fix: improve monitoring functionality with session-reset signal and payload adjustments

CLAUDE.md

@@ -582,17 +582,33 @@ All confirmed from 4-8-26/2ndtry BW TX/S3 capture (clean start → 30s monitor
 Standard two-step read (probe at offset 0x00, data at offset 0x2C).
 Response SUB = 0xFF − 0x1C = **0xE3** (standard formula — no exception).
 
-Payload length indicates mode:
+**Payload length is ~46–49 bytes in BOTH idle and monitoring states** — length alone
-- **44 bytes (0x2C)** — unit is **idle**: full status block with battery + memory
+is NOT a reliable mode indicator.  Earlier note claiming "12 bytes when monitoring"
-- **12 bytes** — unit is **monitoring**: abbreviated block, no battery/memory fields
+was wrong (confirmed 2026-04-08 from 4-8-26/mid-monitor captures).
 
-**Field offsets (idle payload, relative to the 11-byte section header start):**
+**Monitoring flag (confirmed from 4-8-26/2ndtry byte-by-byte comparison):**
+- `section[1] == 0x00` → unit is **idle**
+- `section[1] == 0x10` → unit is **monitoring** (flips exactly at start/stop transitions)
+
+Battery and memory fields are present in **both** states.
+
+**Field offsets (relative to `data[11:]` = section, confirmed from 2ndtry IDLE frames):**
 
 | Offset | Field | Type | Notes |
 |---|---|---|---|
-| `[0x2F:0x31]` | battery voltage × 100 | uint16 BE | `0x02A8` = 680 → 6.80 V |
+| `[36:38]` | battery voltage × 100 | uint16 BE | `0x02A8` = 680 → 6.80 V |
-| `[0x31:0x35]` | memory total (bytes) | uint32 BE | e.g. 983040 = 960 KB |
+| `[38:42]` | memory total (bytes) | uint32 BE | e.g. 983026 ≈ 960 KB |
-| `[0x35:0x39]` | memory free (bytes) | uint32 BE | |
+| `[42:46]` | memory free (bytes) | uint32 BE | decreases as events are stored |
+
+### SESSION_RESET signal (`41 03`) — required for monitoring units
+
+Confirmed from 4-8-26 BW TX captures: Blastware sends a 2-byte `41 03` (ACK + ETX,
+no STX) immediately before the first POLL probe AND between the probe and data frames.
+This signal is **required to wake units that are actively monitoring** — without it
+the unit does not respond to POLL over TCP.  Harmless for idle units.
+
+`SESSION_RESET = bytes([0x41, 0x03])` is defined in `framing.py` and sent by
+`protocol.startup()` before and between POLL frames.
 
 ### SUB 0x96 — Start monitoring
 

minimateplus/client.py

@@ -1767,25 +1767,32 @@ def _decode_monitor_status(data: bytes) -> MonitorStatus:
     # The data section starts at offset 11 (after the S3 section header).
     section = data[11:] if len(data) > 11 else data
 
-    # Log the raw payload at WARNING level so we can see it in the server logs
+    log.debug(
-    # and confirm the field offsets and is_monitoring detection are correct.
-    log.warning(
         "_decode_monitor_status: total data=%d bytes  section=%d bytes  hex=%s",
         len(data), len(section), section.hex(),
     )
 
-    # Mode: idle payload is 44 bytes; monitoring is shorter (12 bytes observed)
+    # Monitoring flag confirmed from 2ndtry 4-8-26 capture:
-    is_monitoring = len(section) < 20
+    #   section[1] == 0x00 → idle
+    #   section[1] == 0x10 → monitoring (flips exactly at start/stop transitions)
+    # Payload length is ~46-49 bytes in BOTH states — length alone is unreliable.
+    is_monitoring = len(section) > 1 and section[1] == 0x10
 
     battery_v     = None
     memory_total  = None
     memory_free   = None
 
-    if not is_monitoring and len(section) >= 0x39:
+    # Battery and memory fields confirmed from 2ndtry IDLE S3 frames:
-        batt_raw     = struct.unpack(">H", section[0x2F:0x31])[0]
+    #   section[36:38]  battery × 100  uint16 BE   0x02A8 = 680 → 6.80 V
+    #   section[38:42]  memory_total   uint32 BE   bytes = total flash
+    #   section[42:46]  memory_free    uint32 BE   bytes = free flash
+    # These fields appear in BOTH idle and monitoring payloads (battery/memory
+    # are available regardless of mode).
+    if len(section) >= 46:
+        batt_raw     = struct.unpack(">H", section[36:38])[0]
         battery_v    = batt_raw / 100.0
-        memory_total = struct.unpack(">I", section[0x31:0x35])[0]
+        memory_total = struct.unpack(">I", section[38:42])[0]
-        memory_free  = struct.unpack(">I", section[0x35:0x39])[0]
+        memory_free  = struct.unpack(">I", section[42:46])[0]
 
     return MonitorStatus(
         is_monitoring=is_monitoring,

minimateplus/framing.py

@@ -438,6 +438,14 @@ def bulk_waveform_term_params(key4: bytes, counter: int) -> bytes:
 POLL_PROBE = build_bw_frame(0x5B, 0x00)   # length-probe POLL  (offset = 0)
 POLL_DATA  = build_bw_frame(0x5B, 0x30)   # data-request POLL  (offset = 0x30)
 
+# Session-reset signal (ACK + ETX, no STX/payload).
+# Confirmed from 4-8-26 BW TX captures: Blastware sends this 2-byte sequence
+# immediately before the first POLL probe, and again between the POLL probe
+# and the POLL data request.  Required to wake a unit that is actively
+# monitoring — without it the unit does not respond to POLL over TCP.
+# Harmless for idle units (they respond to POLL regardless).
+SESSION_RESET = bytes([0x41, 0x03])
+
 
 # ── S3 response dataclass ─────────────────────────────────────────────────────
 

minimateplus/protocol.py

@@ -37,6 +37,7 @@ from .framing import (
     bulk_waveform_term_params,
     POLL_PROBE,
     POLL_DATA,
+    SESSION_RESET,
 )
 from .transport import BaseTransport
 
@@ -190,6 +191,13 @@ class MiniMateProtocol:
         log.debug("startup: draining boot string")
         self._drain_boot_string()
 
+        # Send session-reset signal (ACK+ETX) before the first POLL probe.
+        # Confirmed from 4-8-26 BW TX captures: Blastware always sends this
+        # 2-byte signal at session start.  Required to wake units that are
+        # actively monitoring — without it they don't respond to POLL over TCP.
+        log.debug("startup: session reset signal")
+        self._send(SESSION_RESET)
+
         log.debug("startup: POLL probe")
         self._send(POLL_PROBE)
         probe_rsp = self._recv_one(
@@ -200,6 +208,10 @@ class MiniMateProtocol:
             "startup: POLL probe response page_key=0x%04X", probe_rsp.page_key
         )
 
+        # Send another session-reset between probe and data (matches BW behavior).
+        log.debug("startup: session reset signal (inter-frame)")
+        self._send(SESSION_RESET)
+
         log.debug("startup: POLL data request")
         self._send(POLL_DATA)
         data_rsp = self._recv_one(