Add Power Distribution Hub (PDH) documentation

- REV-11-1850, 20x 40A high-current + 3x 15A low-current + 1 switchable
- CAN telemetry, USB-C diagnostics, LED voltage display
- WAGO toolless terminals, reverse polarity protection
- Wire gauge specs, fusing strategy

sources/2890/power-distribution-hub.md

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+---
+title: "Power Distribution Hub — REV-11-1850"
+tags:
+  - hardware
+  - power
+  - electrical
+  - REV
+  - 2890
+  - ion
+type: hardware-spec
+owner: 2890
+status: active
+sources:
+  - "https://www.revrobotics.com/rev-11-1850/"
+  - "https://docs.revrobotics.com/ion-control/pdh/overview"
+---
+
+# Power Distribution Hub — REV-11-1850
+
+## Overview
+
+The **Power Distribution Hub (PDH)** is Team 2890's central power distribution board. It takes battery power and routes it to all robot systems — motors, controllers, sensors, and accessories. Every wire from the battery goes through the PDH first.
+
+## Key Features
+
+- **20 high-current channels** (40A max each) — for motors and motor controllers
+- **3 low-current channels** (15A continuous, 20A peak) — for pneumatics, sensors
+- **1 switchable low-current channel** — on/off control for LEDs, accessories
+- **Toolless WAGO terminals** — color-coded, latching (no screws)
+- **CAN connectivity** — telemetry feedback to robot controller
+- **USB-C** — hardware client diagnostics and firmware updates
+- **LED voltage display** — real-time battery voltage reading
+- **ESD protection**
+- **Reverse polarity protection** — protects the PDH itself (not downstream devices)
+
+## Channel Allocation
+
+| Channel Type | Count | Max Current | Typical Use |
+|--------------|-------|-------------|-------------|
+| High-current | 20 | 40A | SPARK Flex, motors, mechanisms |
+| Low-current | 3 | 15A/20A peak | Pneumatics, sensors |
+| Switchable | 1 | 15A | LEDs, indicators |
+
+## Electrical Specifications
+
+| Parameter | Value |
+|-----------|-------|
+| Operating voltage | 4.7–18V |
+| Power input gauge | 18–6 AWG (solid), 18–4 AWG (stranded) |
+| Wire strip length | 0.72–0.79 in |
+| CAN termination | 120Ω (configurable) |
+| CAN wire gauge | 26–14 AWG |
+
+## Wiring Notes
+
+- **Reverse polarity protection** on the PDH — but it does NOT protect downstream devices. Double-check polarity before wiring.
+- Use ferrules with square or hex crimps for reliable connections
+- CAN bus requires 120Ω termination on last device
+
+## Connection to Training
+
+**For students:** The PDH is the heart of the robot's electrical system. Key concepts:
+- **fusing** — each channel protected by ATO/ATM fuse or breaker. Without a fuse, a stalled motor can melt wiring.
+- **voltage drop** — long wire runs lose voltage. PDH gives real-time reading so you can catch battery sag before it kills a motor.
+- **current division** — total current = sum of all channel currents. 20 motors × 40A = you need thick battery cables.
+- **CAN telemetry** — PDH reports voltage, current per channel back to the roboRIO. This is how you see "low battery" warnings on the driver station.
+
+**Related training modules:**
+- [[neo-vortex-motor]] — motor that draws from PDH channels
+- [[spark-flex]] — controller that connects to PDH high-current channels
+- [[ion-build-system]] — integrates with REV ION electrical system
+- [[frc-electrical-basics]] — wire gauge, fusing, common faults
+
+## Source Links
+
+- Product: https://www.revrobotics.com/rev-11-1850/
+- Docs: https://docs.revrobotics.com/ion-control/pdh/overview
+- Specs: https://docs.revrobotics.com/ion-control/pdh/specs
+
+## Notes
+
+The PDH replaced the old "breaker panel + PDP" approach. Teams used to run separate wires from a central breaker to each load. The PDH centralizes it with CAN monitoring — you can see exactly how much current each mechanism is drawing in real time. Useful for debugging why the climber feels sluggish.