Glossary · Automation fundamentals, platforms and components
Hot swap
Also known as: Hot plugging, Module replacement during operation
German: Hot-Swap
In automation and computing, hot swap is the replacement of a module or component while the system is powered and running, without shutting down the rest of the system.
- Automation components
In one sentence
Hot swap means replacing a module or component while the system remains powered and running, without shutting down the rest.
Example
A defective I/O module in a redundant station is pulled and replaced during production; the controller detects the new module and resumes its channels.
How it applies
- Engineering: Hot swap requires hardware designed for it and a configuration that tolerates the missing module; not every module or system supports it.
- Maintenance: Even where hot swap is supported, the process connected to the module is affected while it is out. Outputs may drop and actuators move.
- Documentation: Instructions must state which modules may be hot-swapped, under which conditions and with which precautions. Warn that hot swap is not a substitute for isolating hazardous energy, and that hazardous voltages may be present.
Hot swap vs. warm and cold swap
In a cold swap, the system is switched off. In a warm swap, power remains on but the affected part is stopped. In a hot swap, the rest of the system keeps operating. Manuals should use the vendor's exact definitions.