate
authorized after last Dark operation:
Function
Command
Value returned
Minimal rate
Get the minimal authorized rate (query only)
$FRM
Lowest sampling rate (in Hz).
8.1.3 “Fast” Dark
136B
The « Fast Dark » command only refreshes the dark signal for the current sampling
frequency and the current LED brightness. The signal is refreshed in the sensor
RAM, without saving the acquisition in the EEPROM.
If the dark signal measured is too high, the CCS Initial returns a « not valid
<CRLF> » string and the previous dark signal continues in use.
This command has two optional arguments:
n is an integer indicating the number of successive acquisitions to be averaged in
order to obtain the reference dark (default value = 40).
m (default value = 100) indicates the influence of the acquisitions made on the new
reference dark according to the formula:
New Dark = (m x Average acquisition + (100 - m) x Old Dark)
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Fast Dark
Acquire the Dark signal for the current sampling rate
only
without saving in the sensor memory
$FDK or $FDKn,m
n = averaging factor for Dark 1..99
m = weighting factor
1..100
return « Ready » or « Not valid »
Function
Command
Parameter/Value
returned
Note: in case the rate or the LED brightness are modified after a “Fast Dark”
command, the dark signal should be measured again.
8.2
Sampling rate
56B
In the “Single Frequency” mode the sampling rate of the sensor may be managed by
two methods:
Selection of a preset sampling rate from a list (“Preset Rate”)
Definition of a specific sampling rate (“Free rate” or “Exposure Time”)
The first method is recommended for most applications. In this method, the sampling
rate is defined by its index. The second method provides greater flexibility in the
choice of sampling rate: The “free” sampling rate can be specified in Hz, or the
exposure time (inverse of the free rate) can be specified in µs.
This paragraph describes the different methods, followed by some examples.
The “Double Frequency” mode is described in the “Auto-adaptive modes”, section 11.
8.2.1 Selecting a preset sampling rate
137B
The CCS Initial has five preset sampling rates:
Index
00
01
02
03
04
05
Sampling rate (HZ)
free rate
100
200
400
1000
2000
Exposure time (µs)
Free exposure time
10000
5000
2500
1000
500
A preset rate may be selected from the “Basic” configuration page of “CCS
Manager”, or by sending the ‘Preset Rate’ command.
Function
Command
Parameter/Value
returned
Preset Rate
Set/request the index of a preset sampling rate
$SRAn or $SRA?
n = sampling rate index (2 digit integer 0 - 5)
Note: limited by the min authorized rate
Note: the command $SRA0 selects the free rate. The value attributed to the free
rate may be set by the “Free rate“ command or by the “Exposure time“ command
described below.
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8.2.2 “Free” sampling rate
138B
A free rate may be selected from the “Basic” configuration page of “CCS Manager”,
or by sending the ‘Free Rate’ command.
The ‘Free Rate’ command is used to set the sensor sampling rate to a free value
between 100 Hz and 2000 Hz, or to request the value of the free rate.
The index of the free rate in the list of preset rates is 0 (see table above). The last
value set to the free rate either by the “Free Rate” command or by the “Exposure
time” command may be later activated by sending “$SRA0”.
Note: The Processor may modify slightly the specified value of free rate in order to
comply with its internal constraints (the exposure time in µs should be integer),
and returns the real value immediately after the echo (see example bellow).
Free rate
Set/request the value in Hz of the free rate.
$FRQn or $FRQ?
n = value of the free sampling rate, in Hz (5 digit integer
between 100 and 2000), limited by the min authorized rate
m ( 5 digit integer between 100 and 2000) is the closest
rate value m>=n such that the exposure time in µs is an
integer
Command: $FRQ1995
Response: $FRQ1995 1996
Note: 1996 Hz corresponds to an integer exposure time
(501 µs).
Function
Command
Parameter
Value returned
Example
8.2.3 Exposure time
139B
The ‘Exposure time’ command is used to set/request the free exposure time in µs.
The operator can specify any integer exposure time between 00500 and 10000 µs.
The free sampling rate is set to 1 000 000/exposure time.
Exposure time
Set/request the exposure time
$TEXn or $TEX?
n = value of the free exposure time, in µs (5 digit integer
between 00500 and 10000) ), limited by the min authorized
rate.
Function
Command
Parameter
8.2.4 Examples
140B
In the following dialog the operator alternates “Preset rate”, “Free Rate” and
“Exposure Time” commands, and interrogates the sensor to view the results of
each command. Read this dialog carefully and make sure you understand the
response of the sensor in each case.
Command
Comment
$SRA04
Sets the preset sampling rate index to
4 (1000 Hz)
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Response
from
the sensor
$SRA
04<CR>
ready
$SRA?
Interrogates the sensor for the index of
the current preset sampling rate
Interrogates the sensor for the rate in
Hz
Interrogates the sensor for the exposure
time in µs
1000 = 1 000 000/ 1000
Sets exposure time to 530 µs (and sets
the sampling rate index to 0)
Interrogates the sensor for the rate in
Hz
1886 = 1 000 000/ 530
Interrogates the sensor for the index of
the current preset sampling rate
Sets the free rate to 1995 Hz
The sensor selects a close value (1996)
Interrogates the sensor for the exposure
time in µs
501 = 1 000 000/ 1996
Attempts to set exposure time to a nonauthorized value
$SRA?04 ready
Sets the preset sampling rate index to
1 (100 Hz)
This ends the “free rate” mode
Interrogates the sensor for the rate in
Hz
$SRA01
ready
$SRA00
Sets the preset sampling rate index to
0 (“free rate”)
$SRA00
ready
$FRQ?
Interrogates the sensor for the rate in
Hz
1996 is the last value attributed to the
free rate
$FRQ? 1996
$FRQ?
$TEX?
$TEX00530
$FRQ?
$SRA?
$FRQ1995
$TEX?
$TEX00120
$ SRA01
$FRQ?
8.3
$FRQ?01000 ready
$TEX?01000 ready
$TEX00530<CR>0
0530 ready
$FRQ? 1886
SRA? 00 ready
$FRQ1995
<CR>
1996
$TEX?00501
$TEX120 not valid
ready
<CR>
FRQ?00100 ready
<CR>
Measuring modes
57B
The different measuring modes are described in the ‘Going further ‘chapter.
Index
Measuring mode
0
Distance
1
Thickness
The measuring mode can be selected from the “Basic” configuration page of “CCS
manger” or by sending the ‘Mode’ command.
Function
Command
Value returned
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Set/request the current measuring
mode
$MODn or $MOD?
n = Id of the measuring mode (0-1)
38
8.4
Refractive index
58B
The sample refractive index is necessary in the “Thickness” measuring mode.
Refractive index can be set from the “Basic” configuration page of “CCS manger” or by
sending the ‘Refractive Index’ command.
8.4.1 Setting a constant refractive index
14B
Function
Command
Value returned
Example
Refractive Index
Set/request the sample refractive index
$SRIx or $SRI?
x = sample refractive index (up to 4 decimal digits)
$SRI1.5120
8.4.2 Selecting a Refractive index file
142B
Refractive index file are used to describe the variation of refractive index within the
measuring range (see Advanced Topics in section 14).
The “Refractive index file” command is used to load a previously saved refractive
index file.
Refractive index file
N Function
o Command
t
e Parameter
t
h Values returned
e
Set/request the sample refractive index
$INFn
n = 0 : constant refractive index (determined by last SRI
command)
n=1..8 : id of an existing refractive index file
s: file name
x1,x2,x3:
the minimal, the maximal and the average
refractive index values in the file
Command: $INF3 or $INF?
Response: $INF3,”BK7”, 1.5090, 1.5253, 1.5133
----------------------------------------------------------Command: $INF0
Response: $INF0,”CONSTIND”,1.520,1.520,1.520
m
a Example
t
e
r
Serial name “CONSTIND” attributed in case the file id is 0.
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8.5
Adjustment of the LED brightness
59B
Note: the only type of light source that can be adjusted by command is the LED
(internal light source).
LED Brightness can be set from the “Basic” configuration page of “CCS manger” or by
sending the ‘LED brightness’ command.
Function
Command
Value returned
LED brightness
Set/request the sample refractive index
$LEDn or $LED?
n = brightness level (0..100)
For each frequency there exists a minimal brightness level below which the LED
cannot go:
Measuring Rate
Minimal brightness
level
Maximal
brightness level
Up to 500 Hz
10%
100%
500 Hz – 2000 Hz
25%
100%
$LED0 – puts the LED off
$LEDX
with
X≤Minimal level
sets the LED to the minimal level
$LEDX
with
X>Minimal level
sets the LED to level X.
In addition to the LED command, the CCS features an “auto-adaptive LED” mode in
which the sensor adapts itself automatically to the reflectivity of the measured sample.
This mode is described in the “Auto-adaptive modes” chapter.
8.6
Averaging
60B
The averaging of the measurements by the sensor, improves the signal/noise ratio.
When the averaging factor is greater than 1, the sensor transmits the data at the rate
fD
FD = fS / M,
Where : fD = data transmission rate,
averaging factor.
fS = sampling rate = 1/exposure time,
M=
Thus, for a sampling rate of 1000 Hz, and an averaging factor of 10, the sensor
provides 100 measurement points per second. In order to obtain measurements
without averaging, set the averaging to 1.
Averaging is especially useful for difficult samples, for which the signal is low even at
the minimum sampling rate. Sometimes averaging is used simply to reduce the data
transmission rate.
Recommendation: Do not use high averaging for moving samples, this reduces
the transverse resolution and may cause false measurements.
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Averaging can be set from the “Other Settings” configuration page of “CCS manger” or
by sending the ‘Data averaging’ command.
Function
Command
Parameter/Value
returned
8.7
Averaging
Set/request data averaging
$n or $AVR ?
n = averaging (between 1 and 9999)
Holding the last valid value
61B
The “Hold last value mode” is useful for samples with a great number of non
measurable points, due to large local slopes or to a very low reflectivity. When
measuring such samples it may be convenient that the value delivered for those
positions will not be zero. Instead, the sensor sends the last valid measurement.
Note: if a given data cannot be measured and the last measured value is sent, the
“hold last value” bit of the corresponding data item in the “State” data is set (cf.
§14.7).
This mode can be configured in the “Other Settings” configuration page of “CCS
manger” or by sending the ‘Hold last Value’ command.
Hold last Value
Function
Set/request max number of points for “Hold last value
mode”
Command
$HLVn
Parameter/Value
returned
n = max number of points to hold (between 1 and 999)
8.8
or $HLV ?
Getting the serial number and the firmware version
63B
To know the firmware version of the sensor, you may use either the “About” menu of
“CCS Manager”, or send the ‘Version’ command.
Function
Command
Value returned
Version
Request the firmware version
$VER
String of characters defining the serial number and the
firmware version,
Recommendation: Before contacting the supplier for after-sales service, use the
« $VER » command and record the response from the sensor.
8.9
Saving the current configuration
64B
The « Save setup » command is used to save the current configuration of the CCS
Initial sensor on the non-volatile memory. This is essential for the sensor to be able to
retrieve the configuration when it is next switched off and on again. If this is not done,
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the next time the sensor is switched on the sensor will lose all the latest modifications
made.
Function
Command
Parameter/Value
returned
Save Setup
Save the current configuration in the sensor EEPROM
$SSU
none
The configuration can also be saved using the “CCS manager” Menu.
Recommendation: Use the « Save Setup » command to avoid the sensor losing
the configuration when the equipment is switched off.
8.10 Resetting the sensor
65B
Resetting the sensor means recovering the factory default values for all parameters.
Files saved in the sensor non volatile memory (Calibration lookup tables, dark signal,
refractive index files) are not affected by this operation, but current configuration is
irreversibly lost.
To reset the sensor proceed as following:
Press simultaneously the 2 buttons (“Dark” button and “Set Zero” button) located on
the sensor front panel for more than 3 seconds.
When you let off the 2 buttons The 3 LED indicators blink in yellow.
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9. Digital Outputs
8B
The CCS Initial features two types of digital I/O:
USB 2.0
RS232 serial link
The USB link is destined both for sending commands and for data acquisition. For this
link all measured data may be transmitted at all rates.
The RS232 is destined Initialrily for sending commands to the sensor. At low measuring
rates this link allows data transmission. At medium rates the number of transmissible
data is limited, and at 2000 HZ, it is not possible at all. These limitations are described in
section 9.2.
The two links may be connected simultaneously to two different applications (be careful
in this case to avoid sending conflicting commands).
The present chapter is dedicated to the basic features related to data transmission. The
advanced features, such as the details of the command language syntax, the data format
or the rules for decoding the data, which are not necessary for most users, are not
treated here. Software developers who use low-level commands may find this
information in the “Advanced Features” section of this manual.
9.1
Selection of the data to be transmitted
6B
9.1.1 Available data
14B
The sensor measures several data items in parallel at each point of the sample. The
table below shows the available data items for both measuring modes:
Data item
index
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Data items in “Distance”
mode
Distance MSB
Distance LSB
Auto-adaptive mode data
Intensity
not used
not used
Barycenter
not used
State
Counter
Encoder 1 LSB
Encoder 1 MSB
Encoder 2 LSB
Encoder 2 MSB
Encoder 3 LSB
Encoder 3 MSB
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Data items in “Thickness” mode
Thickness
Distance face 1
Distance face 2
Auto-adaptive mode data
Intensity face 1
Intensity face 2
Barycenter face 1
Barycenter face 2
State
Counter
Encoder 1 LSB
Encoder 1 MSB
Encoder 2 LSB
Encoder 2 MSB
Encoder 3 LSB
Encoder 3 MSB
9.1.2 Meaning of the data
145B
In “Distance” measuring mode, the “Distance” is the position of the sample in the
measuring range of the optical pen.
The “Distance” data may be transmitted either in 30-bit resolution or in 15 bit
resolution. By default the sensor transmits the distance at full resolution; for this
purpose both the “Distance MSB” data and the “Distance LSB” data should be
transmitted.
In some applications it is necessary to limit the number of data items transmitted;
For such applications, the sensor may be configured to transmit only the “Distance
MSB” data. The Distance data provided by the DLL or the “CCS Manager” in this
case has 15-bit resolution.
Intensity is the signal level as percentage of the dynamic range of the sensor. The
meaning of this data is discussed in the tutorial (cf. §6.10)
Barycenter is the position of the spectral peak on the internal photodetector, in
pixels. This data is used in factory for generating the sensor lookup table.
In “Thickness” measuring mode:
There are two Distance data, two Intensity data and two Barycenter data for the
two faces of the sample + one Thickness value. Face 1 is the one closer to the
optical pen.
The Distance data and the thickness data are transmitted with 15-bit resolution.
The Encoder data is data read from up to 3 digital encoders synchronously with the
sensor data. The value is relative to the “Re-Center value” (value at the center of
the measuring range) determined by the “$RCD” command.
The “Counter” data is a 15-bit cyclic counter incremented at each measured point:
this data is supplied as a tool for software developers. This data is particularly
useful in the case of “trigger modes”. The Adaptive mode data and the State Data
are described in the “Advanced Topics” chapter.
9.1.3 Data Selection
146B
Configuring the digital output means determining for each individual data item,
whether or not it is to be transmitted and, eventually, on which type of digital
output. This can be done from the “Digital Output” configuration page of “CCS
manger”, or by sending the ‘Set Digital Output Data’ command.
Function
Command
Parameter/Value
returned
Set Digital Output Data
Set/request which data is to be transmitted via the serial link.
$SOD
n0,n1,n2,n3,n4,n5,n6,n7,n8,n9,n10,n11,n12,n13,n14,n15
or
$SOD ?
Ni = 0 (data not transmitted), or
1 (data transmitted on RS serial link), or
9 (data transmitted on USB)
i = 0..15 (index of the data item)
Note: The last null values may be omitted for convenience, e.g.:
$SOD9,9,0,9,0,0,0,0,0,0,0,0,0,0,0 may be replaced by $SOD9,9,0,9
Examples:
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In « Distance» measuring mode, for the sensor to transmit the values of the
Distance and Intensity at each measurement via the RS link, the following
command must be sent : $SOD1,1,0,1
In « Distance» measuring mode, for the sensor to transmit the value of the
Distance only via the USB link, the following command must be sent : $SOD 9,9
In “Thickness” measuring mode, for the sensor to transmit the Thickness on USB
and the Counter on RS232, the following command must be sent :
SOD9,0,0,0,0,0,0,0,0,1
Warning: For the RS link the transmission capacity depends on the sampling
rate and the data format (see further in this chapter). Before sending the
$SOD command, check that the number of data items selected is compatible
with these parameters in order to avoid data overflow.
There is no limitation on the number of transmitted data items for the USB
link.
9.2
Specific features of the RS232 link
67B
The RS232 connector at the CCS Initial controller back panel should be connected to a
free COM Port on the host computer or on the device used for communicating with the
sensor, using a direct (non-crossed) serial link wire as described in section 3.1.2
No specific driver is required.
The baud rate of the sensor RS link should be matched to that of the host computer.
9.2.1 Configuring of the COM port of the host computer
147B
The host computer COM port should be configured as follows:
Data bits : 8
Parity : None
Stop bit : 1
Flow control : None
Transmission baud rate: As high as possible, matched to the sensor baud rate. (*)
(*) The CCS Initial offers baud rates up to 460800 bauds. Note that standard PC
COM ports (COM1 and COM2) are limited to 115200 bauds, for higher baud rates
a dedicated RS board is required.
The ‘Baud rate” command sets the baud rate of the CCS Initial RS link.
Baud Rate
Set/request the sensor RS baud rate
$BAUn or $BAU?
n= 9600 or 19200 or 38400 or 57600 or 115200 or 230400 or
Parameter
460800
Note that this command has no effect on the PC baud rate that should be set
independently.
Function
Command
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9.2.2 Limits of simultaneous data transmissible
148B
The max number of data items transmissible simultaneously per measured point via
the RS232 link depends on the sensor sampling rate and on the RS232 link baud
rate. As far as possible, the highest baud rate available should be used.
Standard RS232 ports on PC mother boards can be configured for baud rates up to
115200 baud. The maximal number of transmissible data items at this baud rates is
given by the following tables:
Binary Transmission format –115200 Baud
Measuring
rate (Hz)
100
200
400
1000
2000
Max
Number of
transmitted
data
All
All
10
4
1 (*)
Ascii Transmission format –115200 Baud
Measuring
rate (Hz)
Max
Number of
transmitted
data
100
200
400
1000
2000
All
8
3
1
-
Commercially available fast RS-Boards may often work at rates up to 460800 bauds.
The maximal number of transmissible data items at this baud rates is given by the
following tables:
Binary Transmission format – 460800 Baud
Measuring
rate (Hz)
Max
Number of
transmitted
data
100
200
400
1000
2000
All
All
All
All
All
Ascii Transmission format - 460800 Baud
Measuring
rate (Hz)
Max
Number of
transmitted
data
100
200
400
1000
2000
All
All
All
7
3
When using these tables, please take into consideration the fact that in the
“Distance” measuring mode the distance information may be transmitted with 30
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bit resolution using 2 data: “Distance MSB” and “Distance LSB”. The two data
should be enabled for transmission.
In case the user is limited by the capacities of the RS232 link, it is possible to
transmit the Distance-MSB data only.
Examples:
Distance measuring RS232 link, 115200 baud, ASCII format:
Up to 400 Hz, distance data may be transmitted at full resolution.
At 1000 Hz, distance data may be transmitted at 15-bit resolution.
At 2000 Hz no data may be transmitted.
If the Binary format is used, the distance may be transmitted at full precision up to
1000 Hz and at 15-bit precision up to 2000 Hz.
Distance measuring RS232 link, 460800 baud, ASCII format:
The RS232 may transmit full-resolution distance (2 data) + Intensity (1 data) up to
2000Hz.
Data overflow
In case the number of transmitted data items specified by the SOD command
exceeds the limit, the “Error” led indicated turns to orange and the “data overflow”
bit in the “State” data is set.
9.3
Specific features of the USB link
68B
9.3.1 USB driver
149B
Before using the USB channel, a dedicated driver should be installed on the PC.
This driver requires XP Operating system with SP2, or more recent (refer to section
3.3)
9.3.2 Using the USB link
150B
The USB connector at the CCS Initial controller front panel should be connected to
a free USB Port on the host computer as described in section 3.1.3.
For communicating with the sensor via the USB link it is recommended to use one
of the software: described in §5 (“CCS Manager”, or “CHR DLL”) and not low-level
communication.
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10.
Auto-adaptive modes
10B
The CCS Initial features three auto-adaptive modes: the “auto adaptive dark” mode,
the ”auto adaptive LED” mode and the “double frequency” mode In these modes the
sensor adapts its inner parameters automatically to variations in the ambient
temperature (“auto adaptive dark” ) or to variations in the intensity of the light beam
reflected from the sample (”auto adaptive LED” and the “double frequency”).
The auto-adaptive modes are mutually exclusive: only one of them may be enabled at a
time.
10.1 “Auto-adaptive Dark” mode
71B
In this mode the sensor measures automatically the Fast Dark signal (i.e. the Dark
signal in the sensor RAM) and adapts it permanently. To do so, the sensor analyses
the internal photodetector signal, determines the zone occupied by the signal, and
adapts the Fast Dark signal in all other zones.
This mode is particularly useful for compensating slow variation of Dark signal due to
temperature change when the sensor configuration (measuring rate, LED brightness)
is constant.
Recommendation : To get good results with this mode, wait at least 15
minutes after the sensor and the light source have been powered; Then measure
the DARK and enable the “auto adaptive Dark” mode.
Function
Command
Parameter/Value
returned
Activation of auto-adaptive Dark
Enable/Disable the auto-adaptive Dark mode
$ADKb or $ADK?
b = 0 or 1
10.2 “Auto-adaptive LED” mode
72B
In this mode the sensor adapts automatically the LED brightness to compensate for
variations in the level of the signal returned by the sample.
This mode is very useful for measuring samples with smoothly variable reflectivity or
with smoothly variable local slope (e.g. for measuring a lens).
Function
Command
Parameter/Value
returned
Auto-adaptive LED
Enable/Disable the auto-adaptive LED mode
$AALb or $AAL?
b = 0/1
The threshold value for this mode is determined by the “Threshold for Auto-adaptive
mode” command.
Function
Command
Parameter/Value
returned
Acuity Intial Confocal Sensor
Rev 1.0
Threshold for Auto-adaptive mode
Set the threshold value for the auto-adaptive LED
mode
$VTHn or $VTH?
n = 0..4095
(higher threshold will result in higher
measured intensity)
Recommended values: 2500 to 3500.
48
Notes:
The instantaneous intensity of the LED is coded in the “Auto-adaptive mode” data
Physically, the LED brightness may vary between a minimal level and 100%. When the
LED reaches its maximal level, setting the VTH parameter to higher values will not
increase the measured intensity.
10.3 “Double Frequency” mode
73B
This mode is useful for samples characterized by strong, rapid point-to-point
reflectivity variations, such as samples composed of highly reflective metallic motifs
deposited on glass. For such samples it is difficult to select a measuring rate that is
well suited to all measured points, as a rate which gives sufficient intensity from the
glass surface will generate saturation on the on metallic surface. Another example
when the “double frequency” mode is useful is that of samples comprising deep holes
or sharp slope variations.
In the “double frequency” mode the sensor switches permanently between two
frequencies: the low frequency f1 (long exposure time) and the high frequency f2
(short exposure time). It computes the data independently for each frequency, and
then selects, for each measured point, the optimal frequency.
The criteria for selecting the optimal frequency are resumed in the following table:
Case
Low frequency
High frequency
1
2
3
4
5
6
Saturated
Saturated
Saturated
Correct
Correct
Null
Saturated
Correct
Null
Correct
Null
Null
Selected
frequency
high
high
low
low
low
high
Each couple of acquisitions (one with long exposure and the other with short exposure)
is called “a cycle”. The sensor delivers one “synchro out” signal per cycle. Measured
data is transmitted once per cycle on the digital outputs and updated once per cycle
on the analog outputs. The cycle rate fc is given by the relation:
1/fc = 1/f1 + 1/f2
10.3.1 Activation
15B
The “double frequency” mode can be activated from the “Basic” configuration page
of “CCS manager”. Or by the DFA command :
Function
Command
Parameter/Value
returned
“Double Frequency” Activation
Enable/Disable the double frequency mode
$DFAb or $DFA?
b = 0/1 (1 to enable)
This command is not authorized when the “auto-adaptive LED” or the “autoadaptive dark” modes are active (the query form “DFA?” Is authorized).
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10.3.2 Frequencies
152B
The DFF command sets (or requests) the 2 frequencies for the mode
“Double Frequency” frequencies
Set/Request the 2 frequencies for the “double frequency”
mode
$DFFf1,f2 or $DFF?
f1 = low frequency, f2= high frequency in Hz
conditions: frm ≤ f1 < f2 ≤ 1850 Hz,
where frm is the min authorized rate of the sensor
Function
Command
Parameter/Value
returned
10.3.3 Intensity
153B
The intensity measured by the sensor depends, on one hand, on the characteristics
of the sample (reflectivity, slope) and on the other, on the exposure time. In
standard operation mode (“single frequency”) the exposure time is constant so that
observed intensity variations are directly related to the intensity of reflected from
the sample. In the “double frequency” mode both factors vary at the same time so
that the interpretation of the Intensity data may be difficult.
For this reason a new parameter, the “normalized intensity” is computed. This is an
intensity computed for a fixed frequency (the high frequency), so that it is directly
related to the sample characteristics.
Let :
ILF be the intensity measured for the low frequency
IHF be the intensity measured for the high frequency
The following table shows the difference between the “raw” (standard) intensity
and the “normalized” intensity.
Available intensities in « Double Frequency » mode
Selected
Frequency
Low (f1)
High (f2)
« Raw » Intensity
ILF
IHF
« Normalized »
Intensity
ILF *f1/f2
IHF
By default, the transmitted Intensity data is the “Normalized” one. This option may
be modified from the “Basic” configuration page of “CCS Manager”, or using the
“DFI” command.
Function
Command
Parameter/Value
returned
“Double Frequency” Intensity
Select the type of transmitted Intensity
$DFIb or $DFA?
b = 0 for “Normalized” intensity, 1 for “Raw” Intensity
10.3.4 Selected frequency bit
154B
The selected frequency for a given cycle is indicated in bit 8 of the “State” data
(see section 14.7.2).
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Note for users familiar with previous versions of the CCS Sensor
firmware:
The “selected frequency” bit replaces the “trigger flip flop” bit of
previous versions.
0 indicates that the high frequency was selected, 1 that that low frequency was
selected.
10.3.5 Compatibility with other commands/modes
15B
The mode is compatible with most other commands and modes, and in particular:
triggering, averaging and manual setting of the LED brightness.
It is not compatible with: auto-adaptive LED mode, auto-adaptive dark mode, fast
dark.
Command
AAL, ADK, FDK
DRK
TRG, TRE, TRN,
TRS, TRF
AVR, HLV
LED
FRQ, TEX, SRA
Response when the sensor is in “double
frequency” mode
Not authorized
Authorized
Authorized
Authorized
Authorized
Authorized (the rate/exposure time is memorized. It is
applied when the sensor quits the double frequency
mode)
10.3.6 Intensity LED indicator in “Double Frequency” mode
156B
In the “Double Frequency” mode the “Intensity” LED indicator on the front panel is
correlated to the High Frequency:
If it is red the signal is saturated at both frequency: you must lower the LED
intensity
or increase f2.
If it is green, measurement is OK
If it is yellow, it should be ignored.
10.3.7 Synchronization in “double frequency” mode
157B
This paragraph is relevant for applications where the sensor is synchronized with
external devices as a “master”, using the “Sync out” TTL signals, and the sensor is
configured to double-frequency mode.
In single-frequency mode these signals are emitted at the middle of the exposure
cycle. As an example, with no averaging the exposure cycle is simple the exposure
of a single frame, so that the “sync out” pulses are emitted in the middle of the
exposure time of each individual frame. With averaging of 4, the acquisition cycle
consists of the exposure of 4 frames, and the “sync out” pulses are emitted just
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between the end of exposure of the second frame and the beginning of the
exposure of the third frame of the cycle. If the sample is moving, the instant these
signals are emitted corresponds to the average position of the sample during the
exposure.
In double-frequency mode there are two exposures, one of which is used and the
other one abandoned. During the exposure the sensor does not “know” yet which
exposure will be selected: the decision is taken only after both images have been
read and processed. For this reason the “sync out” pulses are always sent at the
middle of the “short” exposure (high rate).
If the short exposure is selected, there is no need for correction. If the long
exposure is selected, the “sync out” is shifted by t relative to the exact instant
where they should have been emitted. Suppose now that these pulses are used to
latch (read) the position of an encoder and that the sample moves at a velocity V.
The temporal shift generates a position shift x between the position latched from
the encoder and the “real” position at the middle of the “long” exposure:
t = - 0.5 * fc
x =V * t
Where fc is the cycle frequency given by the relation:
1/fc = 1/f1 + 1/f2
In some applications it is desirable to compensate for this shift. As an example
consider the application where the depth, width and slope of a scratch on the
surface of a flat surface should be measured. Double frequency may be required for
this application as the intensity from the slope and/or from the bottom of the
scratch is very low, while the intensity from the flat surface is very high. The depth
is derived from the difference of the distance values measured on the surface and
on the bottom – this data is exact, there is no need for any correction. However the
width and the slope involve both sensor data and position data, so that correction
should be applied to the position data by post-processing.
The “selected frequency” bit in the “State” data may be used for this purpose:
{
Correction =
{
0
if “selected frequency bit”=0
{
V *t
if “selected frequency bit”=1.
If the sample is scanned back and forth please note that the sample velocity V is a
signed quantity.
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11. Synchronization
1B
It is often necessary to synchronize the sensor with an external device, such as an
encoder, a motion controller or a photocell indicating the approach of an object traveling
on a conveyor belt.
The Acuity Initial may be synchronized with an external device as “master” (using the
“Sync out” TTL signals), as a “slave” (using the “Sync in” TTL signals), or in a mixed
mode (using both types of signals). The “Sync in” and “Sync out” signals are 0V-5V TTL
signals connected to the coaxial (BNC) sockets on the front panel of the controller.
The “Sync in” signals are used in combination with “Trigger modes”, which specify the
way the sensor should respond to rising or falling edges of the “Sync in” signals. The
common feature to all trigger modes is that the sensor stops measuring and stands by
for an “active” edge on “Sync in” connector. Trigger modes may be enabled and disabled
from the “Trigger” page of the “CCS manager” program, by the DLL or by low-level
commands. By default, all trigger modes are disabled, and the sensor transmits data
without interruption immediately after startup. When no trigger mode is enabled, rising
and falling edges of the “Sync in” signal are simply ignored.
11.1 “Sync out” signals
74B
Synchronizing the sensor as a “master” means that the “Sync out” TTL signals emitted
by the sensor are used to trig (latch) the external device.
The sensor emits one “Sync out” pulse for each measured point at the middle of the
Cycle Exposure Time (CET).
CET = EET * AVR
Where EET = Elementary Exposure Time = 1/measuring rate, AVR = averaging factor.
Example: for a measuring rate of 100 Hz, the Elementary Exposure Time is 10 ms.
By default, the sensor measures with no averaging (AVR=1), so that the Cycle
Exposure Time equals the Elementary Exposure Time. If the sensor is configured to an
averaging factor of 5, the CET equals 50 ms, as 5 frames are acquired and averaged
for each measured point.
In the case of double-frequency rate, please refer to section 11.3.7.
The duration of the “Sync out” pulse (high state) is 10 µs, irrespective of the CET.
“Sync out” pulses are emitted automatically, with no need for any special
configuration.
When the sensor is in stand-by for a trigger, no “sync out” pulses are emitted.
11.2 “Sync in” signals
75B
Synchronizing the sensor as a “slave” means that the sensor stands by for a trigger
signal from an external device. So long as no trigger signal arrives, the sensor is
“silent”: it does not transmit any data and does not emit any “Sync out” pulse. As
soon as it detects a trigger signal on the “Sync in” connector, the sensor starts
measuring and emitting “Sync out” pulses.
The “Sync in” signals are 0V-5V TTL signals generated by external devices and
intercepted by the sensor. The “active” edge of the « Sync in » signal is the edge
which triggers measurement. The active edge (rising edge or falling edge) may be
selected by command. The duration of the « Sync in » pulses should be at least 1.2 µs.
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11.3 The “Start on edge” trigger mode
The simplest trigger mode is the “Start on edge” trigger. It is enabled by sending the
“$TRG” command, either from the Command Terminal or from the “Trigger” page of
the “CCS Manager” program.
On receipt of the command, the sensor stands by for the trigger signal. Measurement
starts as soon as an “active” edge is detected at the "Sync in" input, with repeatability
(jitter) better than 1 µs.
Once the first "Sync in" pulse is received, the sensor exits the “Start on edge” Trigger
mode and resumes normal operation. Additional "Sync in" pulses are simply ignored.
A typical application for this trigger mode is for starting successive scan lines during a
2D scan of a sample: the excellent repeatability ensures that there is no jitter on the
beginning of successive scan lines.
11.4 Training
•
Connect the « Sync in » socket to device capable of generating 0-5V pulses, such
as a “signal generator”, using a coaxial (BNC) cable. If possible select a device capable
of emitting a single pulse. Check that the signal is on 0V.
•
In the “Digital output” page, configure the sensor to transmit “Distance” and
“Counter”.
•
Select the “Trigger” page of the “CCS Manager” software. Set Data 1 and Data 2
to “Counter” and observe the counter data in the two data frames.
•
Select the “Start” trigger type and “Rising edge” as the “active” edge. Click on the
“Enable the selected mode” button to enable the mode.
•
If previous steps have been carried out correctly, the counter data displayed in
the data frames “freezes”.
•
Send a single TTL pulse to the “Sync In” input in order to trigger the
measurement: data transmission starts immediately.
•
Click on “Disable the selected trigger mode” button.
•
Set Data 1 and Data 2 to “Distance” and “intensity”. Place a sample in the
measurement range of the pen and adjust the sampling rate and/or the LED intensity.
•
Click on “Enable the selected trigger mode” button to enable the “Start on edge”
trigger mode again: the Data display in the data frames freezes again.
•
Go to the “measurement” page, set the number of points to 100.
•
Send a single TTL pulse to the “Sync In” input in order to trigger the
measurement: Measurement starts immediately and the curves are displayed.
Trouble shooting:
The Command Terminal of « CCS Manager » does not handle correctly trigger-related low-level
commands: use the “Trigger” page of this program to set the trigger modes.
If you wish to send low-level trigger-related commands, use WindowsTM “HyperTerminal”
utility.
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11.5 Additional Trigger modes
Besides the “Start en edge” trigger mode described above, the sensor offers 3
additional trigger modes:
•
In the “Start/Stop on State” trigger mode, data transmission starts and stops
according to the state of the "Sync in" signal. As an example, data transmission starts
when the "Sync in" signal is high (5V) and stops when it is low (0V).
•
The “Start/Stop on Edge” trigger mode is similar to the “Start/Stop on State”,
with one difference: data transmission starts and stops by successive "Sync in" pulses
and not by changes in signal state.
•
In the “Burst” trigger mode, the sensor “latches” (transmits) the data of a preset
number of points each time it receives a "Sync in" pulse.
The “Select active edge” ($TRF) command allows to select the active edge, i.e. the
edge which triggers measurement (rising or falling edge). In the case of “Start/Stop
on State” trigger mode, this command selects the active state (high or low).
Trigger modes and active edge are presented graphically in the “Trigger page” of the
“CCS Manager” software. Select the different trigger types and observe the graphics
showing chronograms of the “Sync In” signal and of measurement. Next, modify the
active edge selection, and observe the modified chronograms.
Unlike the “Start en edge” trigger mode which is disabled automatically by the first
“Sync in” pulse received, the “Start/Stop on State”, “Start/Stop on edge” and “Burst”
trigger modes should be explicitly disabled by commands. As long as these trigger
modes are enabled, successive “Sync in” pulses keep triggering measurements. When
all trigger modes are disabled, the sensor resumes normal operation and additional
“Sync in” pulses are ignored.
For all trigger modes, the emission of “sync out” pulses starts and stops at the same
time as data transmission.
The table next page resumes sensor behavior upon receipt of active and inactive
“Sync in” edges in the different trigger modes.
Active trigger
mode
“Start”
“Start/Stop on
State”
“Start/Stop on
Edge”
Sensor Response to active
“Sync in” edges
st
1 active edge starts measurement
Next ones are ignored
Starts measurement
st
Response to inactive
“Sync in” signal edges
Ignored
Stops measurement
ignored
“Burst”
1 active edge starts measurement,
nd
2 active edge stops measurement,
rd
3 active edge starts measurement,
And so forth.
Measure a pre-fixed number of points (N)
None
Ignored
Ignored
Ignored
11.6 Identification of the first point measured after trigger
When operating in triggered mode the sensor starts and stops measuring according to
the state of the “Sync out” signal. This signal is usually generated by an external
device, it arrives to the sensor and not to the user program running on the PC. Except
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in the case of the “burst” trigger, the user program does “know” how many points are
measured during each time the trigger is “open”.
As an example consider a case of a sensor located above a conveyor belt. The sensor
is configured to the “Start/Stop on state” mode and the “Sync in” signal, generated by
an optical sensor, is high whenever a product is present inside the sensor’s field of
view. The user program has to process the data profiles and identify the products
which do not comply with certain specifications. This program uses one or more large
buffers for accumulating the sensor data. The first difficulty that this program has to
face is the identification of the limits of each profile, in other words, the identification
of the data corresponding to the first point measured after the “sync in” signal goes
from low to high.
The solution to this problem resides in the “Counter” data: the counter is reset each
time the sensor starts measuring after standby, for all trigger modes. By configuring
the sensor to transmit this data together with the “Distance” and the “Intensity” data
the user program can easily detect the limits of each profile.
11.7 Trigger configuration
7B
11.7.1 “Start” (“TRG”) trigger
158B
The « Start Trigger » command puts the sensor on standby for a trigger signal. As
soon as an active edge is detected at the "Sync in" input, the sensor starts
measuring. Additional “Sync in” signals are ignored.
Function
“Start” trigger
Enable “Start” trigger mode.
Command
$TRG
Parameter/Value
returned
None
To disable this mode without a hardware trigger, send a “$” or a $”CTN” command,
and the sensor starts measuring again.
Function
Command
Parameter/Value
returned
Continue
Disable « Start Trigger » mode
$$CTN or “$”
None
11.7.2 “Start/stop on state” trigger (“TRN”)
159B
Data is transmitted when the “Sync in” signal is at the active state. The Active state
(high or low) is determined by the “TRF” command.
Function
“Start/stop on state” trigger
Enable/Disable the “Start/Stop on State” trigger
Command
$TRNb
Parameter/Value
b=1/0
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returned
11.7.3 “Start/stop on edge” (“TRS”) trigger
160B
Data transmission starts and stops alternatively by successive “Sync in” pulses.
Function
Command
Parameter/Value
returned
“Start/stop on edge” trigger
Enable/Disable the “Start/Stop on State” trigger
$TRSb
b=1/0
11.7.4 “Burst” (“TRE”) trigger
16B
When the “Sync in” signal is received, the sensor transmits the data of a preset
number (n) of measured points and stops immediately. Each successive “Sync in”
signal triggers the transmission of new group of n measured points, until the mode
is disabled.
Function
Command
Parameter/Value
returned
“Burst” trigger
Enable/Disable the “Burst” trigger and determine the
number of points to latch.
$TREn (to enable the mode) or $TRE0 (to disable the
mode)
n = number of points to latch on each “Sync in” pulse (19999)
11.7.5 Selecting the active edge/active state
162B
The $TRF command allows to select the active edge, i.e. the edge which triggers
measurement (rising or falling edge). In the case of “Start/Stop on State” trigger
mode, this command selects the active state (high or low).
Function
Command
Parameter/Value
returned
Active edge/active state
Determines which edge is active for TRG, TRE, TRS
Trigger modes
Determines which state is active for TRN Trigger mode
$TRFb
b = 0 for rising edge and high state,
b =1 for falling edge and for low state.
11.7.6 Software trigger
163B
The “STR” command may be used as software trigger in the “TRE” and “TRS”
trigger modes.
Obviously, the software trigger does not have the temporal precision of the
hardware trigger.
Function
Command
Parameter/Value
returned
Acuity Intial Confocal Sensor
Rev 1.0
Software Trigger
Replace a hardware trigger in the “TRE” or “TRS” modes
$STR
None
57
Trouble shooting:
The Command Terminal of the “CCS Manager” command does not handle the “STR”
command correctly.
The software trigger is not available in the “TRN” mode since it simulates a pulse,
not a state.
If you wish to use software trigger, use the “TRS” mode instead.
11.8 Maximum rate of “Sync in” pulses
79B
The maximum rate of the “Sync in” pulses is limited by the cycle time required for the
exposure, signal reading, data computation and data transmission.
For the “Start/Stop on State” and “Start/Stop on Edge” modes, the cycle time is CYCSS
CYCSS = 2/MR + Te
is the cycle time with no averaging
CYCSS = (1+A)/MR + Te
is the cycle time with averaging
MR is the measuring rate, Te Te ≤ 0.2 ms 0.2 ms, A= Averaging factor
For the “Burst” mode, the cycle time is CYCB
CYCB = (1+N) / MR
+ Te
CYCB = (1+N*A) / MR + Te
is the cycle time with no averaging
is the cycle time with averaging
MR is the measuring rate, Te ≤ 0.2 ms, and N is the number of measured points per
burst.
Active trigger mode
Maximum “Sync in”
pulse rate
Not applicable (a single
pulse)
1/ CYCSS
1/ CYCSS
1/ CYCB
“Start”
“Start/Stop on State”
“Start/Stop on Edge”
“Burst”
Examples for computing the max rate of “Sync in” pulses:
“Start/Stop on State” mode,
max rate= 49.5 Hz
measuring rate= 100 Hz, CYCSS = (2*10 +0.2)ms,
“Start/Stop on State” mode,
max rate= 833.3 Hz
measuring rate=2000 Hz, CYCSS = (2*0.5+0.2)ms,
“Burst” mode with N=5,
max rate= 312.5 Hz
measuring rate=2000 Hz, CYCB = (6*0.5+0.2)ms,
Acuity Intial Confocal Sensor
Rev 1.0
58
12.
3Advanced topics
1BdA
12.1 Detection threshold
86B
Detection threshold is the minimum Intensity level for a peak to be detected. Smaller
peaks are considered as noise.
When measuring a double peak the noise level is often higher. For this reason the CCS
controllers feature 3 distinct detection thresholds:
Detection threshold for:
“Distance/strongest peak” measuring
mode
“Distance / 1st peak” measuring
mode
“Thickness”
measuring
strongest peak (*)
“Thickness”
measuring
weaker peak (*)
Parameter/Value returned
Command
MNPx or MNP?
MNPx or MNP?
mode:
SPPx or SPP?
mode:
SDPx or SDP?
0 < x <= 1
(*) The value of the SDP parameter should always be set smaller or equal to the
value of the SPP parameter.
In most cases the factory-default values of the detection thresholds are optimal. It is
recommended that non-expert users do not modify these values without consulting
the fabricant.
Experienced users may decrease the thresholds down to 0.005 (for measuring difficult
samples in metrological lab conditions) or increase it up to 0.050 when the noise level
is particularly high (High temperature, dark signal rarely updated, non optimal
measuring rate, etc.). Another case when it may be necessary to increase the
detection threshold is when measuring a double peak or a volume-scattering sample.
Detection thresholds should be matched to the noise level and not be used as a means
for peak selection.
Troubleshooting:
The physical quantity which is compared to the threshold is the raw signal after
dark subtraction (and not the preprocessed signal shown in the “Signal” page of
CCS manager software, which is a normalized quantity).
12.2
87B
Light source test
The purpose of the light source test is to indicate when the light source should be
replaced. When the light source is the internal white LED this test is not indispensable,
as this source has a very long life time. However for external light sources (TungstenHalogen lamp or Xenon-arc lamp) is recommended to enable the test, as the life time
of these sources is shorter.
Acuity Intial Confocal Sensor
Rev 1.0
59
12.2.1 Enabling/Disabling the test
167B
Function
Command
Parameter/Value
returned
Activation of light source test
Enable/Disable the light source test
$SLPb or $SLP?
b = 0 or 1
Note: when the light source is an internal LED, the test is operational only for LED
brightness level 80% to 100%.
12.3
“First peak” mode
8B
“First peak” mode is a feature of the “Distance” measuring mode that is useful for
samples comprising one or more transparent layers, e.g. samples whose surface is
partially covered with a transparent coating. In this case the sensor “sees” 2 peaks,
one from the outer coating surface and one from the substrate. For such samples the
reflection of the surface beneath the coating may be stronger than that from the outer
coating surface. For the sensor to detect the first peak (instead of the strongest peak,
which it does by default), the “First peak” mode should be enabled.
In this mode the sensor selects the first peak that is higher than the detection
threshold.
Function
Command
Parameter/Value
returned
“First peak” mode
Enable/Disable the “First peak” mode
$MSPb or $MSP?
b = 0 (Strongest peak) or 1 (First Peak).
Notes:
In the “Thickness” measuring mode this command has no effect. The detection
threshold in this mode is determined by the MNP command. This mode is very
sensitive to noise. In case of false detection of noise peak:
update the dark signal measurement
increase the threshold.
12.4 “Altitude” mode
89B
“Altitude” mode is a feature of the “Distance” measuring mode. When this mode is
enabled, the Distance scale is reversed (Altitude instead of Distance):
In Distance mode, Altitude is computed as:
Altitude=Measuring range –Distance
In Thickness mode, the effective measuring range is n*measuring range in air (n is
the refractive index), so that Distance2 may be greater than the measuring range. To
avoid negative values, the Altitudes are computed as:
Acuity Intial Confocal Sensor
Rev 1.0
60
Altitude1= 2*Measuring Range – Distance1
Altitude1= 2*Measuring Range – Distance2
Note that this means that the Altitude origin is not the same for Distance mode and
for Thickness mode.
Function
Command
Parameter/Value
returned
“Altitude” mode
Enable/Disable the “Altitude” mode
$RVSb or $RVS?
b = 0 (Distance) or 1 (Altitude).
12.5 Handling of unmeasured peak in Thickness mode
90B
It may happen a single peak is detected while the sensor is configured to “Thickness”
mode; this may occur if one of the other of the sample faces is outside the measuring
range, or if one of the signals is too weak. The “Unmeasured peak handling” command
determines the behavior of the sensor in such a case:
Option 1 (default)
set Distance1, Intensity1 and Barycenter1 to measured values of the single peak
set Distance2, Intensity2 and Barycenter2 equal to Distance1, Intensity1 and
Barycenter1, respectively
set the thickness to 0
Option 2:
set Distance1, Intensity1 and Barycenter1 to measured values of the single peak
set Distance2, Intensity2 and Barycenter2 to 0
set the thickness to 0
“Unmeasured peak handling” in Thickness mode
Determine the values of
Distance2, Intensity2 and
Barycenter2 data
in case a single peak is detected while the sensor is in
“Thickness” mode
Command
$RSPb or $RSP?
Parameter/Value
b = 0 (Option 2 above) or 1 (option 1 above).
returned
Function
12.6 Watchdog
91B
The sensor features software “Watchdog”, i.e. a permanent test that validates that the
sensor operates normally. In case it does not, the Watchdog resets the sensor after 40
seconds.
This feature is useful for the case the sensor is blocked due to an incomplete
command or another reason, in particular for sensors that are not easily accessible. It
may be disabled and enabled with the “Watch dog” command.
Acuity Intial Confocal Sensor
Rev 1.0
61
Function
Command
Parameter/Value
returned
Watchdog activation
Enable/Disable the watchdog
$WDEb or $WDE?
b = 0 /1
12.7 “Counter”, “State” and “Auto-adaptive mode” data
92B
Besides measured data (Distance, Intensity, Barycenter) the sensor also delivers 3
data for controlling the sensor state and for facilitating its integration. These data may
be sent on the digital output at the same time as measured data, using the SOD
command or any of the software described in section 5.
12.7.1 The “Counter” data
168B
The “Counter” data is an aid for software developers who wish to check that there
is no data loss in their acquisition software.
The 15-bit counter is reset each time a Trigger signal is received when the sensor
is one of the trigger modes: TRE, TRN, TRS or TRG.
12.7.2 The “State” data
169B
The “State” data is an aggregate of various flags.
bit
0
flag
HLV Barycentre face 2
bit
8
1
2
HLV Barycentre face 1
HLV Distance face 2
9
10
3
4
5
6
7
HLV Distance face 1
HLV Thickness
HLV intensity face 2
HLV Intensity face 1
Saturation flag
11
12
13
14
15
flag
Selected frequency (DF
mode) (*)
Light source test Failure
Data
overflow
for
RS
transmission
The HLV bits are set if the corresponding data is not measured but “held” at last
valid value in “Hold last value” mode.
Saturation flag indicates signal saturation. It is set at the same time the “Intensity”
LED indicator color turns to red.
The “selected frequency” flag is significant on double-frequency mode only. 0
indicates that the high frequency was selected, 1 that the low frequency was
selected.
(*) Note: This bit replaces the “Trigger Flip-flop” bit of previous versions. (The
“Trigger Flip Flop” bit was redundant with the “Counter” data).
The “light source test failure” flag indicates lamp should be replaced. Note that this
bit is set at the same time as the “Error” LED-indicator turns red. If the light source
test is disabled, or if the LED brightness is set to a level lower than 80%, this bit is
always zero.
Acuity Intial Confocal Sensor
Rev 1.0
62
The “data overflow” flag indicates that the number of transmitted data directed to
the RS232 port exceeds the max number of transmissible data (cf. § 9.2). Note
that this bit is set at the same time as the “Error” LED-indicator turns Orange.
Note: for multiplexed sensors see section 13.5
12.7.3 The “Auto-adaptive mode” data
170B
In the “Auto-adaptive LED” mode, this data contains the instantaneous LED
brightness coded over 8 bits (0..255). This may be useful for analyzing the relative
intensity of the signal returned from the sample, as in this mode the “Intensity”
data is practically constant.
Relative Intensity = measured Intensity / n.
n = Auto adaptive mode data value
12.8 Synchronization mode
93B
For compatibility with earlier firmware versions, the “Synchronization mode” command
allows choosing between two modes:
“Sync out” signals emitted at the end of the acquisition cycle (like in previous
versions),
“Sync out” signals emitted at the middle of the acquisition cycle (default)
Function
Command
Parameter/Value
returned
Acuity Intial Confocal Sensor
Rev 1.0
Synchronization mode
Select the instant when sync out pulses are emitted
$SYNb or $SYN?
b = 0 /1 (0 : end of the acquisition cycle,
1: middle of the acquisition cycle).
63
13. Low-level Commands
14B
If you use « CCS Manager » or the DLL for configuring the sensor, you may skip this
chapter.
13.1 Command Language
94B
Command language is identical for the two digital I/O channels. The command
language syntax and the basic commands are common to all Acuity point sensor
controllers (CHR, CCS, INITIAL). However, each controller has some specific
commands.
13.1.1 Command syntax
17B
Every command transmitted to the sensor must start by a $ character.
Every command must end with a <CRLF> (carriage return, line feed) sequence.
Command name consists of 3 higher case letters.
When a command has one or more parameters, the parameters come immediately
after the command name.
There should be no comma between the name of the command and the first
parameter.
When a command includes several parameters, the parameters are separated by
commas.
For query the parameter is replaced by “?”
Note: in USB communication, the entire command should be sent as a single
packet.
13.1.2 Sensor response
172B
When powered on, the sensor transmits data according to the last saved
configuration. On receipt of character $, the sensor stops sending data and waits
for the remaining command characters. Each received character (including $) is
echoed back.
After processing the command, the sensor responds with one of the following
strings, and switches back to normal operation.
echo + optional parameters + “ready<CRLF>": the command has been
successfully executed
echo + “invalid cde<CRLF>": the received command is illegal
echo + “not valid<CRLF>":
are illegal
the received command is legal put parameter values
echo + ”error<CRLF>":
execution has failed.
the command and its parameters are legal but
The table below shows some examples of commands and sensor responses.
Acuity Intial Confocal Sensor
Rev 1.0
64
Function
Command
Response
Measuring Mode
(query)
Acquire
dark
signal
Set
Measuring
Mode
$MOD? <CRLF>
$MOD? 1 ready<CRLF>
$DRK <CRLF>
$DRK 3 ready <CRLF>
$MOD1<CRLF>
$MOD1<CR> ready<CRLF>
Select
Distance
and
Intensity
data
to be transmitted
on USB port
$SOD9,0,0,9<CR
LF>
$SOD9,0,0,9 <CR>ready<CRLF>
Select
Output
Data (query)
$SOD? <CRLF>
$SOD?9,0,0,9,0,0,0,0,0,0,0,0,0,0,0ready<
CRLF>
Set ASCII format
$ASC<CRLF>
$ASC ready<CRLF>
13.2 Command List for the CCS Initial
95B
Command
AVR
MOD
SEN
SCA
Parameter
Action
Basic Settings
Averaging
value
(1Data averaging
9999)
Measuring mode Id (0/1 )
Measuring mode selection
Optical pen Id (0 - 19)
Optical
pen
(calibration
selection
Measuring range of selected
Measuring range in µm
only)
table)
(Query
LUL
List of calibration tables
Measuring ranges of all (Query only)
MNP
0.0-1.0
SPP
0.0-1.0
SDP
0.0-1.0
SRA
FRQ
TEX
Preset rate Id (*)
Rate in Hz (*)
Exposure time in µs (*)
Detection threshold for Distance
mode
Detection threshold for Thick. mode
(1st peak)
Detection threshold for Thick. mode
(2nd peak)
Preset rate selection
Free rate setting
Exposure time setting for free rate
FRM
HLV
Min Authorized Rate in Hz
Max nb of points to hold
(0- 999)
0/1
0/1
MSP
RSP
RVS
SRI
0/1
x.xxxx
refractive
Acuity Intial Confocal Sensor
Rev 1.0
index
file
65
id
Min authorized rate (Query only)
« Hold Last value » mode
“First Peak” mode enabling
“Unmeasured peak handling” in thick.
mode
“Altitude” Mode enabling
Refractive index value
InF
DRK
FDKn,m
SSU
VER
RCD
SOD
ASC
BIN
BAU
ANA
SOF
SLP
LED
AAL
VTH
ADK
DFA
DFF
DFI
TRG
CTN
TRE
TRS
TRN
TRF
SYN
WDE
CHA
(0/n)
Refractive index file selection
(*) parameter value are
limited
by
the
Min
Authorized Rate
Basic Functions
Minimal authorized rate
Acquire and save Dark at all rates
(returns Min authorized rate id)
n=
Dark
averaging,
Acquire Dark at current rate
m=weighting
Save all parameters to non-volatile
memory
Serial number & firmware version
(Query only)
b1,b2,b3
bi=1:reset
Reset encoder position
encoder i
Digital I/O
n0,n1..n15
with
Select transmission channel for all
ni=0/1/9
data items
ASCII mode
Binary mode
9600..460800
Baud rate (for RS232)
Analog I/O
Configuration of analog output
Output Id, data id, 0V&10
values
0/1
Set/Reset 0V values
Light Source
0/1
Light source test enabling
0..100
LED brightness adjustment
Auto-adaptive modes
0/1
“Auto-adaptive LED” mode enabling
0..4095
Threshold for “Auto-adaptive LED”
mode
0/1
”Auto-adaptive Dark” mode enabling
0/1
“Double Frequency” mode activation
f1, f2 in Hz where frm ≤
“Double Frequency” mode frequency
f1 < f2 ≤ 1850 Hz,
setting
0/1
“Double Frequency” mode intensity
selection
Trigger
“Start” Trigger mode enabling
“Start” Trigger mode disabling
0/n, n=1..9999
0/1
“Burst” Trigger mode enabling and
setting
0/1
“Start /stop on edge” Trigger mode
enabling
0/1
“Start/stop on state” Trigger mode
enabling
Select active edge
0/1
Compatibility with previous modes,
cf. §14.8
Watch Dog
0/1
Watch dog enabling
Multiplex CCS
1/2 or 1/2/3/4
Select multiplex channel
Acuity Intial Confocal Sensor
Rev 1.0
66
DKA
minimal authorized rates
Dark all channels
14. DATA FORMAT AND DATA ENCODING
15B
If you use « CCS Manager » or the DLL for acquiring the data, you may skip this chapter.
14.1 Data transmission formats
96B
The sensor provides 2 data transmission formats: the ASCII format and the binary
format.
Data transmission formats are set by commands.
14.1.1 Ascii Format
173B
Function
Command
Parameter/Value
returned
Ascii
Configure the sensor to ASCII transmission format
$ASC
None
In ASCII format, 5 characters (digits) are transmitted for each data item. The data
from the same point are separated by commas, and the successive points are
separated by <CRLF> sequence.
Example
Measuring mode = « Thickness »,
Data selected = Thickness, Distance face 1, Distance face 2.
The successive measurement points are identified as A, B, C etc.
The table below shows the first 36 characters transmitted:
ASCII transmission format
X
X
X
Thickness – point A
X
X
,
DSe
p
6
X
X
X
X
Distance face 1 - point A
X
7
8
11
,
DSe
p
12
1
4
5
CR
PSep
18
LF
X
X
X
Thickness – point B
20
21
22
X
X
23
24
X
X
X
X
Distance face 1 – Point B
X
26
30
,
DSe
p
31
2
3
X
X
X
X
Distance face 2 – point A
13
14
15
16
,
DSe
p
25
27
X = digit (0-9)
(CRLF)
28
X
17
29
19
9
10
X
X
X
X
Distance face 2 – Point B
X
32
36
DSep = Data separator (comma)
33
34
35
PSep= Point separator
Note that in thickness mode the distance information is provided with 15 bits
resolution (one data item).
Acuity Intial Confocal Sensor
Rev 1.0
67
14.1.2 Binary format
174B
In Binary format, 2 bytes are transmitted for each data item with no data separator.
Successive points are separated by two consecutive bytes OxFF (decimal value =
255).
Binary
Configures the sensor to binary transmission format
$BIN
Function
Command
Parameter/Value
returned
None
Example
Measuring mode = « Distance »,
Selected data = Distance MSB and Distance LSB
A,B,C = Successive measurement points. The table below shows the first 12 bytes
transmitted:
Binary transmission format
X
X
X
Dist – MSB
Point A
1
2
X
Dist – LSB
Point A
3
4
OxF
F
PSep
OxF
F
5
6
X
X
Dist – MSB
Point B
7
8
X= 1 byte of data
X
X
Dist – LSB
Point B
9
10
OxF
F
PSep
OxF
F
11
12
PSep = Point separator
14.2 Decoding the data
97B
All data are encoded as integer number. The following rules allow converting them to
physical quantities.
14.2.1 Data decoding for the Distance measuring mode
175B
The Distance is encoded over 30 bits (2 data items: MSB and LSB, 15 bits each). To
obtain The Distance in µm, use the following relation:
Distance = (Transmitted value of MSB *215 + Transmitted value of LSB)*
Measurement range / 230
The measurement range depends on the optical pen. To get the measuring range of
the currently connected confocal optical pen, send the “SCA?” command.
In some cases 15-bit resolution is sufficient. In such cases a simplified relation may
be used:
Distance [µm] ~ Transmitted Value of MSB x Measurement range 
32767
Intensity is encoded over 12 bits (0-4095). To obtain the Intensity in % of the
sensor dynamics, use the following relation:
Intensity [% ]= Transmitted Value x 100%  4095
Acuity Intial Confocal Sensor
Rev 1.0
68
The position of the Barycenter (pixel index of the spectral peak on the
photodetector signal) is encoded over 15 bits (0-32767). To obtain the position of
the barycenter in pixels, use the following relationship :
Barycenter = (transmitted value  Bs) + Bo
Bs is Barycenter scale, Bo is Barycenter offset. The default values of these
parameters for the CCS Initial are:
Bs=32,
Bo= 520
Encoder data is coded over 30 bits and transmitted in 2 words of 15 bits each.
The “Reset value” (536 870 912 = 2^30 / 2) is attributed to the position where
the “$RCD” command is sent. Each unit equals 1 encoder microstep.
The State data is a word composed of independent bits (cf. § 14.7).
The counter and the Auto-adaptive mode data are described in the “Advanced
topics” chapter.
14.2.2 Data decoding in Thickness measuring mode
176B
In Thickness mode Distance1, Distance2 and the Thickness data are encoded over
15 bits (0-32767).
As the refractive index of the sample is generally greater than 1.0, the Thickness
and Distance2 may be greater than the measuring range in air. For this reason the
scale is twice the measuring range in air.
Note: To get the measuring range of the currently connected confocal optical pen,
send the “SCA?” command.
Thickness =Transmitted value x Measurement Range x Scale factor  32767
Distance face 1 =Transmitted value x Measurement range x Scale factor 
32767
Distance face 2 =Transmitted value x Measurement range x Scale factor 
32767
Scale factor =2
All the other data are encoded in the same way as for the CCI/Distance mode.
Acuity Intial Confocal Sensor
Rev 1.0
69
15. Maintenance
16B
15.1 Handling the fiber optics
98B
When no fiber optics is connected, the fiber socket located on the controller front
panel must at all times be fitted with its protection cap to avoid contamination of the
fiber tip, which could result in malfunctioning of the sensor.
Avoid putting anything on the fiber optics or laying it on the floor (not to stamp it).
Avoid wringing or bending it upwards 70 degrees.
The best way to avoid contamination of the fiber optics lead is to keep it
permanently connected at both ends, or if it is necessary to disconnect it, to
immediately fit a protective cap on the socket at the controller front panel.
15.2 High Dark signals
9B
The first symptom indicating the presence of dust or dirt on the fiber optics tips or
inside a fiber connector is an increase in the level of the dark signal. In such a case on
completion of the dark acquisition sequence the color of the blinking LED Indicators is
orange or red. This means that the acquired dark signal is too high at some sampling
rates (orange) or at all sampling rates (red).
Note: For sensors equipped with a custom light source, the dark signal is often
higher as these light sources are more intense. For such sensors the warning
message should not be interpreted as an indication of a problem.
A high dark signal is not necessarily a problem: If you wish to measure at 2 kHz and
the sensor cannot be configured to 100 Hz, there is clearly no reason to be alarmed.
However if you wish to measure at 200 Hz and the sensor cannot be configured to 100
Hz, it is recommended to proceed as following:
Step 1: Check that the dark signal was acquired with no object present within the
measuring range.
Mask the extremity of the optical pen with a piece of paper, acquire the dark signal
again, and watch the color of the blinking LED Indicators at the end of the operation.
If the problem persists:
Step 2: Check if the problem comes from the controller or from the fiber optics
connected to the optical pen.
Disconnect the fiber optics from the controller front panel (do not cover the socket
with the protecting cap). Acquire the dark signal, and watch the color of the blinking
LED Indicators at the end of the operation. If it is orange or red, the problem comes
from the fiber optics inside the controller. If it is green, the problem comes from the
fiber optics connected to the optical pen.
Step 3: If the problem comes from the optical pen, clean the fiber optics tip:
Acuity Intial Confocal Sensor
Rev 1.0
70
Raise the black protecting cap over the fiber
optics plug, and clean the fiber optics tip
carefully. Use absorbent cotton, or a paper
towel, soaked with alcohol (e.g. Ethanol or
Methanol). Perform circular movement so as
to push the dust grains away from the fiber
tip.
If you have tried cleaning the fiber tip once
or twice and the problem persists, it means
that the fiber optics is damage. In this case,
replace the fiber optics cable by a new one.
Step 4: If the problem comes from the controller clean the fiber coupler inside the
controller:
Turn the Initial controller OFF
Remove the 2 screws on the “Fiber Optic Input” connector:
Pull gently the fiber feedthrough connector out of the controller
Unscrew the metallic fiber connector; when completely unscrewed pull
it out in order to remove it from the feedthrough connector
The fiber extremity is now exposed. Clean it carefully with alcohol-soaked cotton
Acuity Intial Confocal Sensor
Rev 1.0
71
Replace the optical fiber on the feedthrough connector.
Insert carefully the feedthrough connector into the blue box.
Fasten the 2 screws.
Restart the controller and launch a new a dark measurement.
15.3 Diagnostics File
10B
The “CCS Manger” program can collect automatically the sensor configuration and
generate a diagnostics file. Diagnostics file can be generated by a simple mouse click,
from the “Maintenance” page of this program and saved to the computer hard disk (if
your computer is connected to Internet, you may email the file directly). Whenever
you contact your vendor for technical support, do not forget to join this file to your
query.
15.4 Firmware update
10B
The “Maintenance” page of “CCS Manager” may be also used to upload a new
firmware version into the sensor. Please refer to the “Help” page describing this
feature (To access help, click on the “?” mark in the menu).
15.5 Technical support
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If after reading the manual you have more questions concerning the optimal way to
use the sensor, please contact you Acuity for technical support.
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16. Appendix: Chronograms
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The following chronograms describe the temporal behavior of some of the principal tasks
performed by the sensor in different configurations.
The chronograms are not required for standard use of the sensor. They are given as an
aid to software developers who wish to integrate the sensor in more complex systems.
The following table defines the 4 configurations:
N°
Trigger mode
Data Averaging
Frequency mode
1
2
3
4
None
“Start” trigger
None
None
None
None
AVR=3
None
Single frequency
Single frequency
Single frequency
Double frequency
The tasks shown are:
Task
photodetector exposure
Duration (typical values)
Texp = 1 / measuring rate
photodetector readout
TRO ~ 0.4 ms
data processing
TPR ~ 80 µs
Sync out pulse on the “Sync out”
connector
TSO = 10 µs
Read the positions of connected digital
encoder
(if any).
modification of the analog output
voltage
Starts at the same time as the “Sync
out”
transmission of the data on the digital
outputs
TDT: duration of data transmission is
very variable, it depends on the
connection type (RS or USB) and of the
digital
output
configuration
(SOD
command and data format)
1 cycle time
Chronogram Description:
1. Frames
For each individual frame, the steps are:
Exposure
Photodetector Readout
Processing
Frames are handled as a pipeline: at the same time that frame i is being exposed, frame
(i-1) is read and frame (i-2) is being processed.
2. Cycles
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A « cycle » corresponds to one measurement.
With no averaging, the cycle is a single frame (in “Single Frequency” mode) or a couple
of frames, one with long exposure and one with short exposure (in “Double Frequency”
mode).
For averaging factor N the cycle consists of N frames (“Single Frequency” mode) or N
couples of long exposure + short exposure (in “Double Frequency” mode).
For each cycle, the steps are:
Case I: Continuous Acquisition
All the frames of the cycle are exposed successively
One “Sync Out” pulse is emitted.
In “Single Frequency” mode the pulse is emitted in the middle of the exposure of the
cycle
In “Double Frequency” mode the pulse is emitted in the middle of the exposure of the N
short frames (N≥1)
At the same time as the “Sync Out” pulse, the sensor reads the position of all connected
encoders (if any)
When the processing of the last frame of the cycle is done, the data (and eventually the
encoder position) is transmitted on the digital port and the voltage analog outputs is
refreshed.
Case II: Triggered acquisition
The sensor stands by for Incoming Trigger pulse on the “Sync in” connector.
During stand by nothing comes out of the sensor, but acquisition goes on internally.
Upon reception of the trigger, the current exposure is aborted and the exposure of a new
frame starts immediately (cf. chronogram 2).
The same steps as in case I follow.
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Chronogram 1: Continuous Acquisition, No Averaging, Single Frequency
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Chronogram 2 : Start Trigger, Active Edge = Rising, No Averaging, Single Frequency
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Chronogram 3 : Continuous Acquisition, Averaging = 3, Single Frequency
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Chronogram 4: Continuous Acquisition, No Averaging, Double Frequency
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