diff --git a/ophyd_devices/__init__.py b/ophyd_devices/__init__.py
index c6527a8..b88c1f3 100644
--- a/ophyd_devices/__init__.py
+++ b/ophyd_devices/__init__.py
@@ -1,6 +1,6 @@
 from .galil.galil_ophyd import GalilMotor
 from .npoint.npoint import NPointAxis
 from .rt_lamni import RtLamniMotor
-from .sim.sim import SynAxisMonitor, SynAxisOPAAS, SynFlyer, SynSLSDetector
+from .sim.sim import SynAxisMonitor, SynAxisOPAAS, SynFlyer, SynSignalRO, SynSLSDetector
 from .sls_devices.sls_devices import SLSOperatorMessages
 from .smaract.smaract_ophyd import SmaractMotor
diff --git a/ophyd_devices/sim/__init__.py b/ophyd_devices/sim/__init__.py
index 2fdb490..464d315 100644
--- a/ophyd_devices/sim/__init__.py
+++ b/ophyd_devices/sim/__init__.py
@@ -1 +1 @@
-from .sim import SynAxisMonitor, SynAxisOPAAS, SynFlyer, SynSLSDetector
+from .sim import SynAxisMonitor, SynAxisOPAAS, SynFlyer, SynSignalRO, SynSLSDetector
diff --git a/ophyd_devices/sim/sim.py b/ophyd_devices/sim/sim.py
index eb1156a..57ec57f 100644
--- a/ophyd_devices/sim/sim.py
+++ b/ophyd_devices/sim/sim.py
@@ -2,7 +2,6 @@ import os
 import threading
 import time as ttime
 import warnings
-from email.message import Message
 from typing import List
 
 import numpy as np
@@ -19,6 +18,22 @@ class DeviceStop(Exception):
     pass
 
 
+class SynSignalRO(Signal):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._metadata.update(
+            write_access=False,
+        )
+
+    def wait_for_connection(self, timeout=0):
+        super().wait_for_connection(timeout)
+        self._metadata.update(connected=True)
+
+    def get(self, **kwargs):
+        self._readback = np.random.rand()
+        return self._readback
+
+
 class _ReadbackSignal(Signal):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
@@ -284,6 +299,12 @@ class DummyController:
     some_var = 10
     another_var = 20
 
+    def on(self):
+        self._connected = True
+
+    def off(self):
+        self._connected = False
+
     def controller_show_all(self):
         """dummy controller show all
 
@@ -297,6 +318,10 @@ class DummyController:
         print(self.some_var)
 
 
+class DummyControllerDevice(Device):
+    USER_ACCESS = ["controller"]
+
+
 class SynFlyer(Device, PositionerBase):
     def __init__(
         self,