Data Loggers: Quick Intro

Data loggers are an essential component of any data logging, quality control, and environmental monitoring system. These compact devices are designed to collect, monitor, and store location-specific environmental data via external or built-in sensors.

Data loggers evolved to replace stylus-based electromagnetic chart recorders that gained traction in the early 1990s. Equipped with onboard memory and often powered by batteries, these devices had become the go-to method of environmental monitoring in a wide array of industries, ranging from healthcare and pharmaceutical to food and beverage.

They could be found in warehouses, production environments, freezers, cold rooms, autoclaves, research labs, and even shipping containers. Keep reading to get the low-down on what data loggers are all about.

What are Today’s Data Loggers?

Today’s data logger is a dedicated digital device that allows organizations to observe, monitor, and capture a variety of data on specific processes or environmental parameters. They typically work remotely, collecting and documenting data in applications where measurement of critical conditions is needed to be taken consistently and regularly.

Data loggers are often leveraged in all sorts of production, research, performance, analysis, and environmental monitoring applications. Because of this, they are usually found in a raft of industries, including biopharmaceutical, aerospace, food, agriculture, and manufacturing.

Modern digital data loggers (DDLs) are designed to capture and store large volumes of detailed and precise monitoring data, typically to track consistency in critical environmental variables, such as pressure, humidity, and temperature. The core objective of using data loggers for environmental monitoring is to ensure high-quality and safe products, as well as protect sensitive assets and ensure regulatory compliance.

Today, the vast majority of data loggers are highly portable, autonomous, and compact devices that form an indispensable part of data logging technology. Because of their versatility and size, digital data loggers (DDLs) can be used in just about any setting and are often regarded as robust, convenient, and powerful upgrades to less flexible, old-school data acquisition technologies like electromagnetic chart recorders.

How Do They Work?

Again, data loggers can be employed in a broad range of industries to monitor conditions in various environments. They are often used to track and capture environmental data in production workspaces, storage environments, HVAC systems, operating rooms, ovens, and wherever else there’s a need for constant monitoring of environmental controls.

The way data loggers work is pretty straightforward, and it usually involves a three-prong mechanism. The first part is the sensory input, which uses a sensor or a series of sensors that take frequent and consistent measurements of environmental variables, such as voltage, humidity, temperature, or atmospheric pressure. The information is usually received in the form of electrical impulses and signals.

By design, a sensor can ‘log’ only one type of environmental variable or parameter. As such, temperature sensors cannot collect information on changes in humidity. The other way around is also accurate – a humidity sensor can’t detect or gather temperature data.

Most data loggers have a small, multi-functional computer chip (also known as a microprocessor) responsible for processing environmental information gathered by the sensors. Essentially, the microprocessor converts electrical signals into machine-readable environmental data.

A data logger also has an onboard data storage unit and an assortment of other peripheral features and accessories. While most loggers store data on an onboard memory chip, modern versions are additionally equipped with wired and wireless connectivity technologies for real-time data transmission.

Once the environmental data is stored in the device, you can download it using a USB disk or upload it automatically to a cloud-based service. Of course, the data can be transmitted to a computer, server, or even a smart device.

From the storage point, environmental data can then be analyzed, visualized, and (if necessary) validated. On top of that, data loggers are also fitted with configurable alert systems that ring an alarm when certain monitored conditions go out of desired range. What’s more fascinating is that some DDLs can be configured to send out alerts via text, instant messaging, phone calls, or emails when such scenarios happen.

Common Types of Data Loggers

Data loggers come in all shapes, sizes, and designs. However, they are typically classified based on variables that they measure.

– Temperature data loggers

As the name suggests, these data loggers are designed to measure, record, and monitor temperature data over a given period of time. Their sensory inputs usually consist of thermistors or thermocouples installed in the target environments. You can also find special temperature data loggers with probes designed for extreme temperature application, while others are meant to be submerged.

These loggers can measure product temperature (such as vaccine temperature), environmental temperature (such as temperature inside a warehouse), or both. In either case, temperature data loggers are often required to ensure consistency in product conditions and provide verifiable data for regulatory compliance.

For example, pharma companies like Pfizer and Moderna pack compact data loggers along with their Covid-19 vaccines. They will continuously measure, record, and report vaccine temperature, along with the batch location and timeline.

– Humidity data loggers

These loggers monitor and document the percentage relative humidity (%RH) readings of products, processes, and environments like greenhouses, clean rooms, hospitals, shipping equipment, and so on. They can also obtain water vapor concentration and dew point readings. Certain loggers (collectively called thermal data loggers) monitor both humidity and temperature changes.

– CO2 data loggers

Constant monitoring of CO2 levels is essential in various industries, as CO2 levels in facilities can impact  air quality and worker health. According to Dickson, most CO2 loggers are installed as part of an HVAC system, helping monitor and control Indoor Air Quality (IAQ).

– Pressure data loggers

The majority of pressure data loggers are employed to measure vacuum, atmospheric, and gauge pressure. However, some specific models are designed especially for monitoring water depth and differential pressure.

Other types include open-close data loggers, voltage/current data loggers, contamination data loggers, and light data loggers. They can also be classed based on the method of data transmission, with the most common being USB data loggers, WIFI data loggers, NFC data loggers, and Bluetooth data loggers.


Data loggers are essential pieces of environmental monitoring and quality control equipment. They acquire and transmit essential data on conditions like temperature, humidity, or equipment voltage. For this reason, they are popularly used in many industries, including healthcare, medical device, pharmaceutical, food and beverage, and aerospace, among many other regulated sectors.

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