csaxs_bec/bec_ipython_client/plugins/flomni/AI_docs/PANDA_POSITION_VALIDATION.md

@@ -47,7 +47,11 @@ and known-good (used successfully in reconstruction):
   not against `target_x`/`_y`.
 - `rt_positions_data_stdev_x_st_fzp`/`_y` — RT's own per-point stdev, useful
   as a sanity scale for how much residual noise to expect (order 0.005 µm in
-  the validated scan).
+  the validated scan). See §9 for a raw-PandA cross-check against this value.
+  Don't confuse this with `rt_positions_data_average_stdeviations_x_st_fzp`/
+  `_y`, which is a running/cumulative mean of `stdev_x_st_fzp` up to that
+  point in the scan (confirmed by direct comparison, 2026-09-23), not a
+  per-point noise value — it's the wrong field for a per-point comparison.
 
 One row per scan point (472 points in the validated scan, `S06313`).
 
@@ -351,3 +355,65 @@ never overlaps a gated exposure.
 **Reduced data mode** (`S00399`) validated cleanly at full accuracy — see
 §6 for the row-count/gate-fraction characterization. No contamination, no
 missing points, same R² bar as the other burst scans.
+
+## 9. Per-point stdev cross-check against RT's control-loop stdev (`S06313`, 2026-09-23)
+
+Besides the per-point mean position (§4), PandA's raw samples let you
+cross-check RT's own per-point noise estimate
+(`rt_positions_data_stdev_x_st_fzp`/`_y`, §2) against an independent
+measurement — a single-frame scan has ~998 raw PandA samples landing within
+each point's gate window (`CLOCK1`'s free-running rate over one exposure),
+so each point's within-group sample scatter is itself a noise estimate.
+
+### 9.1 Method
+
+For each grouped point (§3.2, after applying §3.3's stale-prefix drop where
+needed), compute `pos_x_um`/`pos_y_um` (§3.4's full formula) **per
+individual raw sample**, not just on the group mean, then take the
+within-group sample stdev (`ddof=1`). Compare against
+`rt_positions_data_stdev_x_st_fzp`/`_y` (not
+`average_stdeviations_x_st_fzp`/`_y` — see the note in §2).
+
+### 9.2 The analog `cap_voltage_fzp_x`/`_y` term is required, not optional
+
+Naively computing per-sample stdev from `interf_st_fzp_x`/`_y` alone
+(skipping the `CapX_FZP_microns`/`CapY_FZP_microns` subtraction in §3.4)
+gives a wildly wrong noise estimate:
+
+| | X stdev (µm) | Y stdev (µm) | corr. with RT stdev (472 points) |
+|---|---|---|---|
+| Interferometer only, no cap term | 0.072 | 0.049 | 0.22 / 0.24 |
+| Full formula (interf − cap, §3.4) | 0.0074 | 0.0063 | 0.98 / 0.99 |
+| RT's own stdev | 0.0065 | 0.0058 | — |
+
+Within a single point, `interf_st_fzp_x` and `cap_voltage_fzp_x` are
+anti-correlated at **r ≈ −0.96** (checked on point index 5, n=998 raw
+samples). The raw interferometer counts carry a large common-mode
+noise/drift component roughly 10x bigger than the true positional noise; the
+capacitive-sensor subtraction in §3.4 is what cancels it — the same
+combination that's already required for the mean position (§4) turns out to
+be even more load-bearing for the noise estimate. Both `FMC_IN.VAL1/VAL2`
+(the capacitive analog inputs) and `INENC1`-`4.VAL` (the encoder position
+inputs) are captured with `CAPTURE=Value` off the same `CLOCK1` tick (see
+`docs/developer/panda_box_free_running_setup.md`), so this isn't a
+sampling-rate mismatch between the two channels — the interferometer signal
+genuinely is that much noisier on its own.
+
+**Practical implication:** any future per-sample noise/variance analysis of
+Mode B data must use the full interf+cap combination (§3.4), never the raw
+interferometer signal alone — skipping the cap term breaks the noise
+estimate far more severely than it breaks the mean position.
+
+### 9.3 Result (`S06313`, all 472 points)
+
+PandA's within-point stdev (full formula) runs ~8–14% higher than RT's own
+stdev (X: 0.0074 vs 0.0065 µm; Y: 0.0063 vs 0.0058 µm), and the two
+independent noise estimates correlate at r ≈ 0.98 (X) / 0.99 (Y)
+point-by-point. The small systematic excess is expected, not a discrepancy:
+RT's stdev comes from its own already-averaged control-loop samples, while
+PandA's ~998 raw samples per point pick up additional high-rate noise RT's
+loop doesn't report, plus whatever small residual noise the interf/cap
+combination itself adds. This doesn't affect the mean-position validation in
+§4 (a noise-floor cross-check, not a bias check) — it's a useful additional
+confirmation that PandA's raw stream and RT's control loop are seeing
+consistent underlying physics, not just consistent means.

csaxs_bec/device_configs/bl_detectors.yaml

@@ -1,5 +1,26 @@
+# Eiger detectors (JungfrauJoch). Only one may be enabled at a time -- the JFJ broker
+# serves a single selected/initialised detector, so switching the active one here also
+# requires selecting/initialising the matching detector on the JFJ broker itself.
+# JungfrauJoch-side config (detector selection/init, pixel mask, azimuthal integration
+# settings) is done in the Web UI at http://sls-jfjoch-001.psi.ch:8080.
+# The Eiger 2 Si 500K detector server itself is reachable at 129.129.122.159.
+# eiger2_si_500k:
+
+#   description: Eiger 2 Si 500K detector
+#   deviceClass: csaxs_bec.devices.jungfraujoch.eiger2_si_500k.Eiger2Si500K
+#   deviceConfig:
+#     detector_distance: 1000
+#     beam_center: [200, 200]
+#   onFailure: raise
+#   enabled: True
+#   readoutPriority: async
+#   softwareTrigger: False
+#   deviceTags:
+#     - bl_detectors
+#     - eiger
+
 eiger_1_5:
-  description: Eiger 1.5M in-vacuum detector 
+  description: Eiger 1.5M in-vacuum detector
   deviceClass: csaxs_bec.devices.jungfraujoch.eiger_1_5m.Eiger1_5M
   deviceConfig:
     detector_distance: 2200
@@ -10,9 +31,10 @@ eiger_1_5:
   softwareTrigger: False
   deviceTags:
     - bl_detectors
+    - eiger
 
 # eiger_9:
-#   description: Eiger 9M detector 
+#   description: Eiger 9M detector
 #   deviceClass: csaxs_bec.devices.jungfraujoch.eiger_9m.Eiger9M
 #   deviceConfig:
 #     detector_distance: 6975.225
@@ -21,6 +43,9 @@ eiger_1_5:
 #   enabled: True
 #   readoutPriority: async
 #   softwareTrigger: False
+#   deviceTags:
+#     - bl_detectors
+#     - eiger
 
 # ids_cam:
 #   description: IDS camera for live image acquisition

csaxs_bec/device_configs/ptycho_flomni.yaml

@@ -21,7 +21,7 @@ feyex:
   userParameter:
     in: -16.453
     out: -1
-    fttrx_in: -2.4
+    fttrx_in: -2.3
     fttrx_out: -27
   deviceTags:
     - ptycho_flomni
@@ -66,7 +66,7 @@ fheater:
   userParameter:
     #in: -0.5
     in: -11.5
-    enabled: 1
+    enabled: 0
   deviceTags:
     - ptycho_flomni
 

csaxs_bec/devices/jungfraujoch/eiger.py

@@ -114,7 +114,7 @@ class Eiger(PSIDeviceBase):
 
     Args:
         name (str) : Name of the device
-        detector_name (str): Name of the detector. Supports ["EIGER 9M", "EIGER 8.5M (tmp)", "EIGER 1.5M"]
+        detector_name (str): Name of the detector. Supports ["EIGER 9M", "EIGER 8.5M (tmp)", "EIGER 1.5M", "Dectris EIGER2 Si 500K"]
         host (str): Hostname of the Jungfrau Joch server.
         port (int): Port of the Jungfrau Joch server.
         scan_info (ScanInfo): The scan info to use.
@@ -141,7 +141,9 @@ class Eiger(PSIDeviceBase):
     def __init__(
         self,
         name: str,
-        detector_name: Literal["EIGER 9M", "EIGER 8.5M (tmp)", "EIGER 1.5M"],
+        detector_name: Literal[
+            "EIGER 9M", "EIGER 8.5M (tmp)", "EIGER 1.5M", "Dectris EIGER2 Si 500K"
+        ],
         host: str = "http://sls-jfjoch-001",
         port: int = 8080,
         detector_distance: float = 100.0,
@@ -224,11 +226,18 @@ class Eiger(PSIDeviceBase):
             message (dict): The message received from the preview stream.
         """
         if message.get("type", "") == "image":
-            data = message.get("data", {}).get("default", None)
-            if data is None:
+            channels = message.get("data", {})
+            # The data dict's key varies by detector: "default" for eiger_1_5/eiger_9,
+            # but a threshold name (e.g. "threshold_1") for the multi-threshold-capable
+            # Eiger2 Si 500K. Prefer "default" when present, else take whichever single
+            # channel the broker actually sent.
+            frame = channels.get("default")
+            if frame is None:
+                frame = next(iter(channels.values()), None)
+            if frame is None:
                 logger.error(f"Received image message on device {self.name} without data.")
                 return
-            self.preview_image.put(data)
+            self.preview_image.put(frame)
 
     # pylint: disable=missing-function-docstring
     @property

csaxs_bec/devices/jungfraujoch/eiger2_si_500k.py

@@ -0,0 +1,62 @@
+"""
+Eiger 2 Si 500K specific integration. It is based on the Eiger base integration for the JungfrauJoch backend
+which is placed in eiger_csaxs, and where code that is equivalent for the Eiger9M, Eiger1.5M and
+Eiger2 Si 500K is shared.
+
+Please check the eiger_csaxs.py class for more details about the relevant services.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from csaxs_bec.devices.jungfraujoch.eiger import RAISE_ON_MISSING_PACKETS, Eiger
+
+# Gap this model needs between the end of an acquisition and the next trigger. Kept
+# per model on purpose -- readout is a detector property, not a beamline constant. The
+# delay generator's gap (DDG2 DEFAULT_READOUT_TIMES["ab"]) must be at least as large as
+# the largest value among the detectors in a scan, or the slowest one overruns.
+EIGER2_SI_500K_READOUT_TIME = 2e-4  # s -- placeholder until a measured value exists
+DETECTOR_NAME = "Dectris EIGER2 Si 500K"
+
+
+if TYPE_CHECKING:  # pragma no cover
+    from bec_lib.devicemanager import ScanInfo
+    from bec_server.device_server.device_server import DeviceManagerDS
+
+
+# pylint:disable=invalid-name
+class Eiger2Si500K(Eiger):
+    """
+    Eiger 2 Si 500K specific integration.
+
+    The logic implemented here is coupled to the DelayGenerator integration,
+    repsonsible for the global triggering of all devices through a single Trigger logic.
+    Please check the eiger.py class for more details about the integration of relevant backend
+    services. The detector_name must be set to "Dectris EIGER2 Si 500K":
+    """
+
+    USER_ACCESS = Eiger.USER_ACCESS + []  # Add more user_access methods here.
+
+    def __init__(
+        self,
+        name: str,
+        detector_distance: float = 100.0,
+        beam_center: tuple[float, float] = (0.0, 0.0),
+        scan_info: ScanInfo = None,
+        device_manager: DeviceManagerDS = None,
+        readout_time: float = EIGER2_SI_500K_READOUT_TIME,
+        raise_on_missing_packets: bool = RAISE_ON_MISSING_PACKETS,
+        **kwargs,
+    ) -> None:
+        super().__init__(
+            name=name,
+            detector_name=DETECTOR_NAME,
+            readout_time=readout_time,
+            raise_on_missing_packets=raise_on_missing_packets,
+            detector_distance=detector_distance,
+            beam_center=beam_center,
+            scan_info=scan_info,
+            device_manager=device_manager,
+            **kwargs,
+        )

csaxs_bec/devices/omny/galil/galil_ophyd.py

@@ -249,7 +249,7 @@ class GalilController(Controller):
         if not limit:
             raise GalilError(f"Failed to drive axis {axis_Id}/{axis_Id_numeric} to limit.")
         else:
-            print("Limit reached.")
+            print("Limit switch reached.")
 
     def find_reference(self, axis_Id_numeric: int, verbose=0, raise_error=1) -> None:
         """

csaxs_bec/file_writer/csaxs_nexus.py

@@ -3,6 +3,38 @@ from __future__ import annotations
 import numpy as np
 from bec_server.file_writer.default_writer import DefaultFormat
 
+# Physical metadata for the NXdetector block, per Eiger model. Looked up by the device
+# name resolved via _active_eiger_name(); a model not listed here (e.g. a future one)
+# still gets a working NXdetector group via _DEFAULT_EIGER_INFO rather than silently
+# losing its data links, which is the failure mode this table replaces.
+_EIGER_DETECTOR_INFO = {
+    "eiger_1_5": {
+        "description": "Eiger 1.5M detector, in-house developed, Paul Scherrer Institute",
+        "type": "Single-photon counting detector, 320 micron-thick Si chip",
+        "pixel_size_um": 75.0,
+        "orientation_transpose": 1,
+        "orientation_rot90": 3,
+    },
+    "eiger2_si_500k": {
+        "description": "Dectris EIGER2 Si 500K detector",
+        "type": "Single-photon counting detector, 450 micron-thick Si chip",
+        "pixel_size_um": 75.0,
+        # TODO orientation not yet determined for this detector -- confirm with beam
+        # during commissioning, then fill these in (see eiger_1_5 for the convention).
+        # JungfrauJoch-side config (pixel mask, azimuthal integration settings, detector
+        # selection/init) is done in the Web UI at http://sls-jfjoch-001.psi.ch:8080.
+        "orientation_transpose": None,
+        "orientation_rot90": None,
+    },
+}
+_DEFAULT_EIGER_INFO = {
+    "description": "Eiger detector (Dectris/PSI, JungfrauJoch)",
+    "type": "Single-photon counting detector",
+    "pixel_size_um": 75.0,
+    "orientation_transpose": None,
+    "orientation_rot90": None,
+}
+
 
 class cSAXSNeXusFormat(DefaultFormat):
     """
@@ -35,7 +67,10 @@ class cSAXSNeXusFormat(DefaultFormat):
           /slit_3 … slit_5
           /filter_set
           /beam_stop_1 … beam_stop_2
-          /eiger_1_5              NXdetector
+          /<active eiger>         NXdetector  ← named after whichever Eiger-family
+                                                device (deviceTag "eiger") is enabled
+                                                in bl_detectors.yaml, e.g. eiger_1_5
+                                                or eiger2_si_500k; see _active_eiger_name
           /mcs                    NXdetector
           /flOMNI                 NXpositioner
 
@@ -48,7 +83,8 @@ class cSAXSNeXusFormat(DefaultFormat):
     bs1x / bs1y    →  bs1x / bs1y
     bs2x / bs2y    →  bs2x / bs2y
     dettrx         →  dettrx
-    eiger_4        →  eiger_1_5
+    eiger_4        →  eiger_1_5, eiger_9 or eiger2_si_500k (whichever carries the
+                       "eiger" deviceTag and is enabled -- see _active_eiger_name)
     mcs            →  mcs
     filter_array   →  filter_array_1_x … filter_array_4_x
     xbpm3          →  xbpm3x / xbpm3y  (stage positions; signal readouts TODO)
@@ -94,6 +130,23 @@ class cSAXSNeXusFormat(DefaultFormat):
         except Exception:
             pass
 
+    def _active_eiger_name(self) -> str | None:
+        """Name of the currently enabled Eiger-family detector, if any.
+
+        Resolved via the 'eiger' deviceTag rather than a hardcoded device name, so this
+        layout follows whichever Eiger model is actually active in bl_detectors.yaml
+        (only one is ever enabled at a time).
+        """
+        try:
+            candidates = [
+                dev
+                for dev in self.device_manager.devices.get_devices_with_tags(["eiger"])
+                if dev.enabled and dev.name in self.file_references
+            ]
+        except Exception:
+            return None
+        return candidates[0].name if candidates else None
+
     def _slit_blades(self, group, prefix: str) -> None:
         """
         Store individual blade motor positions for a 4-blade slit set.
@@ -118,7 +171,8 @@ class cSAXSNeXusFormat(DefaultFormat):
 
         # Canonical paths referenced by multiple groups
         RT_POS_PATH = "/entry/instrument/flOMNI/rt_positions"
-        EIGER_COLL  = "/entry/collection/file_references/eiger_1_5"
+        eiger_name = self._active_eiger_name()
+        EIGER_COLL = f"/entry/collection/file_references/{eiger_name}" if eiger_name else None
 
         # ── Root entry ────────────────────────────────────────────────────────
         entry = self.storage.create_group("entry")
@@ -157,11 +211,12 @@ class cSAXSNeXusFormat(DefaultFormat):
         nxdata.attrs["NX_class"] = "NXdata"
         nxdata.attrs["signal"]   = "data"
         # Detector frames
-        try:
-            for k in self.file_references["eiger_1_5"].hinted_h5_entries.keys():
-                self._safe_soft_link(nxdata, k, f"{EIGER_COLL}/{k}")
-        except Exception:
-            pass
+        if eiger_name:
+            try:
+                for k in self.file_references[eiger_name].hinted_h5_entries.keys():
+                    self._safe_soft_link(nxdata, k, f"{EIGER_COLL}/{k}")
+            except Exception:
+                pass
         # Scan positions
         self._safe_soft_link(nxdata, "positions", RT_POS_PATH)
 
@@ -172,11 +227,12 @@ class cSAXSNeXusFormat(DefaultFormat):
         # Convenience group mirroring the old /entry/data hardlink from layout.xml.
         data_soft = entry.create_group("data_soft")
         data_soft.attrs["NX_class"] = "NXentry"
-        try:
-            for k in self.file_references["eiger_1_5"].hinted_h5_entries.keys():
-                self._safe_soft_link(data_soft, k, f"{EIGER_COLL}/{k}")
-        except Exception:
-            pass
+        if eiger_name:
+            try:
+                for k in self.file_references[eiger_name].hinted_h5_entries.keys():
+                    self._safe_soft_link(data_soft, k, f"{EIGER_COLL}/{k}")
+            except Exception:
+                pass
 
         # ── /entry/control ────────────────────────────────────────────────────
         control = entry.create_group("control")
@@ -357,38 +413,34 @@ class cSAXSNeXusFormat(DefaultFormat):
             units="mm", description="Detector x-translation stage",
         )
 
-        # ── Eiger 1.5M detector ───────────────────────────────────────────────
-        if (
-            "eiger_1_5" in self.device_manager.devices
-            and self.device_manager.devices.eiger_1_5.enabled
-            and "eiger_1_5" in self.file_references
-        ):
-            eiger = instrument.create_group("eiger_1_5")
+        # ── Eiger detector (whichever model is currently active) ────────────────
+        if eiger_name:
+            info = _EIGER_DETECTOR_INFO.get(eiger_name, _DEFAULT_EIGER_INFO)
+            eiger = instrument.create_group(eiger_name)
             eiger.attrs["NX_class"] = "NXdetector"
-            eiger.create_dataset("x_pixel_size",    data=75.0).attrs["units"] = "um"
-            eiger.create_dataset("y_pixel_size",    data=75.0).attrs["units"] = "um"
+            eiger.create_dataset("x_pixel_size",    data=info["pixel_size_um"]).attrs["units"] = "um"
+            eiger.create_dataset("y_pixel_size",    data=info["pixel_size_um"]).attrs["units"] = "um"
             eiger.create_dataset("polar_angle",     data=0.0).attrs["units"]  = "degrees"
             eiger.create_dataset("azimuthal_angle", data=0.0).attrs["units"]  = "degrees"
             eiger.create_dataset("rotation_angle",  data=0.0).attrs["units"]  = "degrees"
-            eiger.create_dataset(
-                "description",
-                data="Eiger 1.5M detector, in-house developed, Paul Scherrer Institute",
-            )
-            eiger.create_dataset(
-                "type",
-                data="Single-photon counting detector, 320 micron-thick Si chip",
-            )
+            eiger.create_dataset("description", data=info["description"])
+            eiger.create_dataset("type", data=info["type"])
             orientation = eiger.create_group("orientation")
             orientation.attrs["description"] = (
                 "Orientation defines the number of counterclockwise rotations by 90 deg "
                 "followed by a transposition to reach the 'cameraman orientation', "
                 "looking towards the beam."
             )
-            orientation.create_dataset("transpose", data=1)
-            orientation.create_dataset("rot90",     data=3)
+            # Only written once known for this model (see _EIGER_DETECTOR_INFO); a model
+            # pending commissioning gets the group and convention documented but no
+            # guessed values.
+            if info["orientation_transpose"] is not None:
+                orientation.create_dataset("transpose", data=info["orientation_transpose"])
+            if info["orientation_rot90"] is not None:
+                orientation.create_dataset("rot90", data=info["orientation_rot90"])
             # Soft-link recorded frame data from the BEC collection
             try:
-                for k in self.file_references["eiger_1_5"].hinted_h5_entries.keys():
+                for k in self.file_references[eiger_name].hinted_h5_entries.keys():
                     self._safe_soft_link(eiger, k, f"{EIGER_COLL}/{k}")
             except Exception:
                 pass
@@ -396,7 +448,7 @@ class cSAXSNeXusFormat(DefaultFormat):
             try:
                 eiger.create_ext_link(
                     "pixel_mask",
-                    self.file_references["eiger_1_5"].file_path,
+                    self.file_references[eiger_name].file_path,
                     "/entry/instrument/detector/pixel_mask",
                 )
             except Exception:

tests/tests_devices/test_eiger.py

@@ -31,6 +31,10 @@ from csaxs_bec.devices.jungfraujoch.eiger import (
 )
 from csaxs_bec.devices.jungfraujoch.eiger_1_5m import EIGER1_5M_READOUT_TIME, Eiger1_5M
 from csaxs_bec.devices.jungfraujoch.eiger_9m import EIGER9M_READOUT_TIME, Eiger9M
+from csaxs_bec.devices.jungfraujoch.eiger2_si_500k import (
+    EIGER2_SI_500K_READOUT_TIME,
+    Eiger2Si500K,
+)
 
 if TYPE_CHECKING:  # pragma no cover
     from bec_lib.messages import FileMessage
@@ -73,7 +77,7 @@ def mock_scan_info(request, tmpdir):
     yield scan_info
 
 
-@pytest.fixture(scope="function", params=[(1,), (2,)])
+@pytest.fixture(scope="function", params=[(1,), (2,), (3,)])
 def detector_list(request) -> Generator[DetectorList, None, None]:
     """Fixture for the detector list."""
     current_id = request.param[0]
@@ -109,6 +113,21 @@ def detector_list(request) -> Generator[DetectorList, None, None]:
                 min_count_time_ns=100000,
                 type="EIGER",
             ),
+            DetectorListElement(
+                id=3,
+                description="Dectris EIGER2 Si 500K",
+                serial_number="123456",
+                base_ipv4_addr="192.168.0.1",
+                udp_interface_count=1,
+                nmodules=1,
+                width=512,
+                height=512,
+                pixel_size_mm=0.1,
+                readout_time_ns=100000,
+                min_frame_time_ns=1000000,
+                min_count_time_ns=100000,
+                type="EIGER",
+            ),
         ],
         current_id=current_id,
     )
@@ -142,9 +161,23 @@ def eiger_9m(mock_scan_info) -> Generator[Eiger9M, None, None]:
             dev.destroy()
 
 
-def test_eiger_wait_for_connection(eiger_1_5m, eiger_9m):
+@pytest.fixture(scope="function")
+def eiger2_si_500k(mock_scan_info) -> Generator[Eiger2Si500K, None, None]:
+    """Fixture for the Eiger 2 Si 500K device.
+    Currently only on_connected is different for both devices, all other methods are the same."""
+    name = "eiger2_si_500k"
+    dev = Eiger2Si500K(name=name)
+    dev.scan_info.msg = mock_scan_info
+    try:
+        yield dev
+    finally:
+        if dev._destroyed is False:
+            dev.destroy()
+
+
+def test_eiger_wait_for_connection(eiger_1_5m, eiger_9m, eiger2_si_500k):
     """Test the wait_for_connection metho is calling status_get on the JFJ API client."""
-    for eiger in (eiger_1_5m, eiger_9m):
+    for eiger in (eiger_1_5m, eiger_9m, eiger2_si_500k):
         with mock.patch.object(eiger.jfj_client.api, "status_get") as mock_status_get:
             eiger.wait_for_connection(timeout=1)
             mock_status_get.assert_called_once_with(_request_timeout=1)
@@ -188,6 +221,44 @@ def test_eiger_1_5m_on_connected(eiger_1_5m, detector_list, detector_state):
             assert mock_jfj_preview_client.start.call_count == 1
 
 
+@pytest.mark.parametrize("detector_state", ["Idle", "Inactive"])
+def test_eiger2_si_500k_on_connected(eiger2_si_500k, detector_list, detector_state):
+    """Test the on_connected logic of the Eiger detector."""
+    eiger = eiger2_si_500k
+    detector_id = 3
+    with (
+        mock.patch.object(eiger.jfj_client, "stop") as mock_jfj_client_stop,
+        mock.patch.object(
+            eiger.jfj_client.api, "config_select_detector_get", return_value=detector_list
+        ),
+        mock.patch.object(
+            eiger.jfj_client.api, "status_get", return_value=BrokerStatus(state=detector_state)
+        ),
+        mock.patch.object(eiger.jfj_client, "set_detector_settings") as mock_set_det,
+        mock.patch.object(eiger.jfj_client.api, "config_file_writer_put") as mock_file_writer,
+        mock.patch.object(eiger, "jfj_preview_client") as mock_jfj_preview_client,
+    ):
+        if detector_state != "Idle" or detector_list.current_id != detector_id:
+            with pytest.raises(RuntimeError):
+                eiger.on_connected()
+            mock_jfj_client_stop.assert_called_once()
+            assert mock_jfj_preview_client.call_count == 0
+        else:
+            eiger.on_connected()
+            assert mock_set_det.call_args == mock.call(
+                DetectorSettings(frame_time_us=500, timing=DetectorTiming.TRIGGER), timeout=5
+            )
+            assert mock_file_writer.call_args == mock.call(
+                file_writer_settings=FileWriterSettings(
+                    overwrite=True, format=FileWriterFormat.NXMXVDS
+                ),
+                _request_timeout=10,
+            )
+            mock_jfj_client_stop.assert_called_once()
+            assert mock_jfj_preview_client.connect.call_count == 1
+            assert mock_jfj_preview_client.start.call_count == 1
+
+
 @pytest.mark.skip(
     reason="This test is currently disabled because the Eiger 9M config is replaced by the 8_5M config."
 )
@@ -471,6 +542,29 @@ def test_eiger_preview_callback(eiger_1_5m):
                 mock_preview_put.assert_not_called()
 
 
+def test_eiger_preview_callback_falls_back_to_non_default_channel(eiger2_si_500k):
+    """The Eiger2 Si 500K's multi-threshold preview data has no "default" key (it's
+    named after the threshold, e.g. "threshold_1" -- confirmed against a live capture
+    of the JFJ preview stream); the callback must still forward that single channel.
+    """
+    eiger = eiger2_si_500k
+    frame = np.array([[1, 2], [3, 4]])
+    msg = {"type": "image", "data": {"threshold_1": frame}}
+    with mock.patch.object(eiger.preview_image, "put") as mock_preview_put:
+        eiger._preview_callback(msg)
+        mock_preview_put.assert_called_once_with(frame)
+
+
+def test_eiger_preview_callback_logs_when_data_is_truly_empty(eiger_1_5m):
+    """No channel at all (empty or missing data dict) must still be treated as missing,
+    not silently pass through some other unrelated dict key."""
+    eiger = eiger_1_5m
+    for msg in [{"type": "image", "data": {}}, {"type": "image"}]:
+        with mock.patch.object(eiger.preview_image, "put") as mock_preview_put:
+            eiger._preview_callback(msg)
+            mock_preview_put.assert_not_called()
+
+
 def test_eiger_acquisition_matches_the_gated_window(eiger_1_5m):
     """The detector must acquire for exp_time - readout, not for the whole period.
 
@@ -546,7 +640,7 @@ def test_eiger_minimum_exposure_check_is_unchanged(eiger_1_5m):
             eiger.stage()
 
 
-def test_eiger_models_may_declare_their_own_readout_time(eiger_1_5m, eiger_9m):
+def test_eiger_models_may_declare_their_own_readout_time(eiger_1_5m, eiger_9m, eiger2_si_500k):
     """Readout is a detector property, so each model states its own value.
 
     They coincide today, but nothing should force them to: a 9M has more modules
@@ -554,6 +648,7 @@ def test_eiger_models_may_declare_their_own_readout_time(eiger_1_5m, eiger_9m):
     """
     assert eiger_1_5m._readout_time == EIGER1_5M_READOUT_TIME
     assert eiger_9m._readout_time == EIGER9M_READOUT_TIME
+    assert eiger2_si_500k._readout_time == EIGER2_SI_500K_READOUT_TIME
 
 
 def test_eiger_readout_time_is_overridable_per_deployment(mock_scan_info):
@@ -575,7 +670,7 @@ def test_eiger_subclasses_name_readout_time_for_the_device_server():
     **kwargs silently drops readout_time -- and passing it explicitly used to raise
     'got multiple values for keyword argument'.
     """
-    for cls in (Eiger1_5M, Eiger9M):
+    for cls in (Eiger1_5M, Eiger9M, Eiger2Si500K):
         assert "readout_time" in inspect.signature(cls).parameters
 
 
@@ -697,5 +792,5 @@ def test_eiger_missing_packet_tolerance_is_overridable_per_deployment(mock_scan_
 def test_eiger_subclasses_name_raise_on_missing_packets_for_the_device_server():
     """Same rule as readout_time: a deviceConfig key only reaches a device if the
     class signature names it, so **kwargs alone would silently drop it."""
-    for cls in (Eiger1_5M, Eiger9M):
+    for cls in (Eiger1_5M, Eiger9M, Eiger2Si500K):
         assert "raise_on_missing_packets" in inspect.signature(cls).parameters