USER GUIDE Model RPM33 Laser Photo / Contact Tachometer
Introduction Congratulations on your purchase of the Extech Laser Photo / Contact Tachometer, Model RPM33.
Description Meter Description 1. Surface (circumference) wheel accessory is shown connected to shaft (rubber cone and concave accessories are also supplied) 2. Adaptor shaft 3. Removable collar (Photo sensor and laser source are located at the top of the meter under this collar) 4. MEM (Memory) button 5. Battery compartment (rear) 6. MEASURE button 7. MODE button 8.
Safety WARNING! Do not directly view or direct the laser pointer toward an eye. Low power visible lasers do not normally present a hazard, but present potential for hazard if viewed directly for extended periods of time. The Laser in this unit complies with: FDA 21 CFR 1040.10 and 1040.11, IEC 60825‐1 (2001‐2008) Edition 1.2. EN 60825‐ 1:1994/A11:1996/A2:2001/A1:2002 CAUTION! Rotating and linear moving objects can be dangerous. Use extreme care. 4 RPM33-EU-EN V1.
Preparing for Measurements Non‐Contact (Photo) Tachometer Preparation 1. Apply a square piece of reflective tape to the surface of the object under test (nominal tape size: 0.5”/12mm). Be sure to affix the tape as close to the outer edge of the object under test as possible. See diagram below. 2. If not already done, unscrew and remove the meter collar (item number 3 in the Description section diagram) 3. Proceed to the “Taking Measurements” section below. Contact Tachometer Preparation 1.
Taking Measurements Non‐Contact (Photo) Tachometer Measurements 1. Prepare for the Non‐Contact measurement as described in the Measurement Preparation section above. 2. Use the MODE button (momentarily presses) to select RPM (rotations per minute) or Hz (Hertz: rotations per second) as the unit of measure. 3. Press and hold the MEASURE button to begin a measurement session. Hold the MEASURE button down for the duration of the test and release it to end the session. 4.
Contact Tachometer Measurements 1. Prepare for Contact measurements as described in the Measurement Preparation section above. 2. Determine if Surface Speed or Length measurements are to be made. Refer to the section “Surface Speed and Length Measurement Modes” later in this guide for details. 3. Press and hold the MEASURE button. 4. Touch the measurement accessory (cone, wheel, or concave accessory) to the object under test. 5. Read the measurement result from the LCD display. 6.
Datalog Readings The RPM33 can log up to ten (10) “reading sets” for each measurement session (for each unit of measure display).
Datalogging more than one Reading Set per Measurement Session If the MEM button is pressed more than once during a measurement session, more than one reading set will be created for that measurement session (one reading set for each MEM press). This is useful if more than one ‘initial reading’ is desired for a given measurement session. The MIN/MAX/AVG values logged in each reading set represent the MIN/MAX/AVG values recorded between the MEM presses.
Specifications General Specifications Time base Quartz crystal Display 5‐digit LCD Display Laser light source Class 2 laser < 1mW power; Wavelength is 630 to 670nm Detecting Distance 50 to 500mm (2 to 20") Sampling Time 0.5 seconds (over 120 rpm) Tachometer accuracy ± (0.05% reading + 1digit) Memory Measurement data are stored in ‘reading sets’. A reading set consists of one (1) instantaneous measurement plus MIN/MAX/AVG readings.
Measurement Range Specifications Range Resolution Accuracy Revolutions per minute 2 to 99,999 RPM 0.1 rpm (2.0 to 9999.9 RPM) 1 rpm (> 9999 rPm)* 0.05% of reading + 1 digit Frequency 0 to 1666 Hz 1 Hz 2 to 19,999 rpm 0.1 rpm (2.0 to 9999.9 RPM) 1 rpm (> 9999 rPm)* 0 to 2000 meters per minute 1 m/min 0 to 78,720 inches per minute 1 in/min 0 to 6560 feet per minute 1 ft/min Photo‐Tachometer Contact‐Tachometer Revolutions per minute Surface Speed 0 to 2186 yards per minute 1 yd/min 0.
