1. Card: An independent hardware unit that connects to the main system via a slot or interface, such as a PLC I/O card or data acquisition card. Its core characteristics are:
- Physical form: Board-type design, typically conforming to industry standards (e.g., Eurocard standard 160mm × 100mm);
- Dependent on the main system for power supply and communication, lacking independent operating capability;
- Typical expansion interfaces include PCIe, CPCI, etc., with bandwidth up to 16Gbps (refer to PCI-SIG standard).
2. Module: An integrated component that performs a specific function, such as a communication module or power supply module. Its design logic is:
- Protected by a closed enclosure, with a protection level up to IP65 (IEC 60529 standard);
- Supports plug-and-play, and some modules can operate independently (e.g., wireless communication modules);
- High degree of interface standardization, such as compatibility with Modbus, PROFINET, and other protocols.
