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What you need to know about temperature data loggers

Estimated reading time: 7 minutes

What is a temperature data logger? What do you need to know when looking for the right version for you? Dive into this and more right here.

A temperature data logger is a device used for temperature monitoring to automatically measure and save temperatures.

Also read: 5 things to look for in an all-in-one temperature compliance solution (and 11 issues it can solve)

In this article, you can read about:

  1. What is a temperature data logger?
  2. What specifications do you need to think about when choosing a data logger?
  3. What does calibration mean for temperature data loggers?
  4. What are the benefits of using a data logger?
  5. How does Eupry’s WiFi-based data logger work?

6 ways to spend less time on manual temperature compliance

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This guide outlines how.

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What is a temperature data logger?

A data logger is an electronic device that records temperature data in real-time.

Temperature data loggers come in many different shapes and sizes and with a large variety of functions and specifications. For instance:

  • Almost all data loggers are based on microcontrollers. These devices are usually small, battery-powered, portable, and equipped with a microprocessor, which uses internal memory for data storage of temperature measurements.
  • Some data loggers are directly connected to a personal computer. By using specific software programs, it is possible to activate the data logger and view and analyze the collected data remotely.
  • Other types of data loggers are designed as human interface devices that can be used as independent equipment.

Common for all temperature data loggers is that temperature data can be exported and viewed, normally on a pc or on an online platform.

However, the use of temperature data loggers varies for different sectors and industries, and the requirements for the temperature data logger also depend on the use and governmental and other standard requirements.

In many cases, the temperature data logger is used to monitor temperature that is of interest to a process that requires a certain temperature span to be held in order to obtain a specified result.

An example from Pharma is the storage of vaccines, which often need to be held within 2 to 8 degrees in order for the vaccines to be useful.

Also read: How Eupry’s wireless data loggers automate temperature compliance

What specifications do you need to think about when choosing a data logger?

There are some general specifications of temperature data loggers that define how they operate and can be used — in other words, whether they are a good fit for your business needs.

Cost and cost structure

Some temperature data loggers are purchased as single units, and some are purchased as part of a service, sometimes including the software package and calibration.

The cost structure can be based on a yearly fee for the use of the associated software package, and some also include regular calibration.

The running cost for non-service data loggers should also be considered since they can be expensive in the long run.

Battery life

As most temperature data loggers run on battery, the battery life determines how long the temperature data logger can operature before a battery change is necessary.

Export of data

The data stored in the temperature data logger has to be exported from the data logger in order to document the measured data.

This is mostly done either with a data logger being inserted into a computer’s USB port, and then using the associated software to download the data from the data logger, or the data logger can automatically transfer data on a regular basis wirelessly to an online system.

Also read: Compare data loggers with wireless data transfer (Eupry’s) vs. classic USB transfers


The resolution of measurements defines how small temperature changes the data logger is able to measure temperature in. In other words, how many digits the temperature can be measured in.

Temperature span or measurement area

Defines which temperatures the data logger is able to measure. This often has to do with the mechanical construction of the temperature data logger, and covers the span from low to high where the data logger can operate and measure temperatures.


The accuracy / precision defines how accurate temperature can be measured. In other words; how close to the actual temperature does the data logger measure temperatures.


Calibration (described in greater detail below) describes how the temperature data logger is calibrated and to what precision or uncertainty. The calibration of the temperature data logger ensures that the temperature measurements are equal to the measurements of all other temperature-measuring devices. This is one of the main reasons why calibrations are required by many quality standards.

Also read: What kind of temperature calibration should I choose?


The software used for exporting and viewing (and possibly alarming) varies greatly in ease-of-use and functionalities. Some systems are very basic, and only allow for the export and viewing of data, while others include more functionalities such as user management, deviation management, and calibration management.


Depending on whether the data logger was purchased as a one-time cost, or as a service model, the product guarantee can vary.

Some data loggers come with a limited guarantee, and some come with a use guarantee where the product is replaced free of charge in the period of use.

Alarms functionality

Some temperature data loggers not only serve to monitor and document the temperature but also work as an alarm system that can alarm you in the event of a temperature excursion. In this case, an alarm is sent to the user when an out-of-specification temperature is measured, and the user can react to the problem.

Also read: How using data loggers WITH (Eupry’s) vs. without alarms differ (traditional USB loggers)

Storage Capacity

The amount of measurement points stored locally on the data logger is often referred to as the storage capacity, and is in most cases defined as the number of measurements that can be stored before unloading is needed.

Dependent on the measurement interval, the time before unloading is needed varies as a high measurement frequency fills the internal memory faster than a lower one.

What does calibration mean for temperature data loggers?

In most uses of a temperature data logger, calibration is needed in order to ensure that the data logger measures correctly, and that this can be proved.

6 facts about temperature data logger calibration

  1. What it is: Calibration is the process of ensuring that the temperature data logger measures in accordance with international standards.
  2. How it is done: Calibration is done by comparing the readings of the temperature data logger to a reference temperature reader. By comparing the readings of the temperature data logger to the reference, any differences can be observed and noted as measurement errors.
  3. Calibration uncertainty: As the comparison of the temperature data logger and the reference temperature can never be performed completely without error, a calibration is always associated with a certain uncertainty, known as the calibration uncertainty. The amount of uncertainty has to do with the method of calibration, and the accepted uncertainty is often dictated by the quality requirements set forth by governmental or standards requirements.
  4. Calibration certificates: The proof of calibration is known as the calibration certificate and is the document provided by the calibration laboratory. A temperature data logger can only be said to be a calibrated temperature data logger when the calibration certificate is obtained.
  5. Accredited or non-accredited: Based on the requirements, the calibration certificate can either be issued by a non-accredited or accredited laboratory.
  6. Who does it: The calibration can either be purchased at a calibration laboratory by sending in the data logger or be part of the service associated with the data logger system.

Check out: 8 calibration components you should have ready for an audit of temperature compliance

What are the benefits of using a data logger?

One of the main benefits when using a data logger is the ability to automatically collect data 24/7.

After the device is activated, it starts measuring the temperature right away. Afterward, the data logger is normally left unattended to measure and record the temperature data throughout the monitoring period.

This allows an overall and precise view of the environmental conditions being monitored. The process of viewing and analyzing the collected data differs according to the data logger used for temperature measurements.

A WiFi data logger permits access to the data at any time and from anywhere through software or online platforms that can be entered by using any type of device, such as a mobile phone, computer, or tablet.

A USB data logger has to be taken out manually from the cooling equipment and then connected to a computer in order to view and analyze the temperature data. This process interrupts production and operations since it requires the original USB data logger to be replaced with another data logger during the period it is taken out. Meanwhile, a wired data logger, which has high usage in Pharma and Pharmaceutical industries, requires a USB cable to connect to the PC.

One cable is needed for each location when downloading and analyzing the temperature data.

Also read: FDA 21 CFR Part 11 compliant monitoring systems: What to look for?

USB data logger (fourtec Microlite)

Eupry WiFi data logger

How does Eupry's WiFi-based data logger work?

The quick version: The Eupry WiFi Data Logger is a leading solution in the Pharma & Pharmaceutical industries, due to its high level of efficiency, time-saving in operations, and cost-effectiveness in monitoring and support.

The monitoring, alarming, and reporting solutions for refrigerators and freezers, which are a part of the package when acquiring Eupry WiFi Data loggers, reduce the risk of losing temperature-sensitive material and help ensure regulatory compliance.

Tell me more about wireless data loggers

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