The Basics of Data Loggers

Data loggers are small electronic devices used to track and store location-specific data via built-in or external sensors. They are typically battery-powered and equipped with internal memory, and have become the predominant method of monitoring in most contemporary industries, having increasingly replaced the electromagnetic chart recorders that originated back in the early 19th century.

Data loggers are used in a variety of industries and applications that require critical monitoring of environmental variables such as temperature, humidity, and pressure in order to produce and maintain a safe product. These include, but are not limited to, the healthcare industry, manufacturing, aerospace, and food/beverage production and storage.

Below we introduce you to the basics of data loggers, including why they are important, how they work, where they are used, and how to select the right data logger for your business.

Why Data Loggers Are Important

Data loggers are critical when it comes to demonstrating compliance with industry-specific regulations and standards. When implemented correctly, they provide data that can be used to either establish compliance or reveal hidden problem areas to address.

You can then further analyze the data using software to enhance quality and performance, track down problems before they become serious, and visualize data to illuminate trends and fluctuations. In addition, data loggers are key in conditions where there are quality and environmental controls in place, including highly sensitive, dangerous, or otherwise critical environments. Modern data loggers can also work in concert with cloud-based remote monitoring systems to keep you informed of your environment even when you’re not there.

Failure to use data loggers in a sound and systematic manner can, depending on the industry involved, result in time-consuming investigations, hefty fines, and expensive lawsuits. This can also impact those working in research, causing results to come under scrutiny and impact the reputation of individual research or research groups.

How Data Loggers Work

Data loggers can be used to monitor environmental conditions in refrigerators, production workspaces, heat treatment ovens, operating rooms, HVAC air ducts, and anywhere else there is a need for closely monitored environmental control.

The basic functionality of a data logger is quite straightforward: a sensor takes regular measurements of a parameter or variable (such as temperature, humidity, or differential pressure) and the logger stores that data on a memory chip. You control how often data samples are taken and what happens with the data once it is collected.

Once the data is stored, you can transmit it to a server, a computer, or a smart device; upload it to the cloud; or download it. The data is then visualized, analyzed, and (if needed) validated. In addition, data loggers can also be configured to send out alerts or signal an alarm when certain conditions occur. We explore common types of data loggers, below.

Temperature Data Loggers

As the name implies, a temperature data logger autonomously measures and records temperature data over a certain time period. Most probes for temperature data loggers use either thermocouples or thermistors. There are special loggers designed to be submerged (e.g., rated IP68) and certain probes engineered for extreme temperatures (e.g., -300F to 2000F).

Temperature data loggers can record the environmental temperature or the temperature of the product itself, recording the time along with the temperature reading. Such data loggers are often required in order to provide evidence of compliance with applicable regulations. Some loggers are small enough that they can be easily placed inside an insulated shipping container with the product.

An example of where a temperature data logger would be used can be taken from the pharmaceutical industry. Certain medications, such as vaccines, must be kept within a specific temperature range to prevent a reduction in their shelf life or negatively impact their effectiveness. Failure to maintain the product within a certain temperature range can also lead to problems when a compliance audit is performed.

Humidity Data Loggers

Another common type of data logger is used for obtaining percent relative humidity (%RH) readings, dew point, and water vapor concentration. Some loggers provide not just numerical data, but humidity charts as well, and there are also models available that collect both humidity and temperature readings.

Humidity data loggers are used in any industry where it is important to track environmental conditions, such as healthcare, food and beverage, medical devices, and manufacturing. For example, a humidity data logger can monitor humidity levels in a hospital cleanroom or lab, and might be used in conjunction with CO2 and temperature monitors.

Pressure Data Loggers

Pressure data loggers are used to measure gauge, atmospheric, and vacuum pressure, with certain models designed specifically for measuring differential pressure. It is even possible to measure water depth using a sealed pressure data logger.

Pressure data loggers are used in a wide variety of applications and industries. Pressure loggers that are designed for vacuum temperatures are often used in the pharmaceutical or food processing industry. They are also used in wastewater processing plants or to track pressure in municipal water supply lines.

Differential pressure data loggers are used in situations where even a small change in pressure could result in a serious issue. Differential pressure is important when it comes to operating rooms in hospitals, for example, where a negative pressure differential between the OR and other rooms could draw in contaminated air. The reverse could also happen: air from the surgical theater could be drawn out and expose staff and patients to dangerous airborne contaminants.

CO2 Data Loggers

Close monitoring of CO2 levels is a necessity in many industries, especially when indoor air quality is a critical variable. CO2 is emitted with each breath we take, and if the level becomes too high, it can negatively affect alertness and concentration, among other things. The most common way of reducing excessive CO2 in a standard work environment is to bring in outside air through ventilation.

You will often see CO2 loggers implemented as part of an HVAC system to record IAQ (Indoor Air Quality) data. They are also able to assist in controlling IAQ by being configured to trigger outside air ventilation when levels exceed a predetermined amount. 

Open/Close Data Loggers

The main application of open/close data loggers is the remote monitoring of a door (via a magnetic switch) that when opened and closed too often could alter the surrounding environment. This not only includes when the door is opened or closed, but more importantly, whether it has been left open for too long (or vice versa). They are often used as a backup to main temperature alarms with refrigerators, freezers, heat treatment ovens, or any enclosed area whose temperature must be maintained within certain critical limits. They can also provide visibility into the open/close state of areas like loading dock bay doors or clean rooms, and can track how many open/close events have taken place over a period of time. 

Where Are Data Loggers Necessary?

Anytime critical environmental conditions need to be controlled or monitored, data loggers play a pivotal role. The following examples are just some of the major industries that rely heavily on data loggers.

Data Loggers in Healthcare

Given the stakes, it’s no surprise that the healthcare industry has a huge variety of applications for data loggers, spanning across hospitals, pharmaceutical companies, medical device manufacturing, and other areas. The correct use of data loggers can support both FDA and VFC regulatory requirements, along with patient safety. This leads to a reduced risk of asset loss in procedure rooms, blood banks, operating rooms, labs, and storage areas for critical items such as blood or vaccines. 

For example, a vaccines for children (VFC) provider is in need of constant, reliable, accurate tracking of the temperatures for the refrigerators in which vaccinations are stored. Having environmental data loggers installed will gather the appropriate data to demonstrate compliance with the relevant regulatory requirements. In addition, you can configure data loggers to provide real-time alerts should conditions deviate from preset conditions.

Data Loggers in Aerospace

Environmental monitoring in connection with AS9100 and ISO 9001 guidelines is an important part of aerospace manufacturing. Not only must environmental conditions meet certain standards, but those conditions must remain constant. 

Take, for example, the manufacturing of aerospace components such as engines, wings, turbine blades, or any other of a myriad of essential parts. These must be manufactured with strict controls in place in order to ensure their quality and safety, as even minor fluctuations in humidity and temperature can have a serious impact on their quality, integrity, and physical structure. 

Humidity and temperature data loggers are installed at key points along the production line and in storage rooms to gather data and demonstrate compliance with regulatory and internal quality control standards, and can alert you when fluctuations occur so they can be addressed as soon as possible. Monitoring in these areas is critical as excessive humidity or temperature fluctuations can lead to damage of electronic components, and also a problematic curing environment for sealants and coatings.

Data Loggers in Food & Beverage

In the food and beverage industry, data loggers are used in production, transportation, storage, commercial kitchens, as well as grocery and retail operations. Humidity, pressure, differential pressure, and temperature data loggers are most commonly used. They are critical to ensuring that your facilities and processes meet FDA, FSMA (Food Safety Modernization Act), and HACCP (Hazard Analysis Critical Control Point) regulations, as well as internal quality control standards.

For example, both cooked and raw food must be kept within a certain range of temperatures to remain safe for the customer and to comply with applicable regulations. Temperature data loggers are ideal for monitoring or recording temperatures and providing necessary alerts for storage and processing areas.

The addition of an open/close data logger can alert you when the door to a refrigerator has been left open so you can see that it is properly closed before it has a serious impact on temperature levels. It can help prevent major temperature fluctuations before they happen or can be used to track down the source of such fluctuations.

Data Loggers in General Manufacturing

Data loggers have proven essential in manufacturing, including non-sterile, where they can support the production process. This is accomplished by tracking environmental conditions that directly impact the final product. The most commonly used data loggers are for monitoring temperature, humidity, and differential pressure. 

Many products are adversely affected by fluctuations in temperature and humidity. For example, polymers and composite materials can change size and shape when exposed to temperature and humidity changes. When working with such materials, it is important to keep the storage rooms within the desired range—which is where data loggers become crucial. They can record fluctuations to not only provide alerts, but to enable you to track down the source of the fluctuations so they can be better controlled.

How Do I Select and Maintain a Data Logger for My Business?

Once you have recognized the need for a data logger, the next step is to determine what type of measurements you need to take and the typical range for these values. Such determinations provide an excellent starting point for selecting a data logger.

You will also want a general idea of where the data logger needs to be installed so you can make an informed decision based on potentially complicating issues such as installation outdoors (where it will need to be resistant to rain and dust), or in a highly confined space (meaning it needs to be as compact as possible). Another example is high-temperature environments: you will need to make sure that the data logger (not just the sensors) can handle such conditions.

A second consideration involves when you need access to the data. Does your application require real-time monitoring (e.g., a refrigerator storing human tissue samples) or do you just need data that can be downloaded in bulk at a later time? This will also help you significantly narrow down your options for selecting a data logger.

A third factor to weigh is whether you are gathering data in order to adhere to certain industry standards or regulations. If so, you need to make sure that the data logger is appropriate for documenting compliance (21 CFR part 11, for example) and preparing for audits.

Depending on your application, you may need more than just data readings. Mapping the distribution of temperature and/or humidity for cold storage, warehouses, chambers, or other spaces can provide invaluable data for compliance audits and process control and improvement.

Once you have your data logger in hand, it’s time for installation. Your data logger will need to be installed and configured for use. After that, it will need to be tested to ensure that it performs as expected. Then, just like any other piece of equipment, data loggers need to be maintained. Part of that process involves calibration and validation. 

During the calibration process (which includes one-or-more-point calibration testing), the sensor and a standard are placed in a stable environment. The sensor readings are compared against the standard, and if there is a difference, the sensor is adjusted to match the standard. This process is repeated until the sensor gives consistently correct readings.

Validation of data loggers serves several purposes: verifying that the data logging equipment has been properly installed, ensuring that the software is correctly configured, and documenting that everything is in proper order. Validation experts typically perform three types of validation: installation qualification (everything has been installed correctly), operational qualification (equipment is operating correctly and meets design specifications), and performance qualification (equipment is performing correctly and within correct specifications).

Where Can I Learn More about Data Loggers?

Data loggers are a powerful tool when it comes to issues of compliance and quality control. If you would like to learn more about how to choose the best data logger to achieve your business’s monitoring goals, contact the experts at Dickson today.