lt360 user manual - physical-lab

LT360 Precision Turntable

User Manual


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Precision Turntable

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TEL: (503) 612-9565 • FAX: (503) 612-9344 • www.linearx.com • [email protected]

LinearX Systems Inc • 9500 SW Tualatin-Sherwood Rd. • Tualatin, OR 97062-8586 USA

All specifications subject to change without notice.© 2006 All Rights Reserved.Printed in the U.S.A.March-30-2006

Precision TurntableUser ManualPN: 910-0019

Computer Aided Engineering & Measurement Systems


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LT360 Precision TurntableUser Manual

© 2006 LINEARX SYSTEMS INC.All Rights Reserved.

Tel: (503) 612-9565Fax: (503) 612-9344

Printed in the United States of America.March 30, 2006.

This document was produced on a Pentium-4 / 2GHz PC with Win2K usingAdobe PageMaker 7.0, Adobe Illustrator 10.0, Adobe PhotoShop 7.0,MathType 4.0 for mathematics typography, and SnagIt 5.2 for screen captures.Final masters were produced using an Xerox Docutech image setter. Help fileswere composed and compiled using Windows Help Designer 3.1.

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9.3 Calibration Certificate (Example)


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License Agreement and Limited Warranty

Carefully read all of the following terms and conditions of this agreement before opening andusing the contents of this package. The opening of this package indicates your acceptance of the

terms and conditions of this license agreement. If you are not willing to accept the terms andconditions of this agreement, then you should return the entire product, with the package seal

unbroken, to the place of purchase for a full refund of the purchase price.

Copyright OwnershipBoth the program and the documentation are protected under applicable copyright laws. LinearX is the holder of thiscopyright. Your right to use the program and the documentation are limited to the terms and conditions described herein.Use of the software unless pursuant to the terms and conditions of this license, or as otherwise authorized by law, is aninfringement of the copyright.

Limited Non-Exclusive LicenseYou may: (a) use the enclosed program on a single computer, (b) physically transfer the program from one computer toanother provided that the program is used on only one computer at a time, and that you remove any copies of the programfrom the computer from which the program is being transferred, (c) make copies of the program solely for backup or archivalpurposes. You must reproduce and include the copyright notice and label any backup copy.

You may not: (a) distribute copies of the program or the documentation to others, (b) lease, rent, grant sublicenses, or otherrights to the program, (c) provide use of the program in a computer service business, network, time-sharing multiple CPU ormultiple users arrangement without the prior written consent of LinearX, (d) translate or otherwise alter the program orrelated documentation without the prior written consent of LinearX.

TermsYour license to use the program and the documentation will automatically terminate if you fail to comply with the terms of thisagreement. Your license terminates in the event that you receive a license for an updated version of the product thatreplaces this product. If a license expiration date is printed on your documentation, or provided through other means suchas a time limited electronic or software key, your license expires on the day as shown in the documentation, or on the day thatthe electronic or software key expires. If this license is terminated you agree to destroy all copies of the program anddocumentation.

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Power SupplyPower/Type 50W, Universal PFC SMPSLine Voltage World-Wide 85-265VACLine Frequency 50/60HzLine Current Sinusoidal, < 10% THDSwitching Freq 150kHz, Spread SpectrumStandards (TBA, designed to meet)

IEC 60950/61010, UL-1950CISPR-22, FCC Class-B,

Connector IEC-320 Universal AC Inlet

Acoustic NoiseBroadband 50.4dBspl @ 2M, 1 RPM, ANSI-A WeightedSpectrum 1/3 Octave density shown below


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LinearX Systems Inc., 9500 SW Tualatin-Sherwood Rd.,Tualatin, OR 97062-8586 USA, TEL:(503) 612-9565 FAX:(503) 612-9344WEB: www.linearx.com

Copyright 2006, LinearX Systems Inc. All rights reserved. All other Trademarks are the property oftheir respective owners.

Limited WarrantyLinearX warrants to the original licensee that the disk(s) and or electronic key(s) on which the program is recorded will befree from defects in materials and workmanship under normal use for a period of ninety (90) days from the date of purchaseas evidenced by a copy of your receipt. Hardware products or components have a warranty of 1 year. If failure of the productcomponents has resulted from accident, abuse, or misapplication of the product, then LinearX or third party licensors shallhave no responsibility to replace the disk(s) or key(s) under this limited warranty.

This limited warranty and right of replacement is in lieu of, and you hereby waive, any and all other warranties, both ex-pressed and implied, including but not limited to warranties of merchantability and fitness for a particular purpose. Theliability of LinearX or third party licensors pursuant to this limited warranty shall be limited to the replacement of the defectivedisk(s) or key(s), and in no event shall LinearX or third party licensors be liable for incidental, indirect, punitive, or conse-quential damages, including but not limited to loss of use, loss of profits, loss of data or data being rendered inaccurate, orlosses sustained by third parties even if LinearX or third party licensors have been advised of the possibility of such dam-ages. This warranty gives you specific legal rights which may vary from state to state. Some states do not allow the limitationor exclusion of liability for consequential damages, so the above limitation may not apply to you.

In addition to the foregoing, you should recognize that all complex software systems and their documentation contain errorsand omissions. LinearX, its distributors, and dealers shall not be responsible under any circumstances for providing informa-tion on or corrections to errors and omissions discovered at any time in the product, whether or not they are aware of theerrors or omissions. LinearX does not recommend the use of this product in applications in which errors or omissions couldresult in loss of life, injury, or other significant loss.

This license agreement shall be governed by the laws of the state of Oregon and shall inure to the benefit of LinearX, itssuccessors, administrators, heirs and assigns or third party licensors.

United States Federal Government RestrictionsIf this software is acquired by or on behalf of the U.S. Federal government or its agencies, this provision applies. Use,duplication, or disclosure of this software is subject to restrictions set forth in the appropriate FAR 52.227-19 and DFAR252.227-7013 documents, as applicable. The software is "commercial computer software" and is licensed only with "Re-stricted Rights". Other Federal restrictions may also apply.

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9.2 LT360 Electrical SpecificationsControl Panel

Switches (8) Momentary Push ButtonsDisplay 4 Digit, 7-Segment, 0.56 InchMemory Nonvolatile, retention >40 years

LR360 InterfaceConnector PS2, MiniDIN-6 Female Jack

USB InterfaceClass/Rev Low Speed, 1.5Mbps, USB-1.1Connector Type-B

RS-232 InterfaceBaud Rate 9600 default, 115200 maxConfiguration DCE (use straight thru cable)Connector DB-9 Female

Digital InputInput Impedance 100k ΩPulse Trigger Rising or FallingThreshold TTL, LVTTLHysteresis 0.75VPulse Width 10us MinConnector BNC Jack

Analog InputInput Impedance 1M ΩScale Factor 10mV / DegreeUnipolar Range 0 to +3.600V for 0 to 360°Bipolar Range -1.800 to +1.800V for -180° to +180°Driving Source Z 200 Ω Max recommendedConnector BNC Jack

Analog OutputOutput Impedance < 1 ΩScale Factor 10mV / DegreeUnipolar Range 0 to +3.600V for 0 to 360°Bipolar Range -1.800 to +1.800V for -180° to +180°Output Current 5mA MaxShort Duration UnlimitedConnector BNC Jack


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Technical SupportLinearX provides detailed printed manuals and on-line help within the program as the primarysource for user information and assistance regarding the use of this product. If these sourcesdo not contain the answers to your questions, contact LinearX via any of the following meth-ods:

Internet Forums: www.linearx.com/forumsInternet Email: [email protected] Web: www.linearx.comFax: (503) 612-9344 Tel: (503) 612-9565

Technical support is free and unlimited at this time, however we reserve the right to chargefor this service in the future as conditions, overhead, and support personnel requirementsdictate.

When contacting us regarding a technical support issue, PLEASE follow these steps to aidus in understanding and solving your problem:

(1) If your question involves specific details or parameters unique to your project and prob-lem, please include a copy of your design files with the necessary data so that we canreproduce your problem. This is only possible if you are communicating via an electronicmeans such as Email or uploading files directly to our web site.

(2) If the issue regards error messages from the program, please include an exact descrip-tion of the error message and/or address information that the program reports.

(3) If there are specific steps involved to reproduce the issue, please note these exact stepsrequired so that we can reproduce the problem.

Note: A free technical support forum is provided on the LinearX web site at www.linearx.com/forumsGenerally you can find the quickest answers to your questions using this forum which isavailable 24 hours a day 365 days a year.

Technical support hours are: Monday-Friday 9:00AM to 5:00PM Pacific Standard Time.

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Center Through HoleDiameter 1.5 Inches (38mm)

Platter DimensionsHeight 0.75 Inches (19mm)Diameter 16.0 Inches (406mm)Mounting Holes (4) 1/4-20 on 3.0 Inch BCD (76.2mm)Mounting Holes (8) 1/4-20 on 9.0 Inch BCD (228.6mm)Mounting Holes (8) 1/4-20 on 15.0 Inch BCD (381.0mm)

Chassis DimensionsHeight 3.3 Inches (84mm)Width 18.0 Inches (457mm)Length 18.0 Inches (457mm)Mounting Holes (8) 1/4-20 on 6.0 Inch BCD (152.4mm)Mounting Holes (4) 1/4-20 on 12.0 Inch BCD (304.8mm)

Overall DimensionsHeight 4.1 Inches (104mm)Width 18.0 Inches (457mm)Length 18.0 Inches (457mm)Weight 35 lbs (16 kg)


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9.1 LT360 Mechanical Specifications

Main SystemOperation Mount in any orientation, Ta 0° to 40°CPlatter Cast & Machined Aluminum A356-T6Base Cast & Machined Aluminum A356-T6Bearing 5 Inch (125mm) Sealed Ball Bearing ABEC-1Hub 4 Inch Diameter, 0.8 Inch WallAxial Load 1,000 lbs (900 kg) Max, BidirectionalRadial Load 500 lbs (230 kg) MaxDrive System Irreversible Worm DriveScale Accurate Screen Printed 1 DegreeChassis 16ga Steel

Drive SystemMotor NEMA-23 Stepper MotorController Bipolar, Microstepping, MicroprocessorDirection Either Counterclockwise or ClockwiseShaft 0.375 Inch Dia, Steel 1040Worm 0.75 Inch SAE 4340 Hardened SteelWorm Gear 5.75 Inch SAE 65 Phosphor BronzeBearing Sealed Ball Bearings ABEC-3Torque 49 N•M Standard Model, ProgrammableTorque 76 N•M HiTorque Model, ProgrammableVelocity 0.01 ... 3.0 RPM, ProgrammableAcceleration 5 Acceleration FunctionsResolution 0.003125 DegreeStep Size 0.1 Degree MinimumBacklash ±0.07 Degree TypicalOrigin User Resettable


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1.1 LT360 Safety ............................................................. 111.2 TS360 Safety ............................................................. 121.3 LT360 Emergency Stop ............................................. 13

2.1 Rubber Feet ............................................................... 152.2 Mounting to the LT360 ............................................... 162.3 Mounting to the Platter ............................................. 172.4 Mounting to the Base .............................................. 18

3.1 AC Power .................................................................. 213.2 Control Methods ........................................................... 223.3 Computer Interfaces .................................................... 233.4 Pulse Input ................................................................. 243.5 Analog Input ............................................................... 253.6 Analog Output ............................................................ 263.7 LR360 Remote ......................................................... 27

Contents

Chapter 1: Safety First !!! 11

Chapter 2: Mounting 15

Chapter 3: Electrical 21

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4.1 Mechanical Load Capability ....................................... 294.2 Drive System Lubrication ........................................... 30

5.1 Front Panel Functions ........................................ 33

6.1 Acceleration Functions .............................................. 436.2 Velocity Profiles ....................................................... 466.3 Actual Accel/Velocity Profiles ................................... 476.4 Horizontal Torque Capability ....................................... 526.5 Vertical Torque Capability .......................................... 54

7.1 Error Messages ........................................................ 57

Contents

Chapter 4: Mechanical 29

Chapter 5: Front Panel 33

Chapter 6: Acceleration 43

Chapter 7: Error Messages 57

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8.1 LT360 Windows Software ....................................... 658.2 Opening an LT360 Link ............................................. 668.3 Acceleration Function, Smart Torque ....................... 678.4 Motor Home Check .................................................. 688.5 Information, Name .................................................. 698.6 Step Size, Velocity, Torque ........................................ 708.7 Display, Output, Input, Polarity .................................... 718.8 Analog Input, Pulse Input, Direction, Trigger ................ 728.9 CPU, LDR, USB, Firmware, LT360LIB DLL .................. 738.10 Action Buttons ............................................................. 748.11 Position Graphic Readouts ....................................... 758.12 Calibration Button ........................................................ 768.13 Update Button .......................................................... 778.14 Test Button .............................................................. 78

Contents

Chapter 8: Application Software 65

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TestClicking this button will open the Test dialog as shown below.This dialog provides a means to test the LT360 by rotating the platter for aperiod of time, number of cycles, etc. It is mainly used by the factory duringproduct testing and lubrication.


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Chapter 9: Specifications 799.1 Mechanical Specifications ........................................ 799.2 Electrical Specifications .............................................. 819.3 Calibration Certificate ................................................. 83

Contents

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UpdateClicking this button will open the Update dialog as shownbelow. This function will update the firmware for the main 32 bit CPU inthe LT360. The Flash memory will be reprogrammed.

Firmware updates are provided as Hex files with a name such asVader_200.hex. If you are provided an update, first locate the file with thefolder Browse button. They will be located in the C:\ProgramFiles\LT360\Firmware folder. Then click the Program button. Read andfollow the dialog messages that appear.

When the update is completed, the LT360 will reboot and the softwareprogram will close.


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1.1 LT360 Safety

The LT360 turntable should always be operated with care andsafety. Anything attached to the turntable will be in motion,and can cause other objects or people to fall or be hit bystructures connected to the LT360.

Always make sure other people and objects are a safe distanceaway from the area where the turntable is operating.

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CalibrationClicking this button will open the Calibration dialog as shownbelow. Calibration is performed originally at the factory, and in most caseswill be permanent and not be required again. However if your applicationrequires recalibration for NIST compliance, you will probably need to sendin your unit to the factory for recalibration on a periodic basis. Calibration ispossible by other labs, but only if the required equipment and systems areavailable.


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If you are using the TS360, orany other stand, make surethat the test object is securelyattached to the stand byeither, straps, bungi cords, orscrews.

Any object located above theground can fall and causepersonal injury or damage toother equipment.

1.2 TS360 Safety

Keep all otherpeople awayfrom the areawhen testing.

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PositionThis group box contains two graphics: an analogview of the platter position, and a digital readoutof the position.

When the LT360 is rotating, both displays will beupdated several times per second.

However, these two graphics also have activecontrol functions:

Click on the PlatterWhen the platter is rotating, you can clickanywhere on the platter graphic and the rotation will abort/stop. This isuseful as an emergency stop feature.

Click on the ReadoutWhen you click anywhere on the digital readout, the software will read thecurrent position from the LT360 and update the display. Updates will thencontinue if the platter is rotating until it stops.

This feature is useful if the rotation of LT360 has been activated by someother means, such as the front panel switches. This will update the softwaredisplay.


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The rotation of the turntablecan be stopped and abortedat anytime by pressing eitherof the RED switches on theLT360 front panel, or on theLR360 remote module.

If you are using the Win32application software, you canalso abort the rotation byclicking anywhere on theplatter graphic in the mainwindow.

SETORIGIN

SETTORQUE

Precision Turntable

ZERO DEGREFERENCE

% MOTORPOWER

LR360INTERFACE

REMOTE CONTROL MODULE

1234

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1.3 LT360 Emergency Stop

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ActionThis group box contains a number of buttons tocontrol the platter position.

The Step CW and Step CCW buttons will causethe platter to rotate one step, either ClockWiseor Counter ClockWise.

The Goto CW and Goto CCW buttons will cause the platter to rotate to theposition as entered in the Deg field parameter, either by ClockWise orCounter ClockWise rotation.

The Zero CW and Zero CCW buttons will cause the platter to rotate to the0.0 origin, either ClockWise or Counter ClockWise.

The Set Origin button will define the current position as the origin (0.0). Noplatter rotation will occur. The display will change to 0.0.

There is also a text field indicator that will display the rotating status as:Stationary, Moving CW, or Moving CCW.


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CPU FirmwareThis group box displays the version code and date of the32bit CPU firmware in the LT360. Updating the firmwarewill change these fields.

LDR FirmwareThis group box displays the version code and identifier ofthe Boot Loader firmware in the 32bit CPU. It is thesilicon revision level of the CPU.

USB FirmwareThis group box displays the version code and date of theUSB controller firmware in the LT360.

LT360LIB.DLLThis group box displays the file version and dateof the LT360LIB DLL module. This code modulemay be changed or upgraded in the future.


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2.1 Rubber FeetA package of 8 rubber foot pads are provided with the LT360. Dependingon how you intend to mount the LT360, you may or may not wish to usethe optional pads.

If you intend to bolt the LT360 directly to other rigging or fixtures, it isprobably best not to use the feet. This will allow you to bolt the base of theLT360 directly to your fixture without the rubber pads between the inter-face. This will make the joint more rigid.

If you will be using theLT360 on the floor, thenthe rubber feet can beapplied to the bottom ofthe unit.

Turn the LT360 upsidedown. Each of therubber pads has anadhesive backing. Peelthe backing paper off,and then apply the eightpads as shown here.Note that each of thepads has holes whichalign with those of thebottom of the LT360.

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LT360 ANALOG OUTPUT MODES

OU

TP

UT

VO

LT

AG

E

PLATTER MOVEMENT

STARTMODE

STOPMODE

CONTMODE


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2.2 Mounting to the LT360The LT360 drive assembly consists of two aluminum castings, platter andbase, joined through a 125mm ball bearing. The drive assembly providesboth high strength and high precision. A 1.5 In (38mm) clearance hole isprovided through the center of the assembly to route cables if needed.

The platter and base both have pre-tapped 1/4-20 machine screw holes formounting customer fixtures and jigs. The thread depth is 0.5 In (12mm)minimum. When attaching screws to these tapped holes, please make surethe screw length entering the platter or base castings does not exceed about1/2 Inch.

Also, do not overtighten the screws which could damage the tapped holes.Split lock washers should always be used and tightened only until thewasher is flat.

Note: Never use the chassis as structural support. Its purpose is only tocontain the internal electronics and system components.

GREASE PORT (8) 1/4-20 TAPPED HOLES

(20) 1/4-20 TAPPED HOLESCABLE HOLE

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Analog Output ModeThis selection controls the operating mode for the AnalogOutput.

When Continuous is selected, the Analog Output will continuously followthe platter position as it is moving. This is a real time output mode wherethe analog output voltage always represents the current platter position.

When Single Step Start is selected, the Analog Output will only produce asingle step change output voltage representing the final destination positionat the start of the movement. For example, if the current position is 0.0degrees and the destination is 100.0 degrees, the Analog Output voltagewill change from 0.000V to 1.000V at the start of the movement.

When Single Step Stop is selected, the Analog Output will only produce asingle step change output voltage representing the final destination positionafter the movement stops. For example, if the current position is 0.0degrees and the destination is 100.0 degrees, the Analog Output voltagewill remain at 0.000V during the movement and then change to 1.000Vwhen the movement stops. The final output voltage changes 2 secondsafter the platter movemet stops.

If the movement is aborted before it reaches the destination, the outputvoltage will be updated to the correct final value in all modes.


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The platter is 16 Inches (406mm) in diameter and contains (20) 1/4-20tapped holes for mounting. These are located on bolt circle diameters of:(8) - 15.0 In BCD, (8) - 9.0 In BCD, (4) - 3.0 In BCD.

The platter is strongest in the center, and weakest at the rim. The fixturebeing attached to the platter should have its own rigid surface strength andnot depend on that of the platter. It is always best to concentrate the loadin the center region of the platter.

2.3 Mounting to the Platter

(8) 1/4-20 15.0In BCD

(8) 1/4-20 9.0In BCD(4) 1/4-20 3.0In BCD

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Analog InputThis selection will enable/disable the Analog Input feature.When enabled, the LT360 will respond to the DC voltage atthe analog input BNC connector. When it is disabled, it will ignore thatinput. If you are not using the analog input, this input must be disbaled.Otherwise the LT360 will be controlled by any noise received at the input.

Pulse InputThis selection will enable/disable the TTL Pulse Input feature.When enabled, the LT360 will respond to TTL pulses at theBNC connector. When it is disabled, it will ignore any pulses. If you are notusing the Pulse Input, it is probably best to keep this feature disabled toprevent false triggering due to any noise pickup at the open connector.

Pulse DirectionThis selection controls the behavior to a pulse at thePulse Input BNC connector. Values are CCW or CW,meaning Counter ClockWise or ClockWise. When a pulse arrives at thePulse Input BNC input, the platter will rotate either CCW or CW as definedby this setting.

Pulse TriggerThis selection controls the trigger for the Pulse Input BNCconnector. RISE or FALL means that triggering will occuron the rising or falling edge of the pulse.


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The base casting is 13 Inches (330mm) in diameter and is located inside thechassis under the bottom panel. It contains (8) 1/4-20 tapped holes formounting, located on bolt circle diameters of:(4) - 12.0 In BCD, (4) - 6.0 In BCD. Each set is offset 45 degrees.

The 13 In diameter area of the base is the true load bearing surface. Noneof the other exterior portions of the chassis should be used for mounting tojigs or fixtures.

2.4 Mounting to the Base

(4) 1/4-20 12.0In BCD

GREASE PORT

(4) 1/4-20 6.0In BCD

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Display Readout PolarityThis selection controls how the LT360 represents theposition on the front display of the chassis, and here in the software. Whenset to UNIPOLAR, the position is shown from of 0 to 360 degrees. Allposition values are positive. When it is set to BIPOLAR, the range will be 0to ±180 degrees. Both positive and negative values will be shown.

Analog Output PolarityThis selection controls how the LT360 generates the DCvoltage output at the Analog Output connector. Whenset to UNIPOLAR, the LT360 will produce voltages in therange of 0.000 to +3.600 volts. All position values are positive. When it isset to BIPOLAR, the range will be 0.000 to ±1.800 volts. Both positive andnegative output.

Analog Input PolarityThis selection controls how the LT360 interprets the DCvoltage received at the Analog Input connector. Whenset to UNIPOLAR, the LT360 will accept voltages in therange of 0.000 to +3.600 volts. All position values are positive. When it isset to BIPOLAR, the range will be 0.000 to ±1.800 volts. Both positive andnegative values are used.

Voltages higher than the allowable range for the selected mode are invalid.The LT360 has a scale factor of 10mV/deg for the analog input/output.


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Step SizeThis is the Degrees Per Step by which the platter willrotate to either a Step command or pulse. The min stepsize is 0.1 deg. Step size is always positive. Direction iscontrolled by CCW/CW setting for Pulse Input, or theStep commands. The units can also be changed.

VelocityThis is the rotational velocity by which the platter will rotate. The value isset in RPM (revolutions per minute). The allowable range for the parameteris 0.01 to 3.00 RPM. Larger load capability can be increased by reducingthe RPM velocity as needed. The units can also be changed.

TorqueThis is the stepper motor torque for the platter rotation. The value is set inpercent of maximum torque. The allowable range for the parameter is 10.0to 100.0 %. For most typical applications your will want the torque set to100%. If you intend to have the platter in constant motion, than you maywish to set the torque to a lower value such as 70%. This will reduceheating in the motor and drive circuitry. The SmartTorque feature of theLT360 automatically reduces the motor torque to 1/2 its normal rotationalpower when it is not moving. This provides the advantages of maximumtorque when in motion and reduced power consumption when stationary.

Note: There are small arrow buttons to the right side of the editing fields. Tochange a parameter, click ths button and an editing dialog will open.Changes to the parameters will be sent to the LT360.


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InformationThis group box displays the serial number and dates of theLT360 unit. In normal use the factory calibration will probablybe adequate for continued use. If you have an applicationrequiring periodic recalibration for NIST compliance, the unitcan be recalibrated by sending it back to the factory.

NameThis is an arbitrary name which the user canassign to a particular LT360 unit. For example:Horz, Vert, etc. To change the name, click onthe button to the right of the field.

An edit dialog will be pre-sented to change the name.The name can be a maximumof 21 characters.

The default name set by thefactory is SN with the serialnumber appended.


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The LT360 utilizes a high frequency power supply with power factor correc-tion. This provides universal world-wide power support, from 85-265VACwithout user changes.

The LT360 is shipped with an IEC-US power cord. If your power plugrequirements are different, you can obtain a different IEC cord as neededfrom your local electronics retail stores.

3.1 AC Power

POWER

1A/250V85-260VAC

50W 50/60Hz

0l

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Motor Home CheckThis feature allows checking of the stepper motor synchroniza-tion . When Motor Home Check is set ON, the firmwarechecks that the motor returns to its home position after each movement. Ifdisabled, no checking is performed. If checking is enabled and the motordoes not end its operation in the home position, an error message is shownon the front panel display.

The stepper motor produces a specific number steps for a given amount ofplatter rotation. The LT360 utilizes microstepping for additional precisioncontrol. One particular phase of the motor is designated as the Homeposition. For any given platter rotation, the motor should always end in itsHome position.

In normal operation this error should never occur. If it does, the unit mustbe powered off to clear the error, or this feature disabled. It is possible forthis error to be produced by noise in the stepper motor controller, or by theload exceeding the torque capability thereby causing the motor to skipsteps.


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The LT360 is truely a universal turntable offering six different methods ofcontrol for every possible application:

USB (computer) RS-232 (computer) TTL Pulse (computer, analyzer, etc) Analog Input (computer, chart recorder, plotter, etc) Front Panel (manual control) LR360 (remote manual control)

The LT360 Windows application software can control up to 8 turntableswith either USB or RS-232 linking. A Win32 DLL is also provided for customprogramming which can manage up to 128 turntables connected via USB orRS-232. Control of the LT360 can also be facilitated through customprogramming using RS-232.

Note: See the Programming folder on the CD, or in the installed directory, formore information on the LT360LIB.DLL and RS-232 programming methods.

The TTL Pulse Input provides a basic digital interface which can be driven bymany analyzers for simple step control.

The Analog Input provides a highly accurate analog interface for directcontrol of the turntable position.

3.2 Control Methods

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Acceleration FunctionThis group box selects the Acceleration Function used by theLT360. Controlled acceleration/deceleration is an importantfeature that permits heavy loads to be rotated, and withminimal shock and disturbance. For typical applications the 1-Flat function provides excellent performance. See Chapter 7 for details.

Smart TorqueThis feature takes advantage of the fact that the worm geardrive system employed by the LT360 is irreversible. Meaning,the platter is self-locking at its current position. The load cannot rotate theplatter itself. Therefore, it is not necessary to maintain full power on themotor merely to hold its position when the platter is stopped.

When SmartTorque is set ON, the motor is powered down to half thedriving power 2 seconds after each movement stops. Motor power isreturned to full (controlled by Torque setting) when the motor starts again.

The use of SmartTorque greatly reduces the thermal heating in the motorand driver circuitry, and produces a very efficient drive system. Under mostconditions and use, this feature should always be kept ON.

If a particular application demands that the motor power be kept constant atall times, even when stationary (SmartTorque=OFF), then the maximumtorque should be set to 70% or less to prevent excessive heating. It isdifficult to envision what kinds of applications would require this behavior,but the option is available if needed. Otherwise, SmartTorque should alwaysbe kept ON.


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LT360 provides two methods of advanced computer control: USB (UniversalSerial Bus), and the legacy industry standard RS-232. RS-232 has theadvantage of longer cable runs universal support with any serialcommuncations device, computer, or operating system.

The USB interface uses the Low-Speed mode,1.5M bits per second. TheRS-232 interface has parameters of:

DCE Wiring Straight-Through cable (DB-9F) Baud Rate 9600 (factory default) Data Bits 8 Parity None Stop Bits 1 Handshaking None The user can change

the baud rate tohigher values, withthe max baud rate115200. The follow-ing are some typicalbaud rate values:

9600 14400 19200 28800 38400 57600115200

3.3 Computer Interfaces

10mV/DEG

RS-232INTERFACE

USBINTERFACE

ANALOGOUTPUT

ANALOGINPUT

DIGITALINPUT

10mV/DEGTTL PULSE

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The LT360 can be connected to a USB or COM serial port onthe computer. The Link group box has selections for: USB,NONE, COM1, COM2, etc.

If the NONE selection is chosen, the link will be closed. Toopen a link, select the USB or one of the COM ports. If usinga COM port, the baud rate field should be set correctly tomatch the LT360 unit.

If an LT360 unit is found on the port, the link will be activated and thecontents read from the LT360 into the parameter fields and controls. If thebaud rate does not match the LT360, or the unit is not on the selected COMport, an RX error message will be shown. The Port list box wil then beforced back to the NONE selection. For USB links, the Port list box will beforced back to the NONE selection without any message if an LT360 is notfound.

Note: If you are using a USB link, the LT360 driver must be installed.

Once the link is active all of the controls will be enabled.

Note: There is a small arrow button to the right side of the Baud Rate field.To edit the value, click this button and an editing dialog will open. These editbuttons are used to send parameter changes to the LT360.

8.2 Opening an LT360 Link


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3.4 Pulse InputThe Pulse Input provides a simple and basic means of digital control. Theconnector is a standard BNC and responds to 0/5V TTL or 0/3.3V LVTTLlevels. This control method is enabled/disabled by software configuration.

Each pulse will trigger a step. The step size is controlled else where. Thestep can be either CW or CCW depending on the software settings.

The width of the pulse should be at least 10uSec, and the triggering can beset on the rising or falling edge. Any pulses which occur while the LT360 ismoving will be ignored.

If you are not using the TTL pulse input, it is probably best to keep thisfeature disabled to prevent false triggering due to any noise pickup at theopen connector.

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8.1 LT360 Windows SoftwareThe application program provides full control over all of the LT360 functionsand features. Up to (8) units can be managed simultaneously, either linkedby USB or RS-232. The main window of the program is shown below.Fields are grayed out when unlinked.

Each LT360 unit is assignedto a tab. Changing betweentabs will load the parametersof that unit into the controlsand parameter fields.

Two methods of displayingcurrent turntable positionare used: the analog platterdisplay, and the digitalreadout.

Clicking on the plattergraphic will Abort/Stop amove.

Clicking on the digitalreadout will update thedisplay.


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3.5 Analog InputThe Analog Input feature allows for direct positional control of the LT360 viaa DC analog signal. The connector is a BNC, and the internal circuitry isdifferential to improve ground noise rejection.

The Analog Input can be enabled/disabled through software. Whenenabled, the LT360 will respond to the DC voltage at the analog input BNCconnector. When disabled, it will ignore that input.

The LT360 has a scale factor of 10mV/deg for the analog input. The rangecan be either unipolar (0 ... +3.600V) or bipolar (0 ... ±1.800V). The inputimpedance of the analog input is 1M Ohm. Although the input is anunbalanced BNC connector, the actually circuitry is differential. This helpsto reject ground noise.

The input source must be very stable and of low noise. The LT360 has aresolution of 0.1 degrees and therefore responds to changes of 1mV at theanalog input. When this input is enabled, the LT360 will sample the inputand move to the location as indicated by the voltage. After that move iscompleted, it then samples the analog input again and moves to the newposition. Monitoring of the analog input is real time.

If you are not using the analog input, this input must be disabled. Otherwisethe LT360 will be controlled by any noise received at the input.

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3.6 Analog OutputThe LT360 generates a DC voltage at the Analog Output BNC connector.This output is always active. It can be useful for driving plotting devices,chart recorders, or other displays.

There are two polarity modes for this output: Unipolar and Bipolar. Whenset to UNIPOLAR, the LT360 will produce voltages in the range of 0.000 to+3.600 volts. All position values are positive. When set to BIPOLAR, therange will be 0.000 to ±1.800 volts. Both positive and negative values areproduced.

The LT360 has a scale factor of 10mV/deg for the analog output. The rangecan be either unipolar (0 ... +3.600V) or bipolar (0 ... ±1.800V). The outputimpedance of the analog output is <200 Ohms.

Although the output is an unbalanced BNC connector, it is highly recom-mended that the input on the other device be differential to reject groundnoise. Since the smallest resolution of the LT360 is 0.1 degree, the equiva-lent resolution in the output is 1mV. The input impedance of the otherdevice should be at least 100K Ohm to prevent loading errors.

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Error - 11: Display Controller Address FailureThis error indicates that the CPU in the LT360 cannot communicate with thedisplay controller. This error should never occur. If it does, a failure of acomponent in the LT360 is indicated.

Error - 12: Switch Controller Address FailureThis error indicates that the CPU in the LT360 cannot communicate with theswitch controller. This error should never occur. If it does, a failure of acomponent in the LT360 is indicated.

Error - 13: Torque Controller Address FailureThis error indicates that the CPU in the LT360 cannot communicate with thestepper motor torque DAC controller. This error should never occur. If itdoes, a failure of a component in the LT360 is indicated.

Error - 14: Output Controller Address FailureThis error indicates that the CPU in the LT360 cannot communicate with theanalog output DAC controller. This error should never occur. If it does, afailure of a component in the LT360 is indicated.


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3.7 LR360 Remote

Precision Turntable

LR360INTERFACE


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The LR360 remote provides a means to controlthe LT360 turntable manually from a remotelocation. It provides a duplication of the frontpanel switches and display which can be useful ifthe LT360 is located in a difficult to see or operatelocation.

In most cases the user will likely be operating theLT360 via computer. However the LR360 pro-vides a backup control method if necessary forcertain applications.

The LR360 interface uses a standard PS2 cable(Mini-DIN6). The LR360 remote must be con-nected to the LT360 turntable before the power is turned on.

When power is applied, theLT360 searches for thepresence of the LR360. Iffound, its display controllerwill be initialized for userather than the front panelcontrols of the LT360.

Otherwise the LT360controls are used.

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Receiving all of the characters for a command string should take very littletime, on the order of micro or milli seconds, so if a termination charcaterdoes not arrive within 10 seconds, something is wrong. The LT360 uses thistimeout to clear the command buffer every 10 seconds if characters arereceived with no termination character. The termination character ismandatory to notify the LT360 that the entire command string has been sentand it can now process it.


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Error - 7 : RS232 Invalid ReturnThis error indicates that the LT360 was expecting to produce a return valuefor a Get command, but the return value was an empty string. This error willgenerally occur if you are writing your own RS-232 program, and there arebugs in your program. Check the command strings being sent to verify thatthey contain valid LT360 commands and/or parameters. Case is notimportant, but spaces in the right or wrong places can make a difference.

Error - 8 : USB Unknown CommandThis error indicates that the LT360 did not understand the command indexsent via USB. This error is very uncommon. It probably indicates faultycommunication over USB, such as a cable being disconnected or dirtyconnections. Possibly some other unusual problem.

Error - 9 : RS232 Command TimeoutThis error indicates that the LT360 received some characters, but neverreceived a termination character [Null(0) or CR(13)] before the 10 secondtimeout expired. When the first character is sent to the LT360, a timer isstarted. If a termination character is not received within 10 seconds, thenthis error is produced and the command buffer is cleared.


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4.1 Mechanical Load CapabilityThe drive assembly of the LT360 consists of two aluminum castingsmounted between a 125mm (5In) ball bearing. The axial static thrust loadrating for the bearing is 8900 lbs (4000kg).

The load capability for the two castings depends greatly on how evenly theload is attached to the castings. If the load is bolted properly and rigidly to

the surfaces, with theweight concentrated in thecenter region, the castingsshould easily handle 1000lbs.

If the load is not attachedto the platter and baseproperly, than the castingscould fracture with smallerloads.

Therefore it is criticallyimportant that any jigsbeing mounted to theplatter and base providetheir own rigid surfacestrength to avoid excessstress at the outside edges.

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Error - 4 : RS232-BI Break Int ErrorThis error indicates problems with the serial port communications. It can becaused by differences in the communication parameters between thecomputer and the LT360. Make sure that the computer serial port setup is9600 baud, 8 data bits, no parity, and 1 stop bit. If the LT360 baud rate hasbeen changed, then the PC must be set the same.

Error - 5 : RS232 Unknown CommandThis error indicates that the character string sent to the LT360 did notcontain a valid command. This error will generally occur if you are writingyour own RS-232 program, and there are bugs in your program. Check thecommand strings being sent to verify that they contain valid LT360 com-mands. Case is not important, but spaces in the right or wrong places canmake a difference.

Error - 6 : RS232 Invalid ParameterThis error indicates that the LT360 was expecting a parameter value for thiscommand, but did not find one in the command string. Some commandsneed parameters and some do not. This error will generally occur if you arewriting your own RS-232 program, and there are bugs in your program.Check the command strings being sent to verify that they contain validLT360 commands and parameters. Case is not important, but spaces in theright or wrong places can make a difference.


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4.2 Drive System LubricationThe drive assembly of theLT360 is pre lubricated atthe factory. Under typicaluse applications, additionallubrication will likely beunnecessary.

However a grease port isprovided under the chassiswhich appears as a 1/4 Inhole (not tapped).

A grease gun needle or atube of grease long tip canbe inserted in this hole.

The grease should be aNo.2 heavy syntheticlithium gear grease.

It is best to turn the LT360on its side, and rotate theturntable while applyingthe grease.

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Error - 1 : RS232-OE Overrun ErrorThis error indicates problems with the serial port communications. It can becaused by differences in the communication parameters between thecomputer and the LT360. Make sure that the computer serial port setup is9600 baud, 8 data bits, no parity, and 1 stop bit. If the LT360 baud rate hasbeen changed, then the PC must be set the same.

Error - 2 : RS232-PE Parity ErrorThis error indicates problems with the serial port communications. It can becaused by differences in the communication parameters between thecomputer and the LT360. Since the LT360 does not use parity, this error isunlikely. Make sure that the computer serial port setup is 9600 baud, 8 databits, no parity, and 1 stop bit. If the LT360 baud rate has been changed, thePC must be set the same.

Error - 3 : RS232-FE Framing ErrorThis error indicates problems with the serial port communications. It can becaused by differences in the communication parameters between thecomputer and the LT360, or invalid parameters in the computer UART ofthe computer. Make sure that the computer serial port setup is 9600 baud,8 data bits, no parity, and 1 stop bit. If the LT360 baud rate has beenchanged, then the PC must be set the same. You may also need to rebootthe computer to clear and reinitialize the UART in the computer.


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An internal view of the drive line with the grease tube inserted is shownbelow. The grease port is directly over the worm gear. The grease tube canbe inserted until it touches the gear.

With the platter rotating, several small portions of grease can be injected.The rotating worm gear will spread the grease around the main helical gear.Do not over grease. A total amount of grease about 1 Inch long x 1/4 Inchwide is sufficient.

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Most errors produced by the LT360 will be RS-232 command or parametererrors, especially if the user is programming via RS-232. The USB processingroutines also rely on the RS-232 command decoders, so it is very possible tosee RS-232 error codes while using the USB interface.

The basic LT360 serial RS-232 communication parameters are: 9600 baud, 8data bits, no parity, 1 stop bit, and no flow control.

Error - 0 : Motor Home Position ErrorThe stepper motor produces a specific number steps for a given amount ofplatter rotation. The LT360 utilizes microstepping for additional precisioncontrol. One particular phase of the motor is designated as the Homeposition. For any given platter rotation, the motor should always end in itsHome position. This is checked by the firmware continuously, if theMotorHomeChk option is enabled. If the motor position is not in the Homephase at the end of a movement, this error will be shown.

In normal operation this error should never occur. If it does, the unit mustbe powered off, or the MotorHomeChk option disabled, to clear the error.It is possible for this error to be produced by noise in the stepper motorcontroller, or by the load exceeding the torque capability thereby causingthe motor to skip steps.

If this error is shown repeatedly, either there is a noise problem internal inthe LT360 or the torque load is too great for the drive system.


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7.1 Error MessagesThe LT360 can display a variety of error codes on the front panel display.The error message will be displayed over a 4 second interval with a formatsuch as Err0 or Er13.

The following list describes some of the error codes which can appear:

//-------------------------------------------------// Show Error Display Codes//-------------------------------------------------// 0 - Motor Home Position Error// 1 - RS232-OE Overrun Error// 2 - RS232-PE Parity Error// 3 - RS232-FE Framing Error// 4 - RS232-BI Break Int Error// 5 - RS232 Unknown Command// 6 - RS232 Invalid Parameter// 7 - RS232 Invalid Return// 8 - USB Unknown Command// 9 - RS232 Command Timeout// 10 -// 11 - Display Cntrlr Adr Failure// 12 - Switch Cntrlr Adr Failure// 13 - Torque Cntrlr Adr Failure// 14 - Output Cntrlr Adr Failure// 15 -// 16 -// 17 -// 18 -// 19 -// 20 -//-------------------------------------------------


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5.1 Front Panel FunctionsThe front panel contains all of the connectors for the various interfacesincluding: USB (Type-B), RS-232 (DB-9F), TTL Pulse Input (BNC), AnalogInput (BNC), Analog Output (BNC), and the LR360 Remote (MiniDIN-6).

The front panel also provides 8 pushbutton switches arranged in four colorcoded groups which are used for manual control of the turntable. A multi-function 4 digit LED display is also provided.

The controls are recessed under the surface edge of the turntable to helpprevent damage due to objects which might be dropped from above, sincethe turntable is often located on a floor surface.

Most of the functions are self explanatory as listed by the screen printing onthe front panel. However some features are not able to be described on thefront panel surface and will be detailed here in the following pages.

STEPCW

STEPCCW

ZEROCW

ZEROCCW

SETDPS

RESOLUTIONDEG/STEP10mV/DEG

SETRPM

SETORIGIN

SETTORQUE

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RS-232INTERFACE

USBINTERFACE

ANALOGOUTPUT

ANALOGINPUT

DIGITALINPUT

VELOCITYREV/MIN

ZERO DEGREFERENCE

% MOTORPOWER10mV/DEGTTL PULSE

POSITION • DPS • RPM • TORQUE LR360INTERFACE


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Note that the mass load capability in the vertical configuration is not afunction of the RPM or acceleration functions of the LT360. Gravity domi-nates the acceleration entirely.

Larger mass loads can be handled by reducing the radial distance. Reducingthe distance by half will double the mass load capability.

From these calculations it should be clear that the centroid of the mass loadmust be located fairly close to the rotational center, to avoid creating largetorque requirements. In the vertical configuration acceleration due togravity is the limiting factor.


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10mV/DEG

RS-232INTERFACE

USBINTERFACE

ANALOGOUTPUT

ANALOGINPUT

DIGITALINPUT

10mV/DEGTTL PULSE

POSITION • DPS • RPM • TORQUE

USB InterfaceThis is a standard type-B connector providing connection to a USB bus. TheUSB interface of the LT360 uses only Low-Speed connection speed. This ismore than adequate for control of the turntable.

RS-232 InterfaceThe DB-9F connector is wired as a DCE device, so only a straight-throughcable connection is required to the DTE host (computer). The LT360 doesnot require any handshaking, so only the RX and TX signals are used inaddition to Ground. Adapters can be used if needed to provide connectionto DB-25 serial cables.

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The torque load is equal to the product of radial distance and force, whereforce is is the product of mass and acceleration.

F = M•AT = R•F = R•M•AM=T/(R•A)

Since the vertical position is changing, gravity is a factor. Depending on theposition of the load, or the rotational direction, the acceleration due togravity will add or subtract from the rotational acceleration of the LT360.

From the graphs on the previous pages we find that the average accelera-tion for the Flat function is about 0.21M/S2 at 1 RPM and 1 Meter, assumingthe rotation step is at least 3.2 degrees. However the acceleration due togravity is 9.8M/S2 about 50X larger. The actual acceleration due to gravitychanges around the circle from zero at the bottom or top, to the maximumat the sides. Since the rotational acceleration is so much smaller than theeffects of gravity, we will simply assume the worst case acceleration as equalto gravity. Therefore the maximum mass load which can be rotated is:

Standard LT360 (49NM), 1MeterM=T/(R•A) = 49/(1.0•9.8) = 5kg = 11 lbs

HiTorque LT360 (76NM), 1MeterM=T/(R•A) = 76/(1.0•9.8) = 7.8kg = 17 lbs


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Pulse InputThis BNC connector provides a means to step the turntable via a TTL pulse.Each pulse will cause the turntable to rotate by the current step size, and inthe directioon of either CCW or CW.

The pulse width should be a minimum of 10uSec. Triggering based on theRising or Falling edge can be selected.

Pulses are only accepted when the platter is not already in motion. If theplatter is already rotating, the pulse will be ignored.

The Pulse Input can be enabled or disabled, either by using the Win32application program or through USB or RS-232 commands.

Analog InputThis BNC connector provides a means to control the location of the platterby analog voltage. The Analog Input can be enabled or disabled, either byusing the Win32 application program or through USB or RS-232 commands.Note: This input must be disabled if not in use, otherwise it will override allother control methods.

The scale factor is 10mV/deg, and the resolution of the LT360 is 0.1 degree.Therefore, the step size and/or resolution of the analog voltage should be atleast 1mV. The actual input circuitry is differential to help reject groundnoise. The voltage range can either Unipolar (0..+3.600) or Bipolar(0..±1.800) as selected in the software or by commands.

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6.5 Vertical Torque CapabilityThe case of vertical torque is shown in the pictorials below. In this case theLT360 is located vertically relative to the ground surface. In this configura-tion the mass load is being acted upon by the acceleration of gravity. Theacceleration of gravity is 9.8M/S2, generally much larger than the rotationalacceleration of the LT360. For this reason the mass load capability will begreatly reduced.


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The LT360 samples the analog input and then begins a rotation to theindicated position. While it is moving the analog input is ignored. When itreaches that position and stops, it then samples the analog input again, andthe process repeats.

It is critically important that the voltage source be of low noise and highlystable. Since the LT360 responds to resolutions of 1mV (0.1deg), all noiseand hum must be kept below 500uV. The DC accuracy of the source mustalso be better than ±500uV.

Analog OutputThis BNC connector provides a means to obtain an analog control voltagefrom the LT360 at all times. This can be useful if driving some other display,chart recorder, or other plotting device.

The scale factor is 10mV/deg, and the resolution of the LT360 is 0.1 degree.Therefore, the step size and/or resolution of the analog voltage will be 1mV.The actual output circuitry is single ended, but it is highly recommended thatthe other device input be differential to help reject ground noise. It shouldhave at least 100K Ohm input impedance to prevent loading errors. Theoutput voltage range can either Unipolar (0..+3.600) or Bipolar (0..±1.800)as selected in the software or by commands, with different operating modes.

The Analog Output voltage is extremely precise and highly stable over theentire temperature range of 0C to 40C.

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For a Standard LT360 model the maximum platter driving torque is 49NMand for the HiTorque model 76NM (Newton•Meters). We will assume thatthe rotational velocity is set to 1 RPM, and that the Flat acceleration functionis in use.

From the graphs on the previous pages we find that the average accelera-tion for the Flat function is about 0.21M/S2 at 1 RPM and 1 Meter, assumingthe rotation step is at least 3.2 degrees. Therefore the maximum mass loadwhich can be rotated is:

Standard LT360, 1Meter, 1RPM, Flat Profile, Travel ≥ 3.2 DegreesM=T/(R•A) = 49/(1.0•0.21) = 233kg = 513 lbs

HiTorque LT360, 1Meter, 1RPM, Flat Profile, Travel ≥ 3.2 DegreesM=T/(R•A) = 76/(1.0•0.21) = 362kg = 796 lbs

The mass load capability for other operating conditions can also be calcu-lated as easily. It should be noted that the acceleration is proportional tothe square of RPM. Reducing the RPM by a factor of 2, reduces the accel-eration by a factor of 4. Thus the mass load capacity is increased by a factorof 4.

The acceleration scales linearly by radial distance. Reducing the distance byhalf reduces the acceleration by half. However, the radial distance alsoappears again in the equation by itself. Therefore, reducing the distance bya factor of 2 actually increases the mass load capacity by a factor of 4.


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LED DisplayThe four digit LED display is used primarily to givethe current position of the platter. The readout canbe either Unipolar or Bipolar as selected throughthe Win32 software or commands.

However the display has many other purposes. Itis also used to display error messages and variousother parameter values.

When the LT360 is first powered on, the displaywill cycle through various functions including asegment test of all the LED elements.

When various switches are pressed, the display will show either Position(Degrees), Step Size (DegPerStep), Velocity (RPM), Torque (%), or theAcceleration Function (#). The following pages covering the switch func-tions will describe these operations in detail.

POSITION • DPS • RPM • TORQUE

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The case of horizontal torque is shown in the pictorials below. In this casethe LT360 is located on a horizontal surface and the load is rotated in ahorizontal plane with no change in the vertical axis.

The torque load is equal tothe product of radialdistance and force, whereforce is is the product ofmass and acceleration.

F = M•AT = R•F = R•M•AM=T/(R•A)

Since there is no change invertical position, gravity isnot a factor. The onlyacceleration acting on theload is due to the LT360.

6.4 Horizontal Torque Capability

Overhead View


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LR360 InterfaceThis Mini-DIN connector (PS2) is used to connect the LR360Remote Control Module (shown below).

The LR360 provides a means to locate the control switches anddisplay farther away from the LT360 turntable. This can be useful ifthe readouts on the front of the unit are not visible or anothermeans of backup control is desired.

The LR360 remote must be connected to the LT360 turntablebefore the power is turned on. When power is applied, the LT360searches for the presence of the LR360. If found, its displaycontroller will be initialized for use rather than the front panelcontrols of the LT360. Otherwise the LT360 controls are used.

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0 Sec 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 11m 12m 13m 14m 15m 16m

M/S2

0

1

2

3

4

5

6

7

8

9

10

11

12

13

Acceleration vs Time(71.2)

Acc_SIN3 16Acc_SIN2 16

Acc_IMPL 16 @ 1RPM/1MAcc_FLAT 16Acc_RAMP 16

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10m

20m

30m

40m

50m

60m

70m

80m

90m

100m

110m

Velocity vs Time

Vel_SIN3 16Vel_SIN2 16

Vel_IMPL 16 @ 1RPM/1MVel_FLAT 16Vel_RAMP 16

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Step CW / CCW (White SWs)These two switches are mainly used to step the platter by the current stepsize, either clockwise (CW) or counter clockwise (CCW). When the switchis pressed, the platter will rotate by the current step size.

If the platter is already rotating pressing these switches will have no effectuntil the active movement has completed.

Note: To abort / stop a rotation, press either Red swtich.

These switches are also used with other switches to increment/decrementparameter values.

STEPCW

STEPCCW

ZEROCW

ZEROCCW

SETDPS

RESOLUTIONDEG/STEP

SETRPM

SETORIGIN

SETTORQUE

VELOCITYREV/MIN

ZERO DEGREFERENCE

% MOTORPOWER

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M/S2

0

100m

200m

300m

400m

500m

600m

700m

800m

900m

1

1.1

1.2

1.3

1.4

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20m

30m

40m

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60m

70m

80m

90m

100m

110m

Velocity vs Time



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Zero CW / CCW (Green SWs)These two switches are used to move the platter to the origin (0.0) either byclockwise (CW) or counter clockwise (CCW) rotation.

If the platter is already rotating pressing these switches will have no effectuntil the active movement has completed.

Note: To abort / stop a rotation, press either Red swtich.

Set Origin (Blue SW)This switch is used to change the origin to the current platter position. Noplatter movement occurs.

When the switch is pressed, the display will flash "0.0". To change the origin,while this switch is pressed, press either of the White Step switches. Thisdouble switch action is required to prevent accidental changes to the origin.If you do not press a White switch, the original position will be retainedwhen this switch is released.

Set Step Size DPS (Blue SW)This switch is used to change the step size. When this switch is pressed, thedisplay will show the current step size. The step size can then be changedup/dn by pressing the white Step buttons. Holding the Step buttons willproduce auto repeat. The minimum step size is 0.1 degrees.

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0 Sec 25m 50m 75m 100m 125m 150m 175m 200m 225m 250m 275m 300m 325m 350m 375m 400m 425m 450m 475m 500m

M/S

0

10m

20m

30m

40m

50m

60m

70m

80m

90m

100m

110m

Velocity vs Time



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0 Sec 25m 50m 75m 100m 125m 150m 175m 200m 225m 250m 275m 300m 325m 350m 375m 400m 425m 450m 475m 500m

M/S2

0

50m

100m

150m

200m

250m

300m

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400m

450m

Acceleration vs Time



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Set Velocity RPM (Red SW)This switch is used to change the velocity in revolutions per minute. Whenthis switch is pressed, the display will show the current RPM setting. TheRPM can then be changed up/dn by pressing the white Step buttons.Holding the Step buttons will produce auto repeat. The minimum RPM is0.01 and the maximum is 3.00.

Note: Pressing a Red button while the platter is rotating will abort / stop therotation.

Set Torque % (Red SW)This switch is used to change the motor torque in percent. When thisswitch is pressed, the display will show the current torque setting in percent.The torque can then be changed up/dn by pressing the white Step buttons.Holding the Step buttons will produce auto repeat. The maximum value is100% and the minimum is 10%.

The SmartTorque feature of the LT360 automatically reduces motor powerwhen the platter is not in motion. If you are not using the SmartTorquefeature, then you should limit the torque value to 70% or less to reducemotor heating to improves motor life. Using SmartTorque is stronglyrecommended since you receive both maximum torque and motor life.

Note: Pressing a Red button while the platter is rotating will abort / stop therotation.

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The following graphs show the actual acceleration and velocity profiles for 1RPM and with a radial distance 1 Meter from center.

If the rotational travel is 3.2 degrees or more, the 512 point family is used.The average acceleration for the Flat profile is 0.21M/S². Note that thecontrolled acceleration or deceleration phase takes about 500mSec tocomplete. The value of the Impulse step function is about 2.07M/S², about10X large than that of the Flat.

If the rotational travel is 1.0 degrees or more, and less than 3.2 degrees, the160 point family is used. The average acceleration for the Flat profile is0.67M/S². Note that the controlled acceleration or deceleration phase takesabout 155mSec to complete. The value of the Impulse step function isabout 6.7M/S², about 10X large than that of the Flat.

If the rotational travel is 0.1 degrees or more, and less than 1.0 degrees,the 16 point family is used. The average acceleration for the Flat profile is6.7M/S². Note that the controlled acceleration or deceleration phase takesabout 15.5mSec to complete. The value of the Impulse step function isabout 71M/S², about 10X large than that of the Flat.

The acceleration curves can be scaled proportionally by mass load ordistance, and by the square of velocity. For example, reducing the velocityfrom 1.0 to 0.5 RPM will reduce the acceleration to 1/4 that of the thevalues shown in the graphs.


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Set Velocity RPM + Set Torque % (Both Red SWs)Pressing both Red switches together will display the Acceleration Functioncurrently in use. This will be displayed as: Acc0, Acc1, Acc2, Acc3, or Acc4.

The Acceleration Function can then be changed up/dn by pressing thewhite Step buttons. Holding the Step buttons will produce auto repeat. Themaximum value is 4 and the minimum is 0.

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6.3 Actual Accel/Velocity ProfilesTo control the acceleration of the load, a finite amount of rotational travelmust be utilized. Since the rotational travel for a particular movement maybe different, the LT360 utilizes three different families of accelerationfunctions for various step size minimums of: 3.2 degrees, 1.0 degrees, and0.1 degrees. Depending on the size of the rotation, the appropriatefunction family will be chosen.

To describe these functions with actual numeric values, we will assume amass load at a radial distance of 1 Meter from the rotational axis. This isshown in the pictorial here.

The mass travels around acircle with a radius of 1Meter, for a total travel of6.28 Meters.

If we assume a nominalcircular velocity of 1 RPM,then the linear velocity ofthe mass is approx0.105M/S (6.28M/60Sec).

Acceleration at a differentRPM is proportional to thesquare of the change, andis linearly proportional tothe change in radius.


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6.1 Acceleration FunctionsThe LT360 provides several different acceleration functions orprofiles that control how the platter accelerates and deceleratesfrom a stationary position to the constant velocity rotation. Fivedifferent acceleration profiles are provided:

0 - Impulse 1 - Flat 2 - Ramp 3 - SIN2 4 - SIN3

LT360 ACCELERATION PROFILES

ACCELERATION CONSTANT VELOCITY DECELERATION

1-FLAT

2-RAMP

3-SIN2

4-SIN3

NOTE: HEIGHT OF IMPULSE IS 10X FLAT

0-IMPULSE

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LT360 VELOCITY PROFILES

ACCELERATION CONSTANT VELOCITY DECELERATION

0-IMPULSE

1-FLAT

2-RAMP

3-SIN2

4-SIN3

6.2 Velocity ProfilesEach of the acceleration functions has an associated velocity profile.These are shown in the graph below. The Impulse function reachesfull velocity very quickly, much faster than any of the other func-tions. The other four functions all provide a much more gradualacceleration.


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0 - ImpulseThe Impulse function provides the fastest rise time from zero to constantvelocity. However it also greatly reduces the maximum load which theLT360 can rotate, due to its higher acceleration. The acceleration of thisfunction is about 10X that of the others.

The Impulse function is useful for light loads where a fast response time isdesired. However for most typical LT360 applications where a heavy load isbeing rotated, this function is probably the least desireable. Using one of theother softer acceleration functions is preferrable for heavy loads.

1 - FlatThe Flat function provides constant acceleration until the platter reaches theconstant velocity rotational rate, as set by the RPM value. This is probably agood general purpose profile for most typical applications. The load isaccelerated under a constant value which provides maximum torque han-dling and relatively little load disturbance.

2 - RampThe Ramp function provides a more gradual acceleration profile, beginningat zero, ramping to a maximum, then decreasing to zero again as theconstant velocity speed is reached. This acceleration profile is based on aparabolic velocity function.

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3 - SIN2The Sin2 function provides a more gradual acceleration profile, beginning atzero, increasing to a maximum, then decreasing to zero again as theconstant velocity speed is reached. This acceleration profile is based on aSin2 acceleration function.

4 - SIN3The Sin3 function provides a more gradual acceleration profile, beginning atzero, increasing to a maximum, then decreasing to zero again as theconstant velocity speed is reached. This acceleration profile is based on aSin3 acceleration function.

In theory each increasing index of the acceleration functions provides asofter acceleration method. However in many cases the practical differ-ences between functions 1-4 will be very small.

If there is additional rigging and/or a fixture attached to the LT360, therigidity and mass of the additional hardware will play an important factor inthe overall motional system response. No mechanical structure is perfectlyrigid. When the LT360 platter begins to rotate, not all portions of theattached rigging will instantly follow this same motion. The fixture will bend,and can behave with its own time constant and perhaps ringing to therotational motion. The ringing motion or vibration will be controlled by thedamping in the fixture. Proper design of fixtures often requires dampingelements such as rubber pads placed between joints to increase damping.

lt360 user manual - physical-lab

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