Cartesykj Digital Tachometer Calibration Tool For Speedometer

Cartesykj Digital tachometer Calibration Tool for speedometer

1. Overview of the Digital Tachometer Calibration Tool

The digital photoelectric tachometer is a non-contact speed measurement instrument used to detect the rotational speed (RPM) of rotating components such as rollers, wheels, or shafts. It works by detecting a reflective mark or light beam and displays the rotational speed in RPM (revolutions per minute). It is a widely used tool for calibrating vehicle speedometer testers (speed test benches).

2. Importance of Calibration

1. Ensures Testing Accuracy
   The speedometer tester must accurately measure vehicle speed, especially at low-speed conditions. Calibration ensures that the displayed speed is within the required tolerance (typically ±4%) and prevents false test results.

2. Meets Legal Metrology Requirements
   According to national regulations (e.g., for vehicle inspection stations), the speed tester must be periodically calibrated, and the tachometer used for calibration must hold a valid calibration certificate.

3. Ensures Fairness and Legal Traceability
   Proper calibration records serve as legally recognized evidence and are essential in the event of disputes or technical audits.

3. Instructions for Use (Calibrating a Speedometer Tester)

Step 1: Preparation

• Ensure the speedometer tester is operating correctly.

• Clean the roller surface to remove dust or oil that could interfere with the reflective sensor.

• Apply a reflective tape (single point or evenly spaced) to the roller.

• Turn on the digital tachometer and set the unit to RPM.

Step 2: Begin Measurement

• Aim the tachometer at the reflective tape on the roller, maintaining a stable distance (approx. 5–20 cm).

• Start the speedometer tester to rotate the roller at a fixed simulated speed (e.g., 20 km/h).

• The tachometer will detect the reflected signal and display the real-time RPM of the roller.

Step 3: Convert and Compare Data

• Calculate the theoretical vehicle speed using the roller diameter:

  $$V=\frac{\pi \times D\times RPM}{60}\text{(V in km/h, D in meters)}$$

• Convert the measured RPM into vehicle speed and compare it to the speedometer tester's display.

• If the deviation exceeds the allowed range (usually ±3–4%), adjust the tester’s settings via software or control panel.

Step 4: Finalize Calibration

• Record the measured data and device ID.

• Save the calibration report and post it near the equipment for reference.

 4. Notes and Best Practices

• Ensure the tachometer has a valid third-party calibration certificate before use.

• Begin calibration with a low-speed test (e.g., 10–20 km/h) to stabilize the reading.

• Avoid strong ambient light or reflective surfaces that may interfere with the sensor; use shielding if needed.

• It is recommended to perform formal calibration every 6 to 12 months, depending on usage frequency.