Allen-Bradley Logix 5000 Programming Manual
Controllers sequential function charts
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Summary of Contents for Allen-Bradley Logix 5000
- Page 1 Programming Manual Logix 5000 Controllers Sequential Function Charts 1756 ControlLogix, 1756 GuardLogix, 1769 CompactLogix, 1769 Compact GuardLogix, 1789 SoftLogix, 5069 CompactLogix, 5069 Compact GuardLogix, Studio 5000 Logix Emulate...
- Page 2 Flash will cause severe injury or death. Wear proper Personal Protective Equipment (PPE). Follow ALL Regulatory requirements for safe work practices and for Personal Protective Equipment (PPE). Allen-Bradley, Rockwell Software, Rockwell Automation, and TechConnect are trademarks of Rockwell Automation, Inc. Trademarks not belonging to Rockwell Automation are property of their respective companies.
- Page 3 Summary of changes This manual includes new and updated information. Use these reference tables to locate changed information. Grammatical and editorial style changes are not included in this summary. Global changes This table identifies changes that apply to all information about a subject in the manual and the reason for the change.
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Page 5: Table Of Contents
Table of contents Preface Studio 5000 environment....................9 Additional resources ......................10 Legal notices ........................10 Chapter 1 Design a sequential function Introduction ........................13 What is a sequential function chart? ................14 chart Define the tasks ........................18 Choose how to execute the SFC ..................19 Define the steps of the process .................. - Page 6 Table of contents SFC_STOP structure ....................50 Nest an SFC ........................50 Pass parameters ......................52 Configure when to return to the OS/JSR ..............52 Pause or reset an SFC ......................53 Execution diagrams ......................53 Chapter 2 Program a sequential Introduction ........................
- Page 7 Table of contents Verify the routine ....................... 77 Edit an SFC online ......................78 Maintain active SFC step ..................78 Chapter 3 Force steps Introduction ........................79 Precautions .......................... 79 Enable forces ........................79 Disable or remove a force ....................80 Check force status ......................
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Page 9: Preface
Preface This manual shows how to design and program Sequential Function Charts (SFCs) for Logix 5000 controllers to execute. This manual is one of a set of related manuals that show common procedures for programming and operating Logix 5000™ controllers. -
Page 10: Additional Resources
Describes the available instructions for a Logix 5000 Manual, publication 1756-RM003 controller. Logix 5000 Controllers Process and Drives Instructions Describes how to program a Logix 5000 controller for Reference Manual, publication 1756-RM006 process or drives applications. Logix 5000 Controllers Motion Instruction Set Reference... - Page 11 Directory, FactoryTalk Security, FactoryTalk Services Platform, FactoryTalk View, FactoryTalk View SE, FLEX Ex, FlexLogix, FLEX I/O, Guard I/O, High Performance Drive, Integrated Architecture, Kinetix, Logix5000, Logix 5000, Logix5550, MicroLogix, DeviceNet, EtherNet/IP, PLC-2, PLC-3, PLC-5, PanelBuilder, PowerFlex, PhaseManager, POINT I/O, PowerFlex, Rockwell...
- Page 12 Preface Warranty This product is warranted in accordance with the product license. The product’s performance may be affected by system configuration, the application being performed, operator control, maintenance, and other related factors. Rockwell Automation is not responsible for these intervening factors. The instructions in this document do not cover all the details or variations in the equipment, procedure, or process described, nor do they provide directions for meeting every possible contingency during installation, operation, or maintenance.
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Page 13: Design A Sequential Function Chart
• Print the SFC to share the information with other individuals. • Since Logix 5000 controllers support SFCs, you do not have to enter the specification a second time. You are programming your system as you specify it. By using an SFC to program your process, you gain these advantages. -
Page 14: What Is A Sequential Function Chart
Chapter 1 Design a sequential function chart A sequential function chart (SFC) is similar to a flowchart. It uses steps and What is a sequential transitions to perform specific operations or actions. This example shows the function chart? elements of an SFC. The SFC continues on the following page. A step represents a major function of your process. - Page 15 Design a sequential function chart Chapter 1 A simultaneous branch executes more than 1 step at the same time. JSR instruction calls a subroutine. Rockwell Automation Publication 1756-PM006I-EN-P - February 2018...
- Page 16 Chapter 1 Design a sequential function chart Rockwell Automation Publication 1756-PM006I-EN-P - February 2018...
- Page 17 Design a sequential function chart Chapter 1 A selection branch chooses between different execution paths. A text box lets you add descriptive text or notes to your SFC. A wire connects one element to another element anywhere on the chart. This wire takes you to the conveyor step on the first part of this SFC (previous figure).
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Page 18: Define The Tasks
The first step in the development of an SFC is to separate the configuration and Define the tasks regulation of devices from the commands to those devices. Logix 5000 controllers let you divide your project into one continuous task and multiple periodic tasks and event tasks. -
Page 19: Choose How To Execute The Sfc
Design a sequential function chart Chapter 1 Choose how to execute the To execute an SFC, either configure it as the main routine for a program or call it as a subroutine. Then • The SFC is the only routine in the program Configure the SFC as the main routine for the program. -
Page 20: Sfc_Step Structure
Chapter 1 Design a sequential function chart • When you first open an SFC routine, it contains an initial step and transition. Use this step to initialize your process. The controller executes the initial step in these situations. • After a project download when the controller goes into Run mode. •... - Page 21 Design a sequential function chart Chapter 1 If you want to Then select or set this Data type Details member Set a flag when the step has been active for DINT Enter the time in the Preset (PRE) member. When the Timer (T) reaches the Preset a specific length of time (milliseconds) value, the Done (DN) bit turns on and stays on until the step becomes active again.
- Page 22 Chapter 1 Design a sequential function chart If you want to Then select or set this Data type Details member Do something one time on the last scan of BOOL The LS bit is on during the last scan of the step. the step Use this bit only if on the Controller Properties dialog box, SFC Execution tab, you set the Last Scan of Active Step to Don’t Scan or Programmatic reset.
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Page 23: Organize The Steps
Design a sequential function chart Chapter 1 This diagram shows the relationship of the X, FS, SA, and LS bits. Once you define the steps of your process, organize them into sequences, Organize the steps simultaneous branches, selection branches, or loops. Use this structure With these considerations Execute 1 or more steps in sequence... - Page 24 Chapter 1 Design a sequential function chart Use this structure With these considerations • Connect the wire to the step or simultaneous branch to Loop back to a previous step Wire to a previous step page 27 which you want to go. •...
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Page 25: Sequence
Design a sequential function chart Chapter 1 Example situation Example solution At station 12, the machine drills, taps, and bolts a part. The steps occur one after the Sequence other. Step 12 inspects a process for the correct mix of chemicals. Wire •... -
Page 26: Simultaneous Branch
Chapter 1 Design a sequential function chart • The SFC takes the first TRUE path. • The Logix Designer application lets you change the order in which the SFC checks the transitions (see chapter 2, Program a Sequential Function Chart page 59). -
Page 27: Wire To A Previous Step
Design a sequential function chart Chapter 1 • The SFC checks the transition after the last step of each path has executed at least once. Wire to a previous step You can also connect a step to a previous point in your SFC. •... -
Page 28: Add Actions For Each Step
Chapter 1 Design a sequential function chart Use actions to divide a step into the different functions that the step performs, Add actions for each step such as commanding a motor, setting the state of a valve, or placing a group of devices in a specific mode. -
Page 29: Use A Boolean Action
Design a sequential function chart Chapter 1 If you want to Then • Execute your logic without additional routines Embed structured text. • Use structured text assignments, constructs, and instructions When the S_Complete_the_Batch step is active, the S_Open_Outlet action executes. The action sets the Outlet.ProgCommand tag equal to 1, which opens the outlet valve. -
Page 30: Sfc_Action Structure
Chapter 1 Design a sequential function chart Example When the S_Complete_the_Batch step is active, the S_Open_Outlet action executes. When the action is active, its Q bit turns on. A ladder Logic routine monitors the Q bit (S_Open_Outlet.Q ). When the Q bit is on, the JSR instruction executes and opens the outlet valve. You can reuse a Boolean action multiple times within the same SFC. -
Page 31: Describe Each Action In Pseudocode
Design a sequential function chart Chapter 1 If you want to Then select or set this Data type Details member Determine how many times an action has Count DINT This is not a count of scans of the action. become active •... -
Page 32: Choose A Qualifier For An Action
Chapter 1 Design a sequential function chart Each action (non-Boolean and Boolean) uses a qualifier to determine when it Choose a qualifier for an starts and stops. action The default qualifier is N Non-Stored. The action starts when the step is activated and stops when the step is deactivated. -
Page 33: Define The Transition Conditions
Design a sequential function chart Chapter 1 The transition is the physical conditions that must occur or change in order to go Define the transition to the next step. conditions Transitions occur in these structures. For this structure Make sure that Sequence A transition is between each step. -
Page 34: Transition Tag
Chapter 1 Design a sequential function chart Example You want to complete these steps. 1. Turn on 2 compressors. When a compressor is on, the Device1State bit is on. 2. When both compressors are on, go to the next step. Example You want to complete these steps. -
Page 35: Use A Bool Expression
Design a sequential function chart Chapter 1 If you want to Then Use the same logic for multiple transitions. Use a BOOL expression The simplest way to program the transition is to enter the conditions as a BOOL expression in structured text. A BOOL expression uses BOOL tags, relational operators, and logical operators to compare values or check if conditions are TRUE or FALSE. -
Page 36: Transition After A Specified Time
Chapter 1 Design a sequential function chart Each step of the SFC includes a millisecond timer that runs whenever the step is Transition after a specified active. Use the timer to for these situations. time • Signal when the step has run for the required time and the SFC should go to the next step. - Page 37 Design a sequential function chart Chapter 1 The following shows the action of the low and high alarms for a step. Description AlarmEn is on. To use the low and high alarms turn this bit on. Turn the bit on via the properties dialog box or the tag for the step.
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Page 38: Turn Off A Device At The End Of A Step
Chapter 1 Design a sequential function chart Example Here is an example of the use of the Preset time of a step. The functional specification has these requirements. 1. Cook the ingredients in the tank for 20 seconds. 2. Empty the tank. Example Here is an example of the use of the high alarm of a step. -
Page 39: Choose A Last Scan Option
Design a sequential function chart Chapter 1 Use logic to clear data Let the controller automatically clear data Each option requires you to make these decisions. • Choose a last scan option. • Based on the last scan option, develop your logic so that the last scan returns data to the correct values. -
Page 40: Use The Don't Scan Option
Chapter 1 Design a sequential function chart Characteristic During the last scan of a step, this option does Don’t scan Programmatic reset Automatic reset • P and P0 actions execute according to Execution actions Only P and P0 actions execute. They execute All actions execute according to their logic. -
Page 41: Use The Programmatic Reset Option
Design a sequential function chart Chapter 1 • When the SFC leaves the step, all data keeps its current values. This example uses an action to turn on a conveyor at the start of a step. A different action turns off the conveyor at the end of the step. This action turns on the conveyor. - Page 42 Chapter 1 Design a sequential function chart Example When the step is not on its last scan (conveyor_fwd.LS = 0), this statement turns on conveyor_state. When conveyor_state turns on, the conveyor turns on. On the last scan of the step (conveyor_fwd.LS =1), this statement turns off conveyor_state. When conveyor_state turns off, the conveyor turns off.
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Page 43: Use The Automatic Reset Option
Design a sequential function chart Chapter 1 Use the automatic reset option Automatic reset provides a system-defined cleanup of actions (known as postscan) when they are shut down when any of the following occur. • transition out of the associated step •... - Page 44 Chapter 1 Design a sequential function chart • Logix 5000 Controllers General Instructions Reference Manual, publication 1756-RM003 • Logix 5000 Controllers Process and Drives Instructions Reference Manual, publication 1756-PM006 • Logix 5000 Controllers Motion Instruction Set Reference Manual, publication MOTION-RM002 Here is an example that uses a non-retentive assignment to control a conveyor.
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Page 45: Keep Something On From Step-To-Step
Design a sequential function chart Chapter 1 To provide bumpless control of a device during more than one time or phase Keep something on from (step), do one of the following options. step-to-step How do you want to control the device? Option Example... -
Page 46: Store And Reset An Action
Chapter 1 Design a sequential function chart Example A paint operation completes these actions. 1. Transfers the product into the paint shop. 2. Paints the product using 3 separate paint guns. 3. Cleans the guns. 4. Transfers the product to the paint ovens. During the entire process, the system must control the shop fans. -
Page 47: Use One Large Step
Design a sequential function chart Chapter 1 When the SFC leaves the step that stores the action, the Logix Designer application continues to show the stored action as active. By default, a green border displays around the action. This lets you know that the SFC is executing the logic of that action. -
Page 48: End The Sfc
Chapter 1 Design a sequential function chart Example Use a Large Step This action turns on a fan. • fan.ProgProgReq lets the SFC command the state of the fan. • fan.ProgCommand turns on the fan. This action calls another SFC. The SFC sequences the remaining functions of the step. -
Page 49: Restart (Reset) The Sfc
Design a sequential function chart Chapter 1 If the stop element is at the end of a Then • Sequence The entire SFC stops • Selection branch • Path within a simultaneous branch Only that path stops while the rest of the SFC continues to execute. -
Page 50: Sfc_Stop Structure
Chapter 1 Design a sequential function chart If SFC_a_stop.X = on (SFC_a is at the stop) and SFC_a_reset = on (time to reset the SFC) then for one scan (ons[ 0 ] = on): Reset SFC_a to SFC_a_Step_1 SFC_a_stop.X = 0 SFC_STOP structure Each stop uses a tag to provide information about the stop element. - Page 51 Design a sequential function chart Chapter 1 This figure shows one way to nest an SFC. In this method, the last scan option of the SFC is configured for either Programmatic reset or Don’t Scan. If you configure the SFC for Automatic reset, then step 1 in is unnecessary. Reset the nested SFC.
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Page 52: Pass Parameters
Chapter 1 Design a sequential function chart Pass parameters To pass parameters to or from an SFC, place a Subroutine/Return element in the SFC. By default, an SFC executes a step or group of simultaneous steps and then returns Configure when to return to to the operating system (OS) or the calling routine (JSR). -
Page 53: Pause Or Reset An Sfc
Design a sequential function chart Chapter 1 Two optional instructions are available that give you further control over the Pause or reset an SFC execution of your SFC. If you want to Then use this instruction Pause an SFC Pause SFC (SFP) Reset an SFC to a specific step or stop Reset SFC (SFR) Both instructions are available in the ladder logic and structured text... - Page 54 Chapter 1 Design a sequential function chart The following diagram shows the execution of a simultaneous branch. This… …executes like this Rockwell Automation Publication 1756-PM006I-EN-P - February 2018...
- Page 55 Design a sequential function chart Chapter 1 The following diagram shows the execution of a selection branch. Rockwell Automation Publication 1756-PM006I-EN-P - February 2018...
- Page 56 Chapter 1 Design a sequential function chart This… …executes like this The following diagram shows when parameters enter and exit an SFC Rockwell Automation Publication 1756-PM006I-EN-P - February 2018...
- Page 57 Design a sequential function chart Chapter 1 The following diagram shows options for execution control. This SFC… …executes like this Execute current active steps only Execute until FALSE transition Rockwell Automation Publication 1756-PM006I-EN-P - February 2018...
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Page 59: Program A Sequential Function Chart
Chapter 2 Program a sequential function chart Introduction To add SFC elements, use the SFC toolbar. Add and manually connect 1. On the SFC toolbar, click the button for the item that you want to add. elements 2. Drag the element to the required location on the SFC. 3. -
Page 60: Add And Automatically Connect Elements
Chapter 2 Program a sequential function chart Important: Use caution when copying and pasting components between different versions of the Logix Designer application. The application only supports pasting to the same version or newer. Pasting to a prior version of the application is not supported. When pasting to a prior version, the paste action may succeed but the results may not be as intended. -
Page 61: End A Simultaneous Branch
Program a sequential function chart Chapter 2 2. To add a path to the branch, click the first step of the path that is to the left of where you want to add the new path. Click 3. To wire the simultaneous branch to the preceding transition, click the bottom pin of the transition and then click the horizontal line of the branch... -
Page 62: Create A Selection Branch
Chapter 2 Program a sequential function chart 3. Add the transition that follows the simultaneous branch. 4. To wire the simultaneous branch to the transition, click the top pin of the transition and then click the horizontal line of the branch green dot shows a valid connection point. -
Page 63: End A Selection Branch
Program a sequential function chart Chapter 2 End a selection branch 1. Select the last transition of each path in the branch. To select the transitions, do either of these actions. • Drag the pointer around the transitions that you want to select. •... - Page 64 Chapter 2 Program a sequential function chart 2. Clear the Use default priorities check box and select a transition. Use the Move buttons to raise or lower the priority of the transition. 3. When all the transitions have the correct priority, click OK. When you clear the Use default priorities check box, numbers show the priority of each transition.
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Page 65: Connect A Wire To The Step
Program a sequential function chart Chapter 2 You may have to reposition a wire after you connect it to a step. This example Connect a wire to the step shows how to go to Step_001 from Tran_003. Click the lower pin of the transition that signals the jump. Then click the top pin of the step to which you want to go. -
Page 66: Hide A Wire
Chapter 2 Program a sequential function chart If a wire gets in the way of other parts of your SFC, hide the wire to make the SFC Hide a wire easier to read. To hide a wire, right-click the wire and select Hide Wire. To see the SFC element to which the wire goes, click the grid location on the wire. -
Page 67: Configure Alarms For A Step
Program a sequential function chart Chapter 2 Configure alarms for a step Follow these steps to turn on an alarm if a step executes too long or not long enough. 1. Click the button of the step. 2. In the Step Properties dialog box, on the General tab, select the Alarm Enable check box. -
Page 68: Program A Transition
Chapter 2 Program a sequential function chart Browse for a tag Choose a function Choose an operator Create a tag 4. Enter a numeric expression that defines the time. Use the buttons on the right side of the dialog box to help you complete the expression. 5. -
Page 69: Call A Subroutine When Programming A Transition
Program a sequential function chart Chapter 2 Call a subroutine when 1. In the SFC, right-click the transition and then click Set JSR. programming a transition 2. In the Routine box, select the routine to call. 3. Click OK. Add an action To add an action to a step, right-click the step in which the action executes and then click Add Action. -
Page 70: Calculate A Preset Time At Runtime
Chapter 2 Program a sequential function chart 2. In the Action Properties dialog box, on the General tab, select the qualifier for the action. If you chose a timed qualifier, type the time limit or delay for the action, in milliseconds. -
Page 71: Mark An Action As A Boolean Action
Program a sequential function chart Chapter 2 Browse for a tag Choose a function Choose an operator Create a tag 4. Enter a numeric expression that defines the preset time. Use the buttons on the right side of the dialog box to help you complete the expression. 5. -
Page 72: Call A Subroutine In An Action
Chapter 2 Program a sequential function chart Call a subroutine in an action Use a Jump to Subroutine (JSR) instruction to execute a subroutine when the action is active. 1. In the SFC, right-click the action and then click Set JSR. 2. -
Page 73: Document An Sfc
Program a sequential function chart Chapter 2 following shows dragging Action_002 from after Action_001 to before Action_001. You can document these SFC components. Document an SFC To document this And you want to Do this General information about the SFC ----------------------------------------->... -
Page 74: Add Structured Text Comments
Chapter 2 Program a sequential function chart enable language switching, you can dynamically switch between languages as you use the software. Project documentation that supports multiple translations includes these variables: • Component descriptions in tags, routines, programs, Equipment Phases, Equipment Sequences, user-defined data types, and Add-On Instructions •... -
Page 75: Add A Tag Description
Program a sequential function chart Chapter 2 Add a tag description 1. Click the button of the element. 2. In the element Properties dialog box, click the Tag tab and type the description for the element. 3. Click OK. 4. Drag the description box to the correct location on the SFC. Add a text box A text box lets you add notes that clarify the function of an SFC element (step, transition, or stop. -
Page 76: Show Or Hide Text Boxes Or Tag Descriptions
Chapter 2 Program a sequential function chart 5. Click the pin symbol in the text box and then click the SFC element to which you want to attach the text box. A green dot shows a valid connection point. Show or hide text boxes or tag You have the option of showing or hiding both text boxes and tag descriptions. -
Page 77: Configure The Execution Of The Sfc
Program a sequential function chart Chapter 2 The SFC Execution tab of the controller properties lets you configure these Configure the execution of decisions. the SFC • What to do when a transition is TRUE. • Where to start after a transition to the Run mode or recovery from a power loss. -
Page 78: Edit An Sfc Online
Chapter 2 Program a sequential function chart b. Correct the error according to the description in the in the Output window on the Search Results tab. c. Repeat step 1. 3. To close the Results window, press Alt+1. To check your SFC, you can use either of these options. •... -
Page 79: Force Steps
Chapter 3 Force steps Introduction Use a force to override data that your logic either uses or produces. • Test and debug your logic. • Temporarily keep your process functioning when an input device has failed. Use forces only as a temporary measure. They are not intended to be a permanent part of your application. -
Page 80: Disable Or Remove A Force
Chapter 3 Force steps Important: If you download a project that has forces enabled, the programming software prompts you to enable or disable forces after the download completes. When forces are in effect (enabled), a and TRUE or FALSE appears next to the forced element. -
Page 81: Force Led
Force steps Chapter 3 Forces tab status Means • If the project contains any forces of this type, they are overriding your logic. Enabled • If you add a force of this type, the new force immediately takes effect Disabled Forces of this type are inactive. -
Page 82: Gsv Instruction
Chapter 3 Force steps GSV instruction This example shows how to use a GSV instruction to get the status of forces. Important: The ForceStatus attribute shows only the status of I/O forces. It does not show the status of SFC forces. -
Page 83: When To Use An Sfc Force
Force steps Chapter 3 To override the logic of an SFC, you have these options. When to use an SFC force If you want to Then Override the conditions of a transition each time the SFC Force a transition. reaches the transition Prevent the execution of one or more paths of a Force a simultaneous path. - Page 84 Chapter 3 Force steps For example, to exit this branch, the SFC must be able to complete these actions. • Execute Step_011 at least once • Get past Tran_011 and execute Step_012 at least once • Determine that Tran_012 is TRUE Rockwell Automation Publication 1756-PM006I-EN-P - February 2018...
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Page 85: Force A Simultaneous Path
Force steps Chapter 3 Force a simultaneous path To prevent the execution of a path of a simultaneous branch, force the path FALSE. When the SFC reaches the branch, it executes only the un-forced paths. This path executes. This path does not execute. -
Page 86: Add An Sfc Force
Chapter 3 Force steps To override the logic of an SFC, use an SFC force. Add an SFC force ATTENTION Forcing can cause unexpected machine motion that could injure personnel. Before you use a force, determine how the force will affect your machine or process and keep personnel away from the machine area. -
Page 87: Remove Or Disable Forces
Force steps Chapter 3 Make sure you understand the following before using forces. Remove or disable forces ATTENTION Changes to forces can cause unexpected machine motion that could injure personnel. Before you disable or remove forces, determine how the change will affect your machine or process and keep personnel away from the machine area. - Page 89 Index action 69 enable assign qualifier 67 force 77 boolean 29 EOT instruction 69 call a subroutine 69 expression choose between boolean and non-boolean 28 BOOL expression 34, 66 data type 30 numeric expression 65, 68 non-boolean 28 program 28 reset 46 store 46 force...
- Page 90 Index programmatic reset option 41 reset 38, 49, 50 periodic task restart 49 application for 17 selection branch 25 postscan sequence 25 sequential function chart 38 show or hide documentation 74 program simultaneous branch 26 action 28 step 23, 64 boolean action 29 stop 48 programmatic reset option 41...
- Page 91 Index task define 17 text box sequential function chart 73 show or hide in sequential function chart 74 transition BOOL expression 34 call a subroutine 35, 67 choose program method 34 EOT instruction 69 use of a subroutine 69 verify routine 75 wire sequential function chart 27...
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