diff --git a/ophyd_devices/sim/sim_waveform.py b/ophyd_devices/sim/sim_waveform.py
index 884a0e9..22581b1 100644
--- a/ophyd_devices/sim/sim_waveform.py
+++ b/ophyd_devices/sim/sim_waveform.py
@@ -90,7 +90,7 @@ class SimWaveform(Device):
         compute_readback=True,
         kind=Kind.hinted,
     )
-    data = Cpt(AsyncSignal, name="data", ndim=1)
+    data = Cpt(AsyncSignal, name="data", ndim=1, max_size=1000)
     # Can be extend or append
     async_update = Cpt(AsyncUpdateSignal, value="add", kind=Kind.config)
     slice_size = Cpt(SetableSignal, value=100, dtype=np.int32, kind=Kind.config)
@@ -132,13 +132,13 @@ class SimWaveform(Device):
         """Delay updates in-between slices specified by waveform_shape and slice_size."""
         return self._delay_slice_update
 
-    @typechecked
     @delay_slice_update.setter
+    @typechecked
     def delay_slice_update(self, value: bool) -> None:
         self._delay_slice_update = value
 
     @property
-    def registered_proxies(self) -> None:
+    def registered_proxies(self) -> dict[str, Any]:
         """Dictionary of registered signal_names and proxies."""
         return self._registered_proxies
 
@@ -229,6 +229,11 @@ class SimWaveform(Device):
             signals={self.waveform.name: {"value": value, "timestamp": time.time()}},
             metadata=metadata,
         )
+
+        self.data.put(
+            {self.data.name: {"value": value, "timestamp": time.time()}}, metadata=metadata
+        )
+
         # Send the message to BEC
         self.connector.xadd(
             MessageEndpoints.device_async_readback(
diff --git a/ophyd_devices/utils/bec_signals.py b/ophyd_devices/utils/bec_signals.py
index d7b115e..59a3f74 100644
--- a/ophyd_devices/utils/bec_signals.py
+++ b/ophyd_devices/utils/bec_signals.py
@@ -695,7 +695,13 @@ class DynamicSignal(BECMessageSignal):
 
     def _check_signals(self, msg: messages.DeviceMessage) -> None:
         """Check if all signals are valid."""
-        available_signals = [name for name, _ in self.signals]
+        if len(self.signals) == 1:
+            if self.name not in msg.signals:
+                raise ValueError(
+                    f"Signal {self.name} not found in message {list(msg.signals.keys())}"
+                )
+            return
+        available_signals = [f"{self.name}_{name}" for name, _ in self.signals]
         if self.strict_signal_validation:
             if set(msg.signals.keys()) != set(available_signals):
                 raise ValueError(
@@ -744,6 +750,7 @@ class AsyncSignal(DynamicSignal):
         *,
         name: str,
         ndim: Literal[0, 1, 2],
+        max_size: int,
         value: messages.DeviceMessage | dict | None = None,
         async_update: dict | None = None,
         **kwargs,
@@ -753,7 +760,10 @@ class AsyncSignal(DynamicSignal):
 
         Args:
             name (str): The name of the signal.
+            ndim (Literal[0, 1, 2]): The number of dimensions of the signal(s).
+            max_size (int): The maximum size of the signal buffer.
             value (AsyncMessage | dict | None): The initial value of the signal. Defaults to None.
+            async_update (dict | None): Additional metadata for asynchronous updates. Defaults to None.
         """
         kwargs.pop("kind", None)  # Ignore kind if specified
         super().__init__(
@@ -766,5 +776,6 @@ class AsyncSignal(DynamicSignal):
             value=value,
             bec_message_type=messages.DeviceMessage,
             async_update=async_update,
+            signal_metadata={"max_size": max_size},
             **kwargs,
         )
diff --git a/tests/test_utils.py b/tests/test_utils.py
index eb909c1..b22695c 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -282,7 +282,7 @@ def test_utils_dynamic_signal():
     }
 
     # Put works with Message
-    msg_dict = {"sig1": {"value": 1}, "sig2": {"value": 2}}
+    msg_dict = {"dynamic_signal_sig1": {"value": 1}, "dynamic_signal_sig2": {"value": 2}}
     msg = messages.DeviceMessage(signals=msg_dict)
     signal.put(msg)
     reading = signal.read()