• Accepts inputs like proximity switch, photo sensors, voltage pulses...
• P.L.L. Multipliers and quartz crystal timebase.
• Accuracy ± 1 R.P.M.
• No mechanical moving parts.

PRINCIPLE

An output coming from a transducer is filtered, signal conditioned and chopped. Finally it is converted into square waves. The square wave is passed through RLL multipliers. This output is gated by a precise time base generated through piezo crystals and then counted. This counts are displayed on bright LED's .... It's nothing but R.P.M. with accuracy of±1 R.P.M.!!!

MEASURING RANGE

A) RLL circuitry requires minimum 2.5 pulses per second i.e. 2.5 x 60 = 150 R.P.M. It's lower limit. If more than one pulse is given in one rotation then lower limit is reduced, eg if 2 pulses in one rotation than 75 R.P.M. i.e. If n pulses per rotation can give measurement of 150 * R.P.M.
B) 60 tooth gear wheel can give R.P.M. upto 10.