Programming Manual Logix5000 Controllers I/O and Tag Data 1756 ControlLogix, 1756 GuardLogix, 1768 Compact GuardLogix, 1769 CompactLogix, 1789 SoftLogix, PowerFlex with DriveLogix
Important user information Read this document and the documents listed in the additional resources section about installation, configuration, and operation of this equipment before you install, configure, operate, or maintain this product. Users are required to familiarize themselves with installation and wiring instructions in addition to requirements of all applicable codes, laws, and standards.
Summary of changes This manual contains new and updated information. The following table contains the changes made to this revision.
Table of Contents Preface Studio 5000 environment...........................................................................................9 Additional resources.................................................................................................. 10 Chapter 1 Communicate with I/O modules Introduction................................................................................................................ 11 Requested packet interval ....................................................
Table of Contents Alias tags....................................................................................................................... 47 Display alias information ................................................................................. 49 Assign an alias...................................................................................................... 49 Indirect addresses .......................................................................................................
Table of Contents Index Constant value tags.................................................................................................... 76 Configure constant tags ........................................................................................... 77 Set up a constant in the New Tag dialog box .............................................. 77 Configure a constant in the Tag Properties dialog box ............................ 78 Designate a constant in the Tag Editor .........................
Preface This manual shows how to access I/O and tag data in Logix5000 controllers. This manual is one of a set of related manuals that show common procedures for programming and operating Logix5000 controllers. For a complete list of common procedures manuals, refer to the Logix5000 Controllers Common Procedures Programming Manual, publication 1756PM001. The term Logix5000 controller refers to any controller that is based on the Logix5000 operating system.
Preface Additional resources These documents contain additional information concerning related Rockwell Automation products. Resource Description Logix5000 Controllers Program Parameters Programming Manual, publication 1756-PM021 Describes how to use program parameters when programming Logix5000 controllers. Product Certifications website (http://ab.rockwellautomation.com) Provides declarations of conformity, certificates, and other certification details.
Chapter 1 Communicate with I/O modules Introduction To communicate with an I/O module in your system, you add the module to the I/O Configuration folder in the Controller Organizer. When you add the module, you also define a specific configuration for the module.
Chapter 1 Communicate with I/O modules Requested packet interval The Logix5000 controller uses connections to transmit I/O data. Term Definition Connection A communication link between two devices, such as between a controller and an I/O module, PanelView terminal, or another controller. Connections are allocations of resources that provide more reliable communications between devices than unconnected messages. The number of connections that a single controller can have is limited.
Communicate with I/O modules Chapter 1 formats. Each format uses a different data structure. The communication format that you choose also determines: • Direct or rack-optimized connection on page 13. • Ownership on page 14. Direct or rack-optimized connection The Logix5000 controller uses connections to transmit I/O data. These connections can be direct connections or rack-optimized connections.
Chapter 1 Communicate with I/O modules Ownership In a Logix5000 system, modules multicast data. This means that multiple devices can receive the same data at the same time from a single device. When you choose a communication format, you have to choose whether to establish an owner or listen-only relationship with the module. Term Definition Owner controller The controller that creates the primary configuration and communication connection to a module.
Communicate with I/O modules If module is And another controller And you want to Owns the module ------------------------------------> Chapter 1 Then use this type of connection Listen-only There is a noted difference in controlling input modules versus controlling output modules. The following table lists the differences. Controlling This Ownership Description Input modules Owner An input module is configured by a controller that establishes a connection as an owner.
Chapter 1 Communicate with I/O modules Important: Changing Electronic Keying parameters online interrupts connections to the device and any devices that are connected through the device. Connections from other controllers can also be broken. If an I/O connection to a device is interrupted, the result can be a loss of data. Electronic Keying is based on a set of attributes unique to each product revision.
Communicate with I/O modules • Same catalog number • Same or higher Major Revision • Minor Revision as follows: Chapter 1 • If the Major Revision is the same, the Minor Revision must be the same or higher. • If the Major Revision is higher, the Minor Revision can be any number. Disable Keying Disable Keying indicates the keying attributes are not considered when attempting to communicate with a device.
Chapter 1 Communicate with I/O modules Address I/O data I/O information is presented as a set of tags. • Each tag uses a structure of data. The structure depends on the specific features of the I/O module. • The name of the tag is based on the location of the I/O module in the system. • When you add a module to the I/O Configuration folder, the software automatically creates controller-scoped tags for the module in Controller Tags.
Communicate with I/O modules Buffer I/O Chapter 1 Where Is SubMember Specific data related to a Member. Bit Specific point on a digital I/O module; depends on the size of the I/O module (0–31 for a 32-point module) Buffering is a technique in which logic does not directly reference or manipulate the tags of real I/O devices. Instead, the logic uses a copy of the I/O data. Buffer I/O in the following situations: • To prevent an input or output value from changing during the execution of a program.
Chapter 1 Communicate with I/O modules The drill routine executes the logic for the drill machine. The map_outputs routine copies the values of output tags in the drill routine to their corresponding output devices. The following example uses the CPS instruction to copy an array of data that represent the input devices of a DeviceNet network. Example: Buffer I/O using CPS instruction Local:0:I.Data stores the input data for the DeviceNet network that is connected to the 1756-DNB module in slot 0.
Chapter 2 Organize tags Introduction With a Logix5000 controller, you use a tag (alphanumeric name) to address data (variables). Term Definition Tag A text-based name for an area of the controller’s memory where data is stored. • Tags are the basic mechanism for allocating memory, referencing data from logic, and monitoring data. • The minimum memory allocation for a tag is four bytes.
Chapter 2 Organize tags Example: Tags Item Description Analog I/O Device Integer Value Storage Bit Counter Timer Digital I/O Device Tag type The tag type defines how the tag operates within your project.
Organize tags Chapter 2 Data type Term Definition Data type The data type defines the type of data that a tag stores, such as a bit, integer, floating-point value, string, and so forth. Structure A data type that is a combination of other data types. • A structure is formatted to create a unique data type that matches a specific need. • Within a structure, each individual data type is called a member. • Like tags, members have a name and data type.
Chapter 2 Organize tags The minimum memory allocation for a tag is four bytes. When you create a tag that stores data that requires less than four bytes, the controller allocates four bytes, but the data only fills the part it needs. Data Type Bits 31 16 15 8 7 1 0 BOOL Not used 0 or 1 SINT Not used -128…+127 INT Not used -32,768…+32,767 DINT -2,147,483,648…+2,147,483,647 38 -3.40282347E …-1.17549435E-38 (negative values) 0 -1.17549435E-38-…3.
Organize tags Tag scope Chapter 2 When you create a tag, you define it as either a controller tag (global data) or a local tag for a specific program (local data). A Logix5000 controller lets you divide your application into multiple programs, each with its own data. There is no need to manage conflicting local tag names between programs. This makes it easier to reuse both code and tag names in multiple programs. Data at the program scope is isolated from other programs.
Chapter 2 Organize tags • Routines cannot access data that is at the local scope (local tag) of another program. • You can reuse the tag name of a local tag in multiple programs. • For example, both Program_A and Program_B can have a local tag named Tag_4. • You can also use program parameters to share data between programs as an alternative to controller-scope tags. See Program parameter scope on page 27. Avoid using the same name for both a controller tag and a local tag.
Organize tags Program parameter scope Chapter 2 Program parameters are similar to tags: • You create program parameters at the program level, and use them to manage data. • Program parameters behave like controller-scope tags in that they can pass data between programs. Among other benefits, program parameters allow you to clearly define the inputs to the routines in a program, and the outputs from those routines.
Chapter 2 Organize tags Guideline Details Use arrays to quickly create a group of similar tags An array creates multiple instances of a data type under a common tag name. • Arrays let you organize a block of tags that use the same data type and perform a similar function. • You organize the data in one, two, or three dimensions to match what the data represents. For example, use a two-dimensional array to organize the data for a tank farm. Each element of the array represents a single tank.
Organize tags Guideline Chapter 2 Details These tags are easier to read Than these tags Tank_1 TANK_1 Tank1 TANK1 tank_1 tank1 Consider the alphabetical order of tags Logix Designer application displays tags of the same scope in alphabetical order. To make it easier to monitor related tags, use similar starting characters for tags that you want to keep together. Starting each tag for a tank with ‘Tank’ keeps the tags Otherwise, the tags may end up separated together. from each other.
Chapter 2 Organize tags Guideline Details Using extended properties in logic (continued) In the Function Block Editor, you can access extended properties in logic by wiring an Input Reference to a block’s input pins. In the Structured Text Editor, you can access limit extended properties in logic on the right hand side of an assignment operation or in a comparison statement. You can also access limit extended properties in logic when you embed structured text in the Sequential Function Chart Editor.
Organize tags Guideline Details Using extended properties in logic (continued) • Array Tags are constrained Chapter 2 A constraint on array tags applies if the array tag uses indirect addressing to access limit extended properties. If an array tag is using indirect addressing to access limit extended properties in logic, the following conditions apply.
Chapter 2 Organize tags 1. In the Controller Organizer, right-click Controller Tags and then click Edit Tags. p 2. In the Tag Editor, from the Scope box, choose a scope for the tag using the following table as a guide.
Organize tags Chapter 2 2. If the Properties pane is not visible, click Properties. 3. In the Properties pane, click Extended Properties, and select the properties that you want to add. The entries in the list depend on the tag’s data type. You can select more than one property.
Chapter 2 Organize tags Create an array Data Type Range DINT -2,147,483,648...2,147,483,647 INT -32,768...32,767 LINT 0...32535129599999999 SINT -128...127 REAL -3.402823E38 to -1.1754944E-38 (negative values) and 0 and 1.1754944E-38 to 3.402823E38 (positive values) Logix5000 controllers also let you use arrays to organize data. Term Definition Array A tag that contains a block of multiple pieces of data. • An array is similar to a file.
Organize tags Item Chapter 2 Description To expand a structure and display its members, click the + sign. To collapse a structure and hide its members, click the – sign. Six elements of timer_presets. This two-dimensional array contains nine elements (three by three array). This one-dimensional array contains six elements of the DINT data type. In this example, a single timer instruction times the duration of several steps. Each step requires a different preset value.
Chapter 2 Example: Organize tags Two-dimension array A drill machine can drill one through five holes in a book. The machine requires a value for the position of each hole from the leading edge of the book. To organize the values into configurations, use a two-dimension array. The first subscript indicates the hole that the value corresponds and the second subscript indicatates how many holes are to be drilled one through five). In the Tag Editor, the elements are in the order in the following graphic.
Organize tags Chapter 2 Configure an array To create an array, you create a tag and assign dimensions to the data type. 1. In the Controller Organizer, right-click Controller Tags and then click Edit Tags. 2. In the Tag Editor, from the Scope box, choose a scope for the tag using the following table as a guide.
Chapter 2 Organize tags User-defined data types Example: User-defined data types (structures) let you organize your data to match your machine or process. User-defined data type that stores a recipe. In a system of several tanks, each tank can run a variety of recipes. Because the recipe requires a mix of data types (REAL, DINT, BOOL, so forth), a user-defined data type is used. An array that is based on this data type looks like this example.
Organize tags Example: Chapter 2 User-defined data type that stores the data that is required to run a machine. Because several drill stations require the following mix of data, use a user-defined data type. An array that is based on this data type would look like this example.
Chapter 2 Organize tags Guidelines for user-defined data types When you create a user-defined data type, use the following guidelines. • If you include members that represent I/O devices, you must use logic to copy the data between the members in the structure and the corresponding I/O tags. Refer to Address I/O data on page 18. • If you include an array as a member, limit the array to a single dimension. Multi-dimension arrays are not permitted in a user-defined data type.
Organize tags Chapter 2 4. Click Add Member to add a new data type member. 5. In the member Name box, type a name for the data type member. 6. In the member Data Type box, enter the data type for the member. You can also click the Browse button and then in the Select Data Type dialog box, choose a data type for the tag. Limit any arrays to a single dimension. See Configure an array on page 37. 7. (optional) In the member Description box, type a description for the data type member. 8.
Chapter 2 Organize tags 1. In the Properties pane, click the box next to External Access, and select an attribute. 2. To display the value of the member in a different style (radix), click the box next to Style, and select the style. 9. Click Apply. 10. Repeat this procedure to add as many members as needed. Add extended properties to a user-defined data type You can add Min, Max, Engineering Units, State 0, and State 1 properties to a data type or its member.
Organize tags Chapter 2 5. Select one or more properties that you want to add. The properties in the list depend on the selected data type or member’s data type. For data type You can add the following extended property Array and string Engineering Unit Bool State 0 State 1 Engineering Unit DINT, INT, LINT, SINT, and REAL Min Max Engineering Units Important: The list is unavailable for other types of data type members.
Chapter 2 Organize tags Describe a user-defined data type In version 13 or later, the Logix Designer application lets you automatically build descriptions out of the descriptions in your user-defined data types. This greatly reduces the amount of time you have to spend documenting your project. As you organize your user-defined data types, keep in mind the following features of the Logix Designer application.
Organize tags Chapter 2 Paste pass-through description—Use the data type and array description as a basis for more specific descriptions. In this example, Tank became West Tank. The Logix Designer application uses different colors for descriptions. If the Color of the Description Is It is a Gray Pass-through description Black Manually entered description Activate pass-through and append descriptions Follow these steps to use pass-through descriptions and append to base tag descriptions. 1.
Chapter 2 Organize tags 3. Check Show Pass-Through Descriptions and Append to Base Tag Descriptions. 4. Click OK. Paste a pass-through description Choose this command to paste a pass-through value of an item into the Description, Engineering Unit, State 0, or State 1 field of another item. Follow these steps to use a pass-through description as the starting point for a more specific description. 1. In the Controller Tags Editor, right-click the Description box, and then click Paste Pass-Through. 2.
Organize tags Address tag data Chapter 2 A tag name follows this format. Where Is Name Name that identifies this specific tag. Element Subscript or subscripts that point to a specific element within an array. • Use the element identifier only if the tag or member is an array. • Use one subscript for each dimension of the array. For example: [5], [2,8], [3,2,7]. To indirectly (dynamically) reference an element, use a tag or numeric expression that provides the element number.
Chapter 2 Organize tags The tags window displays alias information. Item Description drill_1_depth_limit is an alias for Local:2:I.Data.3 (a digital input point). When the input turns on, the alias tag also turns on. drill_1_on is an alias for Local:0:O.Data.2 (a digital output point). When the alias tag turns on, the output tag also turns on. north_tank is an alias for tanks[0,1]. The (C) indicates that the tag is at the controller scope.
Organize tags Chapter 2 The following logic was initially programmed by using descriptive tag names, such as stop and conveyor_on. Later, the tags were converted to aliases for the corresponding I/O devices. • stop is an alias for Local:2:I.Data.1 (the stop button on the operator panel) • conveyor_on is an alias for Local:0:O.Data.0 The starter contactor for the conveyor motor) Display alias information Follow these steps to show (in your logic) the tag to which an alias points. 1.
Chapter 2 Organize tags 3. In the cell, click . 4. Select the tag that the alias represents. To Do This Select a tag Double-click the tag name. Select a bit number 1. Click the tag name. 2. To the right of the tag name, click +. 3. Click the required bit. 5. Click another cell. Indirect addresses If you want an instruction to access different elements in an array, use a tag in the subscript of the array (an indirect address).
Organize tags Example: Chapter 2 Step through an array. The timer_presets array stores a series of preset values for the timer in the next rung. The north_tank.step tag points to which element of the array to use. For example, when north_tank.step equals 0, the instruction loads timer_presets[0] into the timer (60,000 ms). When north_tank.step_time is done, the rung increments north_tank.step to the next number and that element of the timer_presets array loads into the timer. When north_tank.
Chapter 2 Organize tags You can use these operators to specify the subscript of an array. Format your expressions as shown in the following table. If the operator requires Use this format Example One value (tag or expression) operator(value) ABS(tag_a) Two values (tags, constants, or expressions) value_a operator value_b • tag_b + 5 • tag_c AND tag_d • (tag_e ** 2) MOD (tag_f / tag_g) Array subscript out of range Every instruction generates a major fault if the array subscript is out of range.
Organize tags Chapter 2 For more information on handling major faults, refer to the Logix5000 Controllers Major and Minor Faults Programming Manual, publication 1756PM014. Tag documentation The table outlines the four types of tags that you can create and the descriptions that you can document for each one. Important: The Logix Designer application automatically assigns what are called pass-through descriptions of the tags you create. You may or may not want to use these descriptions.
Chapter 2 Organize tags You can store project documentation for multiple languages in a single project file rather than in language-specific project files. You define all the localized languages that the project supports and set the current, default, and optional custom localized language. The application uses the default language if the current language's content is blank for a particular component of the project.
Chapter 3 Force I/O Introduction Use a force to override data that your logic either uses or produces. For example, use forces to: • Test and debug your logic. • Check wiring to an output device. • 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. Precautions When you use forces, take these precautions.
Chapter 3 Force I/O Disable or remove a force To stop the effect of a force and let your project execute as programmed, disable or remove the force. • You can disable or remove I/O and SFC forces at the same time or separately. • Removing a force on an alias tag also removes the force on the base tag. ATTENTION: Changes to forces can cause unexpected machine motion that could injure personnel.
Force I/O Chapter 3 Force status indicator If your controller has a FORCE Status Indicator, use it to determine the status of any I/O forces. Important: The FORCE Status Indicator shows only the status of I/O forces. It does not s(how that status of SFC forces. FORCE Status Indicator Then Off • No tags contain force values. • I/O forces are inactive (disabled). Flashing • At least one tag contains a force value. • I/O forces are inactive (disabled). Solid • I/O forces are active (enabled).
Chapter 3 Force I/O When to use I/O force Use an I/O force to override: • An input value from another controller (that is, a consumed tag). • An input value from an input device. • Your logic and specify an output value for another controller (that is, a produced tag). • Your logic and specify the state of an output device. Important: • Forcing increases logic execution time. The more values you force, the longer it takes to execute the logic.
Force I/O Chapter 3 Force an input value Forcing an input or consumed tag: • Overrides the value regardless of the value of the physical device or produced tag. • Does not affect the value received by other controllers monitoring that input or produced tag. Force an output value Forcing an output or produced tag overrides the logic for the physical device or other controller. Other controllers monitoring that output module in a listen-only capacity also see the forced value.
Chapter 3 Force I/O To force a Do this BOOL value Right-click tag and then click Force On or Force Off. Non-BOOL value In the Force Mask column for the tag, type the value that you want to force the tag. Press Enter. 5. Verify that I/O forces are enabled (see step 1). If they are not, on the Menu bar, click Logic > I/O Forcing > Enable All I/O Forces, and then click Yes to confirm. Remove or disable forces ATTENTION: Changes to forces can cause unexpected machine motion that could injure personnel.
Force I/O Chapter 3 4. Right-click a tag or element that has the force and then click Remove Force. Disable all I/O forces To disable, on the Menu bar, click Logic > I/O Forcing > Disable All I/O Forces. Click Yes to confirm. Remove all I/O forces To remove, on the Menu bar, click Logic > I/O Forcing > Remove All I/O Forces. Click Yes to confirm.
Chapter 4 Data access control Introduction In version 18 or later of the Logix Designer application, there are two tag attributes that allow you to control access to tag data. These attributes are: • External Access • Constant The External Access attribute controls how external applications, such as HMIs, can access tags. It has possible values of Read/Write, Read Only, and None. See Configure external access on page 64. The Constant attribute value determines if controller logic can change a tag.
Chapter 4 Data access control Configure external access • FactoryTalk Historian software. • Other third-party software. You configure external access from a menu when you create a new tag or data type. You can also change that value just like other tag attributes. You can make these changes throughout the application. For example, you can make the changes in the User-defined Data Type Editor, New Tag dialog box, and the Tag Properties dialog box.
Data access control Chapter 4 Important: For alias type tags, the External Access list is unavailable. You are not allowed to change the external access of an alias tag. However, the External Access list updates its value to be the same as the external access of the base target. See Find a base tag with Go To on page 69 for procedures to locate the base tag for an alias. See External access availability on page 70 for additional tag considerations.
Chapter 4 Data access control 3. In the External Access list, choose an external access option. 4. Click OK.
Data access control Chapter 4 As shown in the following example, the External Access list is unavailable for an alias tag. There may be many alias tags in a program. To locate an associated base tag to assign an external access, use the Go To feature. See Find a base tag with Go To on page 69 for details. For other tag considerations, see External access availability on page 70. The Connection button (next to the Type box) becomes active when you select either a produced or consumed tag type.
Chapter 4 Data access control 1. In the Tag Editor, right-click a tag and then click Edit (tag name) Properties. 2. In the Tag Properties dialog box, in the Type list, choose a tag type. 3. In the External Access list, choose an external access option. The External Access list is unavailable for an alias tag. If a tag is a module tag, the only external access option is Read/Write. See External access availability on page 70 for other considerations. 4. Click OK.
Data access control Chapter 4 View and select external access status on the Tag Editor You can view the external access status of a tag in the Tag Editor. The External Access column displays the tag as Read/Write, Read Only, or None. Follow these steps to select multiple rows and set the external access at one time on the Tag Editor. 1. To select multiple individual rows, hold down the Ctrl key and click the desired rows. 2.
Chapter 4 Data access control 1. In the Tag Editor select the alias tag, and then on the Logix Designer application Menu bar, click Search > Go To. You can also right-click the alias tag and then click Go To. 2. In the Go To dialog box, in the Go to what list, choose Base Tag. The Go To box displays the target of the alias tag. If there is an alias chain, all alias tags in this chain appear in the Go to list. 3. In the Go to list, choose a target of the alias tag. 4. Click Go To.
Data access control Dialog Box/Window Considerations New Tag The External Access list is unavailable if: • The tag is an alias tag. Chapter 4 • The controller is user locked online. Changing the tag type from base to alias also makes the External Access list unavailable. If you select a target for an alias tag in the Alias For list, the External Access list remains unavailable, but the external access value for the target tag appears in the External Access list.
Chapter 4 Data access control 1. In the Controller Organizer, right-click the data type and then click Properties. 2. In the Data Type editor, click the Properties tab to display the Properties pane. Click the pushpin icon to keep the Properties pane open. 3. In the External Access list, choose the external access option. Three external access rules apply for members of User-defined data types. 72 • You can only set external access for the top members of that User-defined data type.
Data access control • Chapter 4 If the member’s data type is User-defined and the child-member has a different external access level from its parent, the more restrictive external access level applies to the child-members. The following table describes the conditions in which the External Access column is unavailable. To pick Considerations Change existing data type The External Access column is unavailable if: • You do not have permission to change the external access settings(2).
Chapter 4 Data access control You can configure the external access of an Add-On Instruction’s parameters and local tags in the Add-On Instruction Definition dialog box and on the Add-On Instruction Parameters and Local Tags dialog boxes. For alias parameters, the external access type is equal to the type configured for the base local tag.
Data access control Dialog Box/Window Considerations Add-On Instruction Definition - Parameters Tab The External Access column is unavailable for: • InOut parameters, for which there are no external access options. Chapter 4 • EnableIn and EnableOut parameters, which default to Read Only. The External Access column is unavailable when: • You do not have permission to change the external access settings.(3) • The controller is online. • The tag is an alias tag.
Chapter 4 Data access control Tag mapping considerations Only tags with external access settings of Read/Write or Read Only can be mapped to a PLC-2 controller and PLC-5/SLC controllers. 1. In the PLC-2 or PLC-5/SLC Mapping dialog box, type a file number. 2. Choose a tag from the Name list. Only eligible tags that are set to either Read/Write or Read Only appear in the menu. If you manually type the name of a tag whose external access is set to None, an error message appears. 3. Click OK.
Data access control Chapter 4 Use FactoryTalk security to control who is permitted to change values of constants and who can change the constant attribute of a tag. To change the value of a constant, you must have the Tag: Modify Constant Tag Values permission. To change the constant attribute of a tag, you must have the Tag: Modify Constant Property permission. For details on setting permissions, see the FactoryTalk Security System Configuration Guide, publication FTSEC-QS001.
Chapter 4 Data access control 2. In the New Tag dialog box, in the Type list, choose a tag type. 3. Select the Constant check box. 4. Click Create. See Constant check box availability on page 80 for considerations. Configure a constant in the Tag Properties dialog box Follow these steps to designate a tag as a constant on the Tag Properties dialog box. 1. On the Tag Editor, right-click a tag and then click Edit (tag name) Properties.
Data access control Chapter 4 2. In the Parameter/Local Tag Properties dialog box, select the Constant check box. 3. Click OK. See Constant check box availability on page 80 for considerations. Designate a constant in the Tag Editor The Constant column in the Tag Editor lets you designate tags that cannot be modified in the Logix Designer program. The Constant property applies to an entire tag; all members of the tag take on the same setting.
Chapter 4 Data access control 1. In the Controller Organizer, right-click Controller Tags and then click Edit Tags. In the Tag Editor, select the check box in the Constant column. Important: In the Tag Monitor, the Constant setting for the tag appears in the same Constant column as shown in the previous illustration. However, you cannot change the value. The Constant column also is available on the Equipment Phase Tag Editor and Equipment Phase Tag Monitor.
Data access control Chapter 4 Dialog Box/Window Considerations Tag Monitor You can change the value of a constant tag in the Tag Monitor if you have both standard Tag: Modify Values permission and Tag: Modify Constant Tag Values permission. You cannot change a constant value in any of the language editors or any other tag browser. The icon in the Value column indicates that you are changing a constant value tag’s value.
Index A access external 63 add extended properties to a tag 32 add extended properties to user-defined data type 42 Add-On Instruction constant value considerations 81 external access variables 73 address assign indirect 50 tag 47 tag I/O module 18 alias create 49 show/hide 49 use of 47 array calculate subscript 51 create 37 index through 50 organize 27 overview 34 availability constant value 80 external access 70, 71 B base tag, find, 69 buffer I/O data 19 C communication format 12 ownership 14 I/O modul
Index I tag description 44 user-defined data type 44 E electronic keying electronic keying 17 enable force 55 exact match electronic keying 16 keying 15 expression calculate array subscript 51 extended properties 23 adding extended properties to a tag 32 user-defined data type 42 external access 63 Add-On Instruction 73 availability 70, 71 configure 64 configure tag dialog 65 configure tag properties 67 options 64 user-defined data type considerations 71 view tag editor 69 F file See array 34 force disa
Index O ownership I/O module 14 P pass-through description 44 program parameters 12, 19, 25, 27 tags 25 program parameters 12, 19, 25, 27 project documentation 53 R rack-optimized connection 12 remove force 56 requested packet interval (RPI) 12 S scope guidelines 27 parameters 12, 19, 25, 27 tag 25 sequential function chart force element 55 structure create 40 organize 27 overview 23 user-defined 40 structured text force a value 55 symbol See alias.
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