Allen-Bradley
9/Series CNC
Mill
Operation and
Programming
Manual
Important User Information
Because of the variety of uses for the products described in this publication,
those responsible for the application and use of this control equipment must
satisfy themselves that all necessary steps have been taken to assure that
each application and use meets all performance and safety requirements,
including any applicable laws, regulations, codes and standards.
The illustrations, charts, sample programs and layout examples shown in
this guide are intended solely for purposes of example. Since there are
many variables and requirements associated with any particular installation,
Allen-Bradley does not assume responsibility or liability (to include
intellectual property liability) for actual use based upon the examples shown
in this publication.
Allen-Bradley publication SGI-1.1, Safety Guidelines for the Application,
Installation, and Maintenance of Solid State Control(availablefromyour
local Allen-Bradley office), describes some important differences between
solid-state equipment and electromechanical devices that should be taken
into consideration when applying products such as those described in this
publication.
Reproduction of the contents of this copyrighted publication, in whole or in
part,without writtenpermissionofAllen-Bradley Company,Inc.isprohibited.
Throughout this manual we make notes to alert you to possible injury to
people or damage to equipment under specific circumstances.
WARNING: Tells readers where people may be hurt if
procedures are not followed properly.
CAUTION: Tells readers where machinery may be damaged or
economic loss can occur if procedures are not followed properly.
Warnings and Cautions:
- identify a possible trouble spot
- tell what causes the trouble
- give the result of improper action
- tell the reader how to avoid trouble
Important: We recommend that you frequently back up your application
programs on an appropriate storage medium to avoid possible data loss.
PLC is a registered trademarkof Allen-Bradley Company, Inc.
Paramacro and PALaretrademarks of Allen-Bradley Company, Inc.
Summary of Changes
9/Series Mill
Operation and Programming Manual
October 2000
New Information
RevisionBars
The following is a list of the larger changes made to this manual since its
last printing. Other less significant changes were also made throughout.
Error Message Log
Paramacro Parameters
Softkey Tree
Error Messages
We use revision bars to call your attention to new or revised information.
A revision bar appears as a thick black line on the outside edge of the page
as indicated here.
Chapter
1-2
Table of Contents
Index (General)
9/Series Mill
9/Series PALReference Manual
Operation and Programming Manual
Chapter 1
Using This Manual
1.0ChapterOverview 1-1..........................................................
1.1Audience 1-1................................................................
1.2ManualDesign 1-1............................................................
1.3ReadingthisManual 1-3........................................................
1.4Terms and Conventions 1-4......................................................
1.5Warnings,Cautions,and ImportantInformation 1-5......................................
1.6RelatedPublications 1-5........................................................
Chapter 2
Basic Control Operation
2.0ChapterOverview 2-1..........................................................
2.1OperatorPanelOperations 2-1....................................................
2.1.1Keyboard 2-3.............................................................
2.1.2CalculatorFunction 2-4......................................................
2.1.3Softkeys 2-8..............................................................
2.1.4CRT 2-10................................................................
2.1.5Portable OperatorPanel 2-11...................................................
2.2The MTB Panel 2-12............................................................
2.3SoftwareMTB Panel{FRONTPANEL} 2-15............................................
2.4PowerProcedures 2-21..........................................................
2.4.1Turning Power On 2-21.......................................................
2.4.2TurningPower OFF 2-22.....................................................
2.5ControlConditions atPower-Up 2-23................................................
2.6EmergencyStopOperations 2-24...................................................
2.6.1Emergency StopReset 2-24...................................................
2.7Access Control 2-25............................................................
2.7.1Assigning Access Levelsand Passwords 2-26......................................
2.7.2Password ProtectableFunctions 2-29............................................
2.7.3EnteringPasswords 2-31.....................................................
2.8ChangingOperatingModes 2-33...................................................
2.9Displaying Systemand MachineMessages 2-37........................................
2.9.1Clearing ActiveMessages {CLEAR ACTIVE} 2-40....................................
2.10The Input Cursor 2-41..........................................................
2.11 {REFORMMEMORY} 2-41.......................................................
2.12Removingan Axis (Axis Detach) 2-43...............................................
2.13TimeParts CountDisplay Feature 2-43..............................................
Chapter 3
Offset Tables and Setup
3.0ChapterOverview 3-1..........................................................
3.1Tool OffsetTable{TOOLGEOMET}and {TOOLWEAR} 3-1...............................
3.1.1ToolOffsetDimensionalParameters 3-2..........................................
i
Table of Contents
Index (General)
9/Series PALReference Manual
Operation and Programming Manual
3.1.2SettingTool OffsetTables 3-5..................................................
3.1.3SettingOffset DataUsing {MEASURE} 3-9........................................
3.1.4ToolOffsetRange Verification 3-10...............................................
3.2Changingthe ActiveToolOffset{ACTIVEOFFSET} 3-12..................................
3.3WorkCoordinateSystemOffsetTables {WORKCO-ORD} 3-14..............................
3.3.1SettingWorkCoordinateSystemTables 3-15.......................................
3.4BackingUp OffsetTables 3-17.....................................................
3.5Programmable ZoneTable 3-21....................................................
3.6SingleDigitFeedrate Table 3-23....................................................
9/Series Mill
Chapter 4
Manual/MDI Operation Modes
4.0ChapterOverview 4-1..........................................................
4.1ManualOperatingMode 4-1......................................................
4.1.1J ogging an Axis 4-2........................................................
4.1.2Continuous Jog 4-3.........................................................
4.1.3IncrementalJog 4-3........................................................
4.1.4HPG Jog 4-4.............................................................
4.1.5ArbitraryAngle Jog 4-5......................................................
4.1.6J og Offset 4-6.............................................................
4.1.7ResettingOvertravels 4-6.....................................................
4.2MechanicalHandleFeed(Servo Off) 4-8.............................................
4.3Removingan Axis(AxisDetach) 4-8................................................
4.4ManualMachineHoming 4-8.....................................................
4.5MDIMode 4-11................................................................
4.5.1MDI Basic Operation 4-12.....................................................
Chapter 5
Editing Programs Online
5.0ChapterOverview 5-1..........................................................
5.1Selectingthe ProgramToEdit 5-2..................................................
5.2EditingPrograms at theControl(Online) 5-3..........................................
5.2.1 Movingthe Cursor {STRINGSEARCH} andCursorSize {CHAR/WORD} 5-5................
5.2.2EnteringCharactersand Blocks 5-7.............................................
5.2.3Changingand Inserting{MODIFY INSERT} 5-7.....................................
5.2.4Erasing Characters and Blocks 5-11.............................................
5.2.5Sequence Numbers{RENUMPRGRAM} 5-13.......................................
5.2.6Merging Part Programs {MERGEPRGRAM} 5-15....................................
5.2.7ExitingEditMode{EXITEDITOR} 5-16............................................
5.3 Programming Aids {QUICK VIEW} 5-17............................................
5.3.1Selectinga QuickViewPlane 5-19...............................................
5.3.2Using {QPATH+ PROMPT}SamplePatterns 5-20....................................
5.3.3G--code FormatPrompting{GCODEPROMPT} 5-24..................................
5.3.4 Mill Cycle Format Prompting 5-26...............................................
ii
Table of Contents
Index (General)
9/Series Mill
9/Series PALReference Manual
Operation and Programming Manual
5.4Digitizing a Program(Teach) 5-28...................................................
5.4.1Linear Digitizing 5-30.........................................................
5.4.2 Digitizing anArc (3 Points) 5-32.................................................
5.4.3Digitizingan Arc Tangentat End Points 5-34........................................
5.5Deleting Program{DELETE PRGRAM} 5-37..........................................
5.6RenamingPrograms{RENAMEPRGRAM} 5-38........................................
5.7Displayinga Program {DISPLYPRGRAM} 5-39........................................
5.8CommentDisplay{PRGRAMCOMENT} 5-40..........................................
5.9CopyingPrograms{COPYPRGRAM} 5-41............................................
5.10Selecting theProtectable PartProgram Directory 5-43...................................
5.10.1ProtectedProgramEncryptionandDecryption 5-46..................................
5.10.2StoringEncryption/DecryptionTable to BackupMemory 5-49..........................
Chapter 6
Editing Part Programs Offline (ODS)
6.0ChapterOverview 6-1..........................................................
6.1Selectingthe PartProgram Application 6-2...........................................
6.2EditingPart Programs OffLine 6-2.................................................
6.3Interfacing the WorkstationwiththeControl 6-5........................................
6.4DownloadingPart Programs fromODS 6-5...........................................
6.5UploadPartProgramsto ODS 6-12.................................................
Chapter 7
Running a Program
7.0ChapterOverview 7-1..........................................................
7.1SelectingSpecial Running Conditions 7-1............................................
7.1.1Block Delete 7-1...........................................................
7.1.2MiscellaneousFunctionLock 7-2..............................................
7.1.3Sequence Stop{SEQSTOP} 7-2...............................................
7.1.4Single Block 7-4..........................................................
7.2Selecting a Part ProgramInputDevice 7-5............................................
7.3Selectinga Program 7-6.........................................................
7.4Deselecting a Part Program 7-9...................................................
7.5 ProgramSearch {SEARCH} 7-10...................................................
7.6 SearchWith Recall {MID ST PRGRAM} 7-13..........................................
7.7BasicProgramExecution 7-17.....................................................
7.7.1 {QUICK CHECK} 7-19........................................................
7.7.2Axis Inhibit Mode 7-20.......................................................
7.7.3Dry RunMode 7-21.........................................................
7.7.4Part Production/AutomaticMode 7-23............................................
7.8Interrupted ProgramRecover {RESTRT PRGRAM} 7-25..................................
7.9Jog Retract 7-28...............................................................
7.10BlockRetrace 7-31............................................................
iii
Table of Contents
Index (General)
9/Series PALReference Manual
Operation and Programming Manual
9/Series Mill
Chapter 8
Display and Graphics
8.0ChapterOverview 8-1..........................................................
8.1Selection ofAxisPositionDataDisplay 8-1...........................................
8.2PAL DisplayPage 8-22..........................................................
8.3ChangingLanguages 8-23........................................................
8.4Graphics 8-24.................................................................
8.4.1Selectingthe Programfor Graphics 8-24..........................................
8.4.2Running Graphics 8-25......................................................
8.4.3DisablingGraphics 8-27......................................................
8.4.4Changing Parameters 8-27....................................................
8.4.5Graphics in Single-Block 8-33..................................................
8.4.6ClearingGraphics Screen 8-33.................................................
8.4.7DisplayingMachineInformation in Graphics 8-33....................................
8.4.8Zooming Graphics 8-33......................................................
8.6PowerTurn-onScreen 8-37.......................................................
8.7ScreenSaver 8-39.............................................................
Chapter 9
Communications
9.0ChapterOverview 9-1..........................................................
9.1Setting Communications 9-1......................................................
9.1.1SettingCommunication Port ParameterValues 9-1...................................
9.1.2Communication PortParameters 9-3.............................................
9.2Inputting PartPrograms from a Tape Reader 9-9.......................................
9.3Outputting Part Programs to aTape Punch 9-13.........................................
9.4VerifyingPartProgramsAgainstSource Programs 9-17...................................
9.5ErrorConditions(Inputting and OutputtingPartPrograms) 9-18..............................
Chapter 10
Introduction to Programming
10.0ChapterOverview 10-1.........................................................
10.1Tape Format 10-1.............................................................
10.2ProgramConfiguration 10-6......................................................
10.2.1Program Names 10-8.......................................................
10.2.2Sequence Numbers 10-9....................................................
10.2.3CommentBlocks 10-10.......................................................
10.2.4Block Delete andMultiLevel Delete 10-10.........................................
10.2.5End ofBlock Statement 10-11..................................................
10.3UsingSubprograms 10-12........................................................
10.3.1Subprogram Call (M98) 10-13..................................................
10.3.2Main and SubprogramReturn(M99) 10-14.........................................
10.3.3Subprogram Nesting 10-16....................................................
10.4WordFormatsand Functions 10-17.................................................
iv
Table of Contents
Index (General)
9/Series Mill
9/Series PALReference Manual
Operation and Programming Manual
10.4.1 Minimumand MaximumAxisMotion (ProgrammingResolution) 10-21.....................
10.5WordDescriptions 10-22.........................................................
10.5.1A_ L_ ,R_ ,C_ (Quick Plus andRadius-Chamfer Words) 10-22..........................
10.5.2Axis Names 10-22.........................................................
10.5.3D --and H-- Words (ToolOffsets) 10-22............................................
10.5.4F--words(Feedrate) 10-23....................................................
10.5.5G --codes(PreparatoryFunctions) 10-24..........................................
10.5.6I ,J,and K IntegrandWords 10-30.............................................
10.5.7M --codes(MiscellaneousFunctions) 10-30........................................
10.5.7.1Auxiliary MiscellaneousFunction(B--word) 10-37..................................
10.5.8N--words(Sequence Numbers) 10-37............................................
10.5.9O --words(ProgramNames) 10-37..............................................
10.5.10P ,L(MainProgramJumps and SubprogramCalls) 10-37.............................
10.5.11S--word(SpindleSpeed) 10-38................................................
10.5.12T--words(Tool Selection) 10-40................................................
Chapter 11
Coordinate Systems Offsets
11.0 Chapter Overview 11-1.........................................................
11.1 Machine CoordinateSystem(Absolute) 11-1..........................................
11.1.1MotionintheMachineCoordinateSystem(G53) 11-2.................................
11.2 Preset Work Coordinate Systems (G54-59.3) 11-4......................................
11.2.1AlteringWork Coordinate Systems (G10L2) 11-7....................................
11.3 Work Coordinate System ExternalOffset 11-9.........................................
11.3.1AlteringExternalOffset(G10L2) 11-11............................................
11.4 Offsetting the WorkCoordinateSystems 11-13..........................................
11.4.1CoordinateOffsetUsing ToolPosition(G92) 11-13....................................
11.4.2OffsettingCoordinateZero Points(G52) 11-16.......................................
11.4.3 {SET ZERO}Offset 11-18.....................................................
11.4.4Jogging an Offset 11-19.......................................................
11.4.5CancelingCoordinateSystem Offsets (G92.1) 11-20..................................
11.4.6Canceling Selected Coordinate System Offsets (G92.2) 11-21..........................
11.5 PAL Offsets 11-22..............................................................
Chapter 12
Overtravels and Programmable Zones
12.0ChapterOverview 12-1.........................................................
12.1HardwareOvertravels 12-2......................................................
12.2Software Overtravels 12-3.......................................................
12.3Programmable Zone2 (G22,G23) 12-5..............................................
12.4Programmable Zone3 (G22.1,G23.1) 12-7...........................................
12.5Resetting Overtravels 12-13.......................................................
v
Table of Contents
Index (General)
9/Series PALReference Manual
Operation and Programming Manual
9/Series Mill
Chapter 13
Coordinate Control
13.0ChapterOverview 13-1.........................................................
13.1Rotating theCoordinateSystems 13-1...............................................
13.1.1RotatingtheCurrentWorkCoordinateSystem(G68, G69) 13-2.........................
13.1.2External Part Rotation 13-6...................................................
13.2PlaneSelection(G17, G18, G19) 13-11...............................................
13.3Absolute/IncrementalModes (G90,G91) 13-12.........................................
13.4Inch/Metric Modes (G20,G21) 13-13................................................
13.5Scaling 13-14.................................................................
13.5.1Scaling and AxisPosition DisplayScreens 13-17....................................
13.5.2Scaling Magnification Data Screen 13-17..........................................
13.5.3Scaling Restrictions 13-19....................................................
Chapter 14
Axis Motion
14.0 Chapter Overview 14-1.........................................................
14.1 PositioningAxes 14-1..........................................................
14.1.1 Rapid PositioningMode (G00) 14-1.............................................
14.1.2 Linear Interpolation Mode(G01) 14-3...........................................
14.1.3 CircularInterpolationMode (G02, G03) 14-5......................................
14.1.4 HelicalInterpolation Mode (G02, G03) 14-10.......................................
14.1.5 PositioningRotary Axes 14-12.................................................
14.1.6 CylindricalInterpolation 14-14..................................................
14.1.7 PALAxisMover 14-20.......................................................
14.2 PolarCoordinate Programming (G15, G16) 14-21.......................................
14.2.1 Polar ProgrammingSpecial Cases 14-25.........................................
14.3 AutomaticMotionToand From Machine Home 14-29....................................
14.3.1 Automatic MachineHoming(G28) 14-29.........................................
14.3.2 Automatic ReturntoMachineHome(G28) 14-30....................................
14.3.3 AutomaticReturn From MachineHome (G29) 14-32.................................
14.3.4 MachineHome Return Check (G27) 14-33........................................
14.3.5 Returnto AlternateHome(G30) 14-34...........................................
14.4 Dwell (G04) 14-35.............................................................
14.4.1 Dwell- Seconds 14-36......................................................
14.4.2 Dwell- Number of Spindle Revolutions 14-36......................................
14.5 ProgrammableMirrorImage(G50.1- G51.5) 14-36......................................
14.5.1 Manual MirrorImage 14-38...................................................
14.6 AxisClamp 14-39..............................................................
14.7Feed to HardStop(G24) 14-40....................................................
vi
Table of Contents
Index (General)
9/Series Mill
9/Series PALReference Manual
Operation and Programming Manual
Chapter 15
UsingQuickPathPlust
15.0 Chapter Overview 15-1.........................................................
15.1 Using QuickPath Plus 15-1......................................................
15.2 Linear QuickPath Plus 15-3......................................................
15.3 CircularQuickPathPlus(G13,G13.1) 15-7...........................................
Chapter 16
Using Chamfers and Corner Radius
16.0 Chapter Overview 16-1.........................................................
16.1 Chamfers and CornerRadius 16-1.................................................
Chapter 17
Spindles
17.0 Chapter Overview 17-1.........................................................
17.1 Controlling Spindle (G12.1,G12.2, G12.3) 17-1........................................
17.2 Spindle Orientation (M19) 17-3...................................................
17.3 Spindle Direction(M03,M04,M05) 17-5.............................................
17.4 Synchronized Spindles 17-6.....................................................
17.4.1Using theSpindleSynchronizationFeature 17-7...................................
17.5SpecialConsiderations forSpindle Synchronization 17-9.................................
Chapter 18
Programming Feedrates
18.0 Chapter Overview 18-1.........................................................
18.1 Feedrates 18-1...............................................................
18.1.1 Feedrates Applied During CutterCompensation 18-2................................
18.1.2 Inverse TimeFeed Mode (G93) 18-4..........................................
18.1.3 Feed--Per--MinuteMode(G94) 18-5...........................................
18.1.4 Feed--Per--RevolutionMode (G95) 18-5.........................................
18.1.5 Rapid Feedrate 18-6......................................................
18.1.6 Feedrate Overrides 18-7...................................................
18.1.7 Feedrate Limits (Clamp) 18-8................................................
18.2Feedratesto ControlTorque Adaptive Feed (G25) 18-9..................................
18.3SpecialAMPAssignedFeedrates 18-12..............................................
18.3.1Single DigitF--words 18-12...................................................
18.3.2External Feedrate Switch 18-13...............................................
18.4Automatic Acceleration/Deceleration(Acc/Dec) 18-14....................................
18.4.1ExponentialAcc/Dec 18-15...................................................
18.4.2Linear Acc/Dec 18-16.......................................................
18.4.3S--CurveAcc/Dec 18-17.....................................................
18.4.4ProgrammableAcc/Dec 18-18.................................................
18.4.5Precautions on CornerCutting 18-20............................................
18.4.6Spindle Acceleration(Ramp) 18-22..............................................
vii
Table of Contents
Index (General)
9/Series PALReference Manual
Operation and Programming Manual
18.4.7Short Block Acc/Dec G36, G36.1 18-22.........................................
9/Series Mill
Chapter 19
Dual---axis Operation
19.0 Chapter Overview 19-1.........................................................
19.1 Dual--axisOperation 19-1.......................................................
19.1.1 Parking a DualAxis 19-3...................................................
19.1.2 Hominga DualAxis 19-4...................................................
19.1.3 Programminga Dual Axis 19-5...............................................
19.1.4 OffsetManagementfora DualAxis 19-7.......................................
Chapter 20
Tool Control Functions
20.0 Chapter Overview 20-1.........................................................
20.1 Programming a T--word 20-1.....................................................
20.2 Tool LengthOffsetFunction(G43,G44,G49) 20-3......................................
20.2.1 Activating Tool Length Offsets 20-8............................................
20.2.2ToolLength Offset(TLO)Axis Selection(G43.1,G44.1) 20-9...........................
20.3 RandomTool 20-11............................................................
20.4 ProgrammingAlterations of the Offset Tables (G10L10 -- G10L13) 20-18.......................
20.5 AutomaticTool Life Management 20-19..............................................
20.5.1ToolDirectoryData 20-20....................................................
20.5.2Assigning DetailedTool Data 20-25.............................................
20.5.3 Programming Data andBacking Up Tool ManagementTables (G10L3, G11) 20-29............
20.5.4 Programming UsingTool Management 20-33......................................
Chapter 21
Cutter Diameter Compensation (G40, G41, G42)
21.0 Chapter Overview 21-1.........................................................
21.1 Active CutterCompensation 21-3..................................................
21.2 CutterCompensationGenerated Blocks G39,G39.1 21-7................................
21.3 CutterCompensation(Type A) 21-10................................................
21.3.1 CutterCompensation TypeA EntryMoves 21-10...................................
21.3.2 CutterCompensation Type AExitMoves 21-14....................................
21.4 CutterCompensation (Type B) 21-20...............................................
21.4.1 CutterCompensation TypeB EntryMoves 21-20...................................
21.4.2 CutterCompensation TypeB Exit Moves 21-24...................................
21.5 Tool PathDuring CutterCompensation 21-30..........................................
21.6 CutterCompensationSpecial Cases 21-35............................................
21.6.1 Changing CutterCompensation Direction 21-35....................................
21.6.2 TooMany Non-Motion Blocks 21-39............................................
21.6.3 Corner MovementAfterGeneratedBlocks 21-41...................................
21.6.4 Changing CutterRadiusDuringCompensation 21-43................................
21.6.5 MDIor Manual MotionDuringCutterCompensation 21-46.............................
viii
Table of Contents
Index (General)
9/Series Mill
9/Series PALReference Manual
Operation and Programming Manual
21.6.6 Moving To/From Machine Home 21-48..........................................
21.6.7 Changing or OffsettingWork Coordinate System 21-49...............................
21.6.8 Block Look-Ahead 21-50....................................................
21.7 Error Detection for CutterCompensation 21-51.........................................
Chapter 22
Using Pocket Milling Cycles
22.0 Chapter Overview 22-1.........................................................
22.1 Pocket Milling RoughingCycle(G88.1) 22-1..........................................
22.1.1 RectangularPocketRoughingUsing G88.1 22-2.................................
22.1.2 RectangularPocketEnlargingUsingG88.1 22-5...................................
22.1.3 SlotRoughingUsing G88.1 22-8..............................................
22.1.4 CircularPocketRoughingUsingG88.1 22-10......................................
22.1.5 CircularPocketEnlargingUsingG88.1 22-13......................................
22.2 Pocket Milling FinishingCycle (G88.2) 22-15..........................................
22.2.1 RectangularPocketFinishingUsingG88.2 22-16...................................
22.2.2 CircularPocketFinishingUsing G88.2 22-19......................................
22.2.3 SlotFinishingUsingG88.2 22-20..............................................
Chapter 23
Using Post Milling Cycles
23.0 Chapter Overview 23-1.........................................................
23.1 PostMilling Roughing Cycle (G88.3) 23-1............................................
23.1.1 RectangularPostRoughingUsingG88.3 23-2.....................................
23.1.2 CircularPostRoughingUsingG88.3 23-5.......................................
23.2 PostMilling Finishing Cycle (G88.4) 23-7............................................
23.2.1 RectangularPostFinishingUsingG88.4 23-8.....................................
23.2.2 CircularPostFinishingUsing G88.4 23-11.......................................
Chapter 24
Using Hemisphere Milling Cycles
24.0 Chapter Overview 24-1.........................................................
24.1 Hemisphere MillingRoughing Cycle (G88.5) 24-1......................................
24.1.1 Concave Hemisphere RoughingUsingG88.5 24-2.................................
24.1.2 Convex Hemisphere RoughingUsingG88.5 24-5..................................
24.2 Hemisphere MillingFinishing Cycle (G88.6) 24-7.......................................
24.2.1 Concave Hemisphere Finishing UsingG88.6 24-8.................................
24.2.2 Convex Hemisphere Finishing UsingG88.6 24-10..................................
Chapter 25
Irregular Pocket Milling Cycles
25.0 Chapter Overview 25-1.........................................................
25.1 IrregularPocket Milling 25-1.....................................................
25.1.1 IrregularPocketRoughing(G89.1) 25-2.........................................
ix
Table of Contents
Index (General)
9/Series PALReference Manual
Operation and Programming Manual
25.1.2 IrregularPocketFinishing(G89.2) 25-10..........................................
9/Series Mill
Chapter 26
Milling Fixed Cycles
26.0 Chapter Overview 26-1.........................................................
26.1 Milling Fixed Cycles 26-2........................................................
26.2 Positioningand Hole MachiningAxes 26-4...........................................
26.3 Parameters 26-7.............................................................
26.4 Milling Fixed Cycle Operations 26-8................................................
(G73):Deep HolePeck DrillingCycle with Dwell 26-9....................................
(G74):Left-HandTapping Cycle 26-10................................................
(G74.1):Left-HandSolid-Tapping Cycle 26-12...........................................
(G76): Boring Cycle,SpindleShift 26-15.............................................
(G80): Cancel or EndFixed Cycles 26-18............................................
(G81): Drilling Cycle,No Dwell/RapidOut 26-18........................................
(G82): DrillCycle,Dwell/Rapid Out 26-20............................................
(G83): Deep Hole Drilling Cycle 26-21...............................................
(G84): Right-HandTapping Cycle 26-23.............................................
(G84.1):Right-HandSolid-TappingCycle 26-25.........................................
(G85): Boring Cycle, No Dwell/FeedOut 26-28........................................
(G86): Boring Cycle, SpindleStop/Rapid Out 26-30.....................................
(G87): Back BoringCycle 26-32...................................................
(G88): Boring Cycle, SpindleStop/ManualOut 26-34....................................
(G89): Boring Cycle, Dwell/FeedOut 26-36...........................................
26.5 Altering Milling Fixed Cycle Operating Parameters 26-38..................................
26.6 Examples of Drilling Cycles 26-40..................................................
Chapter 27
Skip, Gauge, and Probing Cycles
27.1 Chapter Overview 27-1.........................................................
27.2 External Skip,Gauge,and ProbeFunctions 27-1.......................................
27.2ExternalSkip Functions (G31codes) 27-2..........................................
27.3 Tool GaugingExternalSkip Functions (G37 codes) 27-4.................................
27.4 Hole Probing (G38) 27-8.......................................................
27.5 ParallelProbingCycle(G38.1) 27-12................................................
27.6 Probing ParametersTable 27-15..................................................
27.7 Adaptive Depth (G26) 27-18......................................................
x
Table of Contents
Index (General)
9/Series Mill
9/Series PALReference Manual
Operation and Programming Manual
Chapter 28
Paramacros
28.0 Chapter Overview 28-1.........................................................
28.1 Paramacros 28-1.............................................................
28.2 ParametricExpressions 28-2.....................................................
28.2.1 Basic MathematicalOperators 28-2............................................
28.2.2 Mathematical Function Commands 28-4........................................
28.2.3 ParametricExpressions asG-- or M--Codes 28-6..................................
28.3 Transferof ControlCommands 28-7................................................
28.3.1 ConditionalOperators 28-7..................................................
28.3.2 GOTOand IF-GOTOCommands 28-8.........................................
28.3.3 DO-ENDand WHILE-DO-END Commands 28-10...................................
28.4 ParameterAssignments 28-12...................................................
28.4.1Local Parameter Assignments 28-12............................................
28.4.2 CommonParameters 28-15..................................................
28.4.3 SystemParameters 28-15...................................................
28.4.4 PALParameters 28-33......................................................
28.4.5Shared Dual-ProcessParameters(#7100 -7199) 28-35..............................
28.5 Assigning ParameterValues 28-36.................................................
28.6 Macro CallCommands 28-44.....................................................
28.6.1Non-Modal ParamacroCall(G65) 28-45..........................................
28.6.2Modal Paramacro Call (G66) 28-46.............................................
28.6.3Modal Paramacro Call (G66.1) 28-48............................................
28.6.4AMP-definedG-CodeMacroCall 28-50..........................................
28.6.5AMP-DefinedM-CodeMacroCall 28-51..........................................
28.6.6AMP-DefinedT--, S--, and B--Code MacroCall 28-51.................................
28.6.7Nesting Macros 28-52.......................................................
28.7 Macro OutputCommands 28-54...................................................
Chapter 29
Program Interrupt
29.0 Chapter Overview 29-1.........................................................
29.1 Enabling and Disabling Interrupts (M96/M97) 29-1......................................
29.2 InterruptRequestConsiderations 29-4..............................................
29.3 InterruptTypes 29-5...........................................................
29.4The InterruptProgram 29-8......................................................
Chapter 30
Using a 9/Series Dual-processing System
30.0ChapterOverview 30-1.........................................................
30.1Defining ofa Dual- processing System 30-1...........................................
30.2Operating a Dual-processingSystem 30-2............................................
30.3SynchronizingMultiplePartPrograms 30-7...........................................
30.4SpindleControlfor Dual-- processing Systems 30-12.....................................
xi
Table of Contents
Index (General)
9/Series PALReference Manual
Operation and Programming Manual
30.5 Using Interference Checking with a Dual-process Mill 30-12................................
30.5.1Measuring InterferenceBoundaries 30-16.........................................
30.5.2Entering InterferenceValuesManually 30-19......................................
30.5.3Entering InterferenceValuesthroughProgramming (G10L5 and G10L6) 30-21...............
30.5.4Backing UpInterference Tables 30-23...........................................
30.6Shared Axes onDual--processing Systems 30-26.......................................
30.6.1Operatinga SharedAxis 30-26.................................................
30.6.2Switchinga Shared Axistoa DifferentProcess 30-28................................
30.6.3Settingup aShared Axis 30-29................................................
30.7DualAxes ona Dual--processingSystem 30-31.........................................
30.7.1Decoupling a Dual Axis Group 30-32...........................................
30.7.2IndependentlyProgramming Dual Axis Members 30-33...............................
9/Series Mill
Chapter 31
Using Transfer Line Cycles
31.0ChapterOverview 31-1.........................................................
31.1TransferLine Cycles 31-2.......................................................
31.1.1Using TransferLine Cycles 31-3..............................................
31.1.2Selectingthe ProgramtoEditorCreate 31-6....................................
31.1.3Creatinga Transfer LinePartProgram 31-9.......................................
31.1.4EditingPartPrograms 31-12..................................................
31.1.5Reloading Part Program Templates 31-17.........................................
31.1.6Running theCycles 31-25...................................................
31.2Understandingthe QuickViewTemplates 31-25.........................................
Appendix A
Softkey Tree
AppendixOverview A-1............................................................
Understanding Softkeys A-1.........................................................
Describing Level1 Softkeys A-3......................................................
UsingtheSoftkeyTree A-3.........................................................
Appendix B
Error and System Messages
Overview B-1...................................................................
Appendix C
G-code Tables
AppendixOverview C-1............................................................
G-codeTables C-1...............................................................
xii
Table of Contents
Index (General)
9/Series Mill
9/Series PALReference Manual
Operation and Programming Manual
Appendix D
Allen-Bradley 7300 Series CNC Tape Compatibility
AppendixOverview D-1............................................................
G-codeCompatibility Considerations D-1................................................
M-code Compatibility Considerations D-3...............................................
Offset Compatibility Considerations D-4.................................................
Additional Feature Compatibility Considerations D-6........................................
9/Series G-codesApplicabletothe 7300 SeriesCNC D-9....................................
7300 Series Features NotSupported D-10...............................................
xiii
Table of Contents
Index (General)
9/Series PALReference Manual
Operation and Programming Manual
9/Series Mill
xiv
1
Using This Manual
Chapter
1.0
ChapterOverview
1.1
Audience
1.2
Manual Design
This chapter describes how to use this manual. Major topics include:
how the manual is organized and what i nformation can be found in it.
how this manual is written and what fundamentals are presumed to be
understood by reader.
definitions for certain key terms.
We intend this manual for use by those who program and/or operate any one
of the family Allen-Bradley 9/Series CNCs. We assume that a person has
some familiarity with the operation and programming of a CNC.
We divided the manual this way:
For information about: Refer to:
howto operatethe control chapters3 -- 9
howto programthe control chapters10 -- 29
softkeys appendixA
errorand operatormessagesin alphabeticalorder appendixB
standardG-codesused to programthe control appendixC
theAllen-Bradley7300 SeriesCNC tape reader appendixD
We placed section headings in the left margin of each page, and included
illustrations and examples as aids in programming and operating the
control.
Table 1.A provides a summary of each chapter.
1-1
Chapter 1
Describesthefixedcycles(cannedcycles)fordrillingoperationsandtheG-wordsandparameter
s
usedtodefinethem.
Using This Manual
Table 1.A
Manual Organization
Chapter Title Summary
1 ManualOverview Manualoverview,intendedaudience, definition of key terms, how toproceed.
2 BasicControlOperation Abrief descriptionofthe control’sbasic operationincluding powerup, MTBpanel, operatorpanel,
accesscontrol,and E-STOP.
3 Offset Tablesand Setup Basicsetupof theoffsettable,other initialoperatingparameters.
4 Manualand MDIOperation Howto use the manualoperate modeincluding,homingthe machine,jog hand-wheel,jog
continuous,and jogincrement. Alsocovered are thebasics forMDI operation.
5 Editing ProgramsOn Line Howto create,edit,andsave a partprogramonline.
6 EditingPartProgramOffLine Howto create,edit,and save a partprogramsfromODS offline.
7 Runninga Program Howto selectand execute a programautomatically. Thiscovers programcheckingas well as part
production. Alsodetails on specialrunning conditions.
8 Displays/Graphics Howto access and interpret the differentposition displays. How to use theQuick Check and Active
Programgraphicsfeatures.
9 Communications Communications withperipheral devices. Includes sectionson communication port parameters,
inputtingand outputting AMP,PAL,Offsets, and programs.
10 Introduction toProgramming Tape format,structure and formatofthe programminglanguage forthe control.
11 CoordinateSystemOffsets Machine coordinate system,PresetWorkcoordinate systems,PAL offsets, and external offsets
12 Overtravels and Programmable
Zones (G22,G23)
13 CoordinateControl Describesabsolute/incrementalmodes, inch/metric modes,radius/diameter modes,and scaling
14 Axis Motion G-wordsdefinehow the toolis positioned tothe endpointof a move. Alsosectionson automatic
15 QuickPath Plus DescribesQuickPathPlus programming
16 UsingChamfersand Corner Radius Describesthe ,C-and ,R-wordsprogrammed forchamfering and cornerradius
17 Spindles Describesspindle speedcontrol,spindleorientation,spindledirection,and VirtualC axis
18 Programming Feedrates Describesacc/dec,AMP-assignedfeedrates,feedrate control,shortblock acc/dec
19 DualAxis Operation Describesparking,homing,programming,offsetmanagementfora dual axis
20 ToolControl Selectinga tool. Activatingand deactivatingtoollength offsets. Alsotool controlfeaturessuch as
21 CutterCompensation Describesthe Tool Tip RadiusCompensation feature (TTRC) thatoffsets fordifferenttooldiameters.
22 Using Pocket Milling Cycles
23 Using PostMillingCycles
24 Using HemisphereMilling Cycles
25 Using IrregularPocketMilling Cycles
26 Milling Fixed Cycles
27 Skipand Gauging Cycles Describesthe 9/Series Probing features. Includesthe toolmeasuring gauge feature.
28 Paramacros Describesparamacrosincluding calling,arithmetic functions,looping,decision making
29 ProgramInterrupts Describesthe programinterruptfeature. This feature is used tocalla subprogramor paramacro
30 DualProcessing Systems Necessaryinformationon capabilitiesand programmingmethods fordual processing systems.
31 Transfer Line Cycles Describes operationand programmingofT-Line-9part programtemplatesfortransferlinecontrols.
Hardwareand softwareovertravels, programmable zone 2 (G22,G23), programmable zone 3
(G22.1,G23.1),and resetting overtravels
machinehome,dwell,mirroring, and axis clamp
RandomTooland ToolLife Management.
Describesthe fixed cycles (cannedcycles) for drillingoperations and theG-wordsandparameters
programwhenevera signal correspondingto thatprogramis sent toPALby the operator.
1-2
Chapter 1
Using This Manual
Table 1.A (cont.)
Manual Organization
Appendix Title Summary
AppendixA Softkeys Describes softkeysand theirfunctionsforsoftkeylevels 1 and 2. Alsothe softkeytreedisplaying all
levelsof softkeysand theirlocationis shown.
AppendixB Errorand OperatorMessages Analphabetical listingof 9/Seriessystemmessages withbrief descriptions.
AppendixC Gand M Code Tables Liststhe G-codesusedto programthe control.
AppendixD A-B7300 SeriesCNC TapeReader Detailed7300 Series CNC tapecompatibility featuredeveloped on the control.
1.3
Reading this Manual
To make this manual easier to understand, we included these explanations
of terms and symbols:
All explanations, illustrations, and charts presented are based on
standard CNC functions. Operations may differ from the basic
information provided in this manual depending on the configuration of
the machine tool. For details, refer to the manuals prepared and supplied
by the system installer.
Some of the softkey functions may be purchased as optional features.
This manual assumes that all of the optional features have been
purchased.
Explanations and illustrations are presented based on the movement of
the cutting tool on a fixed workpiece.
The control allows the use of any alphabetic character for expressing a
numerically controlled axis. This manual uses X, Y, and Z for the first,
second, and third axes on the basic coordinate system respectively. I, J,
and K represent the integrand words for the axes.
The term AMP is an abbreviation for Adjustable Machine Parameters.
These parameters are used to configure a control to a specific machine.
Setting of AMP is usually done by the system installer.
Key names designated between the [ ] symbols are found on the
operator panel.
Key names designated between the { } symbols are softkeys found
below the CRT.
Switch and button names on the standard MTB panel are designated
between the < > symbols.
1-3
Chapter 1
Using This Manual
The term PAL is an abbreviation for Programmable Application Logic.
This is a ladder logic program that processes signals between the CNC
and the machine. It is usually programmed by the system installer.
System Characteristics:
Metric
Absolute
IPM
1.4
Terms andConventions
To make this manual easier to read and understand, we shortened the full
product names and features. Shortened terms include:
AMP — Adjustable Machine Parameters
Backup — Memory storage area not requiring battery maintenance
CNC — Computer Numerical Control
CPU — Central Processing Unit (the computing part of the control)
CRT — Cathode Ray Tube (the control’s monitor screen)
the control — the 9/230, 9/240, 9/260 or 9/290 CNC
ESTOP — Emergency Stop
Flash memory — programmable, non-volatile memory
HPG — Hand Pulse Generator
I/O — Input/Output
MDI — Manual Data Input
modal — an operating condition that remains in effect on the control
until cancelled or replaced
MTB — Machine Tool Builder
ODS — Offline Development System
PAL — Programmable Application Logic
RAM — Random Access Memory resident on the 9/240
softkeys — the row of keys directly below the screen
1-4
system installer — the company or contractor responsible for installing
this control on the machine
Chapter 1
Using This Manual
1.5
Warnings, Cautions, and
Important Information
1.6
Related Publications
We indicate information that is especially important by the following:
WARNING: indicates circumstances or practices that can lead
to personal injury as well as to damage to the control, the
machine, or other equipment.
CAUTION: indicates circumstances or practices that can lead
to damage to the control or other equipment.
Important: indicates information that is necessary for successful
application of the control.
9/SeriesDocumentation
Pub.No. Document Name
8520-4.3 9/SeriesCNCPALReference Manual
8520--5.1.1 9/SeriesCNC Lathe Operationand Programming Manual
8520--5.1.3 9/SeriesCNC Mill Operationand Programming Manual
8520--5.1.4 9/SeriesCNC GrinderOperation and Programming Manual
8520-5.1.5 9/SeriesDataHighway PlusCommunicationModule UserManual
8520-5.1.6 9/SeriesMMS/EthernetCommunicationModuleUser Manual
8520--5.2 9/SeriesCNC OCI UserManual Supplement
8520-6.2 9/SeriesCNCIntegrationand MaintenanceManual
8520-6.4 9/SeriesCNCAMP ReferenceManual
8520-6.5 T-Line-9 TransferLine QuickStartGuide
8520--6.6 9/SeriesCNC OCI Installation Manual
8520--6.7 9/SeriesCNC OCI APIDeveloper’sGuide
MCD-5.1 Offline DevelopmentSystemUser’s Manual
END OF CHAPTER
1-5
Chapter 1
Using This Manual
1-6
Chapter
2
2-1
BasicControl Operation
2.0
ChapterOverview
This chapter describes how to operate the Allen-Bradley 9/Series control,
including:
Topic: On page:
MTBpanel 2-12
{FRONT PANEL} 2-15
Power-up 2-23
Emergencystops 2-24
Access control 2-25
Changingmodes 2-33
Displaysystem and messages 2-37
Inputcursor 2-41
{REFORM MEMORY} 2-41
Removingan axis 2-43
Timepartcount 2-43
We also tell you about the control conditions automatically assumed at
power up.
2.1
Operator Panel Operations
Use the operator panel to perform these operations:
display a part program
display control status and tool position
edit a part program
display and enter tool offset data
display the status of input/output signals
display and enter programmable zone boundaries
set the level of protection of part programs, tool offset data, AMP data,
etc.
Use the operator panel to perform many other operations. We describe
these operations in the remaining chapters of this manual.
Chapter 2
2-2
Basic Control Operation
Figure 2.1 shows the different operator panels available. The color
operator panel has identical keys and softkeys in a slightly different
configuration. The portable operator panel has the same key locations as
the monochrome operator panel but can be removed from the 9/Series I/O
ring.
Figure 2.1
Operator Panels
9/SERIES
Monochrome Operator Panel
Removable Operator Panel
9
78
456
123
.
0:
N
+
_
$
=
CALC
!
G
O
X
P
_
I
F
Z
Y
A
W
R
M
Q
K
J
SHIFT
#
D
H
,
?
E
B
C
L
C
&
SP
T
S
[
]
SELECTSELECT
DISP
DEL
EOB
)
(
LINE
PROC
ColorOperatorPanel
(CRTand FlatPanel)
CAN
TRANSMIT
RES
CNTRL
19436
Chapter 2
2-3
Basic Control Operation
2.1.1
Keyboard
Table 2.A explains the functions of keys on the operator panel keyboard.
In this manual, the names of operator panel keys appear between [ ]
symbols.
Table 2.A
Key Functions
Key Name Function
Addressand NumericKeys Usethese keys toenter alphabeticand numeric
characters. Ifa key has twocharactersprintedon it,
pressingit normallyentersthe upperleft character.Holding
downthe [SHIFT] key while pressingit entersthelower
rightcharacter.
CursorKeys • , • ,• , •
[SHIFT] and • or •
[SHIFT] and • or •
CalculationKey[CALC] Pressingthiskey enables a calculatortype function on the
Delete Key [DEL] Pressingthiskey deletes thecharacterto theleftofthe
[SHIFT] and [DEL] Pressingthis key deletesall keyed-indata currently
[CAN] Clearthemostrecently generated,activeerrormessage
Transmit Key [TRANSMIT] Thedata enteredand displayed ontheinput linesis sent to
BlockReset [RESET] Thisperforms a block reset. See page 2-4 .
ControlReset[RESET] +
[SHIFT]
DisplaySelect
[DISP SELECT]
End of Block [E.O.B.] Usethiskey to enteran End of Blockcharacterwhen
[PROC SELECT] This keyis used for dual processlathe systemsonly.
[SHIFT] and [• ] Pressthe [SHIFT] keywhile holding down the[• ]
Usethese keys tomove the cursorleft,right,up and down
inthe data displayarea (lines4-21)of thescreen. We
refertothese keys as theleft,right,up, and downcursor
keys respectively.
Pressthe rightor leftcursorkeys while holdingdown the
[SHIFT] keyto move thecursor rightand lefton any
lineon which thatdata is being input. (normallyscreen
lines2-3).
Pressthe up ordown cursorkeywhile holding down the
[SHIFT] keyto roll thedisplay page forwardor
backwards.
control. Basicmathematicalexpressionsmay be evaluated
usingthis feature. For details,see page2-4.
cursoron inputlines.
displayedon input lines.
thecontrolwhen the [TRANSMIT] keyispressed,for
examplea password ora programblock.
Pressingthe resetkey whileholding down the shiftkey
performs a controlreset. See page 2-4 fordetails.
Usethis key todisplay the differentaxis positiondisplay
softkeys.
editinga programor when writingan MDIprogram.
Pressingthiskey toggles thecontrolfrom processto
process.
softkeytojump to theonline searchmonitorscreen. Press
thesekeys again toreturntothe previousscreen.
Chapter 2
2-4
Basic Control Operation
Reset Operations
Block Reset
Use the block reset feature to force the control to skip the block execution.
To use the block reset function, program execution must be stopped. If
program execution stops before the control has completely finished the
block execution, a block reset aborts any portion of that block that has not
been executed. If program execution stops after the complete block
execution (as in the case of single block execution or a M00 etc.), the
control aborts the execution of the entire following block.
Press
[RESET] key on the operator panel to perform a block reset.
Control Reset
You can return the control to the default parameters, clear any
programming errors, and cancel any MDI commands by executing a
control reset. After you execute a control reset, any active program resets
to the first block; any programmed offsets or rotations of the coordinate
systems reset to default, and any MDI command is discarded. All of the
operating parameters return to the standard AMP-assigned values,
including any AMP-assigned G-codes active at power-up (except
Inch/Metric which remains in its last programmed state at control reset).
2.1.2
Calculator Function
Press the
[SHIFT] key to execute a control reset.
[RESET] key on the operator panel while holding down the
The 9/Series control is equipped to evaluate simple mathematical
expressions during the course of operation or programming.
To use the calculator function, line 2 of the screen must be blank. There
can be no prompt on the input line of the screen when you attempt to do
calculations. This completely disables any calculation operation when in
MDI mode. If you attempt to enter the calculator function while another
prompt is active, the control generates the error message “CANNOT
CALCULATE - PROMPT PRESENT.”
Use the calculator function as follows:
1. Press the
[CALC] key on the operator panel. The “CALC:”prompt
appears on the input line of the screen (line 2).
2. Enter a mathematical equation on the input line by pressing the
desired keys on the operator panel.
3. Press the
[TRANSMIT] key to evaluate the expression. The answer to
the expression is displayed on the input line.
Chapter 2
2-5
Basic Control Operation
Expressions entered on the input line cannot exceed a total of 25
characters. Only numeric or special mathematical operation characters as
described below can be entered next to the “CALC:”prompt. Any
character that is not numeric or an operation character you enter on the
input line generates the error message “INVALID CHARACTER.”
The largest number you can enter for a calculate function is 214748367.
You cannot enter a number larger than 10 digits. If control displays a
number that is too large (longer than 10 digits), the control displays t he
error message “NUMBER IS OUT OF RANGE”. If the number entered or
calculated is greater than 10 digits, control displays the error message
“MATHOVERFLOW.”
Any fractional numbers cannot exceed .999999 (6 decimal places). If you
exceed this number of decimal places, the control automatically rounds off.
If this seventh digit is less than 5, the control rounds down. If this seventh
digit is 5 or greater, the control rounds up.
Any data entered on the input lines can be edited as described on page
2-41.
To disable the calculator function, press the
[CALC] key again. The
“CALC:”prompt is removed from the input line.
Use the characters in Table 2.B to indicate mathematical operations.
Table 2.B
Mathematical Operators
* Multiplication
/ Division
+ Addition
- Subtraction
[] Brackets
#
GetParamacroValue
The control executes mathematical operations in this order:
1. Any part of the expression that is between the brackets [ ] is
evaluated first. The values of paramacro variables are also
substituted for the #xxxx as the first operation performed.
2. Multiplication and division are evaluated second.
3. Addition and subtraction are evaluated last.
If the same level of evaluation is performed the left most operation takes
priority.
Chapter 2
2-6
Basic Control Operation
Example 2.1
Mathematic Expressions
Expression Entered Result Displayed
12/4*3
12/[4*3] 1
12+2/2 13
[12+2]/2 7
12-4+3 11
12-[4+3]
9
5
Table 2.C lists the function commands available with the [CALC] key.
Table 2.C
Mathematical Functions
Function Meaning
SIN Sine (degrees)
COS Cosine(degrees)
TAN Tangent (degrees)
ATAN ArcTangent(degrees)
ASIN Arc Sine (degrees)
ACOS ArcCosine (degrees)
SQRT Square Root
ABS Absolute Value
BIN Conversion fromDecimalto Coded Decimal
BCD Conversion fromCoded Decimalto Decimal
ROUND RoundingOff(nearestwhole number)
FIX Truncation Down
FUP Truncation Up
LN Logarithms(naturallog)
EXP Exponent
When you program these functions, place the value that the function is to
be performed on in brackets, for example, SIN [10]. The exception to this
is the arc tangent function. The format for ATAN requires the division of
two values. For example, ATAN [10]/[2] is used to calculate the arc
tangent of 5.
The functions in Table 2.C are executed from left to right in a program
block. These functions are executed before the control executes any
mathematical operators like addition or subtraction. This order of
execution can only be changed by enclosing operations in brackets [ ].
Operations enclosed in brackets are executed first.
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