Glossary · System coordination, integration and orchestration
Handshake programming
Also known as: handshake logic
German: Handshake-Programmierung
In control software engineering, handshake programming is the implementation of handshake sequences in PLC or controller code, typically as state machines that set request signals, wait for acknowledgments, supervise timeouts and handle aborts.
- System integration
In one sentence
Handshake programming implements request, acknowledge and timeout sequences in PLC or controller code, usually as state machines.
Example
A reusable function block implements the four-phase handshake with the vision system, including timeout supervision and an error code for each step.
How it applies
- Engineering: Encapsulate handshakes in reusable function blocks with a clear interface and explicit states. Duplicated ad-hoc handshake code is a common source of subtle timing errors.
- Verification: Unit-test handshake blocks with a simulated partner that delays, repeats or skips responses. Check the behavior after a controller restart in every state.
- Documentation: Document the function block in the software library documentation: inputs, outputs, states, error codes and timeout parameters. Use the same step numbers in the code, the HMI diagnostics and the manual so that a technician can connect a displayed error to a step.
Handshake programming vs. communication configuration
Configuring a fieldbus or OPC UA connection makes data available between controllers. Handshake programming defines what the exchanged signals mean and in which order they change. Both are needed for a working interface.