Chronological Event List & Alarm Message List (CEL / Audit Trail)

To ensure high productivity and save resources it is important to identify errors and their causes quickly so one can respond directly to the situation. With its alarm capabilities and the documentation of events in the Chronological Event List (CEL), zenon provides all the necessary tools. With preconfigured functions, the simple setting of parameters, and full compatibility with standards such as FDA CFR 21 Part 11, zenon ensures complete traceability of process chains.

Fast Facts

Compatibility with FDA CFR 21 Part 11
Administration of Alarms, Audit Trail/Sequence of Events and Chronological Events
Definition via limit values or central threshold values
Grouping and prioritization
Alarm shelving capabilities according to ISA 18.2-2016 and IEC 62682
Comprehensive filter possibilities
High performance
Immediate redundancy capabilities
Graphical display with a clear overview
Supported in native Service Engine and Web Visualization Service

Administration and display
zenon offers the following options for displaying alarms and events:

Alarm Message List (AML): Displays alarms with all relevant information. These alarms can either be current ones or alarms that have been put aside (shelved).
Chronological Event List (CEL/Audit Trail/Sequence of Events): Lists process-relevant events and zenon system messages in chronological sequence.

These lists can be individually adapted. The functionalities are fully preconfigured in zenon and can be used without any programming.

Limit values

If limit values of variables are breached, an alarm or a fault report is triggered. Users define which limit violations trigger an alarm and/or cause an entry in the Chronological Event List during the engineering phase. For automatic, event-controlled reactions, you can link these breaches with functions. The linked function can also be executed manually, at the press of a button in an alarm screen. If flittering values often exceed limit values, alarms and messages can be suppressed in a defined hysteresis range or by a threshold value.

Alarms

Alarms can be configured in many ways in zenon. The allocation takes place, for example, according to alarm groups, alarm classes, and alarm areas. If alarms require acknowledgment or a second acknowledgement, it is ensured that the alarm was confirmed in a traceable manner. All actions are logged in detail. The acknowledgment of an alarm in zenon Service Engine can be combined with acknowledgment from the PLC by setting an acknowledgment bit.

Alarm Message List

The Alarm Message List (AML) displays current and historical alarms. Diverse criteria for filtering alarms are predefined in zenon Engineering Studio. In addition, filters can also be created in Service Engine and saved there for any given user. Additional context can also be given to alarms by enabling or requiring the input of alarm causes and comments.

AuditTrail_Screenshot

Alarm Shelving

zenon supports Alarm Shelving according to ISA 18.2-2016 and IEC 62682. Alarms can be put aside (shelved) in case there are many alarms of different priority that need to be treated. Alarms of highest priority have to be treated first, therefore the other alarms have to be shelved by selecting a reason and a time when the alarms are moved back to the regular Alarm Message List again. To display shelved alarms the Alarm Message List can be used as Shelved Alarm Display. All other features like external storage, export of alarms or use within reports do also consider information regarding alarm shelving.

Chronological Event List (CEL) and Audit Trail

The Chronological Event List (CEL) shows process-related events and zenon system messages in a chronological sequence. Just as with alarms, there is also a variety of filter criteria in the CEL. The alarms and Chronological Event List benefit from full redundancy capability, simple administration, and excellent performance, as well as fulfilling FDA 21 CFR Part 11 requirements.

Technical Details

- Real-time stamping (externally from the PLC)
- External and internal timestamp
- Time stamping possible in milliseconds
If not otherwise defined, zenon records all alarms without exception. Alarm logs can be configured to your individual requirements. All data can be exported to different file formats.
Limit values can be defined by:
- States of bit variables
- Value ranges of analog variables
- Conditions of string variables
zenon administers entries for alarms and to the CEL without limitation. To make them visible, current alarms are saved in a freely configurable ring buffer.
In addition to the freely definable filters, the following predefined filters can be used:
- Online alarms
- Historical alarms
- Shelved alarms
- Only pending alarms, unacknowledged alarms, etc.
- Minimum time that alarms need to queue
- Groups, classes, areas, variable name, identification
- Limit text
- Times
- Equipment Model
Alarm groups and alarm classes serve to logically group alarms and allow prioritization. A name, color, and a function can be allocated to each group or class.
- Display and management of process diagnosis reports from Siemens S7-PDIAG in zenon.
- Import of projected reports from S7-PDIAG and use as normal limit values.
- Deactivation option for alarms and the CEL for maintenance work (can be related to groups, classes or individual messages as an option).
- Selective alarm suppression in Service Engine (e.g. for maintenance activities).
- Pending alarms can be suppressed using the shelving function.
Alarm Message Lists fully support redundancy.
- Comments
- Alarm causes

zenon Tutorials

Configuring alarms and events in the zenon Engineering Studio is really straightforward. Even Reaction Matrices can be parameterized quickly. See in our tutorial videos how easy it is.

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