Mitsubishi Electronics FX1S manual Moving Between STL Steps, Using SET to drive an STL coil

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FX Series Programmable Controllers

STL Programming 3

3.4Moving Between STL Steps

To activate an STL step the user must first drive the state coil. Setting the coil has already been identified as a way to start an STL program, i.e. drive an initial state. It was also noted that using an OUT statement to driving a state coil has a different meaning to the SET instruction. These difference will now be explained:

3.4.1Using SET to drive an STL coil

•SET is used to drive an STL state coil to make the step active. Once the current STL step activates a second following step, the source STL coil is reset. Hence, although SET is used to activate a state the resetting is automatic.

	However, if an STL state is driven by a
	series of standard ladder logic instructions,	X000 S040	S020
	i .e . not a preceding STL state, then		S020
	standard programming rules apply.	S020	S030
	In the example shown opposite S20 is not		S030
	reset even after S30 or S21 have been	SET	S021
	driven. In addition, if S20 is turned OFF,	SET	S021
	driven. In addition, if S20 is turned OFF,
	S30 will also stop operating . This is	RST	S022
	because S20 has not been used as an STL	RST	S022
	because S20 has not been used as an STL
	state. The first instruction involving the
	status of S20 is a standard LoaD instruction and NOT an STL instruction.

Note: If a user wishes to forcibly reset an STL step, using the RST or ZRST (FNC 40) instructions would perform this task.

X000

ZRST S21 S28

•SET is used to drive an immediately following STL step which typically will have a larger STL state number than the current step.

•SET is used to drive STL states which occur within the enclosed STL program flow, i.e. SET is not used to activate a state which appears in an unconnected, second STL flow diagram.

3-5

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Contents Programming Manual Page Foreword FX Series Programmable ControllersFX Series Programmable Controllers FAX Back Combined Programming Manual J FX Series Programmable Controllers Software Warnings Hardware WarningsFX Series Programmable Controllers Contents STL Programming Applied Instructions Rotation And Shift Functions 30 to External FX Serial Devices Functions 80 to Execution Times And Instructional 10-1 Viii FX Series Programmable Controllers Chapter Contents Overview IntroductionWhat do You Need to Program a PLC? What is a Programmable Controller?Current Generation CPU all versions Special considerations for programming equipmentManual name Number FX Base Unit Hardware Assocciated ManualsManual name Number FX DU, GOT and DM units Memo Basic Program Instructions FX Series Programmable ControllersBasic Program Instructions What is a Program? Outline of Basic Devices Used in ProgrammingDetailed device information Example How to Read Ladder LogicLoad, Load Inverse OUT instructionProgram example Out Timer and Counter VariationsUse of dual coils Last coil effectDouble Coil Designation Peripheral limitations And, And InverseORI Or, Or InverseSingle Operation flags M2800 to M3071 Load Pulse, Load Trailing PulseLDF ANF OUT Pulse, And Trailing PulseORF ORB Or Pulse, Or Trailing PulseOr Block Batch processing limitationsSequential processing limitations ANB BlockMPS, MRD and MPP usage 13 MPS, MRD and MPPMultiple program examples MCR Master Control and ResetNested MC program example Resetting timers and counters Set and ResetTimer, Counter Out & Reset Retentive timers16.1Basic Timers, Retentive Timers And Counters Availability of devices Bit countersNormal 32 bit Counters High Speed CountersLeading and Trailing Pulse PLFUsages for INV InverseNo Operation No OperationProgram scan 20 EndMemo STL Programming FX Series Programmable ControllersSTL Programming General note What is STL, SFC And IEC1131 Part 3? How STL Operates Each step is a program Look Inside an STL Combined SFC Ladder representation How To Start And End An STL ProgramEmbedded STL programs Activating new statesInitial Steps Terminating an STL ProgramReturning to Standard Ladder Moving Between STL Steps Using SET to drive an STL coilUsing OUT to drive an STL coil OUT is used for loops and jumpsOut is used for distant jumps Basic Notes On The Behavior Of STL programs Rules and Techniques For STL programsT001 K20 K50 Single Signal Step Control Method 1 Using locking devicesMethod 2 Special Single Pulse Flags Restrictions Of Some Instructions When Used With STL Using ‘jump’ operations with STLRestrictions on using applied instructions STL OUT SET Using STL To Select The Most Appropriate ProgramLimits on the number of branches Using STL To Activate Multiple Flows SimultaneouslyLimits on the number of branches Instruction Format General Rules For Successful STL BranchingGeneral Precautions When Using The FX-PCS/AT-EE Software Simple STL Flow Programming ExamplesSET STL Identification of normally closed contactsSelective Branch/ First State Merge Example Program Points to noteFull STL flow diagram/program Advanced STL Use Devices in Detail FX Series Programmable ControllersDevices in Detail Inputs Configuration detailsAvailable devices Device MnemonicOutputs Device Mnemonic YAlias O/P Auxiliary Relays Device Mnemonic MGeneral Stable State Auxiliary Relays External loads Battery Backed/ Latched Auxiliary RelaysSpecial Single Operation Pulse Relays Special Diagnostic Auxiliary RelaysState Relays Device Mnemonic SGeneral Stable State State Relays PLC FX 1S FX 1N FX 2N Battery Backed/ Latched State RelaysMonitoring STL programs Assigned statesSTL/SFC programming IST instructionAnnunciator Flags Jumping to the end of the program PointersDevice availability Device Mnemonic PAdditional applied instructions Interrupt PointersNested levels Pointer positionTimer Interrupts Rules of useInput Interrupts Disabling high speed counter interrupts Driving special auxiliary relaysAdditional notes Disabling Individual InterruptsConstant H Constant KDevice Mnemonic K Example device usage N/ATimers Timer accuracyDevice Mnemonic T General timer operation Selectable TimersDriving special auxiliary coils Retentive Timers Using timers in interrupt or ‘CALL’ subroutinesTimers Used in Interrupt and ‘CALL’ Subroutines Internal timer accuracyTimer Accuracy ConditionCounters Setting ranges for countersHigh speed counters Device Mnemonic CGeneral/ Latched 16bit UP Counters Battery backed/latched countersBattery backed/ latched counters Selecting the counting directionGeneral/ Latched 32bit Bi-directional Counters Further uses None Basic high speed counter operationBasic High Speed Counter Operation Driving high speed counter coilsInput assignment Counter SpeedsAvailability of High Speed Counters Calculating the maximum combined counting speed on FX1S Setting range Device specificationDirection setting Using the SPD instructionRST Device size 11.5 2 Phase Bi-directional Counters C246 to C25011.6 A/B Phase Counters C252 to C255 Data Registers Device Mnemonic DExample device usage None Data register updates Data retentionGeneral Use Registers Use of diagnostic registers Using the FX2-40AW/APBattery Backed/ Latched Registers Special Diagnostic RegistersWriting to file registers Special caution when using FX1SFile Registers Program memory registersUses Externally Adjusted RegistersUse of Modifiers with Applied Instruction Parameters Index RegistersDevice Mnemonic V,Z Available formsUsing Multiple Index Registers Modifying a ConstantMisuse of the Modifiers Bit Devices, Individual and Grouped Bits, Words, BCD and HexadecimalMoving grouped bit devices Assigning I/OAssigning grouped bit devices Interpreting Word Data Word DevicesFX Series Programmable Controllers Word Data Summary Binary Coded Decimal value= ErrorInverted7 Additional1 14.4 Two’s ComplimentSome useful constants Floating Point And Scientific NotationScientific Notation Floating Point Format FLT