diff --git a/ophyd_devices/epics/devices/falcon_csaxs.py b/ophyd_devices/epics/devices/falcon_csaxs.py
index 4a5bd1b..510759e 100644
--- a/ophyd_devices/epics/devices/falcon_csaxs.py
+++ b/ophyd_devices/epics/devices/falcon_csaxs.py
@@ -5,8 +5,11 @@ import time
 from typing import List
 from bec_lib.core.devicemanager import DeviceStatus
 
-from ophyd import EpicsSignal, EpicsSignalRO, EpicsSignalWithRBV, Component as Cpt, Device
+from ophyd import EpicsSignal, EpicsSignalRO, EpicsSignalWithRBV, Component as Cpt
 from ophyd.mca import EpicsMCARecord
+from ophyd import DetectorBase, Device
+from ophyd import ADComponent as ADCpt
+
 
 from bec_lib.core.file_utils import FileWriterMixin
 from bec_lib.core import MessageEndpoints, BECMessage
@@ -17,6 +20,8 @@ from ophyd_devices.utils import bec_utils
 
 logger = bec_logger.logger
 
+FALCON_MIN_READOUT = 3e-3
+
 
 class FalconError(Exception):
     """Base class for exceptions in this module."""
@@ -24,12 +29,19 @@ class FalconError(Exception):
     pass
 
 
-class FalconTimeoutError(Exception):
+class FalconTimeoutError(FalconError):
     """Raised when the Falcon does not respond in time during unstage."""
 
     pass
 
 
+class DeviceClassInitError(FalconError):
+    """Raised when initiation of the device class fails,
+    due to missing device manager or not started in sim_mode."""
+
+    pass
+
+
 class DetectorState(int, enum.Enum):
     """Detector states for Falcon detector"""
 
@@ -160,30 +172,46 @@ class FalconCsaxs(Device):
             **kwargs,
         )
         if device_manager is None and not sim_mode:
-            raise FalconError("Add DeviceManager to initialization or init with sim_mode=True")
+            raise DeviceClassInitError(
+                f"No device manager for device: {name}, and not started sim_mode: {sim_mode}. Add DeviceManager to initialization or init with sim_mode=True"
+            )
+        self.sim_mode = sim_mode
         self._stopped = False
         self.name = name
-        self.wait_for_connection()
-        # Spin up connections for simulation or BEC mode
+        self.service_cfg = None
+        self.scaninfo = None
+        self.filewriter = None
+        self.readout_time_min = FALCON_MIN_READOUT
+        self._value_pixel_per_buffer = None
+        self.readout_time = None
+        self.wait_for_connection(all_signals=True)
         if not sim_mode:
-            from bec_lib.core.bec_service import SERVICE_CONFIG
-
+            self._update_service_config()
             self.device_manager = device_manager
-            self._producer = self.device_manager.producer
-            self.service_cfg = SERVICE_CONFIG.config["service_config"]["file_writer"]
         else:
-            base_path = f"/sls/X12SA/data/{self.scaninfo.username}/Data10/"
-            self._producer = bec_utils.MockProducer()
-            self.device_manager = bec_utils.MockDeviceManager()
-            self.scaninfo = BecScaninfoMixin(device_manager, sim_mode)
-            self.scaninfo.load_scan_metadata()
-            self.service_cfg = {"base_path": base_path}
-
-        self.scaninfo = BecScaninfoMixin(device_manager, sim_mode)
-        self.scaninfo.load_scan_metadata()
-        self.filewriter = FileWriterMixin(self.service_cfg)
+            self.device_manager = bec_utils.DMMock()
+            base_path = kwargs["basepath"] if "basepath" in kwargs else "~/Data10/"
+            self.service_cfg = {"base_path": os.path.expanduser(base_path)}
+        self._producer = self.device_manager.producer
+        self._update_scaninfo()
+        self._update_filewriter()
         self._init()
 
+    def _update_filewriter(self) -> None:
+        """Update filewriter with service config"""
+        self.filewriter = FileWriterMixin(self.service_cfg)
+
+    def _update_scaninfo(self) -> None:
+        """Update scaninfo from BecScaninfoMixing
+        This depends on device manager and operation/sim_mode
+        """
+        self.scaninfo = BecScaninfoMixin(self.device_manager, self.sim_mode)
+        self.scaninfo.load_scan_metadata()
+
+    def _update_service_config(self) -> None:
+        """Update service config from BEC service config"""
+        self.service_cfg = SERVICE_CONFIG.config["service_config"]["file_writer"]
+
     def _init(self) -> None:
         """Initialize detector, filewriter and set default parameters"""
         self._default_parameter()