Data Logger or Data Acquisition System: What Is the Difference?

Off-Balance-Scale-Pictogram

Context

You have a factor to measure, for example temperature. There are several types of precision sensors that require a converter to render temperature data. In your project, however, the display of the data is not enough, you want to keep track of it. Your next question is:

How do I record environmental data?

Whether we are talking about a data logger or a data acquisition system, there are four main components to consider: 

  • the number of channels* needed for your project
  • the number of devices to record all the desired parameters
  • the recording capacity
  • the ease of access to your data.

*Channel: continuous reading of a measurement parameter

The data logger: a compact tool

The data logger is a compact and portable all-in-one tool. Whether you have only one parameter to measure or several, you will find a sensor that meets your needs. Here are the main features of a data logger.

Characteristic

 

Number of channels

Maximum 32 (1)

Number of devices

Stand-alone; difficult to combine

Type of power supply

Often battery powered, sometimes wired

Maximum number of recorded data

Limited by internal memory and sampling rate

Recording media

Internal to the recorder, limited capacity

Data access

Transfer from internal memory to computer

Sampling rate

Typically max 1 reading/second (1 Hz)

In the previous table, note that data loggers are often battery operated, due to their portable nature. For example, Omega presents a portable data logger that runs on a 9V battery and measures temperature with a Pt100 RTD probe.

Also, to allow for a longer sampling time, notice in the table that the sampling rate is limited. This is because the internal memory has a limited capacity. Typically, a data logger is used for a period ranging from 1 to 30 days. Finally, in order to collect the recorded data, it is necessary to extract them from the internal memory and transfer them to a computer for further analysis. 

Data loggers can be equipped with an LCD screen to facilitate the visualization of the data in real time, as in the illustration presented above. However, very few have a mechanism for viewing historical data along with current data. The visualization option is useful if you want to see at a glance the effects of a change on the measured parameters. For example, if you open the door of an incubator and want to see the effect on the stability of the temperature, humidity and carbon dioxide (CO2) level.

The above scenario raises another important point to consider. Data loggers are individual instruments. They provide time-stamped measurements, but if you are going to have several different instruments measuring all your parameters of interest (temperature and humidity, plus CO2), you are going to have to manually harmonize the data from all the instruments. Before you buy a data logger, think about the future: will you need a complete system to measure other parameters? If so, think about the data acquisition system.

The data acquisition system: a powerful tool

Some companies will tell you that data acquisition systems (DAQ systems) can be expensive. If you need a high-powered computer connected to the sensors, this may be the case. However, some DAQ systems work with a desktop computer and give you more data acquisition capability than data loggers.

Characteristic

 

Number of channels

Maximum 100 or more

Number of devices

Several

Type of power supply

Wired

Maximum number of recorded data

Almost unlimited

Recording media

Computer or external SSD drive (2)

Data access

Immediately

Sampling rate

Max 10 readings/second (10 Hz) or more

In the table above, notice that the data acquisition system has much greater capabilities than the data logger. Note the much faster sampling rate and immediate access to the data.

Sometimes DAQ systems seem complicated, such as the one from MCC, which allows you to connect different temperature probes (thermocouple, RTD, thermistor) and access the raw voltage reading. It should also be noted that this solution does not allow you to obtain measurements of different types.

Dracal Technologies' offer

The data acquisition system proposed by Dracal Technologies is so simple that we named it "Plug & Log Solution". The sensors are connected by USB to a desktop computer and the very intuitive graphical interface software allows you to literally plug and log your data in less than 3 minutes.

When you choose Dracal Technologies, you get free access to software tools to view and record your sensor data. DracalView is a graphical user interface that you can install on your Windows, MacOS or Linux computer. Easy to use, it allows you to configure, according to your standards, the recording of your measurements. You will also find a sampling frequency of up to 10 Hz and time-stamped data. With its graphical visualization options, you will be able to see in real time the data you are recording, in addition to the data measured since the sensor was connected. If you want to learn more about DracalView, check out our short video tutorials here.

With our data acquisition system, you will also have command line tools to extract data directly from the sensors. You can use them to integrate the data into your existing measurement system. They are an equivalent alternative to the software since they allow the same configuration options as DracalView, but without having to use the graphical interface to record the data.

The system proposed by Dracal Technologies allows connecting a virtually unlimited number of USB sensors. The only limit is the one imposed by the memory of the computer to which they are connected. Moreover, all measurements will be harmonized, regardless of their type (pressure, temperature, humidity, gas, particles, VOC or ambient light). This means that all measurements will be taken at the same time, at the same frequency, the units will be the same and the logging alignment of each sensor will be simple, accurate and automatic.

In conclusion

When you want to record environmental data, there are two types of devices available to you: data loggers and data acquisition systems. The major difference between the two lies in four main features:

  • the number of channels needed for your project
  • the number of devices to record all the desired parameters
  • the recording capacity
  • the ease of access to your data.

The data acquisition system outperforms the data logger on all four counts. With virtually unlimited recording capacity and a very large number of channels, your environmental data is recorded directly to your computer for immediate access. It also allows you to connect multiple sensors, either identical or different, and obtain harmonized data. Dracal Technologies' solution is to harmonize the data from an unlimited number of sensors, regardless of their type, in order to have a consistent and scalable data acquisition system.

The data logger is portable and often runs on batteries. For a seamless and continuous recording, a wired system is preferable. With Dracal Technologies, the sensors are powered by a USB connection. This type of connection also allows a reliable transmission of the measured data to the computer where they are recorded.

Dracal USB cable connected in a computer

Finally, if you want to consult in real time and in a graphical way the measurements you make, in addition to the past measurements, you need a data acquisition system that has this feature. This is what Dracal Technologies offers you with its USB sensors and software package. 

Contact us to see how we can meet your precision environmental data acquisition needs.

References

  1. Smith, Grant Maloy. 2020. “What Is a Data Logger - the Ultimate Guide | Dewesoft.” Dewesoft.com. April 3, 2020. https://dewesoft.com/daq/what-is-data-logger.
  2. ‌Smith, Grant Maloy. 2022. “Data Acquisition (DAQ) - the Ultimate Guide | Dewesoft.” Dewesoft.com. June 28, 2022. https://dewesoft.com/daq/what-is-data-acquisition.