Oumefar DT2236B Professional Photo/Contact Tachometer User Manual

1. Introduction

The Oumefar DT2236B is a professional handheld digital tachometer designed for accurate measurement of rotational speed (RPM) and surface speed. It utilizes both photo (non-contact) and contact measurement techniques, making it a versatile tool for motor testing, vehicle inspection, and various industrial applications. This device incorporates microcomputer (CPU) and laser technology for reliable performance and features an ultra-large LCD screen for clear readings.

2. Safety Information

WARNING: This device uses a laser. Avoid direct eye exposure to the laser beam. Do not point the laser at people or animals. Use caution during operation.

Read all instructions carefully before operating the device.
Do not attempt to disassemble or modify the tachometer.
Ensure batteries are inserted with correct polarity.
Keep the device away from water, high temperatures, and strong magnetic fields.
Remove batteries if the device will not be used for an extended period.

3. Product Overview and Components

The DT2236B tachometer is designed for ease of use and durability. Below are the main components and package contents.

3.1 Package Contents

1 x Photo/Contact Tachometer (DT2236B)
1 x User Manual (this document)
3 x Reflective Paper sheets
4 x Tachometer Accessories (for contact measurement)
1 x Black Carrying Bag

3.2 Device Layout

Front view of the Oumefar DT2236B Photo/Contact Tachometer — **Figure 1:** Front view of the DT2236B Tachometer, showing the LCD display, mode switch, and memory button.

Various contact tachometer accessories — **Figure 2:** Included contact tachometer accessories for different measurement surfaces.

Close-up of the laser emission point on the tachometer — **Figure 3:** Close-up view of the laser emission point, used for non-contact measurements.

LCD Display: Shows measurement readings, units, and battery status.
Mode Switch: Toggles between Photo Tach (RPM), Contact Tach (RPM), and Surface Speed (m/min) modes.
Memory Button: Stores and recalls maximum, minimum, and last measured values.
Laser Emitter/Receiver: For non-contact (photo) RPM measurements.
Contact Shaft: For attaching contact accessories for contact RPM and surface speed measurements.

4. Specifications

Parameter	Value
Model	DT2236B
Photo Tach Measuring Range	2.5 ~ 99,999 RPM
Contact Tach Measuring Range	0.5 ~ 19,999 RPM
Surface Speed Measuring Range	0.05 ~ 1,999.9 m/min
Resolution (Photo Tach)	0.01 RPM (2.5-999.99 RPM), 0.1 RPM (1,000-9,999.9 RPM), 1 RPM (over 10,000 RPM)
Resolution (Contact Tach)	0.01 RPM (0.5-999.99 RPM), 0.1 RPM (1,000-9,999.9 RPM), 1 RPM (over 10,000 RPM)
Resolution (Surface Speed)	0.01 m/min (0.05-99.99 m/min), 0.1 m/min (over 100 m/min)
Accuracy	±(0.05% + 1 digit)
Sampling Time	0.5 seconds (over 120 RPM)
Detecting Distance (Photo)	50 ~ 500 mm
Screen	5 digits, 18mm (0.6") LCD
Range Select	Auto-Ranging
Test Base	6MHz Quartz crystal
Battery	3 x 1.5V AAA batteries (NOT included)
Power Consumption	Approx. 45mA
Dimensions	20 x 7.5 x 3.5 cm (7.87 x 2.95 x 1.38 in)
Weight	Approx. 286g (10.1 oz)

Dimensions of the DT2236B tachometer — **Figure 4:** Physical dimensions of the DT2236B tachometer.

5. Setup

5.1 Battery Installation

Locate the battery compartment cover on the back of the device.
Slide or unclip the cover to open it.
Insert three (3) 1.5V AAA batteries, ensuring correct polarity (+/-) as indicated inside the compartment.
Replace the battery compartment cover securely.

5.2 Preparing for Photo (Non-Contact) Measurement

For accurate non-contact measurements, a reflective surface is required on the rotating object.

Cut a small piece of the provided reflective paper (approximately 1-2 cm square).
Attach the reflective paper to the rotating shaft or disk of the object to be measured. Ensure it is flat and securely adhered.
The reflective tape should be placed on a clean, non-reflective part of the object.

Tachometer pointing at reflective tape on a rotating object — **Figure 5:** Example of reflective tape application for photo measurement.

5.3 Preparing for Contact Measurement

For contact measurements, select the appropriate accessory from the package.

Identify the contact shaft at the bottom of the tachometer.
Choose the suitable contact accessory (e.g., cone, funnel, or wheel) based on the surface you intend to measure.
Firmly attach the selected accessory to the contact shaft. Ensure it is seated correctly to prevent inaccurate readings or detachment during use.

Close-up of the contact measurement point with an accessory attached — **Figure 6:** Contact measurement point with an accessory attached.

6. Operating Instructions

6.1 Powering On/Off

Press the power button (usually integrated with the measurement trigger) to turn the device on. The LCD will illuminate. Release the button to turn off the device (it may have an auto-off feature after a period of inactivity).

6.2 Selecting Measurement Mode

Use the mode switch located on the front panel to toggle between the three measurement modes:

Photo Tach (RPM): For non-contact rotational speed measurement.
Contact Tach (RPM): For contact rotational speed measurement.
Surface Speed (m/min): For contact linear speed measurement.

Close-up of the LCD screen showing a reading — **Figure 7:** Ultra-large LCD screen for clear reading of measurements.

6.3 Photo (Non-Contact) RPM Measurement

Ensure reflective tape is applied to the rotating object (refer to Section 5.2).
Select the 'Photo Tach' mode using the mode switch.
Hold the tachometer at a distance of 50mm to 500mm from the reflective tape.
Aim the laser beam at the reflective tape. The laser indicator will help you target correctly.
Press and hold the measurement button. The RPM reading will appear on the LCD.
Release the button to stop measurement. The last reading will remain on the display.

Tachometer in use, measuring RPM with laser — **Figure 8:** Tachometer performing a non-contact RPM measurement.

6.4 Contact RPM Measurement

Attach the appropriate contact accessory to the tachometer's shaft (refer to Section 5.3).
Select the 'Contact Tach' mode using the mode switch.
Gently press the contact accessory against the center of the rotating shaft or surface.
Press and hold the measurement button. The RPM reading will appear on the LCD.
Release the button to stop measurement.

6.5 Surface Speed Measurement (m/min)

Attach the wheel-shaped contact accessory to the tachometer's shaft (refer to Section 5.3).
Select the 'Surface Speed' mode using the mode switch.
Place the wheel firmly against the moving surface (e.g., conveyor belt, wire, cable).
Press and hold the measurement button. The surface speed reading in m/min will appear on the LCD.
Release the button to stop measurement.

6.6 Memory Function

The DT2236B automatically stores the maximum, minimum, and last measured values. To recall these values:

After a measurement, press the 'MEMORY' button.
Each press will cycle through: MAX (maximum value), MIN (minimum value), and LAST (last measured value).
The corresponding indicator (MAX/MIN/LAST) will be displayed on the LCD.

7. Maintenance

7.1 Cleaning

Wipe the device with a soft, dry cloth.
Do not use abrasive cleaners or solvents.
Keep the laser lens and contact accessories clean for accurate readings.

7.2 Battery Replacement

When the battery low indicator appears on the LCD, replace all three AAA batteries as described in Section 5.1. Dispose of old batteries responsibly.

7.3 Storage

Store the tachometer in its black carrying bag in a cool, dry place when not in use. Remove batteries if storing for extended periods to prevent leakage.

8. Troubleshooting

Problem	Possible Cause	Solution
Device does not power on	Dead or incorrectly installed batteries	Check battery polarity; replace with fresh AAA batteries.
Low battery indicator appears	Batteries are low	Replace all three AAA batteries.
Inaccurate Photo Tach reading	Reflective tape not properly applied or too small Measurement distance too far or too close Laser beam not consistently hitting reflective tape Ambient light interference	Ensure tape is flat and sufficient size. Maintain distance between 50mm and 500mm. Steady the device and aim carefully. Reduce strong ambient light if possible.
Inaccurate Contact Tach/Surface Speed reading	Contact accessory not firmly attached Accessory slipping on the surface Incorrect accessory for the surface type	Re-attach accessory securely. Apply firm, consistent pressure. Select the correct accessory for the application.
No reading on display	Object not rotating Measurement button not pressed Out of measurement range	Ensure the object is rotating. Press and hold the measurement button. Verify the RPM/speed is within the device's specified range.

9. Warranty and Support

9.1 Warranty Information

This Oumefar DT2236B Tachometer is typically covered by a standard manufacturer's warranty against defects in materials and workmanship. Please refer to your purchase documentation or contact your retailer for specific warranty terms and duration.

9.2 Customer Support

For technical assistance, troubleshooting beyond this manual, or warranty claims, please contact the retailer or the manufacturer directly. Keep your purchase receipt or proof of purchase handy when seeking support.

Oumefar DT2236B