Overview
On the software platform, Tags represent real-time variables and their associated historical records. These Tags typically link to physical devices (like PLC registers), databases, or calculated values, providing a structured way to model and handle process information. Tags have specific data types, support arrays, and can include optional parameters. Tags are used for applications involving process monitoring, control, and analysis, facilitating data collection from several data sources, and enabling informed decision-making.
On this page:
Understanding Tags
This section provides comprehensive guidance on managing tags by covering essential topics such as creating and editing tags, configuring tag properties, formatting tag values, and importing tag definitions.
Creating
You can create tag in two different places on the Unified Namespace. There are different paths to creating new tags:
Using the New Tag On the top of the page, click on
icon.In Unified Namespace / Tags, click on the
icon to create new tags.In Unified Namespace / Asset Tree, right click the folder where you'd like to add a tag or use the 'New Tag' icon
However, specifically, on the Tags interface:
You can do this by pasting from a external table. The table only must has the column Name.
You can create a tag by inserting manually a new entry on the data grid, only filling the Name column giving a unique name for the tag.
You can do this by clicking in the New Tag on the Toolbar to open the Create New Tag dialog.
You can do this by clicking in the New item on the data grid controls to open the Create New Tag dialog.
The Create New Tag dialog allows creating a new Tag and configure additional aspects related to Devices, Alarm and Historian definitions.
When you click selecting a Tag on the data grid. It enables the Map to a Symbol button. It allows link a tag to a symbol.
Create New Tag dialog
Editing
The following dialog will be presented.
The only 2 essential fields to field in are the 'NAME' and the 'TYPE' of the Tag.
To edit the properties of existing local tags:
- At the top toolbar, select the Tag Properties button.
- Go to Unified Namespace / Tags, select the tag you wish to modify and click the Edit icon.
Configuring Tags
Properties Reference
The Properties References section presents a reference that describes and explains each property of Tags on Unified Namespace. The table lists all properties available for the Tags. However, not all properties described in the documentation are displayed in the data grids by default. Right-click column headers to see which property columns are currently displaying. The displayed properties appear with a check mark. By default, the data grid displays the following properties for Tags: Path, Type, Name, Enumeration, Array, Parameters, Domain, and Description.
Field | Description |
|---|---|
ID | Identifies the tag uniquely within the software platform. |
Path | Allows users to associate tags with specific assets. Select the asset you want to associate with the tag. Specifies the tag's location within the Solution hierarchy. |
VersionID | Tracks the version of the tag configuration. |
Name | Defines the name of the tag. |
Type | Determines the data type of the tag (e.g., integer, string, float). The supported Types available are: Digital: Represents binary data, typically used for true/false or on/off states. Integer: Holds whole numbers without decimal points, suitable for counting or indexing. Long: Stores larger whole numbers than Integer, useful for extended range calculations. Double: Represents floating-point numbers with double precision, allowing for very large or very small values. Decimal: Used for high-precision floating-point numbers, ideal for financial calculations where precision is critical. Text: Contains strings of characters, used for textual data. DateTime: Combines date and time into a single value, useful for timestamps and scheduling. TimeSpan: Represents a duration of time, often used for intervals. Image: Stores binary data for images, enabling the inclusion of visual data. Timer: Represents a timer object, useful for time-based operations. Guid: Contains globally unique identifiers, used for uniquely identifying objects. DataTable: Stores structured data in table format, allowing for complex data organization. JSON: Holds JSON (JavaScript Object Notation) formatted data, enabling structured data exchange. Reference: Represents a reference to another object or entity, used for linking related data. |
Array | Defines whether the tag is an array. When this field is blank, the tag is not an array. When the field contains an integer value of N, an array is created from position 0 to N. For example, if the field contains the value 5, the array is created from Tag[0] to Tag[5], resulting in 6 elements. This method accommodates two programming styles: one that counts elements from 0 to less than 5, and one that counts from 1 to 5. |
Enumeration | Defines the set of possible values, messages, and colors for the tag. Connect these types with a Tag or use them directly in script expressions. |
StartValue | Sets the initial value of the tag upon startup. |
Parameters | Configures additional parameters based on the tag type associated with the tag. Double-click the parameters field to see a dropdown menu with applicable options. Deadband: Limits new values saved to the tag. Defines the necessary difference between old and new values. Set Deadband as a percentage or decimal (e.g., 10.5, 10%, 300%, 17.8%). Example 1: With Deadband set to 5 and initial value at 0, the next saved input must be ≥5 or ≤-5. Example 2: With the current tag value at 100 and Deadband set to 10%, the next saved input must be ≥110 or ≤90. EnumerationSet: Use dictionaries to translate tag values into text (e.g., display "on" for 1 and "off" for 0). Configure the display component to use tags with TextOutput set to Tagname, Tagname.Value, Tagname.ValueAsString, or Tagname.DisplayValue to show the numeric or enumeration string value. |
Min | Sets the minimum allowable value for the tag. |
Max | Sets the maximum allowable value for the tag. |
ScaleMin | Defines the minimum scale value for the tag. |
ScaleMax | Defines the maximum scale value for the tag. |
Retentive | Specifies whether the tag retains its value between application restarts. Allows to save the value of the tag and its internal properties to the database whenever the value changes. By enabling this, the software platform retains the tag's value when the application shuts down and makes it available when the application starts again. The option available are: None: Does not retain the value or properties. ValueOnly: Retains only the value. Properties: Retains all properties, including the value. PropertiesOnly: Retains all properties, except the value. Retentive Tag values store in the database defined at Datasets / DBs / Retentive. You can customize this to use any database. Domain Server Tags: Retentive can apply to these tags, allowing cold-start from the Solution without losing operator-input values or other tags that retain their last value between shutdown and startup. Domain Client Tags: Retentive can apply to these tags, creating concepts such as User Configuration settings. These settings store and locate according to the client or user connection. |
Domain | Associates the tag with a specific domain. It defines if the tag value has Server (global) or Client (instance) scope. Server (Default): The software platform synchronizes the tag value across all operator stations accessing the project, making it unique and consistent throughout. Use Server tags for devices communications and historian purposes. This ensures that all tags used by devices and the historian are of the Server type, providing a unified and synchronized data management approach. Client: The software platform keeps the tag value local to each client display instance accessing the project. This means that the tag's value is unique to each user interface session. |
Visibility | Defines the visibility of your tag to external connections. It controls how external systems can access and interact with the tag, ensuring proper data exposure and security. The available options are: Private: The tag remains visible only to the local project and its redundant pair. Use this setting to restrict the tag's visibility, ensuring that only the local project and its backup can access the tag. Protected: The tag becomes visible to external connections for read-only operations. This setting allows external systems to read the tag's value without permitting any modifications, ensuring that the data remains unchanged. Public: The tag becomes visible to external connections for both reading and writing. This setting provides full access to the tag, allowing external systems to both read and modify the tag's value. |
Disable | Indicates whether the tag is disabled. |
DisplayText | Specifies the text to display for the tag. |
Units | Defines the units of measurement for the tag. More information at Units Conversion. |
Format | Specifies the format of the tag's value. It defines the display format of tag values. For example, N2 specifies a number with two decimal places, like 3.14, while N1 specifies a number with one decimal place, like 2.1. These formats follow the specifications provided in Microsoft .NET. Common format strings include: N0: Number with no decimal places. E.g., N0 shows no decimal places, 123. Nn: Number with n decimal places (replace n with any integer). E.g., N2 shows two decimal places, 123.45. X: Hexadecimal (supported only for integral types). E.g., X shows a hexadecimal number, 7B. C: Currency. E.g., C shows a currency format, $123.00. R: A string that can round-trip to an identical number. E.g., R shows a round-trip number, 123.45. P: Number multiplied by 100 and displayed with a percent symbol. E.g., P shows a percentage, 12345.00%. G: The more compact of either fixed-point or scientific notation. E.g., G shows a compact format, 123.45. F: Integral and decimal digits with optional negative sign. E.g., F shows fixed-point, 123.45. E: Exponential notation. E.g., E shows exponential format, 1.234500E+02. D: Integer digits with optional negative sign. E.g., D shows integer format, 123. |
DefaultSymbol | Sets the default symbol for the tag. |
ActiveColor | Specifies the color to use when the tag is active. |
InactiveColor | Specifies the color to use when the tag is inactive. |
ReadSecurity | Defines the security level required to read the tag. |
WriteSecurity | Defines the security level required to write to the tag. |
Level | Specifies the level of the tag within the system. |
Category | Categorizes the tag within the system. |
LockState | Indicates whether the tag is locked. |
DevicePoint | Shows the read-only property, which communication point address relates to the tag (if any). |
LockOwner | Identifies the owner of the lock on the tag. |
DateCreated | Records the date the tag was created. |
DateModified | Records the date the tag was last modified. |
Description | Provides a string message with additional information about the Tag. The string length max is 1024 characters. |
Tag Types
All tags have a specific type for its value, such an integer, text or DateTime. The many pre-defined Tag Types are the Built-in tag types. In addition, the tag type can be an UDT (User Defined Type) or Tag Template .
Tags have also pre-defined properties, such as Description and Array size. Different tag types may have specific properties, but most properties are available to all Tags.
When creating the Tag, some of those properties are defined in the configuration — such as the Description —, some of the properties are only accessible when the application is running — like Value, Quality and Timestamp. The complete set of Tag properties when running the project is referred as the Runtime Tag Properties.
Built-in Tag Types
The built-in tag types are based directly as extensions of the .NET datatypes. The tag types are summarized in the following table:
Built-in Tag Types | ||
|---|---|---|
Tag Type | .Net Type | Description and Value Range |
Digital | System.Int32 | Binary value, 0 or 1. |
Integer | System.Int32 | Integer values, range -2,147,483,648 through 2,147,483,647 |
Long | System.Int64 | Long integer values, range -2,147,483,648 through 2,147,483,647 |
Double | System.Double | Floating point value. ranging -1.79769313486231570E+308 through -4.94065645841246544E-324 for negative values; 4.94065645841246544E-324 through 1.79769313486231570E+308 for positive values |
Decimal | System.Decimal | Extended precision floating point., ranging 0 through +/-79,228,162,514,264,337,593,543,950,335 with no decimal point; 0 through +/-7.9228162514264337593543950335 with 28 places to the right of the decimal; smallest nonzero number is +/-0.000 The Decimal type allows calculation with higher precision than the Double type. However, math operations using Decimal can be 40 times slower than using Double. So the Decimal type should only be used when Double precision is not enough. |
Text | System.String | Text strings composed of Unicode character. Maximum length of the sting is the integer range. |
Timer | System.Int32 | Timer is a built-in integer type that can be used to generate precise timing signals and wave pattenrs. Timers have the following models:
For SquareWave, Pulse, and Comparer, the tag toggles between 0 and the StartValue (instead of 0 and 1) if you set the tag StartValue. |
DateTime | System.DateTimeOffset | From 12:00:00 midnight, January 1, 0001 to 11:59:59 P.M., December 31, 9999 |
TimeSpan | TimeSpan | Data Interval in Days, Hours, Minutes, Seconds and Milliseconds, where each of those properties can hold a Double value |
Guid | Guid | Standard Microsoft Globally Unique Identifier (GUID) |
DataTable | System.Data.DataTable | Holds an in-memory DataTable |
Image | System.Byte[] | Can hold an Image file or any binary content. The Long value is the maximum size of the content. |
Reference Type
Reference tags allow dynamic addressing of variables.
The way you use Reference tags in the project is similar to how you use references in .NET programming, as they both have a defined type. The target type for the Reference is defined in the Parameters columns.
Typed references bring advantages in both the engineering stage and in runtime. In the engineering stage, it allows IntelliSense to directly browse the template members if a reference is pointing to a template. In runtime, it allows string data validation.
All Reference tags have an additional runtime attribute: the Link property, which specifies which tag that the reference will be linked to during execution.
Essentially, the Link property is a string property that needs to receive the target tag name before using the reference tag. You can assign a string directly or by using a string expression. The best way to set the link property is to use the method GetName(), which will create the string based on the current tag name. This way, you can rename the tag without having to search the strings. This also shows the tag names linked on the cross-reference utility.
Examples:
@Tag.Reference1.Link = @Tag.TagName.GetName();
@Tag.Reference1.Link = @Tag.TagName.GetName();
@Tag.Reference1.Link = "Tag.TagName";
@Tag.Reference1.Link = "Tag.TagNa" + "me";
The reason for using the GetName() method instead of using strings directly is that with GetName() you retain the benefits of Cross-Reference and Refactoring.
Working with Tags
Import Tag Definitions
There are many ways to import Tag definition to the project:
Just copy from another Solution and paste it in the Unified Namespace / Tags DataGrid.
Using the import from CSV Files.
Using the Solution Import Tags. We offer a wide range of tools, including .NET Classes, CSV files, OPC Server, OSIsoft PI Historian and PI AF, Prediktor Historian, Rockwell ControlLogix, Siemens, SNMP, SQL DataTable, Tundra, TwinCAT, UnityPro, WirelessHart, and XML files.
Using the EngWrapper API.
After importing the tags, you can organize them using the Asset Modeling feature, which enables you to create a hierarchical structure for your project's tags.
Importing Tags and PLC Addresses from Excel
The "Import from Excel" enables easy importation of tags and PLC addresses. The process is as simple as copying and pasting the content of an Excel table, ensuring that you include the titles of the columns. The feature allows for flexibility in having tables with different columns or arranged differently in your project.
Importing from CSV Files
The importation of CSV files encompasses two main approaches: Individual CSV Files and Extended CSV Files.
Individual CSV Files
In this scenario, you can import items for each individual table available throughout the Engineering Environment. This feature is especially useful for adding items, such as alarms, to your project. When a grid is in focus, the import button on the top bar becomes available. Upon clicking it, a import dialog window will open, allowing you to select the CSV file to be imported. For a more detailed understanding of this process, refer to our detailed guide in Individual CSV File.
Extended CSV Files
Here, the idea is to use a single .CSV table to import information on Tags, Devices, Alarms, and historian items. In this case, the final table is a concatenation of the various grids from the project. This feature can be particularly useful for importing a large amount of correlated information at once. For more information on how to utilize this feature, refer to our comprehensive guide in the Extended CSV Files section.
Tag Properties
Either creating a new tag, or editing tags, in the DataGrid view or the properties dialogs, the tag has the following configuration fields:
Tag main configuration properties | |
|---|---|
Field | Description |
Parent | Specify the Parent Level where the Tag is located in Asset tree. |
Name | Enter a name for the tag. The system lets you know if the name is not valid. If you edit the name of an existing tag, the system automatically updates the name throughout the project. |
Type | Select the tag type, which may be a built-in type or a user-defined Tag Template. |
Parameters |
|
Array | When this field is blank, the tag is not an array. When the field contains an integer value of N, an Array is created from position 0 to N. For example, if the field contains the value 5, the Array is created from Tag[0] to Tag[5]. This means that 6 elements are created. Two programming styles are accommodated by this method; one that counts elements from 0 to less than 5, and one that counts from 1 to 5. |
Enumeration | User defined types that lists a set of values, messages and colors. They can be connected with a Tag, or used directly in script expressions. |
Description | String message with additional information about the Tag, maximum string length is 1024 |
Tag optional configuration properties | |
|---|---|
Column | Description |
Min | Enter the minimum value that is valid for the object. |
Max | Enter the maximum value that is valid for the object. |
ScaleMin | Stores a minimum value to assist scaling charts or communication devices. |
ScaleMax | Stores a maximum value to assist scaling charts or communication devices. |
Units | String with the Engineering units of measure, simplifying the visualization of the value on Displays, and allowing the dynamic change of metric systems. |
Format | Default format for displaying tag value. E.g.: N2 for 2 decimals; See the next table, Formatting Tag Values. |
StartValue | Initial value set to the Tag when the project first runs. This value is overridden if a Retentive option is used. |
| Retentive | Select this option to save the value of the tag and its internal properties to the database every time the value changes. This retains the value when the application shuts down and makes the value available when the next next application starts. None: Does not retain the value or properties. ValueOnly: Retains only the value. Properties: Retains all properties, including the value. PropertiesOnly: Retains all properties, except the value. The values for Retentive Tags are stores at the database defined at Datasets / DBs / Retentive, and it can be customize to use any database. Retentive can be applied to Tags of Domain Server, in this case, you can easily allow the cold-start from the Project, without losing Operator-Inputed values or other Tags that shall keep the last value in between a shutdown and a startup. Retentive can be applied to Tags of Domain Client, in this case, you can falsity create concepts as User Configuration settings, that are stored and located according the client or user connection. |
Domain | Defines if the tag value has Server (global) or Client (instance) scope. Server (Default): the value of tag is unique, synchronize across all operator stations accessing the project. All tags used by Devices Communications and Historian must be or Type Server. Client: The value of tag is local at each Client Displays Instance accessing the project. Common use for client tags are to manage the user interface. |
Visibility | Select the value visibility of your tag to external connection and the built-in OPC server. Private: Tag is visible only to the local project and redundant pair. Protected: Tag is visible on the external connections for read-only operations. Public: Tag is visible on the external connections, for both reading or writing. If not defined, the visibility is Public by default. |
Comment | Enter a short comment about this tag. The comment field is typically used to show a friendly name to the operator on the displays. For instance, a tag name "LV102KP" can have the Comment as "Level Tank 102". The Description field is typically the longer engineering definition of the tag usage. |
Category | Allows to define metadata labels to the tag. Categories are useful for project organization during the engineering phase.Categories are also useful when copy pasting tags directly the draw area, automatically creating symbols. For more information on Categories, go to Dictionaries Categories. |
DevicePoint | Read-only property. Show which communication point address is related to the tag (if any). |
Disable | When checked disable the use of the Tag in the project execution. Default is enabled. |
Other Columns | For definitions of other columns that are available in this table, see Common Column Definitions. |
Tag Value formatting
The format property defines the display format of tag values. For example, N1 defines a number with one decimal place, like 2.1
Proper formatting ensures that the tag values are displayed accurately and are easily understood by users.
These formats follow the specifications provided in Microsoft .NET.
For valid numeric formats, refer to Standard Numeric Format Strings.
For valid date and time formats, refer to Standard Date and Time Format Strings.
For a more in-depth discussion of format strings in .NET, refer to Formatting Types.
Numerical values formatting | |
|---|---|
Specifier | Description |
N0 | Number with no decimal places |
Nn | Number with n decimal places (replace n by any integer number) |
X | Hexadecimal (supported only for integral types) |
C | Currency |
R | A string that can round-trip to an identical number |
P | Number multiplied by 100 and displayed with a percent symbol |
G | The more compact of either fixed-point or scientific notation |
F | Integral and decimal digits with optional negative sign |
E | Exponential notation |
D | Integer digits with optional negative sign |
Date/time formats | |
|---|---|
Specifier | Description |
T (only) | Long time pattern (equivalent to HH:mm:ss). |
d (only) | Short date pattern (equivalent to M/d/yyyy (month/day/year) for en-us). |
dd | Show the day of the month as a number from 01 through 31. |
ddd | Show the abbreviated name of the day of the week. |
dddd | Show the full name of the day of the week. |
MM | Show the month as a number from 01 through 12. |
MMM | Show the abbreviated name of the month. |
yy | Show the year as a two-digit number. |
yyyy | Show the year as a four-digit number. |
hh | Show the hour as a number from 01 through 12. |
HH | Show the hour as a number from 00 through 23. |
mm | Show the minute as a number from 00 through 59. |
ss | Show the second as a number from 00 through 59. |
fff | Show the millisecond as a number from 000 through 999. |
tt | Show the A.M./P.M. designator. |
Alarm, Historian and Device Configuration
Optional configuration properties offer additional customization for tags. These properties can be edited after importing the tags into the project and include:
Alarm Configurations: Settings related to alarms triggered by tag values.
Key Features:
- Condition : Defines a a conditon for a alarm to trigger.
- Groups: Its possible group the alarms items in a group with its own configuration properties.
- Limit: Difines the value of alarm trigger based on the condition defined.
Historian Settings: Configurations for data logging and archiving.
Key Features :
Deadband: The Deadband is a range within which value changes are considered insignificant and, therefore, aren't recorded. This helps in reducing unnecessary logging of data when the value changes are minimal or within an acceptable range.
Table: Defines the specific table where the historical data for this tag will be stored.
Dev/DeadbandType: This is an extension of the Deadband concept. It allows you to define the type of Deadband to be applied. This could be based on an absolute value, percentage, or other criteria, depending on your requirements.
Dev/Deadband Limit: Here, you define the specific threshold for the Deadband. Any changes in the tag value below this threshold won't be recorded. For example, if set at 0.5, only changes greater than this value will be logged.
Device Address: The address or location of the tag in the PLC or data source.
Key Features :
- Node: Determine the node of the channel source where the tag data resides.
- Address: Defines a address for the and PLC/data source.
- AcessType: If the tag will be only Read, Write or ReadWrite.
Runtime Attributes
Access Tags Namespace to see the properties of the alarm server. You can also find two more objects and its properties, they are as follow:
This section describes only some commonly used properties.
Commonly used Tag Properties | ||
|---|---|---|
Property | Type | Description |
Value | Tag Type | Last Value of the Tag |
Quality | Integer | Data Quality field, according OPC standards: 0: bad quality |
Timestamp | DateTimeOffset | Date and time of the last change on the tag value |
For general information and concepts on objects namespaces and attributes, go to the section Objects and Namespaces.
In this section: