Operators ManualDiamond Series OEM/IndustrialDiamond C-70 Liquid-Cooled Laser

5100 Patrick Henry DriveSanta Clara, CA 95054

Diamond C-70 Liquid-Cooled Laser Operators ManualThis document is copyrighted with all rights reserved. Under copyrightlaws, this document may not be copied in whole or in part, or reproducedin any other media, without the express written permission of Coherent,Inc. (Coherent). Permitted copies must carry the same proprietary andcopyright notices as were affixed to the original. This exception does notallow copieswhether or not soldto be made for others; however, all thematerial purchased may be sold, given, or loaned to another person.Under the law, copying includes translation into another language.

Coherent, the Coherent Logo, and Diamond are registered trademarks ofCoherent, Inc.

Every effort has been made to ensure that the data given in this documentis accurate. The information, figures, tables, specifications, part numbers,and schematics contained herein are subject to change without notice.Coherent makes no warranty or representation, either expressed orimplied, with respect to this document. In no event will Coherent be liablefor any direct, indirect, special, incidental, or consequential damagesresulting from any defects in its documentation.

Technical Support

In the US:

Should you experience any difficulties with your laser or need anytechnical information, please visit our Web site www.Coherent.com.Should you need further assistance, please contact Coherent TechnicalSupport via e-mail Product.Support@Coherent.com or telephone,1-800-367-7890 (1-408-764-4557 outside the U.S.). Please be ready toprovide model and laser head serial number of your laser system as wellas the description of the problem and any corrective steps attempted to thesupport engineer responding to your request.

Telephone coverage is available Monday through Friday (except U.S.holidays and company shutdowns). Inquiries received outside normaloffice hours will be documented by our automatic answering system andwill be promptly returned the next business day.

Outside the U.S.:

If you are located outside the U.S., please visit www.Coherent.com fortechnical assistance, or phone our local Service Representative. ServiceRepresentative phone numbers and addresses can be found on theCoherent web site.

Coherent provides telephone and web-based technical assistance as aservice to its customers and assumes no liability thereby for any injury ordamage that may occur contemporaneous with such services. Under nocircumstances do these support services affect the terms of any warrantyagreement between Coherent and the buyer. Operation of any Coherentlaser with any of its interlocks defeated is always at the operator's own risk.ii

Table of ContentsTABLE OF CONTENTS

Preface ................................................................................................................................. viiU.S. Export Control Laws Compliance ............................................................................... viiNotice Concerning Regulatory Status of Diamond Series Lasers ....................................... viiNotice Concerning Warranty ............................................................................................... viiSymbols Used in This Manual............................................................................................ viii

Section One: Description and Specifications................................................. 1-1Introduction......................................................................................................................... 1-1Purpose of This Manual ...................................................................................................... 1-1Specifications and Input Requirements .............................................................................. 1-2Hardware Overview............................................................................................................ 1-2

DC Input Power ......................................................................................................... 1-2Cooling Requirements ........................................................................................................ 1-2

Comparison of Air-Cooling and Liquid-Cooling (Reference) .................................. 1-3Liquid-Cooling Option of the Diamond C-70 ........................................................... 1-3

Laser Head .......................................................................................................................... 1-4RF Power Supply ................................................................................................................ 1-4Specifications...................................................................................................................... 1-5

Section Two: Laser Safety ........................................................................................ 2-1Optical Safety ..................................................................................................................... 2-1Electrical Safety .................................................................................................................. 2-3

Laser Head ................................................................................................................. 2-3Laser Safety Requirements ................................................................................................. 2-4

Safety Interlocks ........................................................................................................ 2-4Compliance to Standards .................................................................................................... 2-5Location of Safety Labels ................................................................................................... 2-5

Waste Electrical and Electronic Equipment (WEEE, 2002)...................................... 2-5

Section Three: Utility Requirements and System Installation........... 3-1Introduction......................................................................................................................... 3-1Unpacking and Inspection .................................................................................................. 3-1

Verifying Delivery ..................................................................................................... 3-1Checking Delivered Items ......................................................................................... 3-1

Safety Issues in Laser Installation ...................................................................................... 3-2Mechanical Mounting ......................................................................................................... 3-2

Mounting Considerations for Diamond C-70 ............................................................ 3-4Liquid-Cooling.................................................................................................................... 3-4

Cooling System Layout ............................................................................................. 3-5Re-Circulation and Coolant Flow Interlock Switch .................................................. 3-5Signal Interface .......................................................................................................... 3-5Thermal Shutdown Switch......................................................................................... 3-5DC Power Relay ........................................................................................................ 3-6iii

Diamond C-70 Liquid-Cooled Laser Operators ManualCondensation of Water Vapor ................................................................................... 3-6Coolant Fittings on Laser System.............................................................................. 3-6Cooling Capacity ....................................................................................................... 3-7Coolant Filtering ........................................................................................................ 3-7Coolant Flow Rate and Pressure ................................................................................ 3-8Pressure Drop............................................................................................................. 3-8

Electrical Power Connection .............................................................................................. 3-9DC Power Supply Requirements ............................................................................. 3-10

DC Power Supply Cabling Requirements ...................................................... 3-10DC Power Supply Over-Voltage Tripping ..................................................... 3-11

Control Signal Connection................................................................................................ 3-11Beam Propagation............................................................................................................. 3-12

Section Four: Laser Operation .............................................................................. 4-1Signal Interface Connectors................................................................................................ 4-1Operating Modes................................................................................................................. 4-2

Typical Waveform ..................................................................................................... 4-2CW Mode................................................................................................................... 4-3Power Stability........................................................................................................... 4-3Gated CW Mode ........................................................................................................ 4-3Variable Output, Power Capability and Pulsewidth Variation .................................. 4-4

Optical Pulse Shape .......................................................................................... 4-4Complex Modulation Waveforms ............................................................................. 4-4

Varying the Pulsewidth..................................................................................... 4-4Protection from Unacceptable Inputs ............................................................... 4-4

Turning the Laser On and Checking Output Power ........................................................... 4-4Electronic Control............................................................................................................... 4-6

Electronic Signals Required to Turn the Laser On .................................................... 4-6Start-up Sequence ............................................................................................. 4-6

Response Times of Laser to RF Enable and Control Enable..................................... 4-7Signals Used for Fault Detection ............................................................................... 4-7VSWR Faults During Initial Turn-On ....................................................................... 4-8C-70 Microcontroller, I/O Signal Operation.............................................................. 4-9

Temperature Fault........................................................................................... 4-11Voltage Fault................................................................................................... 4-12

Section Five: Maintenance and Troubleshooting ....................................... 5-1Maintenance........................................................................................................................ 5-1

Cooling System Maintenance .................................................................................... 5-1Cleanliness of Output Optical Element ..................................................................... 5-1

Troubleshooting .................................................................................................................. 5-2DC Power and Voltage .............................................................................................. 5-2Control Inputs ............................................................................................................ 5-2Over-Temperature Warning....................................................................................... 5-2Over-Temperature Shutdown .................................................................................... 5-2CW Mode................................................................................................................... 5-3Visualizing ................................................................................................................. 5-3iv

Table of ContentsOutput Beam .............................................................................................................. 5-3

Parts List .............................................................................................................................. A-1

Warranty...............................................................................................................................B-1Diamond Series Laser Warranty.........................................................................................B-1Conditions of Warranty ......................................................................................................B-1Responsibilities of the Buyer ..............................................................................................B-1Limitations of Warranty......................................................................................................B-2

Packing Procedure ..........................................................................................................C-1Preparation of Liquid-Cooled Systems/RF Power Supplies...............................................C-2Preparation for Laser Heads ...............................................................................................C-2Shipping Instructions ..........................................................................................................C-3RMA Form Instructions......................................................................................................C-4

Glossary ..................................................................................................................... Glossary-1

Index ................................................................................................................................. Index-1v

Diamond C-70 Liquid-Cooled Laser Operators ManualLIST OF ILLUSTRATIONS

1-1 Diamond C-70 Liquid-Cooled Laser ............................................................................... 1-11-2 Cooling System Diagram................................................................................................. 1-3

2-1 Waste Electrical and Electronic Equipment Label .......................................................... 2-52-2 Location of Safety Labels ................................................................................................ 2-6

3-1 Diamond C-70 Liquid-Cooled Laser Head Dimensions.................................................. 3-33-2 Recommended Liquid-Cooling System Functional Block Diagram ............................... 3-43-3 Diamond C-70 Liquid-Cooling Connections................................................................... 3-73-4 Electrical Connections to Diamond C-70 ........................................................................ 3-93-5 Beam Diameter vs. Distance From Laser Head............................................................. 3-12

4-1 RF Input Waveform and Laser Output Waveform .......................................................... 4-24-2 Typical Warm-Up Behavior from a Cold Start ............................................................... 4-34-3 Fault Detection Circuit..................................................................................................... 4-74-4 Normal Start Sequence .................................................................................................... 4-94-5 SWR Fault Detected ...................................................................................................... 4-104-6 Temperature OK Signal Operation ................................................................................ 4-114-7 Voltage OK Signal Operation........................................................................................ 4-12

A-1 Diamond C-70 Liquid-Cooled Optional Mounting Brackets(Part #1101-12-0016 for a set of 4) .......................................................................... A-2

C-1 Shipping Container ..........................................................................................................C-1C-2 Laser Head Packaged in Plastic Bag................................................................................C-2C-3 Foam Cover Sheet............................................................................................................C-3

LIST OF TABLES

1-1 Comparison: The Benefits of Air-Cooling vs. Liquid-Cooling Methods ........................ 1-31-2 Specifications and Input Requirements for Diamond C-70 Lasers ................................. 1-5

4-1 Signal Interface Description and Connector Pinout ........................................................ 4-1

A-1 Diamond C-70 Laser Component Part Numbers ............................................................ A-1vi

PrefacePreface This is the Operators Manual for the Diamond C-70Liquid-Cooled OEM/Industrial carbon dioxide (CO2) lasersmanufactured by Coherent. These lasers are OEM systems; they aredesigned as components which are to be inserted by the originalequipment manufacturer (OEM) prior to delivery to the end user. Itis strongly recommended that the user read Section Two: LaserSafety, before operating the laser.

Use of controls or adjustments or performance of proceduresother than those specified in this manual may result inhazardous radiation exposure.

U.S. Export Control Laws Compliance

It is the policy of Coherent to comply strictly with the U.S. exportcontrol laws.

Export and re-export of lasers manufactured by Coherent are subjectto the U.S. Export Administration Regulations, which areadministered by the Commerce Department. In addition, shipmentsof certain components are regulated by the State Department underthe International Traffic in Arms Regulations.

The applicable restrictions vary depending on the specific productinvolved, intended application and the product destination. In somecases, U.S. law requires that U.S. Government approval be obtainedprior to resale, export or re-export of certain articles. When there isuncertainty about the obligations imposed by U.S. law, clarificationshould be obtained from Coherent or an appropriate U.S.Government agency.

Notice Concerning Regulatory Status of Diamond Series Lasers

This laser component does not include all safety features that arerequired by the United States Food and Drug Administration (FDA),Center for Devices and Radiological Health (CDRH) in lasersystems sold to end users. It is sold solely to qualified manufacturerswho in their end product, supply interlocks, indicators, and otherrequired safety features, in full compliance with 21 CFR 1040,Subchapter J and/or other applicable national and local regulations.

Notice Concerning Warranty

Operation or handling of this laser component, inconsistent with thismanual, may void the warranty.vii

Diamond C-70 Liquid-Cooled Laser Operators ManualSymbols Used in This Manual

This symbol is intended to alert the operator to the presence ofdangerous voltages associated with the laser that may be ofsufficient magnitude to constitute a risk of electric shock.

This symbol is intended to alert the operator to the presence ofimportant operating and maintenance instructions.

This symbol is intended to alert the operator to the danger ofexposure to hazardous visible and invisible laser radiation.viii

Description and Specifications

SECTION ONE: DESCRIPTION AND SPECIFICATIONS

Introduction This section details specifications and characteristics (includingmechanical, thermal, electrical, and optical interfaces;environmental requirements, and limitations) of the Diamond C-70laser.

The Diamond C-70 laser is a sealed-off, RF-excited CO2 laser,capable of continuous wave (CW) or modulated operation. From thelaser safety point of view, this laser is considered to be a componentand must be integrated into a system by a qualified originalequipment manufacturer (OEM) prior to delivery to the end user.See the section titled Laser Safety Requirements on page 2-4 for acomplete discussion of laser safety issues.

Purpose of This Manual

This manual is designed to assist the original equipmentmanufacturer (OEM) during the integration of the Diamond C-70OEM laser. It contains information about the performance andoperation of the laser as well as installation and control methods.

Figure 1-1. Diamond C-70 Liquid-Cooled Laser 1 - 1

Diamond C-70 Liquid-Cooled Laser Operators ManualSpecifications and Input Requirements

Table 1-2 provides specifications and requirements for coolingwater and power inputs for the Diamond C-70 laser.

Figure 1-1 illustrates the baseline configurations (i.e., without anyoptional hardware additions or deletions) of the Diamond C-70laser. Each laser system consists of a laser head assembly and anintegrated radio frequency (RF) power supply. The RF power supplyconverts 48 VDC, 25 A (35 A peak for 1 ms) power to radiofrequency power.

Connection of the customer-supplied DC power supply to theDiamond C-70 is via a barrier strip with screw terminals on the RFpower supply. These terminals should also be used for theconnection of wires for remote voltage sensing. Such sensing isrecommended to control the voltage at the input to the RF powersupply more precisely.

Hardware Overview

The Diamond C-70 laser is a waveguide, carbon dioxide (CO2)laser. RF electric fields provided by the RF power supply excite theCO2 gas mixture. The standard configuration of this laser operatesat a wavelength near 10.6 m in the infrared region of theelectromagnetic spectrum.

DC Input Power DC input power is provided by the user through customer-suppliedbus wiring, which goes to the RF power supply. The RF powersupply converts this DC electrical power into RF power, which isused to excite the gas in the laser head. The DC power supplyrequirements are discussed in detail in the subsection entitled DCPower Supply Requirements on page 3-10.

Cooling Requirements

Total heat dissipation for the laser is specified in Table 1-2. The laserhead typically dissipates 700 W from its base surface while the RFpower supply typically dissipates 300 W, for a total typical heatdissipation of 1000 W (maximum total heat dissipation is 1230 W).The Diamond C-70 must be provided adequate cooling to keep thelaser operating temperature within acceptable limits. The coolingmethod that is used must not induce stresses that will result inmisalignment of the laser resonator. The Diamond C-70 heat sinksare designed so the assembled structure remains free of excessivestress.1 - 2

Description and SpecificationsComparison of Air-Cooling and Liquid-Cooling (Reference)

Air-cooling and liquid-cooling each have distinct advantages.Table 1-1 describes the factors that should be taken intoconsideration when choosing a cooling system for a laser module.

One should also consider if condensable vapors are present and takesuitable measures to purge sensitive areas, such as optical surfaces,with a suitable gas.

Liquid-Cooling Option of the Diamond C-70

Installation requirements related to the liquid-cooling option of theDiamond C-70 laser are discussed in detail in the section titledLiquid-Cooling on page 3-4. This section is a quick overviewonly. Figure 1-2 shows the recommended connection from thecustomer-supplied refrigerated recirculator to the Diamond C-70laser system.

Coherent recommends that the coolant water flowing from thecustomer-supplied refrigerated recirculator flow to the laser head,then to the RF power supply. Although not shown in Figure 1-2, aflow interlock device must be provided by the customer in thecooling-water-return line to detect the presence of cooling waterwith the required flow rate, and to shut down the laser if adequatecoolant flow is not present.

Table 1-1. Comparison: The Benefits of Air-Cooling vs. Liquid-Cooling Methods

AIR COOLING LIQUID COOLING

Low in cost Low in complexity Low service requirements Easier to install

Offers the highest process stability Can yield the most compact arrangement Suitable for applications in which the ambient air

temperature exceeds 40C Better for applications in which the ambient air is

laden with particulates; it will result in a maintenance requirement of cleaning of air-cooling system and in general lower heat transfer, more performance instability and shorter product life time if air-cooled laser is used

Easier to make a hermetically sealed system

Figure 1-2. Cooling System Diagram

RefrigeratedRecirculator

Laser System

Flow1 - 3

Diamond C-70 Liquid-Cooled Laser Operators ManualTo avoid damage to the laser, never operate the laser without asupply of cooling water meeting the requirements indicated inTable 1-2.

Laser Head The laser head takes RF input power and converts some of it to laserradiation. The rest of the RF input power is exhausted as waste heat.For the Diamond C-70 liquid-cooled laser, this waste heat isexhausted into the cooling water that flows through the laser head.The laser head consists of the folded optical waveguide resonator,the all-metal gas envelope structure, and RF power supply. Infraredlaser radiation is emitted from the optical aperture. Pictures anddimensions drawings for the Diamond C-70 liquid-cooled laser areshown in Figure 1-1 and Figure 3-1.

RF Power Supply The Diamond C-70 RF power supply converts DC input power toRF energy which is sent to the laser head. Heat from the RF powersupply flows into the integrated laser assembly and is exhausted intothe liquid-cooling water. An RJ-45-type connector is used to controlthe laser system. All of the user interfaces (DC power, cooling water,and signal interface) are on one panel of the RF power supply.1 - 4

Description and Specifications

Specifications Table 1-2 describes the specifications and input requirements forDiamond C-70 lasers.

Table 1-2. Specifications and Input Requirements for Diamond C-70 Lasers

SYSTEMPERFORMANCE SPECIFICATIONS

Wavelength 10.55 m to 10.65 m

Optical Output Power1 70 W

Power Stability2 3%

Mode Quality M 2 = 1.2 0.1

Beam Size 3.6 0.5 mm @ output aperture

Beam Divergence < 5 mRad, full angle

Polarization > 100 to 1(Fixed linear, parallel to width dimension)

Operating Frequency & Duty Cycle 0 to 25 kHz, 0 to 100% DC

CONFIGURATION &FACILITYREQUIREMENTS

Weight 9.7 kg (21.5 lbs.)

Dimensions L x W x H 650.4 x 92.5 x 102.61 mm(25.61 x 3.64 x 4.04 in.)

Input voltage 48 VDC < 2% regulation,< 1% P-P Noise/Ripple

25 A Max avg, with 35 A peak for 1 msec minimum, measured at input terminals

Heat Dissipation < 1230 W

Coolant Distilled Water w/ 25 to 35% Dow Frost*

Cooling Flow Rate > 3.8 lpm (1.0 gpm)

Maximum Coolant Pressure 7 kg/cm2 (100 psig)

Max. Pressure Differential(@1.0 gpm)

2.4 bar (35 psig)

Coolant Temperature 15C to 30C (59F to 86F)

Maximum Case Temperature < 60C (140F)

Operating Environment - Temperature 5C to 55C (41F to 131F)

Altitude < 2,000 m (6,500 ft.)

Humidity Non-condensing

Shipping/Storage Environment - 10C to 60C (14F to 140F), Non-condensing

1 Power measured @ 25C & derated by 1%/C for higher laser head temperatures2 Power Stability based on (Pmax-Pmin)/(2*Pmax) average power measurement @ constant duty cycle after 10-minute warm-up @ operating condition*DOWFROST is a trademark of the Dow Chemical Company1 - 5

Diamond C-70 Liquid-Cooled Laser Operators Manual1 - 6

Laser SafetySECTION TWO: LASER SAFETY

Optical Safety The Diamond C-70 laser has undergone extensive testing to ensurethat, with proper usage, it is a safe and reliable device.

Because of its special properties, laser light poses safety hazards notassociated with light from other sources. The safe use of lasersrequires that all laser users and everyone near the laser be aware ofthe dangers involved in laser operation.

Direct eye contact with the output beam from the laser will causeserious damage and may cause blindness.

All personnel in the same room as the laser or anyone who may beexposed to the laser beam should be informed that a laser is inoperation. All personnel must wear laser safety glasses whichprotect against the wavelengths in use.

There is no visible indication at the Diamond C-70 laser headthat it is operating.

Exercise caution to protect against specular reflections, becausereflections at the Diamond C-70 laser wavelength are invisible.

Eye safety is a great concern when using a high-power laser such asthe Diamond C-70 laser. There are often many secondary beamspresent at various angles near the laser. These beams are specularreflections of the main beam from polished surfaces. While weakerthan the main beam, such beams may still be sufficiently intense tocause eye damage.

Laser beams are also powerful enough to burn skin, clothing orpaint. They can ignite volatile substances such as alcohol, gasoline,ether, and other solvents and can damage the light-sensitiveelements in video cameras, photomultipliers, and photodiodes.2 - 1

Diamond C-70 Liquid-Cooled Laser Operators ManualCoherent provides the following recommendations to promote thesafe use of the Diamond C-70 laser. Operators are advised to adhereto these recommendations and employ sound laser safety practicesat all times.

Use protective eyewear when operating the laser and guardagainst inadvertent exposure to skin or clothing. Selecteyewear which is suitable for use with the wavelengths andradiation intensity that the laser emits. Refer to the Guide forSelection of Laser Eye Protection, Laser Institute of America(6th Edition), 2007.

The beam path should be enclosed with a protective cover(ideally with an interlock scheme) and these covers should notbe removed during normal use.

Never look directly into the laser output port when the poweris on.

Set up the laser and all optical components used with the laseraway from eye level. Provide enclosures for the laser beam.

Use the laser in a room with access controlled by doorinterlocks. Post warning signs. When operating the laser, limitaccess to the area to individuals who are trained in laser safety.

Avoid operating the laser in a darkened environment. Do not use the laser in the presence of flammables, explosives,

or volatile solvents such as alcohol, gasoline, or ether.

For additional information on laser safety, refer to the followingpublications:

American National Standard for the Safe Use of Lasers,Z136.1-2007, American National Standards Institute, 2007.

Performance Standard for Laser Products, United States Codeof Federal Regulations, 21CFR1040 10(d).

Laser Safety Guide, Laser Institute of America. (11th Edition).Orlando, FL 2007.

Guide for Selection of Laser Eye Protection, Laser Institute ofAmerica (6th Edition), 2007.

D. Sliney and M. Wolbarsht. Safety with Lasers and OtherOptical Sources,. Plenum Publishing Company, New York,N.Y., 1980.

Many of these documents on Laser Safety are available throughLaser Institute of America, 13501 Ingenuity Drive, Suite 128,Orlando, CA 32826. Phone 800-345-2737 and on their websitewww.laserinstitute.org. Regulatory information is available at theirCDRH website www.fda.gov/cdrh.2 - 2

Laser SafetyElectrical Safety The Diamond C-70 RF power supply requires only 48 VDC inputvoltage. This voltage and other voltages derived within this laser canbe lethal. Every portion of the electrical system should be treated asif it were at a dangerous voltage level.

To avoid potentially fatal electrical shock hazards fromelectrical equipment, follow all applicable electrical codes suchas (in the U.S.) the National Electrical Code.

Laser Head High voltages are present in the laser head when the power is on.There are no serviceable parts or optics within the laser head. Do notremove any covers or make any adjustments to any screw.

To avoid potentially fatal electrical shock hazards fromelectrical equipment, follow all applicable electrical codes suchas (in the U.S.) the National Electrical Code.2 - 3

Diamond C-70 Liquid-Cooled Laser Operators ManualLaser Safety Requirements

This laser does not conform to the United States or Foreign Govern-ment requirements for laser safety. In the United States, it is theresponsibility of the buyer to ensure that the product sold to the enduser complies with all laser safety requirements prior to resell. Theselaser safety requirements are contained in 21 CFR, Sub Chapter J andare administered by the Center for Devices and Radiological Health(CDRH).

The text of this federal law is available from the U.S. GovernmentPrinting Office Bookstore located in most major cities in the U.S. aswell as Washington, D.C. A report detailing how the laser productcomplies with the Federal law is required before the product isshipped. The form of this report is covered in a pamphlet entitled:Guide for Preparing Product Reports for Lasers and ProductsContaining Lasers, Sept. 1995:

U.S. Department of Health and Human ServicesPublic Health ServiceFood and Drug AdministrationCenter for Devices and Radiological HealthDivision of Small Manufactures AssistanceRockville, Md 20857Voice phone: 1-800-638-2041website: http://www.fda.gov/cdrh

For jurisdictions outside of the United States, it is the responsibilityof the buyer of this laser device to ensure that it meets the local lasersafety requirements.

Safety Interlocks The RF power supply and laser head covers are not interlocked. Thesecovers should never be removed. There are no user-serviceablecomponents inside.

Use of controls or adjustments, or performance of proceduresother than those specified herein, may result in hazardousradiation exposure.

To avoid potentially fatal electrical shock hazards from electricalequipment, follow all applicable electrical codes such as (in theU.S.) the National Electrical Code.2 - 4

Laser SafetyCompliance to Standards

The Diamond C-70 units are components and thus the systemintegrator is responsible for meeting the applicable standards for theCE mark. As part of the testing program, the Diamond C-70 hasbeen shown to be compliant with the following standards: radiatedemissions (EN 55011 Group 1 Class A) and radiated immunity (IEC61000-4-2 (1995) Level 3; IEC 61000-4-3 (1995) Level 3; IEC61000-4-6 (1996) Level 3).

Compliance to the applicable standards for a particular laser systemincorporating the Diamond C-70 unit must be demonstrated by themanufacturer of the laser tool. By testing the Diamond C-70 OEMsystem, it is shown that this step is possible. The primary issue forthe system integrator is to show compliance with specific covers,routing or electrical cables to laser safety standards as well as otherapplicable standards.

Location of Safety Labels

Refer to Figure 2-2 for a description and location of all requiredsafety labels. These include warning labels indicating removable ordisplaceable protective housings, apertures through which laserradiation is emitted and labels of certification and identification[CFR 1040.10(g), CFR 1040.2, and CFR 1010.3/EN60825-1,Clause 5].

Waste Electrical and Electronic Equipment (WEEE, 2002)

The European Waste Electrical and Electronic Equipment (WEEE)Directive (2002/96/EC) is represented by a crossed-out garbagecontainer label (Figure 2-1). The purpose of this directive is tominimize the disposal of WEEE as unsorted municipal waste and tofacilitate its separate collection.

Figure 2-1. Waste Electrical and Electronic Equipment Label2 - 5

Diamond C-70 Liquid-Cooled Laser Operators ManualTOP VIEW

SIDE VIEWS

Figure 2-2. Location of Safety Labels (Sheet 1 of 4)

7 1 2 3

3

456

3

3 3

3 32 - 6

Laser SafetyFRONT VIEW BACK VIEW

BOTTOM VIEW

Figure 2-2. Location of Safety Labels (Sheet 2 of 4)

8

3

34

10

9

112 - 7

Diamond C-70 Liquid-Cooled Laser Operators Manual

1. IDENTIFICATION LABEL

2. DANGER OF LASER RADIATION LABEL

3. TAMPER PROOF LABEL

4. QC APPROVAL LABEL

5. MANUFACTURE DATE LABEL

Figure 2-2. Location of Safety Labels (Sheet 3 of 4)

2 - 8

Laser Safety6. ROHS E LABEL

7. VOLTAGE WARNING LABEL

8. WARNING APERTURE LABEL

9. COOLANT SUPPLY LABEL

10. COOLANT RETURN LABEL

11. COOLANT WARNING

Figure 2-2. Location of Safety Labels (Sheet 4 of 4)

2 - 9

Diamond C-70 Liquid-Cooled Laser Operators Manual2 - 10

Utility Requirements and System InstallationSECTION THREE: UTILITY REQUIREMENTS AND SYSTEM INSTALLATION

Introduction This section covers unpacking and installation of the Diamond C-70laser. Operating instructions are detailed in Section Four: LaserOperation.

Unpacking and Inspection

Before unpacking the laser components, inspect the shipping cartonfor evidence of rough handling, and note any damage. If damage tothe shipping carton is evident, request that the carriers agent bepresent when the unit is unpacked. Inform the shipping carrier andCoherent of any evidence of damage in shipment. The Buyer andshipping carrier is responsible for any damage which might occurduring shipment.

Verifying Delivery The shipping container contains the following: Laser head and integral RF power supply Final test sheet This Operating ManualIf any items are missing, report this to Coherent immediately.

Checking Delivered Items

Verify that the delivered laser head model received is the same as theone ordered. If there is any discrepancy found, contact Coherentimmediately.

Coherent recommends that the shipping box and packing materialsbe saved; as these will be required should the laser need to beshipped back to the factory.3 - 1

Diamond C-70 Liquid-Cooled Laser Operators ManualSafety Issues in Laser Installation

Installation of the Diamond C-70 laser must comply with all appli-cable electrical safety and laser safety laws and regulations. ReviewSection Two: Laser Safety for important information relating tosafety.

The negative (return) side of the DC input connection to theDiamond C-70 RF power supply is connected internally to thechassis. The user must ensure that the system into which theDiamond C-70 is built protects against the possibility that theDiamond C-70 laser head or RF power supply chassis could be at ahazardous voltage and that personnel could be exposed to thesevoltages.

To avoid potentially fatal electrical shock hazards from electricalequipment, be sure to follow all applicable electrical codes such as(in the U.S.) the National Electrical Code.

The laser must be secured properly to avoid the possibility of thelaser shifting unexpectedly during operation, creating a hazardouscondition. The location of the output beam of the Diamond C-70laser head is shown in Figure 3-1. The laser output is emitted fromthe aperture shown in the referenced figures and propagates withina full cone angle up to 5. The acceptance angle of the systemaperture must intercept all of the output of the laser.

It is also extremely important to understand the direction,divergence, and magnitude of all reflections that will occur fromoptical surfaces. Infrared (IR) beams, such as those fromDiamond C-70 lasers, can also be located with commerciallyavailable IR screens, such as those produced by MackenInstruments, Inc. [tel. (707) 566-2110]. Coherent recommends thatall beam propagation paths be enclosed and that personnel operatingthe laser be qualified optical technicians who are familiar with thistype of hardware.

Mechanical Mounting

The dimensions for the Diamond C-70 laser head is shown inFigure 3-1. Mechanical mounting of the Diamond C-70 laser headmust result in no distortion or stress the laser head is in any way.Otherwise, optical alignment and power stability could be adverselyaffected.3 - 2

Utility Requirements and System InstallationDimensions are in inches [mm]

Figure 3-1. Diamond C-70 Liquid-Cooled Laser Head Dimensions

3 - 3

Diamond C-70 Liquid-Cooled Laser Operators ManualMounting Considerations for Diamond C-70

Certain aspects of specific customer applications may precludeabsolute interchangeability of laser heads. For example, for certainapplications, the sensitivity of the application to optical beampointing errors may require external optical realignment after thelaser head is replaced in the customers integrated system.Depending on the method of mounting and the sensitivity of theintegrated customer system to beam pointing errors, even removinga laser head from the customers system, then replacing the samelaser head back into the customers system may require externaloptical realignment. This external alignment would be arepositioning of the head itself or adjustment of beam deliverymirrors (positions and angle). Consult Coherent if there is anyquestion about such interchangeability issues. Consult Coherent ifthere is any question about such interchangeability issues.

Coherent recommends using optional brackets (part number1101-12-0016 for a set of 4) that are designed for mounting the lasersafely without inducing any stress onto the laser. Care must be takennot to induce stress onto the laser head, as optical mis-alignment ofthe laser resonator can occur, which would require the laser to bereturned to Coherent for service. A mechanical drawing for thisbracket is provided in Appendix A: Parts List. Coherent stronglyencourages use of this bracket or one of similar design in order toaccommodate the temperature changes in operation while providingsecure mounting.

Liquid-Cooling The Diamond C-70 liquid-cooled laser is cooled by means of liquidcoolant. The cooling system external to the laser head and the RFpower supply are the responsibility of and must be supplied by theuser. A schematic of the recommended configuration of the coolingsystem is shown in Figure 3-2.

Figure 3-2. Recommended Liquid-Cooling System Functional Block Diagram

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$3 - 4

Utility Requirements and System InstallationCooling System Layout

By connecting the laser head and the RF power supply in series, asingle interlock will protect the laser system.

Following the flow of coolant from the refrigerated recirculator, thelaser head is the first element reached by the coolant after it leavesthe recirculator. This assures that the laser head receives thelowest-temperature coolant available.

To prevent inadvertent operation of the laser without adequatecoolant, an interlock must be provided such that laser operation isprevented, unless coolant is provided that meets the requirementsindicated in Table 1-2 on page 1-5.

Re-Circulation and Coolant Flow Interlock Switch

The coolant flow interlock switch should be the last elementtraversed by the coolant before it returns to the coolant filter in thereturn line. This assures that the flow switch verifies that coolant isflowing through the laser system. The flow switch must not beplaced in any other position. The interlock, which is tripped whenthe coolant switch indicates no flow or low flow, cuts off AC powerto the RF power supply to prevent the system from overheating.

Signal Interface The signal interface in the laser interlock system may be used to turnthe laser off when the coolant interlock is breached. With thisapproach, the laser is commanded to shut down via the signalinterface, in the event that the coolant interlock system detects acoolant fault. Coherent recommends that both RF Enable andControl Enable be commanded to the OFF state when the coolantinterlock system detects a coolant fault. These signals are listed inTable 4-1 and described in subsections of Section Four: LaserOperation.

Thermal Shutdown Switch

The Diamond C-70 laser has a thermal protection switch thatprotects the system at case temperatures over 80 C. Coherentrecommends, however, that the OEM install sensors that detectcoolant flow and shuts the laser down in the event of loss of coolant.

The system also provides a high temperature warning. This warningis used to alert the user to the need of maintenance in order to returnthe cooling system performance back to normal, full coolingcapacity. Failure to take action regarding the temperature warningwill result in poorer product performance (outside specifications)and lesser product life time.3 - 5

Diamond C-70 Liquid-Cooled Laser Operators ManualDC Power Relay The recommended DC power relay used to cut DC power to the laseroff in the event of cooling system failure can also be used as part ofthe laser safety interlock system. Similarly, if the signal interface isused to shut down the laser when there is a cooling system fault, thesignal interface can be used to shut down the laser in the event thatthere is a breach of a safety interlock. The design of the interlockcontrols must be in compliance with applicable safety standards,including those described in Section Two: Laser Safety.

Condensation of Water Vapor

If the coolant temperature is below the dew point of the ambient air,water will condense out of the air onto the outside of the laser head,and onto the outside surface and internal surfaces of the RF powersupply. Condensation can damage the output optical element of thelaser head when the laser is turned on, and could damage internalcomponents of the RF power supply if power is applied whilecondensate is present.

Never allow the coolant temperature to fall below the dew pointof the ambient air. Turn the coolant flow off if the laser will beoff or stored for an extended period of time in humid conditions.

If necessary, the laser system can operate with coolant temperaturesslightly below the dew point of the ambient air. This requires specialprocedures to be followed, such as shutting off the coolant flow atall times when the laser is not producing laser output. ContactCoherent Customer Service for more information about this optionbefore attempting to operate the system in ambient air below the dewpoint.

To avoid possible damage to the laser head, never attempt tochange the coolant fittings at the locations where the coolantenters the laser head. If the fittings must be changed for anyreason, return the laser head to Coherent to be serviced byCoherent technicians.

Coolant Fittings on Laser System

The Diamond C-70 liquid-cooled laser has 6-mm O.D. tubing forthe connection interface. The user must supply an appropriatecompression fitting to make the connection with the rest of the userssystem.3 - 6

Utility Requirements and System InstallationCooling Capacity The cooling system must have sufficient capacity to maintain thecoolant temperature at the outlet of the refrigerated recirculatorwithin the range given in Table 1-2. With the laser operating at itsmaximum output power, the cooling system must dissipate up to1230 W. See Section Five: Maintenance and Troubleshooting formaintenance and replacement requirements for the coolant.

Coolant Filtering Coherent recommends that the user incorporate coolant filtering inthe coolant return line to avoid the accumulation of debris in thecooling system, as shown in Figure 3-2. The filter should trapparticles larger than 30 m to 50 m in size, unless specifiedotherwise by the manufacturer of the refrigerated recirculator.

Figure 3-3. Diamond C-70 Liquid-Cooling Connections3 - 7

Diamond C-70 Liquid-Cooled Laser Operators ManualCoolant Flow Rate and Pressure

Requirements on coolant flow rate are listed in Table 1-2 onpage 1-5. To prevent damage to the laser head or the RF powersupply, the gauge pressure of the coolant at the laser head and at theRF power supply must not exceed 100 psig (i.e. the gauge pressure the difference between the absolute pressure of the coolant and theabsolute pressure of the ambient air must not exceed 7 kg/cm2, or690 kPa). Note that the gauge pressure at the laser system includesthe effect of the gravitational pressure change if the refrigeratedrecirculator is mounted much higher than the laser system.

Exceeding the maximum allowed gauge pressure in the laserhead or RF power supply, even for a short period of time, maycause irreversible damage and result in permanent coolantleaks.

Depending on the customers overall cooling system design,portions of the cooling system, other than the laser head and the RFpower supply, may limit the maximum-allowed gauge pressure ofthe coolant to a lower pressure than the value noted above for thelaser head and the RF power supply.

Pressure Drop The pressure drop from the coolant outlet to the coolant inlet of therefrigerated recirculator will depend on many factors, including:

Flow rate Temperature Length and inside diameter of coolant hoses and

connections

Coolant compositionTo achieve the minimum flow rates listed in Table 1-2 on page 1-5,provide a pressure drop of no more than 35 psi (2.5 kg/cm2) betweencoolant inlet and coolant outlet of the laser. In addition, there is somepressure drop in the cooling lines, which depends primarily on thediameter and length of these lines.

The selected arrangement, once configured, should be checked foradequate flow within the specified pressure limits.3 - 8

Utility Requirements and System InstallationElectrical Power Connection

The Diamond C-70 laser requires 48 VDC input DC power. Thispower is carried from the power source to the system through theterminal block on the Diamond C-70. The maximum currentrequired is 25 A.

The negative (return) side of the DC input connection to theDiamond C-70 RF power supply is connected internally to thechassis. The user must assure that the system into which theDiamond C-70 is built protects against the possibility that theDiamond C-70 chassis could be at a hazardous voltage and thatpersonnel could be exposed to these voltages.

Note: Pin #1 of RJ45 control interface is on the left as viewed.

Connect leads to the user-supplied power source last after other connections are made.

Figure 3-4. Electrical Connections to Diamond C-703 - 9

Diamond C-70 Liquid-Cooled Laser Operators ManualTo avoid potentially fatal electrical shock hazards fromelectrical equipment, be sure to follow all applicable electricalcodes, such as (in the U.S.) the National Electrical Code.

Coherent strongly recommends that the user review the precautionsdescribed in Section Two: Laser Safety regarding electrical safetybefore using the Diamond C-70 laser. It is the users responsibilityto provide circuit breakers and/or fusing of the AC power source, inaccordance with all applicable laws and regulations.

DC Power Supply Requirements

Requirements for the customer-supplied DC power supplies includestandards regarding DC power supply cabling and over-voltagetripping.

DC Power Supply Cabling Requirements

Coherent strongly recommends the use of remote voltagesense/regulation at the Diamond C-70. This requires a 4-wirecable (two supply currents and two voltage senses).

The following requirement minimizes the voltage loss from thesupply to the Diamond C-70:

DC Voltage 48 VDC measured at the terminals.Peak Current

Utility Requirements and System InstallationDC Power Supply Over-Voltage Tripping

In the event that the DC power supply trips because of the current,there are two countermeasures that can be applied:

Remote sensing, in which four wires are used to sense theregulation of the DC power supply

Increased capacitance at the laser connection; to do this, add acapacitor at the DC power supply connection of the laser, usinga capacitor of 470 F or greater, rated at > 60 VDC

Control Signal Connection

Electrical control of the Diamond C-70 laser is achieved via a RJ-45connector built into the system. The signals carried on each of thepins are indicated in Table 4-1. Details about controlling the laserthrough the signal interface are discussed in the paragraph titledSection Four: Laser Operation.

Coherent highly recommends use of shielded interface cables.The interface cable shield must connect to the chassis ground ofthe controller. In addition to proper shielding, this shieldprovides a secondary connection for the signal ground (Pin 8).

A floating ground connection (use of un-shielded interface cableor no return path between the host control electronics and thelaser) can present an unsafe condition and result in unstable orunexpected operation of the laser. This condition can arise whenthe control signal ground connection (Pin 8) is lost and theControl Enable (Pin 7) and RF Enable (Pin 1) remain high.Therefore, Coherent strongly recommends that a second safetyground be provided either via a shielded control cable orcommon potential chassis mounting between the laser head andthe control electronics.3 - 11

Diamond C-70 Liquid-Cooled Laser Operators ManualBeam Propagation

The Diamond C-70 delivers a 3.6 0.5 mm diameter beam with a< 5 mRad divergence. The typical beam diameter as a function ofdistance from the laser is shown in Figure 3-5.

Figure 3-5. Beam Diameter vs. Distance From Laser Head

Beam Diameter vs. Z

0.00

2.00

4.00

6.00

8.00

10.00

12.00

0 500 1000 1500 2000 2500

Diamond C-70 Beam Diameter (1/e2) in mmvs. Distance from Laser Head in mm3 - 12

Laser OperationSECTION FOUR: LASER OPERATION

Signal Interface Connectors

For all Diamond C-70 lasers, the signal interface between theDiamond C-70 laser and the customers equipment is through aRJ-45 connector that is built into the RF power supply. The pinassignments for the interface are indicated in Table 4-1. The signalinterface and its use are discussed in detail in this section.

To avoid damage to the RF power supply, ensure that theelectronic controller is compatible with the interface describedin Table 4-1.

Table 4-1. Signal Interface Description and Connector Pinout

PIN NO. SIGNAL DESCRIPTION

1 RF EnableTTL logic input; 1=RF ON, 0=RF OFF; 1 k impedanceThis input turns on the laser. See also Pin 7, Control Enable, below

2 +15 VDC 0.5 VDC, 0.25 Amps maximum output for customer use

3 LASER OKTTL logic output; 1=LASER OK, 0=LASER Fault; IOH = 0.4 mA, IOL= 8 mAOutput is asserted when no faults (SWR, Temp. or Volt.) are detectedIndicates that the temperature of the laser head is < 80 C

4 Temperature OKTTL logic output; 1=Temp OK, 0=Temp Fault; IOH = 0.4 mA, IOL= 8 mAOutput is asserted when the temperature of the laser head is < 60C

5 Voltage OKTTL logic output; 1=Voltage OK, 0=Voltage Fault; IOH = 0.4 mA, IOL= 8 mAOutput is asserted when DC supply voltage (VDD) is between 43 VDC < VDD < 55 VDC

6 Internal Coherent use. Must be grounded

7 Control EnableTTL logic input; 1=Laser Control Enabled, 0=Laser Control DisabledThis input must be asserted before RF enable can be used to turn on laser

8 Customer Logic Ground for all interface signals

1)Connector used is RJ-45 type.2)These specifications are subject to change.4 - 1

Diamond C-70 Liquid-Cooled Laser Operators ManualAs noted in the Laser Safety section of this manual, the signalinterface is designed to provide a high degree of reliability in thecontrol of laser output. Section Two: Laser Safety must be reviewedfor guidance on any use of the signal interface in safety interlocksubsystems, or in any other subsystem which affects personnelsafety.

Operating Modes

All Diamond C-70 lasers can be operated in continuous wave (CW)mode or Gated CW mode. Each mode is described in the followingsections; details about how to operate the laser in each mode are alsodiscussed.

In the following sections, the assumption is that the laser has beeninitially started and the laser is now ready for operation.

Typical Waveform Table 4-1 illustrates a typical periodic-pulsed laser waveform. TheRF input to the laser will generally follow the RF Enable signal(Table 4-1). The laser output will generally follow the RF input, butwill be distorted. The pulse repetition frequency is

T = period of the waveform

The duty cycle is

t = the pulsewidth

PRF 1T---=

DC tT--- 100=

Figure 4-1. RF Input Waveform and Laser Output Waveform

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&&4 - 2

Laser OperationCW Mode To command the laser to operate in CW mode, RF Enable must beset continuously to Logic Level 1 (high), as shown in Figure 4-1.

In addition, Control Enable (Pin 7) must also be set to Logic Level 1(high) prior to using the RF Enable.

Power Stability Figure 4-2 illustrates the C-70 power stability over the course of a30-minute warm-up from a cold start.

Gated CW Mode The Diamond C-70 laser is capable of producing a wide range ofpulse repetition frequencies (PRFs), pulse widths, and duty cycles inGated CW mode. RF Enable pulse widths of less than 1 s and/orPRFs greater than 25 kHz are not advisable. With the exception ofthese restrictions for pulse widths and PRFs, the RF power supplywill support any duty cycle from zero to 100% in Gated CW mode.

Figure 4-2. Typical Warm-Up Behavior from a Cold Start

C-70L (30 min)

0

20

40

60

80

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Time (min)

Op

tica

l Po

wer

(W

)4 - 3

Diamond C-70 Liquid-Cooled Laser Operators ManualVariable Output, Power Capability and Pulsewidth Variation

All Diamond C-70 lasers provide the capability to vary the averagelaser output power continuously from near zero to at least theOptical Output Power specified in Table 1-2 on page 1-5. The usercan alter the average output power by adjusting the pulsewidth of theinput command RF Enable.

Optical Pulse Shape When the pulsewidth of the input digital signal RF Enable isvaried, the pulsewidth of the RF input to the lasers electricdischarge is also varied. Because of the complex dynamics of theelectric discharge and the laser resonator, the optical output from thelaser will be a somewhat altered version of the RF input waveform.

To vary the laser output power, adjust the RF pulsewidth in GatedCW mode, with the recommended lower limit on pulsewidth at 1 s.

Complex Modulation Waveforms

The laser is capable of responding to more complex modulationwaveforms. There are a variety of potentially useful modulationwaveforms that offer advantage over the simple periodic waveformswith a single pulse per period.

Varying the Pulsewidth

Some users may require pulsed output with fixed pulsewidth butvariable pulse energy. It is possible to approximate this desiredoptical output by pulsing the laser at a relatively high PRF (e.g.,25 kHz), then envelope-modulating at a lower PRF (e.g., 1 kHz).Variation of the pulsewidth of the 25 kHz modulation would providethe ability to vary the pulse energy of the 1 kHz pulses continuously.

Protection from Unacceptable Inputs

The Diamond C-70 laser easily accommodates complex modulationwaveforms, and it will protect itself from damage due toinappropriate inputs.

Turning the Laser On and Checking Output Power

The following steps detail the method to turn a Diamond C-70 laseron and to perform an output power check.

1. Ensure that the laser output aperture is clear and free ofpacking material.

2. Place a laser power meter head in a position to intercept theoutput beam, and turn on the power meter.

3. Verify that the system does not have condensation on its outersurfaces.4 - 4

Laser Operation4. Turn the refrigerated recirculator on.

5. Set the temperature to a value within the specified 15 C to30 C range. The coolant temperature setting must be abovethe dew point of the ambient air. (See the section titledCondensation of Water Vapor on page 3-6 for moreinformation.) Coolant temperature in the 20 C to 22 C rangeis preferred if the ambient dew point is below this range.

6. Check the cooling lines and connections for leaks.

7. If the Diamond C-70 laser is built into a system with safetyinterlocks, verify that all required laser safety interlocks arepositioned for laser operation.

8. Verify that other safety features, such as equipment covers,shutters, and warning lights, are functional and operatingproperly.

9. Verify the solid electrical connection between the negative DCinput terminal on the system and earth ground.

10. Ensure that all safety procedures detailed inSection Two: Laser Safety are observed.

11. Turn AC power to the DC power supply on.

12. Turn DC power to the system on.

13. Set the user-supplied control equipment to activate the laser inCW Mode, in accordance with the instructions below.

14. After a few seconds of laser operation, read and verify thepower level. The laser output should meet or exceed the laseroutput power specification given in Table 1-2.

15. Set the user-supplied control equipment to deactivate the laser.

16. Turn DC power off.

17. Turn AC power off.

18. Turn the refrigerated recirculator off.4 - 5

Diamond C-70 Liquid-Cooled Laser Operators Manual

Electronic Control

The Diamond C-70 laser is controlled through the electronicinterface described in Table 4-1. In this section, additionalinformation is provided regarding the use of this control interface.This section supplements the section in the paragraph titledOperating Modes on page 4-2 and its subsections.

Use of the control interface in any strategy for assuring personnelsafety must comply with the design guidelines discussed inSection Two: Laser Safety.

Coherent highly recommends use of shielded interface cables.The interface cable shield must connect to the chassis ground ofthe controller. In addition to proper shielding, this shieldprovides a secondary connection for the signal ground (Pin 8).

A floating ground connection (use of un-shielded interface cableor no return path between the host control electronics and thelaser) can present an unsafe condition and result in unstable orunexpected operation of the laser. This condition can arise whenthe control signal ground connection (Pin 8) is lost and theControl Enable (Pin 7) and RF Enable (Pin 1) remain high.Therefore, Coherent strongly recommends that a second safetyground be provided either via a shielded control cable orcommon potential chassis mounting between the laser head andthe control electronics.

Electronic Signals Required to Turn the Laser On

The laser can be commanded electronically to turn on any timeduring which DC power is applied to the RF power supply and theRF power supply is properly connected to the laser head. Coherentrecommends that all the control signals be set to their OFF conditionuntil DC power is applied to the RF power supply.

Start-up Sequence The following steps detail how to turn the laser on in CW Mode.

1. Apply DC power to the laser.

2. Set Control Enable (Pin 7) to TTL high (logic 1). Thisenables the RF power supply. Note that this signal should notbe used to modulate the laser.

3. After the Laser OK has been asserted, the laser is ready foroperation.

4. Set RF Enable to logic 1 (Pin 1). This activates the RFoutput of the RF power supply.4 - 6

Laser OperationResponse Timesof Laser to RF Enable and Control Enable

The response time of the RF power supply to Control Enable(Pin 7), and to RF Enable (Pin 1) are quite different. The responseto RF Enable is on a microsecond time scale, whereas the responseto Control Enable is on a time scale of milliseconds.

This difference is not significant if the objective is to use the powersupply only in CW mode. However, if it is desired to use the powersupply in gated CW mode, it is important to take into account theresponse time of the power supply.

In general, it is best to assert Control Enable and leave it on whilemodulating RF Enable as required.

Signals Used for Fault Detection

Several of the signals listed in Table 4-1 may be used at thecustomers discretion for diagnosing faults in the laser system. Theapproach that provides the easiest access to these signals is toprovide indicators, such as light-emitting diodes (LEDs), on thecustomers system control console for three of these signals. Oneway to use these signals as shown schematically in Figure 4-3 tosink the current for one LED on the operators control panel witheach of the following three signal leads:

Figure 4-3. Fault Detection Circuit

4 - 7

Diamond C-70 Liquid-Cooled Laser Operators Manual Laser OK (Pin 3): This signal indicates a composites fault ifeither SWR, over temperature, or voltage are at fault. Thetemperature fault will trip at a laser case temperature ofapproximately 80C. Once it trips it will be latched on evenafter the laser is cooled down. To restart the laser, the ControlEnable signal has to be reset after the laser cools down.

Temperature OK (Pin 4). This signal indicates anover-temperature warning. This will trip at a laser headtemperature of approximately 60 C. This temperature warningsignal will be reset automatically when the laser cools downwith a hysteresis of 2C.

Voltage OK (Pin 5). This signal will indicate a fault if VDDexceeds 55 VDC or drops below 43 VDC.

See Section Five: Maintenance and Troubleshooting for guidanceabout how to interpret and use indications by the above signals offaults in the laser.

Do not ignore indications of faults in the laser system, even if thelaser seems to be working normally. Continued operation in thepresence of a fault may result in damage to the laser system.

VSWR Faults During Initial Turn-On

The electric discharge in the laser head is more difficult to start afterextended non-operational periods. As a result, the laser may not startimmediately when it is first commanded to do so after more than afew hours of being turned off (not lasing). This may occasionallyresult in the signal Laser OK becoming Low. This would indicatea VSWR fault (i.e., high standing wave ratio in the RF supply due tofailure of the electric discharge to light) if Voltage OK andTemperature OK are still asserted. Such transient indicationswhen the laser is first turned on do not indicate any failed componentin the laser. To avoid an unwarranted system response to thisoccurrence, Coherent recommends that the VSWR fault is logicallyqualified to true in the system controller for 1.0 seconds after laserRF Enable and Control Enable have been active.

If the VSWR Fault Indicator signal indicates VSWR faults forlonger than a couple of seconds during the first operation of the laseron any given day, this may indicate a genuine fault in the laser. Inthis case, the operator should proceed to Section Five: Maintenanceand Troubleshooting.4 - 8

Laser OperationC-70 Microcontroller, I/O Signal Operation

The sequence shown in Figure 4-4 is the normal sequence when themicrocontroller comes out of power-on reset (POR). Timing startswith the supply voltage (+ 48 VDC) going into regulation at t0.Laser OK then signals the ability for normal laser operation to start.The laser can be commanded first by asserting Control Enable (at t1)and then modulating RF Enable (at t2). Modulation of ControlEnable is not recommended for modulation frequencies above200 Hz.

Figure 4-4. Normal Start Sequence

Supply Voltage

Control_Enable

RF_Enable

Laser_OK

RF Drive

t0 t2t14 - 9

Diamond C-70 Liquid-Cooled Laser Operators ManualIf the laser has been off for a significant amount of time (longer thanfour days), it may not ignite when first commanded to do so. In thiscase, the control electronics will detect high-reflected voltage andwill issue a standing wave ratio (SWR) fault. Modulation dutycycles of less than 20% (< 25 kHz) are considered safe and will nottrip the SWR circuitry.

If an SWR Fault is detected, Laser OK will be de-asserted and thelaser will enter a cool-down period (at time, t1, of Figure 4-5).Immediately following this period, reduced modulation pulses areissued by the control electronics to help start the laser (t2). Duringthis time, Coherent recommends that the customer leave themodulation on RF Enable to increase the effectiveness of thisprocess.

This sequence will repeat until the laser tube reaches properoperation (t3). At that point, Laser OK will be asserted and customermodulation can proceed.

Figure 4-5. SWR Fault Detected

Supply Voltage

Control_Enable

RF_Enable

Laser_OK

RF Drive

t0 t2t1 t34 - 10

Laser OperationTemperature Fault High temperature warnings are issued with the Temperature OKsignal. In the event that cooling to the laser head is impaired, theTemperature OK signal will de-assert at time, (t1) of Figure 4-6, butthe laser head will continue to function normally. If the temperaturecontinues to rise as shown, the laser head will shut down andLaser OK will drop at t2 of Figure 4-6; see Table 4-1 for trip points.To restart the laser, Control Enable has to be reset after laser casetemperature drops below warning level with hysteresis of 2C. At t3,resetting the laser failed because the laser case temperature is stilltoo high. At t4, when Temperature OK becomes true, the laser isreset successfully. Coherent strongly recommends that action betaken immediately upon the issuance of the temperature warningsignal.

Figure 4-6. Temperature OK Signal Operation

80C

60C

Laser Temperature

Temperature_OK

RF_Enable

Laser_OK

RF Drive (Internal)

t0 t2t1

Control_Enable

t3 t44 - 11

Diamond C-70 Liquid-Cooled Laser Operators ManualVoltage Fault Voltage OK is a window comparator function (see Figure 4-7). Thesignal is asserted only when the supply voltage is within regulationlimits. The trip points are widened significantly to allow for transientconditions; see Table 4-1 for trip points.

Note that the control electronics do not provide a crowbar functionfor supply voltages rising without bound. The customer isresponsible for ensuring that the supply voltage never exceeds55 VDC.

Figure 4-7. Voltage OK Signal Operation

55V

43V

Supply Voltage (VDD)

Voltage_OK

RF_Enable

Laser_OK

RF Drive

t0 t2t14 - 12

Maintenance and TroubleshootingSECTION FIVE: MAINTENANCE AND TROUBLESHOOTING

Maintenance The Diamond C-70 laser requires no routine maintenance. However,the customer-supplied cooling system for the Diamond C-70liquid-cooled laser may require some maintenance. Other portionsof the customer equipment may also require routine maintenance,but these requirements are beyond the control of Coherent andtherefore are not addressed in this manual.

The protective covers of the laser should never be removed bythe user. There are no user-serviceable components inside.Opening the cover exposes the operator to potentially fatalelectric shock hazards.

Cooling System Maintenance

The coolant in the customer-supplied cooling system must bechanged when there is any indication of contamination. Coherentrecommends the coolant be checked at least once a year to verifythat the corrosion inhibitor package is still functioning.Alternatively, the coolant can simply be changed once a year.

Coherent recommends that the correct functioning ofcustomer-supplied coolant flow interlock be checked regularly bymomentarily blocking the coolant flow and verifying timelyshutdown of the laser. See the paragraph titled Re-Circulation andCoolant Flow Interlock Switch on page 3-5 for more informationabout how to do this.

The customer-supplied coolant filter may need to be replaced inaccordance with the filter manufacturers recommended schedule,or at any time there is any indication (such as reduced coolant flow)of significant blockage.

Cleanliness of Output Optical Element

The laser head must never be activated if the output optical elementis contaminated by water, dust, dirt, or any other contaminant.Operation of the laser head with any contaminant on the surface ofthat optical element may result in damage to the coating. If anycontamination is present, the laser must be returned to Coherent sothe problem can be corrected. The customers system design shouldalso be reviewed to prevent a recurrence of the contaminationproblem.5 - 1

Diamond C-70 Liquid-Cooled Laser Operators ManualTroubleshooting Coherent recommends that the following checks be performedbefore calling for service.

DC Power and Voltage

Verify that DC power is available to the RF power supply. Verify that the voltage on Pin 2 of the signal interface

connector is (+15 0.5) VDC, as shown in Table 4-1. (Thelocation of the signal interface connector is shown, forexample, in Figure 3-1.)

If the voltage is not within the specified range, the RF powersupply is faulty and the laser must be returned to Coherent.

Control Inputs Verify that the control inputs at the interface connector are setto appropriate values in accordance with Table 4-1.

The response times of RF Enable and Control Enable arediscussed in Response Times of Laser to RF Enable andControl Enable on page 4-7. In Gated CW mode it isimportant to use RF Enable input to modulate the laser toobtain short response time.

The fault detection signals from the RF power supply arediscussed in the paragraph titled Signals Used for FaultDetection on page 4-7.

Over-Temperature Warning

If the fault detection signal named Temperature OK (Pin 4 inTable 4-1, Signal Interface Description and Connector Pinout, onpage 4-1) is active, troubleshoot the cooling system to determinewhy the RF power supply appears to be overheating.

Over-Temperature Shutdown

The Diamond C-70 comes equipped with a temperature fault sensor.This sensor is located inside the RF supply module in the vicinity ofthe RF power amplifier. This sensor detects an over-temperaturecondition when this RF amplifier is approximately 95 C.

Determine why the over-temperature fault is activating andcorrect this problem. The control circuit is setup such that thelaser will not be damaged by an overtemperature. However,overall product life time and performance will be degraded byoperating at elevated temperatures.5 - 2

Maintenance and Troubleshooting If only the fault detection signal Temperature OK (Pin 4 inTable 4-1) is low, the temperature of the laser has exceeded60 C. Troubleshoot the cooling system to determine why thelaser appears to be overheating.

CW Mode If the laser output is non-zero, measure the laser output powerin CW Mode and compare it to the output power specified foryour specific laser model in Table 1-2.

The signal inputs required to place the laser in CW Mode aredetailed in the paragraph titled CW Mode on page 4-3.

Visualizing If the laser output is non-zero and you have access to visually inspectthe spatial structure of the output beam, perform such a visualizationand record the results.

Output Beam If there is evidence that the spatial quality (Transverse Modequality) of the output beam is degraded, examine the outputoptical element of the laser head, looking for evidence ofdamage to the optical coating. This examination must beperformed with AC power to the laser system disconnected.

If any coating damage is present, the laser must be returned toCoherent to be corrected by Coherent technicians.

The customers system design should also be reviewed todetermine if contamination to the optical element could havecontributed to the coating damage.

If, after performing the above checks, there is still a problem withthe laser, proceed to Appendix B, Diamond Series LaserWarranty.5 - 3

Diamond C-70 Liquid-Cooled Laser Operators Manual5 - 4

Parts ListPARTS LIST

The following parts can be ordered by contacting our TechnicalSupport Hotline at 1-800-367-7890 (1-408-764-4557 outside theU.S.); through E-mail (Product.Support@Coherent.com); or yourlocal Coherent service representative. When communicating withour Technical Support Department, via telephone or E-mail, themodel and Laser Head serial number of your laser system will berequired by the Support Engineer responding to your request.

Effective March, 2008 this Coherent laser was released asRoHS-compliant. If your laser system was purchased prior toMarch, 2008 you should contact Coherent Technical Support todetermine if the items listed below are the appropriate part numbersfor your laser system. You can locate the date of manufacturing foryour laser system on the system serial number label.

Table A-1. Diamond C-70 Laser Component Part Numbers

PART NUMBER DESCRIPTION

OPTIONAL MOUNTING BRACKETS

1101-12-0016 Bracket kit - set of 4

1101-10-0099 Individual bracketA - 1

Diamond C-70 Liquid-Cooled Laser Operators ManualNotes

: Dim

ensio

ns m

ay va

ry for

diffe

rent

heat

sink h

eights

.

Dimensions are in inches [mm]

Figure A-1. Diamond C-70 Liquid-Cooled Optional Mounting Brackets(Part #1101-12-0016 for a set of 4)A - 2

Parts ListDimensions are in inches [mm]

Figure A-1. Diamond C-70 Liquid-Cooled Optional Mounting Brackets(Part #1101-12-0016 for a set of 4)A - 3

Diamond C-70 Liquid-Cooled Laser Operators ManualA - 4

WarrantyWARRANTY

Diamond Series Laser Warranty

Coherent, Inc. warrants to the original purchaser that theDiamond C-70 laser system conforms to the specificationspublished by Coherent and is free from defects in materials andworkmanship.

For specific warranty terms and conditions for your Diamond C-70laser, refer to your sales contract.

Diamond C-70 lasers are warranted for parts and labor for a periodof twenty-four (24) months. Warranty begins from the date ofshipment.

Diamond C-70 lasers do not include installation in the purchaseprice.

Conditions of Warranty

For warranty service requiring the return of any product to Coherent,the product must be returned to a service facility designated byCoherent. The Buyer is responsible for all shipping charges, taxesand duties.

Parts replaced under warranty shall become the property of Coherentand must be returned to Coherent, Inc., Santa Clara, or to a facilitydesignated by Coherent. All laser systems must be carefully packedin a suitable shipping container(s). Coherent does not assumeresponsibility for components broken in shipment due to improperpackaging or handling. The Buyer will be obligated to issue apurchase order for the value of the replaced parts and Coherent willissue credit when the parts are received.

Responsibilities of the Buyer

Damage to the Diamond C-70 laser caused by failure of Buyer'sutilities or the Buyer's failure to maintain an appropriate operatingenvironment, is solely the responsibility of the Buyer and isspecifically excluded from any warranty.

The Buyer is responsible for prompt notification to Coherent of anyclaims made under warranty. In no event will Coherent beresponsible for warranty claims later than seven (7) days after theexpiration of the warranty.B - 1

Diamond C-70 Liquid-Cooled Laser Operators ManualLimitations of Warranty

The foregoing warranty shall not apply to defects resulting from:

1. Components or accessories with separate warrantiesmanufactured by companies other than Coherent.

2. Improper or inadequate maintenance by Buyer.

3. Buyer-supplied interfacing.

4. Operation outside the environmental specifications of theproduct.

5. Improper site preparation and maintenance.

6. Unauthorized modification or misuse.

7. Coherent assumes no responsibility for customer-suppliedmaterial.

The obligations of Coherent are limited to repairing or replacing,without charge, equipment that proves to be defective during thewarranty period. Replacement systems may contain reconditionedparts. Repaired or replaced parts are warranted for the duration ofthe original warranty period only. This warranty does not coverdamage due to misuse, negligence or accidents, or damage due toinstallations, repairs or adjustments not specifically authorized inwriting by Coherent.B - 2

Packing ProcedurePACKING PROCEDURE

The following is the factory-recommended packing procedure forthe Diamond C-70 laser system. This procedure must be followed ifthe laser system is to be shipped to another location after initialinstallation, or returned to the factory for service. TheDiamond C-70 laser system requires use of the original shippingcarton with its internal foam shipping restraints. If the originalshipping carton is unavailable, contact Coherent Technical Supportto purchase a new one.

Never ship or store any Diamond C-70 laser head or RF powersupply containing cooling water if it may be exposed totemperatures below the freezing point during such shipment orstorage. Plug or cap coolant inlet and outlet to prevent leaksduring shipment or storage.

Figure C-1. Shipping Container

Cut out for lasercooling tubes

Cut out forexternal opticsC - 1

Diamond C-70 Liquid-Cooled Laser Operators ManualPreparation of Liquid-Cooled Systems/RF Power Supplies

1. Uncouple the laser system from the chiller and drain thecooling lines into the proper drain/receptacle.

2. Blow out the cooling lines on the laser system usingcompressed air (< 75 psi).

3. Seal the cooling lines with the caps/plugs originally suppliedwith the laser system.

Before preparing for shipment, drain all water from the lasersystem by blowing compressed air lightly into the cooling lines.

Liquid-cooled models must have cooling tubes dry and cleanprior to shipping.

Preparation for Laser Heads

After draining and clearing the cooler lines:

1. Seal the output coupler/window with tape.

2. Insert the laser head into a plastic bag and tape it closed.

3. Place the laser head into the crate cutout as shown inFigure C-2.

Figure C-2. Laser Head Packaged in Plastic BagC - 2

Packing Procedure4. Cover the packaged laser head with the foam cover sheetsupplied with the shipping container (Figure C-3).

5. Enclose a copy of the RMA return authorization inside of thecrate. Retain a copy for your records.

6. Seal the shipping container with packaging tape.

7. Place RMA return sheet together with the shipping documentson the outside of the container.

8. Return ship by following the instructions from Coherent. Referto Shipping Instructions on page C-3.

Shipping Instructions

1. Place the return shipping label(s) (located on the page after theRMA Form) on the shipping the container(s) with the RMAnumber clearly visible and ship to Coherent. The shippershould be notified that the contents are fragile and sensitive toshock and moisture.

2. Enclose a copy of the completed RMA Form in the returnshipping container. Retain a copy for your records.

3. Package the laser system carefully in the original Coherentouter shipping container(s).

Figure C-3. Foam Cover SheetC - 3

RMA Form Instructions

Call your local Coherent Service Representative to obtain an RMAnumber prior to filling out this form. After receiving an RMAnumber, this form must be completed and accompany your returnshipment.

1. Date and RMA NumberEnter todays date and RMA number. Upper right hand corner.

2. Requestor InformationProvide all of requestors address and ship to addressinformation. Provide customer reference number if applicable.

3. System InformationProvide system product number, system serial number.Note: Enter None for Service Inventory Returns.

4. Return Part(s) InformationProvide the part number, description, serial number(if applicable) and quantity of returned part(s).

5. Failure Information/CommentsProvide failure details or explain why the part(s) is beingreturned.

tity

ails.Please fill out this form and include with the return shipment.In Order To Process, Form Must Be Complete

*cohereNT1280 Blue Hills AvenueBloomfield, CT 06002(800) 367-7890www.Coherent.com

RMA FORM

Date

RMA Number

Requestor Information Cust Ref #_____________ Ship to InformationOrganization Organization

Contact Contact

Address Address

City City

State / Zip State / Zip

Telephone Telephone

Fax Number Fax Number

System InformationSystem Product Number System Serial Number

Return Part(s) Information Enter the following information, include applicable serial numbers.Part Number Description Serial Number Quan

Failure Information/Comments Explain why this part is being returned and/or provide failure det

SR

S

Rhip to:

1280 Blue Hills AvenueBloomfield, CT 06002Attn.: Customer Service

MA # ________________________

hip to:

1280 Blue Hills AvenueBloomfield, CT 06002Attn.: Customer Service

MA # ________________________

GlossaryGLOSSARY

% PercentC Degrees centigrade or CelsiusF Degrees Fahrenheitm Micrometers = 106 metersrad Microradians = 106 radianss Microseconds = 106 seconds1/e2 Beam diameter parameter = 0.13534

A AmperesAC Alternating currentANSI American National Standards Institute

BNC Type of connector

CaCO3 Calcium carbonateCDRH Center for Devices and Radiological Health (part of the Food and

Drug Administration of the Public Health Service, U.S. Departmentof Health and Human Services)

CFR Code of Federal Regulationscm Centimeters = 102 metersCO2 Carbon dioxideCW Continuous wave

DC Direct currentDCPS DC power supplyDVM Digital voltmeter

EMC Electromagnetic compatibility

FDA Food and Drug Administration (an agency of the U.S. Departmentof Health and Human Services)

FPT Female pipe threadft. Foot (Feet) (length)

gpm Gallons per minute

hex HexagonHz Hertz or cycles per second (frequency)

I.D. Inner diameterIEC International Electrotechnical Commissionin. Inch(s) (length)IR Infrared

kg Kilograms = 103 gramskHz Kilohertz = 103 hertzkPa Kilopascals = 103 pascalskV Kilovolts = 103 voltskW Kilowatts = 103 wattsGlossary - 1

Diamond C-70 Liquid-Cooled Laser Operators Manualk Kilohm(s)

lbs. Pound(s)LED Light emitting diode

m Meter(s) (length)mA Milliamperes = 103 Amperesmg Milligrams = 103 gramsMHz Megahertz = 106 HzmJ Millijoules = 103 Joulesmm Millimeters = 103 metersMNPT Male National Pipe Thread mrad Milliradians = 103 radians (angle)ms Milliseconds = 103 secondsmW Milliwatts = 103 Watts (power)

N2 Nitrogennm Nanometers = 109 meters (wavelength)N-m Newton-meter(s)NPT National Pipe Thread American national standard taper pipe thread