461920 datasheet(4/6 Pages) EXTECH

4 / 6 page

461920 V2.1V 5/07

Meter Operation

1. Apply an appropriately (0.5”/12mm) sized square piece

of reflective tape to the surface of the object under test.

2. Point the meter toward the device under test at a

distance of 2" to 20" (50 to 500mm).

3. Press the Measure button (MEAS) and align the laser

light beam with the reflective tape.

4. Verify that the ((( ))) Monitor Indicator appears on the LCD

when the reflective tape passes through the light beam.

5. To change units (RPM or REV), release the MEAS

button and press the MODE button.

6. When the Measure button is released the last reading

will remain in the display for 5 to 10 seconds before the

Auto Power Off feature turns the meter off.

7. With the meter OFF, press the MEM (memory) button to

recall the MAX, MIN and LAST rpm values or the last

count (REV) from the last measurement period.

Measurement Notes

1. Bright ambient light may interfere with the reflected light

beam. Shading the target area may be necessary in

some cases.

2. The non-reflective are must always be larger than the

reflective area.

3. If the shaft or rotating object is normally reflective, it

must be covered with black tape or paint before the

reflective tape is applied.

4. To improve repeatability of low rpm measurements,

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.

461920 Datasheet(PDF) 4 Page - Extech Instruments Corporation.