A hobbyist IoT sensor
This is somebody's weather station, posting a barometric pressure reading every minute for years. Look at it on a gauge and it never seems to move — it reads 29.9 today, 29.9 tomorrow. Charted once a day against limits worked out months ago, the weather systems are impossible to miss. That is what a drifting sensor looks like on your shop floor too, and the reason we chart it daily rather than every minute is worth a minute of your time: try the sampling control below.
Barometric pressure (ThingSpeak 12397) — individuals & moving range
No points to chart yet
This feed is connected but has not collected a full sampling period yet. The chart appears as soon as the first complete points land.
What just happened
Written out in full, the moment the chart sees it. No statistics knowledge required.
Tick a rule off and its points, its shaded runs and its card below the chart go with it — nothing is refetched, so you are looking at the same readings judged by fewer rules. Change how often a reading is taken and watch the limits move. Sample too often and every reading is almost a copy of the one before it — the chart then thinks the process is far steadier than it is, and draws limits so tight that normal variation looks like a crisis. Only the setting marked (the real one) shows the limits that were locked at baseline and have never been recalculated since.
Data source: ThingSpeak channel 12397. Data from the public ThingSpeak channel 12397 ("WeatherStation"), read through the ThingSpeak public channel API. ThingSpeak is a MathWorks service. SPC Visuals is not affiliated with ThingSpeak channel 12397.
Use this chart
https://www.spcvisuals.com/live/iot-sensor
<iframe src="https://www.spcvisuals.com/live/iot-sensor/embed" width="100%" height="440" style="border:0" title="A hobbyist IoT sensor — live control chart"></iframe>
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I-MR control chart of A hobbyist IoT sensor, drawn from ThingSpeak channel 12397. Limits were computed once from the first 40 points and frozen; they are never recalculated from the visible window. How these charts are built →
https://www.spcvisuals.com/live/iot-sensor/card.png
Your data does this too
Connect a historian, a CSV, or an API. Same charts, same frozen limits, your process.