Unify Signals/Channels around auto-naming, plot-by-channel, and shared vars

Devices: auto-name from OS-reported port description (Device Manager /
udev string) instead of a generic label; default Serial #Channels 1;
consistent simulate-mode checkbox across backends; inline device rename.

Channels: calibration/filters move out of Signals into a Channel
"Operation" (adds Scale/Offset alongside the existing math kinds);
single-physical-source Channels get an embedded Filters block; new
Channels auto-name/auto-ID from their source and reject duplicate
names/IDs on apply; "Create Channel" button on each Signal row; renamed
"Sources" -> "Signals" in the Channels UI; Signals' READ/WRITE dir badge
(was silently-broken IN/OUT) now reflects the real writable flag.

Plot: default layout is one pane per Channel (not per device, not raw
Signals) titled by channel name; "+ Add Channel" is a checkbox dialog
instead of an inline dropdown; traces get up/down reorder; live unit
changes (e.g. a Mark-10 gauge switching lb/kgF/N/ozF) propagate to an
open pane's axis label without clobbering a manually-typed one.

Control Panel: hardware assignment now picks from the same writable-
Signals list instead of a separate device/channel combo with a
hardcoded Arduino pin list; stale visual indicator when a control's
target device/channel disconnects or disappears; documented the `vars`
bridge (Control Panel On Action Script <-> Channel scripts) in both
directions' help text and script templates.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/ui/strip_chart.py b/ui/strip_chart.py
index a212e5c..6c644be 100644
--- a/ui/strip_chart.py
+++ b/ui/strip_chart.py
@@ -79,6 +79,9 @@ class StripChartWidget(QWidget):
         self._cfg: Optional[LayoutConfig] = None
         # (dev_id, ch_id) → [{curve, plot, spec}]
         self._curves: Dict[Tuple, List[dict]] = {}
+        # (dev_id, ch_id) → last unit seen — lets refresh_pane_unit() tell an
+        # auto-seeded pane label apart from one the operator typed by hand
+        self._known_units: Dict[Tuple[str, str], str] = {}
         # Time-axis plots, scrolled continuously by _scroll_timer rather than
         # only when a new sample lands — decouples the visible scroll rate
         # from the (much slower) poll rate so it doesn't look stepped.
@@ -179,6 +182,10 @@ class StripChartWidget(QWidget):
                 key   = (tr.device_id, tr.channel_id)
                 self._curves.setdefault(key, []).append(
                     {"curve": curve, "plot": plot, "spec": spec, "pane": spec})
+                # Seed with the channel's true current unit (not spec.y_label,
+                # which may be pane title text or a custom label) so the first
+                # live unit-change after a layout rebuild is still detected.
+                self._known_units[key] = self._lookup_channel_unit(*key)
 
     def set_theme(self, theme: str):
         """Hot-swap pyqtgraph colours when the user changes theme."""
@@ -196,6 +203,34 @@ class StripChartWidget(QWidget):
         for e in self._curves.get(key, []):
             e["curve"].setVisible(enabled)
 
+    def _lookup_channel_unit(self, device_id: str, channel_id: str) -> str:
+        if device_id == "derived":
+            for dc in self.processor.get_derived():
+                if dc.channel_id == channel_id:
+                    return dc.unit
+            return ""
+        dev = self.registry.get_instance(device_id)
+        ch = dev.get_channel(channel_id) if dev else None
+        return ch.unit if ch else ""
+
+    @pyqtSlot(str, str, str)
+    def refresh_pane_unit(self, device_id: str, channel_id: str, new_unit: str):
+        """A channel's unit changed live (e.g. a Mark-10 gauge switched
+        lb/kgF/N/ozF on its own front panel). Update any open pane's Y-axis
+        label that's still showing the *previous* unit verbatim — but never
+        touch a label the operator typed by hand."""
+        key = (device_id, channel_id)
+        old_unit = self._known_units.get(key)
+        self._known_units[key] = new_unit
+        if old_unit == new_unit:
+            return
+        for entry in self._curves.get(key, []):
+            spec = entry["spec"]
+            if spec.y_label != old_unit:
+                continue
+            spec.y_label = new_unit
+            entry["plot"].setLabel("left", new_unit or spec.title)
+
     @pyqtSlot(str, str, float, float)
     def on_new_data(self, device_id: str, channel_id: str, ts: float, val: float):
         if self._paused or not _HAS_PG or not self._cfg: return