One device switches the motor.
A Delta AS228P runs the conveyor through the K3 contactor. Beneath it, a hardwired safety path needs no software at all.
PLC and hardwired safety path, layers one and two
The only output authority.
Every output comes from the PLC: K3 on Y0.0, the stack light on Y0.1 to Y0.3, the buzzer on Y0.4. The Jetson and the dashboard can only ask.
The PLC starts the line only when the safety relay is healthy, the guard is closed, the heartbeat is good, no fault is latched and a valid start request arrives. The AS228P is a standard PLC, not a safety PLC; protection of people is the hardwired path's job.
Two contactors in series.
K3 is the PLC's run contactor. The safety contactor belongs to the hardwired path: E-stop, light curtain and guard interlock feed a safety relay that switches it. Both must be closed for the motor to turn, so the hardwired path stops the conveyor even if every computer and the PLC program are down.
Watchdogs and no surprises.
No heartbeat edge on X0.5 for 2.0 s latches a fault. It clears only after 3.0 s of healthy heartbeat and a manual RESET.
K3's auxiliary contact on X0.6 must agree with Y0.0 within 0.5 s, or a K3 fault is latched. A start request sounds a 2.0 s warning first. The line never restarts by itself.