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- What is a data logger? | Basics & classification
Data loggers: basics,
functions and classification
Data loggers are used in numerous applications to reliably monitor environmental conditions and measured values. Data loggers continuously capture measured values over a defined period and form the basis for reliable monitoring and documentation of environmental conditions. Depending on the application, data loggers differ in terms of functional scope, technology and degree of integration. This page conveys the fundamental concepts, explains differences between standalone loggers and monitoring systems, and provides a professional classification of key aspects such as measurement practice, alerting and documentation.
What is a data logger?
A data logger is a measuring instrument for the continuous acquisition, storage and evaluation of measured values over a defined period.
Typical measured variables are temperature, humidity, CO2, pressure, vibration or UV radiation.
Data loggers are used to monitor processes, verify quality and detect deviations at an early stage.
Data loggers – precision in series
A data logger from Testo is more than a storage device. It is your guarantee of seamless records. Find out how our devices allow you not only to capture measured values, but also to evaluate them in a process-reliable way – for maximum transparency in your workflows.
Temperature data loggers
Temperature data loggers are used to reliably monitor and document temperature profiles. They play a central role in areas such as storage, transport, production and quality assurance, where stable temperatures are critical. Continuous recording enables seamless traceability and early detection of deviations.
Humidity data loggers
Humidity data loggers capture humidity levels and help to permanently control climatic conditions. They are used to prevent material and quality-related damage, for example in storage areas, production environments or sensitive rooms. Precise humidity measurement supports compliance with defined limit values and standards.
CO2 data loggers
CO2 data loggers are used to monitor carbon dioxide concentrations in indoor spaces and work areas. They are used to assess indoor air quality, optimise ventilation concepts and minimise health and quality-related risks. Continuous measurement creates transparency about air quality and usage situations.
Distinction: data logger vs. monitoring system
Data loggers capture and store measured values locally or transmit them with a time delay.
Monitoring systems enable continuous, usually centralised monitoring with automatic alerting.
The choice between a data logger and a monitoring system depends on criticality, response time and regulatory requirements.
Online monitoring – classification & benefits
Online monitoring enables the continuous monitoring of measured values in real time. In contrast to conventional data loggers, data is transmitted automatically, evaluated centrally and actively reported when limit values are exceeded. This form of monitoring is particularly suitable for critical processes where an immediate response is required.
Standalone vs. radio / stationary data loggers
Standalone data loggers operate autonomously and are read out manually.
Radio or stationary data loggers automatically transmit measured values to a central platform.
Radio solutions are particularly suitable for permanently critical processes and distributed locations.
Networked data loggers for continuous monitoring
Radio and stationary data loggers continuously capture measured values and automatically transmit them to a central data platform. They are suitable for applications with multiple measuring points or a permanent monitoring requirement, where measurement data must be regularly evaluated.
Compared to autonomous standalone data loggers, they reduce manual read-out operations and create a central overview of all measuring points.
Measurement practice & data recording
Sound measurement practice defines measurement intervals, limit values and evaluation periods.
The quality of data recording is decisive for traceability and auditability.
Long-term recordings enable trend analyses and process optimisation.
testo 190 – measurement practice in thermal processes
In thermal processes such as sterilisation, pasteurisation or cleaning, stable measurement conditions and reliable data recording are essential. The whitepaper explains the fundamental requirements for measurement practice, highlights typical challenges in long-term and process measurements, and explains how temperature profiles can be documented under real conditions.
The focus is on the traceability of measurement data and the methodological safeguarding of thermal processes.
testo 191 – data recording under high-pressure conditions
The testo 191 data logger extends measurement practice to applications with elevated pressure, such as those found in autoclaves. In addition to temperature recording, it enables the documentation of pressure and temperature profiles under real process conditions. It is therefore particularly suitable for applications with combined requirements for temperature and pressure stability.
Alerting vs. documentation
Documentation serves as proof and retrospective assessment of measurement data.
Alerting enables an immediate response when limit values are exceeded.
The more critical the process, the more important the combination of alerting and documentation.
testo Smart Connect
Alerting and documentation are central components of reliable monitoring. While documentation serves to ensure traceability and proof of stable conditions, automatic alerting enables an immediate response when limit values are exceeded. Central platforms support the structured acquisition, evaluation and audit-proof documentation of measurement data.
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