Understanding Data Logger Systems: Types, Components, and Manufacturers

A data logger system is a device, or a collection of devices, designed to automatically collect, record, and store data from various sensors, instruments, or sources over a specified period. These systems are widely used in scientific, industrial, environmental, and research settings where continuous or regular monitoring and recording of data are essential.

The data recorded can encompass a broad range of measurements, including voltage, current, temperature, strain, pressure, load, power, resistance, and even events or states.

The core components of a data logger system typically include:

• Sensors/Instruments: These are the devices that actually measure the physical parameters of interest.
• Data Logger Unit: This is the central processing unit that receives data from the sensors, processes it, and stores it.
• Memory Storage: The space where the collected data is stored for later retrieval and analysis.
• Built-in Clocks or Timing Sources: These ensure accurate time-stamping of the data.
• Communication Interfaces: Ports like USB, Wi-Fi, Ethernet, or cellular connections allow data transfer and remote access.
• Software Tools: Applications used to configure the data logger, download data, and analyze the collected information.

Most data loggers employ digital digitizers for data acquisition.

As illustrated in the figure above, a data logging system is composed of sensors, data logging hardware, and data logging software. Sensors, acting as transducers, convert signals from one form to another. The number of sensors varies based on the application, leading to single-channel or multi-channel data loggers.

Data logging hardware receives data from the sensors and stores it in memory for analysis or future use. It also feeds data to the data logging software for display and analysis. With the increasing demand for diverse plots and measurements, applications that analyze and present data in user-friendly formats are crucial. This is achieved through data logging software applications.

Types of Data Loggers

Data loggers can be broadly classified into two types based on their software needs:

• PC-Based Data Loggers: These require a connection to a computer for data logging and analysis.
• Standalone Data Loggers: These can operate independently and store data internally.

Further categorization is based on the number of channels and data formats they support:

• Single Channel Data Loggers: Designed to monitor a single data source.
• Multi-Channel Data Loggers: Capable of monitoring multiple data sources simultaneously.
• Modular Data Logging Systems: Offer flexibility to expand or customize the data logging setup as needed.

A recent offering from Delphin Technology, the Expert Key 100 M, is a compact mobile measuring system. It features 14 analog and 8 digital channel inputs, providing connectivity for sensors, actuators, thermocouples, and RTD sensors. Integrated WLAN AP allows data exchange with tablets or PCs via Wi-Fi. USB and Ethernet provide for wired communication.

Data Logging Software

As mentioned earlier, data logging software either runs directly on the data logger hardware or on a connected PC. The increasing demand for multi-channel applications has driven the development of sophisticated data logging applications.

PC-based data loggers are particularly well-suited for high-efficiency applications, leveraging the substantial processing and memory resources of a PC.

Data logging software is commonly developed using languages such as LabVIEW or .NET, and may require custom drivers for communication interfaces like TCP/IP, CAN, or USB.

Data Logger Manufacturers

Data loggers are available from a variety of manufacturers, each offering solutions tailored to specific parameters and channel counts. Here are a few notable manufacturers:

• MadgeTech: A well-known company specializing in data loggers for diverse applications, including temperature, humidity, pressure, motion, current, voltage, shock, water level, and more. They offer both wired and wireless data loggers.

• Delphin Technology: Manufacturers of data logging hardware, software, and interfaces for GPS data acquisition, measurement data analysis, and mobile/de-centralized data acquisition.

• OMEGA Engineering Inc.: A manufacturer of process measurement and control equipment, offering a wide range of data loggers, including temperature & humidity loggers, voltage and current data loggers, pressure, strain & shock loggers, pH, flow & level data loggers, and multi-channel programmable data loggers. They manufacture both ethernet and wireless loggers.