461995 Datasheet, PDF (5/6 Pages) Extech Instruments Corporation. – Laser Photo / Contact Tachometer

Meter Operation
Reversible LCD Display
The 461995 LCD display indicates Photo Tachometer measurements in one direction and
Contact measurements in the opposite direction. This permits the user to easily read the
measurement digits in both measurement modes with the meter held in either direction.
Photo Tachometer Measurements (refer to diagram below)
1. Apply an appropriately sized square piece of reflective tape to the surface of the object
under test.
2. Move the Function switch to the PHOTO position.
3. Point the laser pointer end of the meter toward the device under test at a distance of 2"
to 79" (50 to 2000mm).
4. Press the Measure button (located on the right side of the meter) and align the laser
pointer beam with the reflective tape.
5. Verify that the Monitor Indicator appears on the upper left hand section of the LCD
when the object under test passes through the light beam.
6. Release the Measure button when the RPM reading stabilizes on the LCD.
7. If the rpm is under 50, apply additional squares of reflective tape. Divide the reading
shown on the display by the number of pieces of reflective tape squares to calculate
the actual rpm.
NOTE: Bright ambient light may interfere with the reflected light beam. Shading the target
area may be necessary in some cases.
CAUTION: Rotating objects can be dangerous. Use extreme care.
Photo Tachometer
Light source
and reflection
Reflective tape
Rotating object
5
461995 V1.3 7/02