Features high sensitivity photoelectric sensor Δ Δ Δ speed automatic measurement of full scale with frequency, period, time and counting functions can be applied to any period measurement Δ Δ measurement and calibration error standard speed device performance analysis printout speed measurement Δ the range of 8 ~ 200000 r / min Δ speed measurement uncertainty of 5 × 10-6 Δ 150 Δ speed measurement maximum declination internal crystal stability 1 × 10-6 Δ Dimensions 230 × 260 × 90 mm3 Δ total weight 3kg