Object: Alarm Group

Symbol:

Function: An alarm group consists of alarms which have a cross-group configuration in addition to their specific configuration. The assignment of text lists, archiving, configuration of the deactivation function, and the display of alarm instances are performed across all groups.

Ideally, the alarms in the table (in the object editor) are combined and grouped by topic. Add suitable alarms to this table. You also complete the specific configuration of an alarm in the table. In the table, click an alarm to display the corresponding details with suitable input support below it.

You can also export alarms to a CSV file and import them back in.

Dialog: Alarm Group

Text list	Name of the text list where the alarm message text is saved (see below: Message). This list is created automatically when an alarm group is created. You can also select an existing text list here.
Archiving	Selection of the alarm storage object for the alarm group Alarm storage is automatically activated when an alarm storage object is specified.
Deactivation	Boolean variable which deactivates all alarms in this group These alarms are no longer triggered, even if the alarm condition is fulfilled. Alarms which are already active are not affected.
Show Alarm Instances	: Generated alarm instances are displayed.

Table 66. Alarm Table

Specify the properties of the individual alarms in the corresponding columns of the table. Depending on the selected observation type, input fields for additional required parameters are available below the table.
ID	Unique ID which corresponds to an ID in the associated text list You can change the ID in the ID field of the table. The ID must always be unique within the alarm group. Important: A change of the ID in the alarm table also directly causes a change in the text list, and the other way around.
Observation Type	Observation type selected from the list box Important Depending on the type, various input fields are available below the alarm table to define the alarm condition and help you configure the alarm condition. See the following tables for the individual observation types: Digital, Upper limit, Lower limit, Outside range, Inside the range, Change, Event (API), Alarm (API)
Details	Alarm condition The details for the observation type (configured in the fields below the table) define the conditions under which the alarm is triggered. Tip You can also specify the condition directly into the field. If you input an expression that does not match the currently selected observation type, the type is automatically adapted.
Deactivation	Optional Variable for deactivating the alarm
Class	Assigned alarm class
Message	Required Entry of a message text (message), which can contain placeholders for information from latch variables (placeholders for data from a latch variable) and can be supplemented with line breaks (Ctrl + Enter). The text entered here is automatically entered in the text list of the alarm group. When an alarm is triggered, this message is displayed in the alarm elements (Alarm Table, Alarm Banner) .
On-Delay Time	Time for switch-on delay Defines the minimum time that the alarm condition must be fulfilled before the alarm is triggered. This can be used to suppress brief alarm events. Example: `T#2s` IEC 61131-compliant format (example: T#2ms).
Off-Delay Time	Time for switch-off delay Defines the minimum time that the alarm condition must be inactive before an alarm is treated as inactive. This can be used in the same way as the switch-on delay to ignore short-term value changes. Example: `T#4s`
Latch Var 1 Latch Var 2	Variable with scalar type (8 bytes), `STRING` or `WSTRING` Latch variables are used to record additional values when an alarm is active. This makes it possible to provide additional information about the alarm. For example, when observing a motor speed, the temperature and the current are also recorded. By default, columns are available for two latch variables. You can add more columns from the context menu which will be available in the Data type property for column configuration of the Alarm Table and Alarm Banner visualization elements. Hint: You can configure the alarm visualization in such as way that displayed alarms are filtered by the contents of the latch variables. For more information, see: Using Latch Variables to Filter Alarm Events
Higher Prio. Alarm	When the alarm is triggered, it can be acknowledged by triggering another alarm. For example, a temperature monitor should issue a warning at `Temp > 60 °C` and an error at `Temp > 90 °C`. If the temperature rises, then the warning is displayed starting at 60°C. As of 90°C, the alarm is triggered for the error. This alarm automatically acknowledges the 60°C warning.

Messages are not saved as a copy in the history.

Effect: If you make a small change to a message (for example, correcting a typing error), then this change has an effect on the history because the corrected message is now displayed there. However, if you completely reconfigure the alarm (change status or condition and update the message), then all previous alarms which were recorded due to the outdated configuration will get the new message in the history. Check on a case-by-case basis whether it is not better to add a new alarm instead of upgrading the outdated alarm.

Table 67. Observation type: Digital

Digital

Alarm condition for observing a Boolean variable

Expression

Expression for comparisons of = or <>

If the expression is TRUE, then the alarm is triggered.

Example: (PLC_PRG.xVariable) = (PLC_PRG.xSpecified)

The variable to be checked is on the left. The specified value is on the right. The button opens the Input Assistant. In the center input field, you can select the desired comparison operator from those available.

Table 68. Observation type: Upper limit

Upper limit

Alarm condition for observing an upper limit

Example: PLC_PRG.iX >= g_iUpperLimit

Expression

Expression for comparisons of > or >= Indicates whether the variable has reached or exceeded the upper limit.

If the expression is TRUE, then the alarm is triggered.

The variable to be observed is on the left. The upper limit value is on the right. The button opens the Input Assistant for the operands. In the center input field, you can select the desired comparison operator from those available.

Limit value

Absolute upper limit with fixed values
- Variable
  Example: g_iUpperLimit
- Literal
  Example: 10
Relative upper limit using an expression
- Example: 0.9 * g_rUpperLimit

Important

The limit value can be specified as absolute or relative. Absolute means that the limit value is defined by a fixed value or a variable that returns a fixed value. Relative means that the limit value depends on an expression.

Hysteresis in %

Optional

Deviation from the limit value where the alarm condition is reset (FALSE).

The alarm condition is fulfilled as long as the upper limit value minus the deviation is exceeded. The size of the deviation is specified as a percentage (%) of the limit value.

Example:

Expression: i_temp >= 30

Hysteresis: 10%

If the variable i_temp reaches or exceeds the value 30, then the alarm becomes active. The alarm is deactivated when the value falls below 27.

Table 69. Observation type: Lower limit

Lower limit

Alarm condition for observing a variable for a lower limit

Expression

Expression for comparisons of < or <= Indicates whether the variable has reached or fallen below the lower limit.

If the expression is TRUE, then the alarm is triggered.

The project variable to be observed is on the left. The lower limit value is on the right. The button opens the Input Assistant for the operands. In the center input field, you can select the desired comparison operator from those available.

Limit value

Absolute lower limit with fixed values
- Variable
  Example: PLC_PRG.iX < g_iLowerLimit
- Literal
  Example: PLC_PRG.iX < 100
Relative limit value using expressions
- Example: PLC_PRG.rX < 0.9 * g_rLowerLimit

Important

Hysteresis in %

Optional

Deviation from the limit value where the alarm condition is reset (FALSE).

The alarm condition is fulfilled as long as the value falls below the lower limit value plus the deviation. The size of the deviation is specified as a percentage (%) of the limit value.

Example:

Expression: i_temp < 10

Hysteresis: 10%

If the variable i_temp falls below the value 5, then the alarm becomes active. The alarm is deactivated when the value rises above 11.

Table 70. Observation type: Outside range

Outside range	Alarm condition for observing a variable outside of a range. Indicates whether the variable reaches, falls below, or exceeds the valid range.
Expression	Expression if the variable to be observed falls below or exceeds the valid range. If the expression is `TRUE`, then the alarm is triggered. The button opens the Input Assistant for the variable to be observed.
Area	The upper limit value is on the left. The variable to be observed is displayed in the center field. The lower limit value is on the right. The button opens the Input Assistant. Between them, select the desired comparison operators from those available. The left field defines an expression for the lower limit of this range. The right field defines an expression for the upper limit. The expression to be observed is displayed in the field in-between. You need to set the comparison operators accordingly. Important The limit value can be specified as absolute or relative. Absolute means that the limit value is defined by a fixed value or a variable that returns a fixed value. Relative means that the limit value depends on an expression.
Hysteresis in %	Optional Difference from the limit values (in %) where the alarm condition is reset (`FALSE`) The alarm condition is fulfilled as long as the limit values only deviate by the difference. The size of the deviation is specified as a percentage (%) of the limit value.

Table 71. Observation type: Inside the range

Inside the range	Alarm condition for observing a variable inside a range. The alarm is triggered when the variable to be observed is within a range.
Expression	Expression when the variable to be observed is within the specified range If the expression is `TRUE`, then the alarm is triggered. The button opens the Input Assistant for the variable to be observed.
Area	The lower limit value is on the left. The variable to be observed is displayed in the center field. The upper limit value is on the right. Between them, the desired comparison operators are selected from those available. The button opens the Input Assistant. Important The limit value can be specified as absolute or relative. Absolute means that the limit value is defined by a fixed value or a variable that returns a fixed value. Relative means that the limit value depends on an expression.
Hysteresis in %	Optional Difference from the limit values (in %) where the alarm condition is reset (`FALSE`) The alarm condition is fulfilled as long as the limit values only deviate by the difference. The size of the deviation is specified as a percentage (%) of the limit value.

Table 72. Observation type: Change

Change

Alarm condition for observing a variable change

Expression

Input field for the variable

If the expression is TRUE, then the alarm is triggered.

Example: (PLC_PRG.iVariable)

Table 73. Observation type: Event (API)

Event (API)

The alarm is triggered programmatically by the application. No configuration is required. No acknowledgment is required at runtime.

For more information, see: Calling Alarm Events in the Program

Table 74. Observation type: Alarm (API)

Alarm (API)

The alarm is triggered programmatically by the application. Depending on the configured alarm class, acknowledgment may be required.

For more information, see: Implementation of an implicit alarm

Context menu in the alarm table

Table 75. Commands in the context menu

Add message column	Adds a new message column
Remove message column	Removes the selected message column
Add latch var column	Inserts a latch variable.
Remove latch var column	Removes the selected variable

Tip

Multiple selected rows in the table can be edited at the same time by means of the context menu.

Table 76. Commands for exporting and importing alarms to and from a CSV file

Export Alarms	The command opens the default dialog for saving a file in the file system. The default file type is Alarm Group Export File (*.csv). The current alarm list can be exported to a CSV file there.
Import Alarms	The command opens the default dialog for searching for a file in the file system. The default file type is Alarm Group Export File (*.csv) for describing alarm definitions. The selected file is imported.