Continuous Point-on-Wave (CPOW)

What Is CPOW?

Continuous Point-on-Wave (CPOW) is a waveform record with no gaps: every sample of every channel, kept around the clock rather than in windows around a trigger. With time-synchronized samples, it is a continuous synchro-waveform record.

Continuous recording is the hard case. A triggered recorder handles the full data rate for seconds at a time; a continuous one handles it every second of every day. One seven-channel sensor at 32 ksps produces roughly 60 GB of raw samples a day, which is why most waveform recording in service is still triggered.

Why Gaps Matter

A gap in the record is where an investigation fails. It is like solving a store theft from security snapshots taken every few minutes instead of continuous video.

• A triggered record holds only what someone anticipated. A sag just short of the threshold, a slow drift in distortion, or a disturbance no one wrote a trigger for leaves no waveform behind.
• Triggered windows at different sites do not line up. Each recorder captures on its own, so the cycles that explain an event may be missing where they matter most.
• A continuous record holds every cycle. New questions can be asked of old data, and next year’s methods run on this year’s record.

Making Sense of a Continuous Record

Recording every cycle is the start, not the result. One sensor’s raw record grows by more than 20 TB a year: nearly two billion cycles at 60 Hz, far more than any engineer can read. The value lies in finding the few cycles that matter, relating them across sensors and sites, and explaining them in physical terms, as the data arrives rather than after the fact.

That is the hardest part of continuous monitoring. It takes deterministic signal processing that runs beside the record, computing standards metrics and detecting events on every cycle, and analysis that steers attention to what changed and explains why. Without it, a continuous record is an archive nobody opens.

Not All Continuous Records Are Equal

What the sample clock follows decides what a continuous record can show.

• Cycle-synchronous capture locks the clock to the line, at a fixed number of samples per cycle. Harmonics land in exact bins, but anything not locked to the mains (interharmonics, supraharmonics, oscillations from inverters and drives) smears as the fundamental frequency wanders.
• Fixed-rate capture samples at a constant absolute rate, so every frequency is kept in absolute hertz, including the ones that move.

The choice is made once, at the sensor: a cycle-synchronous view can be computed from a fixed-rate record, never the reverse.

Questions to Ask of Any Waveform Recorder

1. Is the waveform recorded continuously, or only around triggers?
2. How long is the continuous record kept, and where? A gapless stream that overwrites itself within hours is a buffer, not an archive.
3. What is the time reference, and what accuracy is specified for it?
4. What are the sample rate and bit resolution?
5. Are the stored samples the converter’s own, at a fixed rate, or have they been resampled to a fixed number per cycle, decimated, or compressed with loss? Lossless compression of a resampled stream still loses the original. Resampling also leaves artifacts of its own, so a feature in the record may come from the signal or from the processing, and that doubt can leave a diagnosis inconclusive.
6. Can your engineers reach the raw samples, at full rate, from their own tools?

How Energy Quotient Records CPOW

EQ Wave™ samples three voltage and four current channels simultaneously at a fixed 32 ksps and 24-bit resolution, with no triggering, resampling or summarization. EQ Coherence™ keeps that record gap-free on your premises, with history limited only by storage; EQ Syntropy™ applies physics-grounded AI across devices to find and explain the cycles that matter; and EQ Sight™ puts every cycle in front of your engineers.

For the wider context of disturbances and their cost, see the power quality primer.