Can OPC Data Archiving Be Triggered by External Conditions?

Can OPC Data Archiving Be Started and Stopped Based on External Conditions or Triggers?

OPC Expert supports condition-based automation through its Trigger OPC Events feature, which allows users to define custom conditions based on real-time OPC data values and then execute automated actions when those conditions are met. While the Archive OPC Data module itself captures data continuously once running, the trigger and event system within OPC Expert can be used to execute scripts or external applications that start, stop, or modify archiving behavior in response to conditions such as a production run beginning, an alarm state activating, or a value crossing a defined threshold.

How Trigger OPC Events Enables Conditional Archiving Control

The Trigger OPC Events module monitors OPC data points and evaluates user-defined conditions, including bad data quality flags, value changes, stalled readings, and threshold breaches. When a condition is satisfied, the trigger can execute a batch file, a PowerShell script, or an external application. This mechanism provides a pathway for starting or stopping an archiving process, switching between archiving profiles, or logging an event to an external system without any manual intervention from an operator.

Multiple OPC data points can be combined into a single intelligent trigger, allowing complex logic such as “begin archiving when equipment is running and batch identifier is non-zero” to be expressed without custom programming. The trigger engine evaluates these conditions in real time and fires the configured action immediately when they are satisfied.

Archive OPC Data’s Native Capture Options

Within the Archive OPC Data module itself, data capture can be configured as event-based rather than time-based. Event-based capture records a value only when it changes, rather than at every polling interval, which significantly reduces storage requirements while still maintaining a complete record of when and how values changed. The update rate per item is also configurable, giving engineers precise control over how frequently each tag is sampled and stored.

This combination, event-driven capture within the archive module and condition-based script execution from the trigger module, gives users a flexible architecture for aligning archiving activity with operational reality rather than running a fixed continuous record of everything regardless of plant state.

Relevant Tools

Trigger OPC Events, a feature of OPC Expert, monitors real-time OPC data and executes automated actions including script execution, email alerts, and sound notifications when user-defined conditions are met. Archive OPC Data, also part of OPC Expert, captures OPC values to CSV, SQL, and cloud destinations with configurable event-based and time-based capture modes.

Summary

OPC Expert does not include a native start/stop archiving button tied directly to an OPC tag value, but the combination of the Trigger OPC Events module and the scripting capabilities it exposes provides a practical and flexible mechanism for controlling archiving behavior based on real-time plant conditions. Archive OPC Data’s event-based capture mode further reduces unnecessary data collection when values are stable.