Microsecond Real-Time Lines
The hard-deterministic connections: sub-10-microsecond, jitter-bounded, and the only lines permitted on the safety-critical command path.
The fastest lines in the plant
Microsecond real-time lines carry the hard-deterministic signals of L1 the Control Plane. They connect edge FPGAs to actuators and to each other with bounded jitter and a latency budget under 10 microseconds. These are the lines on which magnet protection and disruption response ride.
What they carry
- FPGA actuation commands to coils, gas valves, and heating systems.
- Synchronized gate signals coordinating multiple actuators in lockstep.
- The autonomous hardware failsafe's quench-dump trigger, which has zero AI dependency.
- Deterministic PLC vacuum interlock signals.
Why determinism, not speed alone
The defining property is not raw speed but bounded worst-case latency. A control action that is usually fast but occasionally late is unacceptable for protecting a REBCO magnet carrying 9.66 MA of plasma current on the breeder or holding a 26.49 T plug on the burner. FPGAs are chosen precisely because their timing is deterministic to the clock.
The invariant they enforce
Microsecond real-time lines are the only lines allowed to touch the sub-10-microsecond command boundary. No AI inference, no network round-trip, and no software scheduler sits on this path. This is what lets the plant be intelligent above L1 while remaining provably safe at L1.
How they are drawn and checked
In the blueprint these lines are visually distinct from telemetry and batch links precisely so that their exclusivity is checkable by eye. Any microsecond real-time line that connected to a block outside L1 — a twin, a copilot, an archive — would be an immediate, visible error. The grammar makes the safety path self-auditing: the reader verifies the invariant by confirming that every such line stays within the control plane and its actuators.
This class is the physical basis of the sub-10 microsecond command boundary and the autonomous hardware failsafe.