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docs(wiring): show the ESP32 tapping the bus, not sitting in it
The redrawn diagram still had A and B entering the module on one side and leaving on the other, which reads as "cut the run and splice the board in." RS485 is multi-drop — the monitor is one more listener on a shared bus, and the CCA-to-TAP wire is never broken. Someone following the old picture literally would cut a working cable. The run is now continuous end to end with three spur wires dropping off it, plus a note that this usually means a second wire under an existing screw terminal. Table reworded from a two-hop chain (CCA->base, base->optimizer) to three spurs. Same correction applied to the Start Here wiring step and the AtomS3R quick steps, which both said daisy-chain. Claude-Session: https://claude.ai/code/session_01RgSnMCa3JQigphGnPbazdw
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‎site/src/content/docs/guides/getting-started.md‎

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@@ -69,9 +69,12 @@ wiring part. That's a completely reasonable call and in some places it's the law
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### 2. Wire it in
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Three wires: **A**, **B**, and **ground**, connecting your CCA or TAP to the
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RS485 base. The board sits in the middle of the existing cable run and eavesdrops.
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Ground is not optional — RS485 needs a shared reference to read reliably.
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Three short wires — **A**, **B** and **ground** — from your CCA or TAP over to the
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RS485 base. Nothing gets cut or unplugged: you're hanging the board off a cable
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that stays exactly as it is, alongside everything already connected to it.
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Ground is not optional. RS485 needs a shared reference or the readings won't be
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reliable.
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Full diagrams, terminal-by-terminal: **[Wiring guide](/esphome-tigomonitor/guides/wiring/)**.
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‎site/src/content/docs/guides/wiring.md‎

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@@ -23,8 +23,9 @@ high-voltage side safe before you open anything.
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Your optimizers talk to your Tigo CCA (the green wall box) or TAP (the small radio
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box) over a **four-wire** cable — **+** and **−** carrying power, **A** and **B**
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carrying the data. That data pair is RS485, and it's the only part we're interested
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in. You're splicing the ESP32 into the existing run — at the CCA's **GATEWAY**
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port — so it hears both sides of the conversation without joining in.
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in. You're tapping the ESP32 onto the existing run — at the CCA's **GATEWAY**
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port — so it hears both sides of the conversation without joining in. Nothing gets
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cut or unplugged.
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**Tap A and B only, plus a ground.** Leave the power pair connected exactly as you
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found it. The terminals are marked on the port; the diagram below shows the order.
@@ -97,43 +98,57 @@ looking at — the GATEWAY port has **four** terminals, and you only touch three
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the common ground, which is the one you connect. **Leave `+` alone entirely** —
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nothing on the ESP32 side goes anywhere near it.
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Now wire it. `A` and `B` pass *through* the module, so it sits inline on the run:
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Now wire it. RS485 is a shared bus, so the ESP32 **hangs off** the existing cable
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rather than sitting in the middle of it — you are adding three short wires, not
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cutting anything:
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```text
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Tigo CCA / TAP ESP32 + RS485 Base Optimizer bus
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┌──────────────┐ ┌──────────────────┐ ┌──────────────┐
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│ │ │ │ │ │
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│ A ──────────┼──────────────┤ A (Terminal) ├──────────────┼────── A │
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│ B ──────────┼──────────────┤ B (Terminal) ├──────────────┼────── B │
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│ │ │ │ │ │
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│ - ──────────┼──────────────┤ GND │ │ │
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│ + (leave) │ │ │ │ │
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└──────────────┘ └──────────────────┘ └──────────────┘
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│
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│ internal
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▼
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┌──────────────────┐
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│ AtomS3R ESP32 │
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│ RX: GPIO5 │
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│ TX: GPIO6 inert │
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│ 38400 baud 8N1 │
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└──────────────────┘
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Tigo CCA / TAP TAP / optimizers
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┌──────────────┐ ┌──────────────┐
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│ │ │ │
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│ A ──────────┼─────┬──────────────────────────────────────────┼────── A │
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│ B ──────────┼─────┼──┬───────────────────────────────────────┼────── B │
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│ - ──────────┼─────┼──┼──┬────────────────────────────────────┼────── - │
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│ + (leave) │ │ │ │ │ + (leave) │
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└──────────────┘ │ │ │ └──────────────┘
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│ │ │ three short spur wires —
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│ │ │ the run itself is never cut
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▼ ▼ ▼
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┌───────────────┐
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│ A B GND │
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│ ESP32 + RS485 │
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└───────────────┘
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│ internal
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▼
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┌──────────────────┐
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│ AtomS3R ESP32 │
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│ RX: GPIO5 │
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│ TX: GPIO6 inert │
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│ 38400 baud 8N1 │
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└──────────────────┘
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```
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`┬` marks where a spur joins a wire; `┼` is just one line crossing another.
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In practice this usually means landing a second wire under the same screw terminal
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that already holds the run, or using a wago/terminal block alongside it. The CCA
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keeps talking to the TAP exactly as before, whether or not the ESP32 is powered.
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TX is wired but inert — the transceiver's driver is held disabled, so the ESP32 only listens. See [Why this is read-only](#why-this-cannot-break-your-solar-system).
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### Wiring Table
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| Connection | From | To |
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|------------|------|-----|
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| RS485 A | CCA/TAP **A** terminal | RS485 Base A terminal |
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| RS485 A | RS485 Base A terminal | Optimizer bus A |
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| RS485 B | CCA/TAP **B** terminal | RS485 Base B terminal |
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| RS485 B | RS485 Base B terminal | Optimizer bus B |
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| GND | CCA/TAP **−** terminal | RS485 Base GND |
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| *(none)* | CCA/TAP **+** terminal | *Not connected — leave as found* |
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Three wires, each one a spur off a terminal that stays connected to whatever it
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was already connected to:
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| Wire | From | To | Notes |
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|------|------|-----|-------|
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| RS485 A | CCA/TAP **A** terminal | RS485 Base **A** | Data |
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| RS485 B | CCA/TAP **B** terminal | RS485 Base **B** | Data |
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| Ground | CCA/TAP **−** terminal | RS485 Base **GND** | Not optional — see below |
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| — | CCA/TAP **+** terminal | *nothing* | Power. Leave exactly as found |
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**Note:** RS485 A and B are daisy-chained through the ESP32 module. The ESP32 monitors traffic in both directions.
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**Note:** the ESP32 is one more listener on a shared bus, not a link in a chain. It sees traffic in both directions, and unplugging it changes nothing for the rest of the system.
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**Ground reference:** RS485 needs a **common ground reference** between the ESP32 and the Tigo bus for reliable signalling — connect GND. It is not optional. (Skip it only if the ESP32 and the Tigo equipment already share a ground through another path, and even then a dedicated GND wire is the safer default.)
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Simplest setup – just plug together and connect RS485 terminals:
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1. Attach AtomS3R to Atomic RS485 Base
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2. Connect A terminal to Tigo RS485 A (daisy-chain)
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3. Connect B terminal to Tigo RS485 B (daisy-chain)
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2. Run a spur wire from the Tigo **A** terminal to the base's A terminal
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3. Run a spur wire from the Tigo **B** terminal to the base's B terminal
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4. Power via USB-C
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5. Flash ESPHome configuration
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