I have a pump that I would like to know when it’s on or off. By extension, this will allow me to calculate the duty cycle. The current peaks at 22A when it first comes on, stabilizes around 8A when running, and is effectively 0A when it’s not running. I don’t need to know the exact current; rather, I need to see if the pump is on or off by assuming on if the current is > 5A and off if below.
The NCD current sensors like this one and this one can’t be queried more than once per second or two. The pump cycles for only a few seconds, so this low of a query resolution would make the duty cycle calculation wildly inaccurate.
I saw another means of measuring the AC current using a Hall effect sensor like this one. I don’t see the response time of this sensor though. I saw on this site someone used an Allegro IC and the specs on that were 4µs. Does that mean I could query that fast? Ideally, querying between 10 and 100 ms should be sufficient. I’m currently using a stopwatch to measure the cycle times, so as long as the query time is faster than my reflex (250 ms?) that should work.