Glossary · System coordination, integration and orchestration
Resource lock
Also known as: Lock, Mutex
German: Ressourcensperre
In automation and software, a resource lock is a mechanism that gives one task, machine or process exclusive use of a shared resource until it releases it; other requesters must wait or are rejected while the lock is held.
- System integration
In one sentence
A resource lock gives one task or machine exclusive use of a shared resource until it is released; others must wait.
Example
Before moving into the shared tool changer, the robot program acquires the tool-changer lock and releases it only after it has left the area.
How it applies
- Engineering: Locks must be acquired atomically, so two requesters cannot both obtain them. Acquire multiple locks in a fixed order to avoid Deadlocks, and hold locks as briefly as possible.
- Fault handling: Define what happens to a lock when its holder crashes or loses communication: timeouts, lease expiry or manual release. A stale lock can stop a whole line.
- Commissioning: Test simultaneous requests, holder failures and restarts with locks held.
- Documentation: List the locks, their holders and the manual release procedure in the service documentation, including the checks required before releasing a lock by hand.
Resource lock vs. lockout/tagout
A resource lock is a control-logic mechanism that coordinates machines or software. Lockout/tagout (LOTO) is a safety procedure in which people physically isolate and lock energy sources before working on equipment. A software lock never replaces lockout/tagout.