Leg rig: wiring

What to wire, wire by wire, for the single-leg rig (docs/leg-prototype-plan.md section 3, task T10). The diagram is exports/rig/wiring.svg (and the list behind it, exports/rig/wiring.json, from tools/rig_wiring.py); the parts and their part numbers are in docs/leg-rig-orders.md; where each part sits in the pod is cad/rig_parts.py POD_PARTS.

The rules

• Nothing on the motors' bus is live unless the pendant is held. The contactor in the pack's positive is closed only by the off-delay relay, and the relay only by the pendant; let go and the leg sits down under software, and 1.0 s later the contactor opens whatever the software did.
• The pendant switches signals only. It closes the relay's trigger input and tells the rig node; it never carries the contactor's coil current (AbleNet publishes no contact rating).
• The packs are the master switch. The rig runs on Gyropup's own bus (D65): two DeWalt DCB609 FLEXVOLTs in 20 V mode, in series in two 20 V dock adapters: 10S, 36 V nominal, 41 V full, 30 V empty. Unplug the pair's XT60 and everything is dead; there is no other switch.
• Jumps and drops start at or under 44.5 V - 40 A x the packs' resistance (about 40.5 V until B6 measures it): the tuck and the landing push up to 40 A back into the packs and the supervisor limps at 45 V (docs/leg-bench-tests.md).
• One ground: the pack's negative at the pod's inlet. The CAN ground, the 12 V rail's 0 V, the rig node's GND and the motors' negatives all meet there. The U2C is not isolated: on the bench supply or a floating pack that is fine; with the laptop on mains and the motors on the bench supply, use the isolated InnoMaker USB2CAN.

Power: pack to motors (12 AWG silicone)

The 12 V rail and the hold-to-run loop

The relay's settings (DIP switches, power off while setting): function OFF DELAY (A off, B on), range 0.1-10 s (C on, D on), the onboard knob (E on, F on); the knob at 1.0 s, checked with a stopwatch on a lamp before the contactor is wired. Check the terminal numbers against the label on the unit before wiring: the T2R is a Macromatic design, pin 5 is its trigger.

How it behaves: pendant held: the trigger closes, the relay's contact closes at once, the coil pulls the contactor in (40 ms). Pendant let go: the rig node stops its RUN frames at once, the laptop's controller sits the leg down in 0.3 s and stops the motors; the relay times 1.0 s and drops the coil; the contactor opens (10 ms). At power-up with the pendant not held the relay stays open (not true of every timer: the Klemsan Z1K-M2A is reported to close for its delay at power-up).

CAN (1 Mbit/s, 29-bit RobStride private protocol)

The junction: two JST BM02B-GHS-TBT headers on a FeatherWing Proto with short 26 AWG tails to its terminal pads, cable-tied to the carriage plate's back next to the leads' slots. Fallback: cut the motors' GH plugs off and join their leads to the trunk in lever connectors (blue to H, brown to L).

Check before any motor is enabled: with everything off, 60 ohm between H and L at the junction (two 120 ohm in parallel); python -m rig.rs04 --iface can0 scan finds both motors.

The rig node (Feather M4 CAN Express in the pod)

Its frames (rig/node.py): RUN 0x700 at 100 Hz while D5 is high (0x5A in byte 0), SENSE 0x701 at 50 Hz, VBUS 0x702 at 100 Hz; it never commands a motor. Its firmware: rig/firmware/feather_rig/ (task T11: CircuitPython; code.py, rig_frames.py and settings.json onto the CIRCUITPY drive, the install steps at the top of code.py).

Connectors