PM870: Waveform capture misses event of interest...

Issue

Customer reports that waveform captures completely miss the triggering event, such as the transition to an under-current or over-voltage condition.

Product Line

PM870

Environment

ION Setup

PM8 platform

Cause

The waveform was configured to trigger on a Standard alarm. On PM8 series devices, Standard alarms have a 1-second detection cycle (see PM8 user guide, page 74). This delay can result in the waveform trigger occurring up to 60 cycles late, causing the event of interest to be missed.

Resolution

Use a Disturbance alarm instead of a Standard alarm to trigger waveform captures. Disturbance alarms operate on a cycle-based delay (e.g., 20ms per cycle at 50 Hz), providing much faster detection.

Steps in ION Setup:

1. Open Onboard Alarms/Events dialog.
• You will see four alarm types: Standard, Disturbance, Digital, and Boolean.
2. Select Disturbance and click Edit.
3. In the Disturbance Alarm Setup dialog:
• Note that the delay is measured in cycles, not seconds.
4. Configure the alarm according to your preferences.
5. Click OK to save.

Released for: Schneider Electric USA