Tacho measures every movement
MOVING belts, chain drives, gear ratios, slippage, rotation count are all items that can be checked and measured using a non-contact, programmable tachometer.
The Speedmate PT431, from Graham White Instruments (GWI), has two programmable speed factors which can be set to give results in engineering units, in addition to a fixed rpm setting. This allows direct display in units such as items/min, metres/min or litres/sec etc. Price of the kit is £125 (01727-859373).