Functional Explanation
Alarm Viewer is the dedicated page for reviewing and managing alarms. It shows the Active Alarms, Suppressed Alarms or Historic Alarms list, selectable by the operator. Active alarms are currently triggered conditions. Suppressed alarms are alarms that are silenced for the time being: shelved by an operator from this page, or suppressed by design through the Parent Alarms or Suppress When setting of the alarm on the Alarms page. Historic alarms are records of past alarm activations that have been resolved or acknowledged.
Alarm Viewer can be embedded in a runtime page with the Alarm Viewer object, or accessed as a full standalone page. The Asset setting of the object opens the embedded viewer filtered on one part of the plant. See the Viewers article.
Active Alarms Columns
The Active Alarms view shows all currently active alarm conditions. Columns can be sorted and resized.
| Column | Description |
|---|---|
| Severity | Alarm severity level: Critical, High, Medium, or Low. |
| Asset | Asset tag of the alarm as configured on the Alarms page. |
| Message | Alarm message text as configured on the Alarms page. |
| OnTime | Timestamp when the alarm became active. |
| OffTime | Timestamp when the alarm condition cleared. Empty while still active. |
| AckTime | Timestamp when the alarm was acknowledged by an operator. |
| AckUser | Username of the operator who acknowledged the alarm. |
| AckComment | Optional comment entered by the operator when acknowledging. |
No rows match the filter.
Two row elements belong to alarm shelving and alarm cascading. Users with the Alarm Shelve Right see a Shelve button (clock icon) in the Actions column of every row; for a severity that is excluded by the Shelvable Severities setting on the Parameters page the button is disabled and its tooltip states the reason. The Shelve button of an Alarm Banner opens the same Shelve Alarm dialog. A parent alarm whose consequences are suppressed shows an N suppressed button next to its message, where N is the number of suppressed alarms that are in alarm. The button unfolds those alarms in place as greyed rows without state color or blinking, marked suppressed by <parent message> and, while a Release Delay is running, releasing at <time>. An alarm with several active parent alarms is folded under the parent that went active first and moves to the next active parent when that one returns to normal.
Suppressed Alarms Columns
The Suppressed Alarms view lists every alarm that is currently shelved or suppressed by design, whether it is in alarm or not. Nothing in this list is annunciated: the rows carry no state color and do not blink. The Suppressed Alarms mode button shows the number of shelved and suppressed alarms. Columns can be sorted, filtered and resized as in the other views.
| Column | Description |
|---|---|
| Severity | Alarm severity level: Critical, High, Medium, or Low. |
| Asset | Asset tag of the alarm as configured on the Alarms page. |
| Message | Alarm message text as configured on the Alarms page. |
| State | In alarm with the time the alarm went active, or Normal. |
| Kind | Why the alarm is silenced: Shelved, Parent alarm, or Condition. An alarm that is shelved and suppressed by design at the same time shows Shelved. |
| Suppressed By | The user who shelved the alarm, Parent: followed by the message of the parent alarm it is folded under, or Condition: followed by the Suppress When expression. A shelve of the type Until the alarm returns to normal is marked (until return to normal). |
| Since | Date and time at which the shelve or the suppression started. |
| Until | For a shelved alarm the expiry date and time with the remaining time, shown in amber during the last 10 minutes. For an alarm suppressed by design: releasing at with the end of a running Release Delay, while a parent alarm is active, or while the expression is true. |
| Reason | The reason entered in the Shelve Alarm dialog, or Parent Alarms setting or Suppress When setting for an alarm suppressed by design. |
No rows match the filter.
The Actions column offers Unshelve and Extend on a shelved row to users with the Alarm Shelve Right, and Show parent in Active Alarms on a suppressed alarm whose parent alarm is listed in Active Alarms. Show parent in Active Alarms switches to the Active Alarms view and unfolds the parent row.
Historic Alarms Columns
The Historic Alarms view shows all past alarm records. The same columns as Active Alarms apply. Historic alarms can be filtered by date range, searched by text, exported to a file, or deleted.
A record that was raised, or folded under its parent alarm, while the alarm was shelved or suppressed by design carries the value Shelved, Parent, or Condition in the Suppression column. The column is hidden by default; use Columns to show it, and its filter to list only silenced occurrences. The value records how the occurrence was raised and is kept when the alarm is annunciated later.
Shelve Alarm Dialog
Press Shelve on an Active Alarms row to open the Shelve Alarm dialog. Press Extend on a shelved row in Suppressed Alarms to open the same dialog as Extend Shelving, where the entered duration replaces the current expiry. The dialog starts with a summary of the alarm (message, severity, asset and the time it went active) and contains the fields below. Press Shelve, or Extend in the Extend Shelving dialog, to apply, or Cancel to leave the alarm as it is.
| Field | Description |
|---|---|
| Shelve for | Duration of the shelve. Preset buttons 30 min, 1 h, 2 h, 4 h and 8 h are offered up to the Maximum Shelve Time (min) setting on the Parameters page, and a minutes field accepts a custom duration up to the same maximum. 1 h is preselected, or the maximum when that is lower. In the Extend Shelving dialog this field is labelled Extend to. |
| For this duration | The alarm stays shelved until the duration has passed. |
| Until the alarm returns to normal, and at most this duration | The shelve ends at the first return to normal of the alarm, or when the duration has passed, whichever comes first. |
| Reason | Free text stored with the shelve and shown in the Reason column of Suppressed Alarms. Required while Shelve Requires Reason is on (Parameters page); the dialog refuses the shelve without it. |
| Expires | The computed date and time at which the shelve ends, updated while the duration is changed. With the option Until the alarm returns to normal, and at most this duration the dialog adds or earlier when the alarm returns to normal. |
No rows match the filter.
The dialog states that the alarm keeps being evaluated and logged, and that it returns to Active Alarms unacknowledged if it is still active when unshelved.
A shelve ends by Unshelve or Unshelve All, automatically at the expiry, or with the option Until the alarm returns to normal, and at most this duration at the first return to normal. An alarm that is still active at that moment returns to Active Alarms unacknowledged with its real On Time. An alarm that returned to normal while it was shelved is closed without an acknowledgement. Alarm actions execute when a shelved alarm goes active, as for any other alarm; they do not execute again when the shelve ends.
Every shelve, Extend, Unshelve and expiry is written to the audit trail with the category Operator and the entity Alarms; the recorded actions are Shelve, Reshelve, Unshelve, Expired and Returned. When Part 11 compliance mode requires an electronic signature for the action key Alarm.Shelve, the Electronic Signature dialog opens before Shelve Alarm and Extend Shelving are applied, with the same two-step flow as Alarm.Ack. Unshelve is audited and does not ask for a signature.
Toolbar Actions
The following actions are available in the Alarm Viewer toolbar depending on the active view and user permissions.
| Action | Description |
|---|---|
| Active Alarms / Suppressed Alarms / Historic Alarms | Switch between the active alarm list, the list of shelved and suppressed alarms, and the historic alarm records. The Suppressed Alarms button carries the number of shelved and suppressed alarms. |
| Acknowledge All | Acknowledge all active alarms at once. On the Historic Alarms view, acknowledges all unacknowledged historic alarms that match the search text and the date range. Requires the user to have alarm acknowledgement rights. |
| Remove All | Remove all active alarms from the active list. Available on the Active Alarms view for users with remove rights. |
| Unshelve All | End every shelve at once. Available on the Suppressed Alarms view for users with the Alarm Shelve Right. Alarms that are still active return to Active Alarms unacknowledged. |
| Search | Filter the displayed alarm records by text search. |
| Date Filter | Filter historic alarm records by a start and end date-time range. |
| Export | Export the current historic alarm records to a CSV file. The first line holds the column names Severity, Asset, Message, OnTime, OffTime, AckUser, AckTime, AckComment and Suppression. Suppression holds Shelved, Parent or Condition for an occurrence that was silenced and is empty otherwise. |
| Delete | Delete the filtered historic alarm records. Available to Administrators only. |
No rows match the filter.
In the Active Alarms view the toolbar shows the counters Critical, High, Medium, Low and Total. They count the alarms that match the search text and the column filters, so a filtered list, such as one opened from a Navigator alarm badge or by an Alarm Viewer object with an Asset setting, shows the counts of that selection. The number on the Suppressed Alarms button follows the search text and the filters of the Suppressed Alarms view in the same way.
Alarm Actions from the Runtime API
The acknowledge, remove, shelve and unshelve actions of the Alarm Viewer are also available through the Runtime API and through the MCP tools, so alarms can be handled from a script, an external system or an AI assistant. These calls apply exactly the same user group rights as the toolbar buttons, and they are refused when the authenticated user does not have the right.
Alarm identifiers are the Id values returned by Get Active Alarms, Get Suppressed Alarms and Get Historic Alarms. Get Active Alarms leaves out shelved and suppressed alarms, as the Active Alarms view does, and returns a SuppressedChildren count on a parent alarm.
| Endpoint | Description | Required right |
|---|---|---|
| POST /API/AcknowledgeActiveAlarms | Acknowledge one or more active alarms with an optional comment. | Alarm Acknowledge. Acknowledging more than one alarm in a single call also requires Alarm Acknowledge All. |
| POST /API/AcknowledgeHistoricAlarm | Acknowledge one historic alarm record with an optional comment. | Alarm Acknowledge. |
| POST /API/RemoveActiveAlarms | Remove one or more active alarms from the active alarm list without acknowledging them. The historic alarm record is kept and each removal is written to the audit trail. | Alarm Remove Active. Removing more than one alarm in a single call also requires Alarm Remove All Active. |
| GET /API/GetSuppressedAlarms | Return the shelved and suppressed alarms as listed in the Suppressed Alarms view, with the shelve (user, since, until, mode, reason) and the suppression cause (kind, the parent alarm it is folded under and its message, since, release time) and the Parent Alarms of the alarm. | Any authenticated user. |
| POST /API/ShelveAlarms | Shelve one or more active alarms. The body carries AlarmIds, Minutes (1 up to Maximum Shelve Time), UntilReturn (true for Until the alarm returns to normal) and Reason (required while Shelve Requires Reason is on). Shelving an alarm that is already shelved replaces its expiry, like Extend. A severity that is excluded by Shelvable Severities is refused. | Alarm Shelve. When compliance mode requires a signature, the action key is Alarm.Shelve. |
| POST /API/UnshelveAlarms | End the shelve of one or more shelved alarms, with an optional Comment. | Alarm Shelve. |
No rows match the filter.
The matching MCP tools are GetSuppressedAlarms, ShelveAlarms and UnshelveAlarms. ShelveAlarms accepts the signatureToken argument for the Alarm.Shelve signature, in the same way as the acknowledge tools accept it for Alarm.Ack.
Notes
Alarm acknowledgement rights are controlled by the Alarm Groups field on each alarm definition in the Alarms configuration page.
Alarm Viewer can be embedded directly in a runtime page with the Alarm Viewer object. See the Viewers article.
Historic alarm records accumulate over time. Use the date filter and Delete function to manage the stored history volume when needed.
When compliance mode requires an electronic signature for alarm acknowledgement, the acknowledge calls answer with signatureRequired instead of acknowledging. Sign first and repeat the call: an API client posts to /API/Signature/Verify with action key Alarm.Ack and repeats the request with the token in the X-Signature-Token header, and an MCP client calls the SignAction tool and repeats the tool call with the token in the signatureToken argument. See the Electronic Signatures article. Shelving follows the same flow with the action key Alarm.Shelve.
The Alarm Viewer can be opened with a filter from a Navigator object: clicking the alarm badges of an asset node or of a UDT instance row opens the viewer with an Asset filter on the node path, which includes every alarm under the node, or with an Instance filter on that instance. The filters appear as chips above the grid and can be removed like any other filter. The same filters apply to an Alarm Viewer object placed on the Alarms Page of the Navigator, where they replace the Asset setting of the object. A filter that opens the viewer is set in all three views. Active Alarms and Historic Alarms share their filters and Suppressed Alarms has its own, so a chip removed in Active Alarms stays in Suppressed Alarms until it is removed there as well.
Shelved and suppressed alarms are not annunciated: they are absent from Active Alarms, from the Alarm Banner and from the SYSTEM.AlarmCount_* and SYSTEM.AlarmUnacked_* counters, so Navigator badges and the Group symbol Alarm Indicator leave them out. The counters SYSTEM.TotalShelvedAlarms and SYSTEM.TotalSuppressedAlarms hold the number of shelved and suppressed alarms.
Shelve, Extend, Unshelve and Unshelve All require the Alarm Shelve Right, set per group on the User Groups page. Members of the Administrators group always hold it.