A PLC (Programmable Logic Controller) is an active control system that automates industrial processes, whereas a data logger is a passive recording device that captures and stores environmental measurements over time. They serve fundamentally different purposes. This article explains when to choose a data logger over a PLC, why PLCs fall short in cold chain logistics, and what a more sustainable monitoring approach looks like.
What is the difference between a PLC and a data logger?
A PLC is designed to control industrial equipment by processing inputs and triggering outputs, such as switching motors on or adjusting valves. A data logger, by contrast, is designed to record conditions, such as temperature or humidity, over a set period without intervening in any process.
PLCs are active systems that require programming, power infrastructure, and integration with other machinery. They are built for fixed environments such as factories or processing plants. Data loggers are passive, standalone devices that simply measure and store readings at defined intervals, making them portable and self-contained.
When should you use a data logger instead of a PLC for monitoring?
A data logger is the right choice whenever monitoring needs to be portable, low-cost, and independent of fixed infrastructure. Here are the key scenarios in which data loggers are clearly the better fit:
- Transport and logistics: Data loggers travel with the shipment across road, sea, air, and rail—something a PLC physically cannot do.
- Regulatory compliance: Cold chain monitoring often requires EN 12830-certified devices, a standard specifically designed for temperature recording during transport, not industrial control.
- Low setup complexity: Data loggers require no programming, wiring, or specialist installation.
- Cost-sensitive applications: Electronic data loggers are significantly cheaper to deploy than PLC-based systems, particularly for single-use or short-term monitoring needs.
- Infrastructure-free environments: Warehouses, shipping containers, and vehicles rarely have the power and network infrastructure a PLC depends on.
What are the key limitations of using a PLC for cold chain monitoring?
PLCs are powerful tools in the right setting, but cold chain logistics is not that setting. Their core limitations make them poorly suited to tracking perishable goods in transit.
Fixed installation requirements mean a PLC must be permanently mounted and wired into a facility. It cannot travel with a pallet of fresh produce from a farm to a distribution centre. Once goods leave the building, monitoring stops.
Beyond portability, PLCs carry high infrastructure costs, requiring specialist engineers to program and maintain them. Data retrieval is also complex, typically involving proprietary software and technical expertise rather than a simple scan. For a shipper who needs a quick, clear temperature record at the point of receipt, this is a significant barrier.
How Tapp makes cold chain data logging smarter and more sustainable
Tapp has developed the world’s first paper-based data logger, addressing the gaps that both PLCs and traditional electronic loggers leave open. Where conventional single-use electronic data loggers rely on plastic housings and lithium batteries—contributing to over 80 million units discarded annually—Tapp’s approach takes a different path entirely.
- Made from agricultural-waste paper: The substrate replaces plastic with a sustainable, recyclable material that can be processed through standard paper waste streams globally.
- Fully lithium-free battery: Unlike single-use electronic loggers, the paper-based logger uses a lithium-free power source, which is both flight-safe and reduces hazardous e-waste by up to 90%.
- No app or hardware needed: Any NFC-enabled smartphone can read the logger with a simple tap, with no USB connections, dedicated readers, or software installations required.
- EN 12830-certified accuracy: Professional-grade temperature recording that meets the regulatory standard for cold chain transport.
- Automatic cloud sync: Data uploads to the TappOS dashboard the moment a label is tapped, giving both sender and receiver instant access.
- All transport modalities: Suitable for road, sea, air, and rail shipments, with a waterproof coating for durability.
- Customisable branding: Labels can carry company logos and colours, integrating monitoring into the wider brand experience.
If you are looking for a cold chain monitoring solution that is simple to use, compliant, and genuinely better for the environment, explore Tapp’s paper-based data loggers and see how they fit your supply chain. Contact the Tapp team for cold chain advice to discuss your specific monitoring requirements.
