Extech Instruments 461700 User Manual page 5

Measurements
RPM Measurements
461700 Photo Tachometer
1. Affix a small (1/4") square of reflective tape to the surface of the device under test.
See rotating gear example diagram below.
2. Allow the device under test to turn at its normal rate.
3. Turn the meter ON.
4. Point the Tachometer's sensor toward the reflective tape. Keep the sensor
perpendicular to the reflective tape for the best results. The distance from meter to
object can be up to 12" (30cm).
5. Read the RPM (rotations per minute) measurement on the LCD.
461750 Contact Tachometer
1. Affix the convex (cone) or concave (funnel) attachment that best fits the application
to the meter shaft as shown below.
2. Turn the meter ON.
3. Use the UNITS button to select RPM (the display will reflect the selection).
4. Touch the attachment to the moving object and read the displayed measurement.
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Reflective Tape: Point
meter sensor toward tape
Rotating Gear
Front view
Rotating
Wheel
Touch the convex or
concave attachment
to the turning object
5
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461700 / 461750 Version 2.3 Mar 2004