Electrical

Two packs in series feed a 48 V bus to 31 actuators through four distribution blocks; six CAN buses carry the commands; 12 V feeds the computer and the gripper servos; USB carries cameras, IMU and grippers. Make every cable from the tables below, then run the checks before a pack is connected.

Power system

Power wiring. Red: 48 V; black: ground. [Full size](../assets/wiring/power-supply-v2.png).

From	To	Voltage	Wire	Connectors
Pack 1 −	Pack 2 + (series link)	44.4 V nominal, 50.4 V full	10 AWG silicone	EC5
Pack +	Surge protector (E18) → 48 V bus	48 V	12 AWG silicone	EC5 at the pack; screw terminals
48 V bus, pack −	Lower-body power and ground blocks (E19): both legs, waist	48 V	12 AWG silicone	Screw terminals
48 V bus, pack −	Upper-body power and ground blocks (E19): both arms, both shoulder_1, four camera motors	48 V	12 AWG silicone	Screw terminals
Power block	Each actuator, daisy-chained	48 V	18 AWG silicone	XT30(2+2), see Harness fabrication
Upper-body power block	10 A inline fuse → 48 V→12 V converter (E11) → computer (E0)	48 V → 12 V	16 AWG silicone (12 V side)	Converter terminals; computer DC jack
Upper-body power block	48 V→12 V converter (E12, one per gripper) → servo driver board (E10)	48 V → 12 V	18 AWG silicone	Board screw terminals

• TVS diodes (E8, ten) sit across power and ground at each block pair.
• A voltage checker (E20) rides on each pack's balance lead.
• The computer is powered only when the upper-body block is live.

CAN bus

Data wiring: USB from the computer to three hubs; six CAN buses from hub 2. [Full size](../assets/wiring/data-wiring-v2.png).

Six buses at 1 Mbit/s, one CANable PRO V2.0 adapter (E13) each. Every bus is a single daisy chain — adapter → motor → motor — with a 120 Ω terminator at each physical end and no stubs.

Bus	Actuators	CAN IDs	Powered from
can22	waist, left and right shoulder_1	1, 10, 20	lower (waist) and upper (shoulders) blocks
can9	left arm: shoulder_2 to wrist_3	11–16	upper block
can21	right arm: shoulder_2 to wrist_3	21–26	upper block
can24	left leg: hip_1 to ankle_2	31–36	lower block
can23	right leg: hip_1 to ankle_2	41–46	lower block
can25	camera yaw and pitch, left and right	7, 8, 5, 6	upper block

USB hub (E16)	Devices
Hub 1	Both RealSense D436 (E14, USB 3 required), IMU (E17)
Hub 2	The six CAN adapters (E13)
Hub 3	Both gripper servo driver boards (E10)

✅ Check: an unpowered bus reads about 60 Ω between CAN_H and CAN_L (120 Ω: a terminator missing; 40 Ω: one too many).

The actuator map

Every joint's ID, bus and model

Joint	ID	Bus	Model	Joint	ID	Bus	Model
waist	1	can22	RS03
left_shoulder_1	10	can22	RS03	right_shoulder_1	20	can22	RS03
left_shoulder_2	11	can9	RS06	right_shoulder_2	21	can21	RS06
left_shoulder_3	12	can9	RS02	right_shoulder_3	22	can21	RS02
left_elbow	13	can9	RS02	right_elbow	23	can21	RS02
left_wrist_1	14	can9	RS02	right_wrist_1	24	can21	RS02
left_wrist_2	15	can9	RS00	right_wrist_2	25	can21	RS00
left_wrist_3	16	can9	RS05	right_wrist_3	26	can21	RS05
left_hip_1	31	can24	RS03	right_hip_1	41	can23	RS03
left_hip_2	32	can24	RS03	right_hip_2	42	can23	RS03
left_hip_3	33	can24	RS03	right_hip_3	43	can23	RS03
left_knee	34	can24	RS04	right_knee	44	can23	RS04
left_ankle_1	35	can24	RS03	right_ankle_1	45	can23	RS03
left_ankle_2	36	can24	RS06	right_ankle_2	46	can23	RS06
cam_yaw_left	7	can25	RS05	cam_yaw_right	5	can25	RS05
cam_pitch_left	8	can25	RS05	cam_pitch_right	6	can25	RS05

IDs are unique robot-wide. Setting them: Motor ID and config.

Harness fabrication

Every cable on the robot is one of the types below. Red is +, black is −; CAN_H is yellow and CAN_L is blue throughout the harness. Solder the XT30 cups (iron about 480 °C), do not crimp them; never mate or unmate a power connector under power.

Cable	Conductors	End A	End B	Carries
Actuator drop	2 × 18 AWG power + 1 twisted pair CAN	XT30(2+2) female, cable side (Amass XT30(2+2)-F.G.B)	XT30(2+2) female	48 V and CAN in one shell: pin 1 +, pin 2 −, pin 3 CAN_L, pin 4 CAN_H. Every actuator has an in and an out socket (board side XT30PB(2+2)-M.G.B), so the drops chain motor to motor
Bus head	1 twisted pair	CANable PRO screw terminals, 120 Ω across H–L	XT30(2+2) female, power pins unused	CAN only, adapter to the first motor
Bus tail terminator	—	120 Ω resistor across CAN_H–CAN_L in an XT30(2+2) shell	—	Plugs into the last motor's out socket
CAN twisted pair	One pair from Ethernet cable	—	—	Coloured conductor → CAN_H (yellow lead), white → CAN_L (blue lead); 3/32 in heat-shrink per lead, ¼ in over the pair
Pack lead and series link	10 AWG silicone	EC5	EC5 / screw terminal	48 V trunk
Block feeds	12 AWG silicone	Screw terminal	Screw terminal	48 V bus to each power block; pack − to each ground block
Computer feed	16 AWG silicone	Converter (E11) 12 V terminals	Computer DC plug	12 V; 10 A inline fuse on the 48 V side
Gripper servo feed	18 AWG silicone	Converter (E12) 12 V terminals	Servo driver board (E10) terminals	12 V, one per gripper
Camera USB	Belkin USB-A to USB-C (E9)	Computer / hub 1	Right-angle USB-C adapter (E21) on the camera	USB 3 (5 Gbit/s)
Gripper servo signal	Servo's own lead	Servo (E15)	Driver board (E10)	Serial bus

Connectors and consumables

Item	Part	Where
Actuator connector, cable side	Amass XT30(2+2)-F.G.B (female, 4-pin: 2 power + 2 signal)	Both ends of every actuator drop, bus head, terminator
Actuator connector, board side	Amass XT30PB(2+2)-M.G.B (male, PCB mount)	Already on every RobStride board, in and out
Pack connector	EC5	Pack leads, series link
Bus terminator	120 Ω resistor	Adapter end and last motor of each bus
CAN pair	One twisted pair from Ethernet cable	All CAN runs
Power wire	Silicone, 12 / 16 / 18 AWG	Trunks / computer / actuator drops and grippers
Heat-shrink	3/32 in per lead, ¼ in over a pair or joint	Every solder joint
Loom	¼ in and ⅜ in	Limb runs

XT30(2+2) is rated 15 A with 18 AWG wire. Quantities are yours to size: Cables and connectors.

✅ Check: each finished cable conducts pin to pin, has no short between pins, and is labelled at both ends with its bus or rail.

Routing

Run	Route
Leg bus (can24 / can23) + 48 V	From the lower-body blocks in the pelvis, down each leg motor to motor under the covers; the tail terminator at the ankle
Arm bus (can9 / can21) + 48 V	From the upper-body blocks, out through the shoulder, motor to motor to the wrist under the covers
can22	Waist actuator in the pelvis; both shoulder_1 in the torso side plates
can25 + 48 V	Up the top plate to both camera columns
Camera USB, gripper servo feed and signal	Down each camera column; up each arm to the wrist

• Leave a service loop at every joint sized for the joint's full travel, not one pose; keep CAN pairs twisted to the connector.
• Sleeve limb runs in ¼ in or ⅜ in loom; tie to the printed covers, never across a moving edge.
• Turn every joint to both ends by hand before a limb is closed: no cable taut, pinched or rubbing.

✅ Check: with the robot suspended, every joint moves through its travel with every cable free.

Pre-power checks

With no pack connected:

1. Every 48 V conductor conducts end to end; + to − on each bus reads open (drive capacitors charge slowly, no steady short).
2. Every XT30(2+2): + at pin 1, − at pin 2, CAN_H at pin 4, checked against the pinout, not the colour.
3. Each of the six buses reads about 60 Ω between CAN_H and CAN_L.
4. Each 48 V→12 V converter gives 12 V on a bench supply before it sees a pack.
5. Both packs: no swelling, cells balanced, then the series link: one pack's + to the other's −.

Then First power-on, robot suspended.