Glossary · System coordination, integration and orchestration
Machine handshake
Also known as: Handshake signal exchange
German: Maschinen-Handshake
In industrial automation, a machine handshake is a defined sequence of signals between two machines or controllers, such as ready, request, acknowledge and done, that confirms each step of an interaction like a part transfer before the next step starts.
- System integration
In one sentence
A machine handshake is a defined exchange of ready, request and acknowledge signals that confirms each step of an interaction between two machines.
Example
Before a robot unloads a press, the press sets Ready, the robot sets Request, the press confirms that the ram is at top dead center and the robot reports Done after it has left the tool area.
How it applies
- Engineering: Specify each handshake as a sequence diagram or state machine: which signal is set by whom, in which order, with which timeouts and what happens when a signal drops unexpectedly.
- Commissioning: Test every branch, including timeouts, signal loss and restarts in the middle of the sequence. Many hard-to-find line faults are handshakes that assume a signal can never disappear.
- Maintenance: Diagnostic screens that show the current handshake step save time when a transfer hangs.
- Documentation: Put the handshake definition in the interface specification or Interface control document (ICD) shared by both suppliers, and describe in the manual how operators recover a transfer that stopped halfway.
Handshake vs. interlock
A handshake coordinates a cooperative sequence and is usually implemented in standard control logic. An Interlock prevents a hazardous or damaging action. If a handshake signal also protects people, for example preventing a robot from entering while a press can move, the protective part must be designed as a safety function; a standard handshake alone is not a safeguard.