Our application sometimes misses the PLC's brief request for sample verification. I'm reviewing that ordinary, non-safety handshake for Universal Robots UR5e in a workshop inspection station awaiting commissioning, with a reference plate in the setup.
Signal ownership and clearing conditions aren't clearly documented. The safety functions are independently engineered and separate from this job interface.
@DanielBarnes0565 Our trace shows it rising and falling between two polls. The PLC clears it without an observed acknowledgement. No wonder the application misses it.
Take an ownership table and a retained-request proposal to the interface owner. A request held until matching acknowledgement should settle the handshake in an offline review.
@SamAli0246 Yes, I overstated that. Retention addresses the missed pulse. The offline review also needs matching identity, reset ownership and restart cases before the design is complete.
@DanielBarnes0565 Should I record readers as well as the single writer? Our existing phrase used by PLC doesn't distinguish setting, reading or clearing a field.
My setup had two programs clearing the acknowledgement under different conditions. Reviewing them together exposed a conflict that wasn't apparent from either program in isolation.