C.16.RM:5.3 - Recompute a rate from retained observations

A flow logger records cumulative pulses and elapsed timestamps in milliseconds. The supplied calibration is one pulse per litre, with no missed pulses or resets in the interval. The receiving question concerns average volume flow over that interval.

Both endpoint timestamps are taken at pulse events. The retained endpoints are 120 pulses at 10,000 ms and 180 pulses at 40,000 ms. A program subtracts the timestamps, divides the count difference by 30,000 and labels its output 0.002 L/s.

The pulse difference represents 60 L. The timestamp difference represents 30 s. Evaluating the intended relation gives:

average flow = 60 L / 30 s = 2 L/s.

The program’s division obtained 0.002 L/ms and then attached the wrong time unit. Convert milliseconds to seconds before division, or convert the resulting rate afterward. Both repairs give 2 L/s. Recompute other affected intervals from their retained counts and timestamps.

A reference input of 10 pulses over 2,000 ms should give 5 L/s. A program result of 0.005 L/s reproduces the conversion fault; 5 L/s confirms this operation for that input. This calculation checks the implementation. Whether the actual instrument counted every litre and its clock tracked elapsed time requires the relevant calibration and observation when those premises are disputed.

The useful result is a repaired average rate from existing observations. Repeating the physical flow measurement is unnecessary for the identified unit-conversion fault while those observations and their calibration remain usable.