One number. Three thresholds.
The Jetson fuses vision and sensor data into a risk index from 0 to 100. The PLC reads it and acts.
Risk index, register D102
Graded, not binary.
At 40 the PLC lights the yellow lamp on Y0.2 and the event is logged. At 70 the buzzer on Y0.4 pulses. At 85 the Jetson's stop request makes the PLC stop the line and record stop code 5.
All three values are placeholders until calibration.
The PLC checks the number too.
The value reaches D102 through the gateway. The PLC trusts it only between 0 and 100 and only while the gateway is alive. Out-of-range values blink the yellow light instead of being acted on.
If the gateway goes silent for 5 s, the PLC raises an alarm and discards stale requests. The line keeps running, and the hardwired path still protects people.
A request, not a command.
At 85 the request sets M13 inside the PLC. The PLC removes its run permissive, drops K3 and records stop code 5. Restarting needs a person: START, then a 2.0 s audible warning before the belt moves.