How does the calibration of a tachograph work?

Calibrating a tachograph is a crucial measure to ensure that the device works accurately and reliably. It ensures that the data recorded on the tachograph – especially speed and driving time – is correct and in accordance with legal requirements. This calibration is not only important for compliance with regulations, but also for safety on the road. In this blog post, we will take a detailed look at the topic of tachograph calibration: What is a tachograph, why is calibration necessary, and how does it work?

What is a tachograph?

A tachograph, also known as a tachograph, is a device that is installed in commercial vehicles, especially trucks and buses, to monitor and record the driver’s driving data. This data includes information such as the speed driven, the distance traveled and the driver’s driving times. The tachograph helps to ensure that legal regulations regarding maximum driving time and rest periods are complied with.

The tachograph has two main functions:

1. Recording of driving data: This data is important for monitoring driving times and breaks and is also used for accident analysis.
2. Evidence in the event of checks: In the event of a check by the police or other authorities, the data from the tachograph is used to determine whether the driver has complied with the applicable regulations.

Why is it necessary to calibrate a tachograph?

A tachograph must be calibrated regularly in order to provide accurate data. This calibration is necessary because the tachograph reacts to various parameters such as speed and distance traveled, which can be influenced by different factors, e.g. the vehicle’s tires, axle ratios or changes in vehicle technology. Incorrect calibration can lead to the records being inaccurate and the driver unintentionally violating legal regulations.

A correctly calibrated tachograph ensures that the data displayed is reliable and correct for both the driver and the authorities. In the event of an inspection, incorrect calibration of the tachograph can lead to fines or other legal consequences. Regular calibration therefore helps to protect the driver and the company from potential legal problems.

How does the calibration of a tachograph work?

Calibrating a tachograph involves several steps and requires specific expertise and special equipment. Here are the essential steps for calibrating a tachograph:

1. preparation of the vehicle

Before calibration can begin, the vehicle must be prepared. It should be parked safely on a level surface and all the necessary equipment should be to hand, including:

• The tachograph
• A calibration device (this can be a tachograph tester)
• A suitable test track (if required)
• Technical documentation of the vehicle, such as tire size and axle ratio, as these factors can influence the calibration

2. checking the vehicle data

To carry out the calibration correctly, the exact vehicle data must be known. These include:

• Tire size: The circumference of the tires has a direct influence on the speed displayed by the tachograph. A larger tire circumference leads to a higher speed on the tachograph, a smaller one to a lower speed.
• Axle ratio: This refers to the ratio between the revolutions of the drive shaft and the wheels. This information is necessary for an exact calculation of the speed.
• Vehicle type: The type of vehicle and its operating conditions can also play a role.

This data is specified either directly in the vehicle or in the vehicle documentation and is of central importance for calibration.

3. calibration of the tachograph

The actual calibration of the tachograph is carried out using a calibration device. The calibration device compares the actual speed of the vehicle with the speed displayed by the tachograph. A signal is sent to the tachograph that simulates the actual speed of the vehicle. This process usually takes place on a test track where the vehicle is traveling at a certain speed while the tachograph is being monitored.

If a discrepancy is detected between the actual speed and the displayed speed, the tachograph is adjusted so that the displayed speed is correct. This can be done by adjusting the calibration value in the tachograph so that it accurately reflects the actual speed of the vehicle.

4. completion of calibration and documentation

Once the calibration is complete, the tachograph is checked again to ensure that all measurements are correct. As a rule, the calibrated tachograph is provided with a sticker or sticker indicating the date of calibration and the next calibration interval.

A calibration certificate is issued for the documentation, which confirms the tests and adjustments carried out. This certificate should be kept in the vehicle so that it can be presented in the event of an inspection by the authorities.

How often does a tachograph need to be calibrated?

A tachograph must be calibrated regularly to ensure that it always works accurately. In the EU, there are clear regulations on the calibration and maintenance of tachographs. According to the regulations, calibration must be carried out every two years, but this period may vary depending on the country and specific requirements.

It is also recommended to calibrate the tachograph before a long journey or after major changes to the vehicle, such as changing the tires or the axle ratio. In some cases, calibration may also be necessary if the tachograph is damaged or a new tachograph has been installed.

Conclusion

Calibrating a tachograph is an essential part of vehicle maintenance for companies that operate commercial vehicles. It ensures that the tachograph records are correct and comply with legal requirements. Incorrect calibration can have serious consequences for both the driver and the operator of the vehicle.

The calibration itself requires specialist knowledge and specialized equipment, which is why it should be carried out by trained personnel. Regular checks and maintenance of the tachograph are necessary to ensure the smooth and safe operation of vehicles. Companies should ensure that all legal deadlines are met to avoid legal problems and fines.