diff --git a/csaxs_bec/bec_widgets/widgets/tomo_params/tomo_params.py b/csaxs_bec/bec_widgets/widgets/tomo_params/tomo_params.py
index 1a5c070..b18e5f1 100644
--- a/csaxs_bec/bec_widgets/widgets/tomo_params/tomo_params.py
+++ b/csaxs_bec/bec_widgets/widgets/tomo_params/tomo_params.py
@@ -162,16 +162,30 @@ class TomoParamsWidget(BECWidget, QWidget):
         super().__init__(parent=parent, **kwargs)
         self.get_bec_shortcuts()
         self._edit_mode = False
-        # widget refs populated by _build_params_panel
         self._pw: dict[str, QWidget] = {}  # key -> input widget
+        self._queue_dlg: Optional["TomoQueueDialog"] = None
+        # check whether the FlOMNI setup is active before building the UI
+        self._flomni_available = self._check_flomni_available()
         self._build_ui()
-        # polling timer – does NOT refresh params (avoid overwriting edits)
         self._poll_timer = QTimer(self)
         self._poll_timer.setInterval(self._POLL_INTERVAL_MS)
         self._poll_timer.timeout.connect(self._on_poll)
-        self._poll_timer.start()
-        # initial load
-        self.refresh()
+        if self._flomni_available:
+            self._poll_timer.start()
+            self.refresh()
+
+    # ── setup detection ──────────────────────────────────────────────────────
+
+    def _check_flomni_available(self) -> bool:
+        """
+        Return True if the FlOMNI setup is active in this BEC session.
+        Uses ``fsamroy`` (the FlOMNI-specific rotation stage) as the
+        discriminator — it is absent in OMNY and LamNI sessions.
+        """
+        try:
+            return getattr(self.dev, "fsamroy", None) is not None
+        except Exception:
+            return False
 
     # ── global-var I/O ───────────────────────────────────────────────────────
 
@@ -212,6 +226,19 @@ class TomoParamsWidget(BECWidget, QWidget):
         root = QVBoxLayout(self)
         root.setSpacing(6)
 
+        if not self._flomni_available:
+            lbl = QLabel(
+                "⚠ FlOMNI setup not detected in this BEC session.\n\n"
+                "This widget is only meaningful when the FlOMNI\n"
+                "BEC session is active (fsamroy device present)."
+            )
+            lbl.setAlignment(Qt.AlignmentFlag.AlignCenter)
+            lbl.setWordWrap(True)
+            root.addStretch()
+            root.addWidget(lbl)
+            root.addStretch()
+            return
+
         # scrollable params panel
         params_scroll = QScrollArea()
         params_scroll.setWidgetResizable(True)
@@ -230,7 +257,6 @@ class TomoParamsWidget(BECWidget, QWidget):
         self._btn_queue.setToolTip("Open the tomo queue manager")
         self._btn_queue.clicked.connect(self._show_queue_dialog)
         root.addWidget(self._btn_queue)
-        self._queue_dlg: Optional["TomoQueueDialog"] = None
 
     def _build_header(self) -> QGroupBox:
         box = QGroupBox("Sample")
@@ -340,6 +366,13 @@ class TomoParamsWidget(BECWidget, QWidget):
         form = QFormLayout(box)
         form.setLabelAlignment(Qt.AlignmentFlag.AlignRight)
 
+        self._add_int(
+            form,
+            "_numprj_type3",
+            "Projections per sub-tomo (type 3)",
+            min_=1,
+            max_=10000,
+        )
         self._add_int(
             form, "golden_ratio_bunch_size", "Bunch size (type 2 only)", min_=1, max_=10000
         )
@@ -448,6 +481,15 @@ class TomoParamsWidget(BECWidget, QWidget):
         self._pw["_requested_total"].blockSignals(False)
 
         self._update_projection_preview()
+
+        # type-3: derive projections-per-subtomo from stored tomo_angle_stepsize
+        # (flomni uses 180 / tomo_angle_stepsize for type 3, hardcoded to 180)
+        stepsize = float(params.get("tomo_angle_stepsize", 10.0))
+        numprj_t3 = int(180.0 / stepsize) if stepsize > 0 else 18
+        self._pw["_numprj_type3"].blockSignals(True)
+        self._pw["_numprj_type3"].setValue(numprj_t3)
+        self._pw["_numprj_type3"].blockSignals(False)
+
         self._update_type_visibility(type_val)
 
     def _read_fields(self) -> dict[str, Any]:
@@ -470,12 +512,19 @@ class TomoParamsWidget(BECWidget, QWidget):
             elif isinstance(widget, QComboBox):
                 params[key] = widget.currentData()
 
-        # derive tomo_angle_stepsize from requested_total + angle_range
+        # derive tomo_angle_stepsize from requested_total + angle_range (type 1)
         angle_range = int(params.get("tomo_angle_range", 180))
         requested = self._pw["_requested_total"].value()
         stepsize = _requested_to_stepsize(angle_range, requested)
         params["tomo_angle_stepsize"] = stepsize
 
+        # type 3: override tomo_angle_stepsize from projections-per-subtomo
+        # (flomni uses 180 / numprj for type 3)
+        if params.get("tomo_type") == 3:
+            numprj = self._pw["_numprj_type3"].value()
+            if numprj > 0:
+                params["tomo_angle_stepsize"] = 180.0 / numprj
+
         # single_point forces stitch to 0
         if params.get("single_point_instead_of_fermat_scan"):
             params["stitch_x"] = 0
@@ -508,19 +557,30 @@ class TomoParamsWidget(BECWidget, QWidget):
     def _update_type_visibility(self, tomo_type: int) -> None:
         self._sec_type1.setVisible(tomo_type == 1)
         self._sec_type23.setVisible(tomo_type in (2, 3))
-        # bunch_size is type-2 only; find its row in the form layout
-        bunch_widget = self._pw.get("golden_ratio_bunch_size")
-        if bunch_widget is not None:
-            bunch_widget.setVisible(tomo_type == 2)
-            # also hide the label in the form layout
-            form = self._sec_type23.layout()
-            if isinstance(form, QFormLayout):
-                idx = form.indexOf(bunch_widget)
-                if idx >= 0:
-                    row, role = form.getItemPosition(idx)
-                    label_item = form.itemAt(row, QFormLayout.ItemRole.LabelRole)
-                    if label_item and label_item.widget():
-                        label_item.widget().setVisible(tomo_type == 2)
+        # _numprj_type3: only visible for type 3
+        _w__numprj_type3 = self._pw.get("_numprj_type3")
+        if _w__numprj_type3 is not None:
+            _w__numprj_type3.setVisible(tomo_type == 3)
+            _form = self._sec_type23.layout()
+            if isinstance(_form, QFormLayout):
+                _idx = _form.indexOf(_w__numprj_type3)
+                if _idx >= 0:
+                    _row, _role = _form.getItemPosition(_idx)
+                    _lbl = _form.itemAt(_row, QFormLayout.ItemRole.LabelRole)
+                    if _lbl and _lbl.widget():
+                        _lbl.widget().setVisible(tomo_type == 3)
+        # golden_ratio_bunch_size: only visible for type 2
+        _w_golden_ratio_bunch_size = self._pw.get("golden_ratio_bunch_size")
+        if _w_golden_ratio_bunch_size is not None:
+            _w_golden_ratio_bunch_size.setVisible(tomo_type == 2)
+            _form = self._sec_type23.layout()
+            if isinstance(_form, QFormLayout):
+                _idx = _form.indexOf(_w_golden_ratio_bunch_size)
+                if _idx >= 0:
+                    _row, _role = _form.getItemPosition(_idx)
+                    _lbl = _form.itemAt(_row, QFormLayout.ItemRole.LabelRole)
+                    if _lbl and _lbl.widget():
+                        _lbl.widget().setVisible(tomo_type == 2)
 
     # ── type-1 projection preview ─────────────────────────────────────────────