A digital data logger is an electronic device that measures and records various environmental conditions. These conditions can be temperature, humidity, pressure, voltage, or current. Measuring them is essential in many industries where compliance regulations exist. The data logger contains a microprocessor that acts as a memory and stores collected data for download later. Some models provide real-time access to the data. A chart recorder is essentially an old-school version of the digital data logger. Instead of using a microprocessor for storage, a chart recorder marks the measurements on a paper chart that shows variations in the values recorded at a glance. In this article, we will take a closer look at each and compare the two.

Understanding Chart Recorders

As stated above, chart recorders differ a great deal from digital data loggers. A chart recorder depends on a pen that is either dragged across a paper chart to indicate such things as temperature or humidity, or the pen is connected to the measuring device. In the latter instance, the pen moves in response to the environment. There are versions of chart recorders where the pen is moved by an electronic sensor. Either way, the main idea behind a chart recorder is that a chart is drawn by a pen showing historic measurements for however long the readings have been collected. The passage of time is reflected by the constant movement of the paper underneath the pen. Depending on the design of the chart recorder, the paper is either a linear strip or a round paper disk.

Understanding Digital Data Loggers

The digital data logger collects the same type of information as a chart recorder but instead of using a pen and paper, an electronic signal is converted into a physical property, such as temperature or humidity. That property is then stored digitally. A data logger stores these readings internally and as such, they are easy to retrieve via direct download to a desktop or laptop computer, or wirelessly to a smartphone. Digital data loggers employ sensors to gather the measurements needed. They can be probes that extend out from the device or sensors that are located within the data logger. And since the measurements are being taken digitally, they are very accurate and do not take much storage so a high volume of data can be collected before it needs to be downloaded.

Chart Recorders vs. Digital Data Recorders: Pros and Cons

There are several pros and cons to chart recorders and digital data loggers. Here is a look at the five most important factors to consider when comparing the two technologies and thinking of making a change. In fact, Dickson suggests several reasons chart recorder users may want to consider switching to digital data loggers.

1. Costs

Both chart recorders and digital data loggers require an initial investment when the new equipment is purchased. However, those costs will continue with chart recorders simply because pens and paper will need to be constantly replaced. This will also include manpower to complete. Then there is the need for storage space for the completed charts. A data logger will require regular calibrations and software licenses. Over time, sensors or probes may require replacement but these costs will not be near what the ongoing expenses of a chart recorder can be.

2. Data

When comparing data backup, archiving, and retrieving is becomes very clear that this will take some time with a chart recorder. Sometimes paper records get ripped and that can result in a critical loss of data. With a digital data logger, information is stored internally until it is required for analysis. Then the data can be transferred to a computer hard drive or a cloud storage solution. With either of these methods, data is far easier to access than with a chart recorder.

3. Software

Chart recorders are not compatible with any type of software program. However, digital data loggers require software to permit data collected to be downloaded and shared. Also, with software, data loggers can be connected to a network where they can be used remotely. This permits the data to be viewed and examined in chart or graph formats without the need to be physically near the location the environmental conditions are being monitored.

4. Compliance

Digital data loggers have a great deal of flexibility compared to chart recorders when comparing the two on matters of compliance. Some industries have heavily regulated guidelines that require environmental conditions monitored for fixed periods of time and may be requested for review within 24-hour windows. Cloud-enabled systems that have incorporated digital data loggers can meet these strict requirements with ease. Although chart recorders can do all of these things, it will take longer to find the required data and that could prove to be problematic in the long run.

5. Alerts and Customization

Alerts can be sent from digital data loggers to specific personnel should the monitored conditions take a sudden step off track. This ensures that human intervention can be exercised promptly to prevent an issue from developing. That issue could result in inventory loss should the situation be left unchecked for any length of time. Temperature and humidity settings could result in product spoilage, as an example. These alerts can be customized to be sent as phone calls, text messages, or emails. A chart recorder will show where a monitored value went off course, but it won’t be noticed until someone looks at the paper chart. 

Conclusion

New technology trumps old technology in many cases. When comparing chart recorders to digital data loggers, the electronic version of an environmental monitoring device is more accurate, reliable, flexible, and capable to do the job and do it better. Sure, they may cost a bit more at first, but the benefits of having better access, the ability to meet compliance requirements quickly, and having the means to alert someone when values begin to fall out of regulated zones far outweighs the old-school way of doing things with a chart recorder.