Mitsubishi Electronics FX1S Battery backed/ latched counters, Selecting the counting direction

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FX Series Programmable Controllers

Devices in Detail 4

4.10.2General/ Latched 32bit Bi-directional Counters

FX1S

FX1N FX2N FX2NC

The counter shown in the example below, activates when its coil is driven, i.e. the C200 coil is driven. On every occasion the input X14 is turned from OFF to ON the current value or current count of C200 is incremented.

X12 Up counting					Up counting
			Down counting
X13
X14					X12
					X12	M8200
						M8200
Counters					X13	RST C200
Counters	4 5
present	4 5	4
value	2 3		3 2		X14	C200
0	1		1 0		0	C200
			-1 -2		C200	K-5
			-1 -2		-5 -4-3	Y1
If output is already			-3 -4-5		-5 -4-3
Y1 turned ON				-6	-7 -8-7 -6

The output coil of C200 is set ON when the current value increases from “-6” to “-5”. However, if the counters value decreases from “-5” to “-6” the counter coil will reset. The counters current value increases or decreases independently of the output contact state (ON/OFF). Yet, if a counter counts beyond +2,147,483,647 the current value will automatically change to -2,147,483,648. Similarly, counting below -2,147,483,648 will result in the current value changing to +2,147,483,647. This type of counting technique is typical for “ring counters”. The current value of the active counter can be rest to "0" (zero) by forcibly resetting the counter coil; in the example program by switching the input X13 ON which drives the RST instruction. The counting direction is designated with special auxiliary relays M8200 to M8234.

Battery backed/ latched counters:

•Counters which are battery backed/ latched are able to retain their status information, even after the PLC has been powered down. This means on re-powering up, the latched counters can immediately resume from where they were at the time of the original PLC power down.

Available devices:

• Please see the information table on page 4-19.

Selecting the counting direction:

•If M8✰✰✰ for C✰✰✰ is turned ON, the counter will be a down counter. Conversely, the counter is an up counter when M8✰✰✰ is OFF.

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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 Detailed device information What is a Program?Outline of Basic Devices Used in Programming Example How to Read Ladder LogicProgram example Load, Load InverseOUT instruction Out Timer and Counter VariationsDouble Coil Designation Use of dual coilsLast coil effect 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 PulseSequential processing limitations Or BlockBatch 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 Reset16.1Basic Timers, Retentive Timers And Counters Timer, Counter Out & ResetRetentive timers High Speed Counters Bit countersAvailability of devices Normal 32 bit 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?Look Inside an STL How STL OperatesEach step is a program Activating new states How To Start And End An STL ProgramCombined SFC Ladder representation Embedded STL programsReturning to Standard Ladder Initial StepsTerminating an STL Program Moving Between STL Steps Using SET to drive an STL coilOut is used for distant jumps Using OUT to drive an STL coilOUT is used for loops and jumps Basic Notes On The Behavior Of STL programs Rules and Techniques For STL programsT001 K20 K50 Method 2 Special Single Pulse Flags Single Signal Step ControlMethod 1 Using locking devices Restrictions on using applied instructions Restrictions Of Some Instructions When Used With STLUsing ‘jump’ operations with STL 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 Device Mnemonic Configuration detailsInputs Available devicesAlias O/P OutputsDevice Mnemonic Y General Stable State Auxiliary Relays Auxiliary RelaysDevice Mnemonic M External loads Battery Backed/ Latched Auxiliary RelaysSpecial Single Operation Pulse Relays Special Diagnostic Auxiliary RelaysGeneral Stable State State Relays State RelaysDevice Mnemonic S PLC FX 1S FX 1N FX 2N Battery Backed/ Latched State RelaysIST instruction Assigned statesMonitoring STL programs STL/SFC programmingAnnunciator Flags Device Mnemonic P PointersJumping to the end of the program Device availabilityPointer position Interrupt PointersAdditional applied instructions Nested levelsInput Interrupts Timer InterruptsRules of use Disabling Individual Interrupts Driving special auxiliary relaysDisabling high speed counter interrupts Additional notesExample device usage N/A Constant KConstant H Device Mnemonic KDevice Mnemonic T TimersTimer accuracy Driving special auxiliary coils General timer operationSelectable Timers Retentive Timers Using timers in interrupt or ‘CALL’ subroutines Condition Internal timer accuracy Timers Used in Interrupt and ‘CALL’ Subroutines Timer AccuracyDevice Mnemonic C Setting ranges for countersCounters High speed countersGeneral/ Latched 16bit UP Counters Battery backed/latched countersGeneral/ Latched 32bit Bi-directional Counters Battery backed/ latched countersSelecting the counting direction Further uses None Basic high speed counter operationBasic High Speed Counter Operation Driving high speed counter coilsAvailability of High Speed Counters Input assignmentCounter Speeds Calculating the maximum combined counting speed on FX1S Using the SPD instruction Device specificationSetting range Direction settingRST Device size 11.5 2 Phase Bi-directional Counters C246 to C25011.6 A/B Phase Counters C252 to C255 Example device usage None Data RegistersDevice Mnemonic D General Use Registers Data register updatesData retention Special Diagnostic Registers Using the FX2-40AW/APUse of diagnostic registers Battery Backed/ Latched RegistersProgram memory registers Special caution when using FX1SWriting to file registers File RegistersUses Externally Adjusted RegistersAvailable forms Index RegistersUse of Modifiers with Applied Instruction Parameters Device Mnemonic V,ZMisuse of the Modifiers Using Multiple Index RegistersModifying a Constant Bit Devices, Individual and Grouped Bits, Words, BCD and HexadecimalAssigning grouped bit devices Moving grouped bit devicesAssigning I/O 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