diff --git a/light9/collector/collector.py b/light9/collector/collector.py
--- a/light9/collector/collector.py
+++ b/light9/collector/collector.py
@@ -35,7 +35,7 @@ def _outputMap(graph: SyncedGraph, outpu
     ret = cast(Dict[Tuple[DeviceUri, OutputAttr], Tuple[OutputUri, DmxMessageIndex]], {})
 
     for dc in graph.subjects(RDF.type, L9['DeviceClass']):
-        log.info('mapping DeviceClass %s', dc)
+        log.info('mapping devices of class %s', dc)
         for dev in graph.subjects(RDF.type, dc):
             dev = cast(DeviceUri, dev)
             log.info('  💡 mapping device %s', dev)
@@ -64,11 +64,13 @@ class Collector:
         self.outputs = outputs
         self.listeners = listeners
         self.clientTimeoutSec = clientTimeoutSec
-        self.initTime = time.time()
-        self.allDevices: Set[DeviceUri] = set()
+
+        self._initTime = time.time()
         self._outputByUri: Dict[OutputUri, OutputInstance] = {}
+        self._deviceType: Dict[DeviceUri, DeviceClass] = {}
+        self.remapOut: Dict[Tuple[DeviceUri, OutputAttr], OutputRange] = {}
 
-        self.graph.addHandler(self._rebuildOutputMap)
+        self.graph.addHandler(self._compile)
 
         # rename to activeSessons ?
         self.lastRequest: Dict[Tuple[ClientType, ClientSessionType], Tuple[UnixTime, Dict[Tuple[DeviceUri, DeviceAttr], VTUnion]]] = {}
@@ -76,28 +78,31 @@ class Collector:
         # (dev, devAttr): value to use instead of 0
         self.stickyAttrs: Dict[Tuple[DeviceUri, DeviceAttr], VTUnion] = {}
 
-    def _rebuildOutputMap(self):
-        self.allDevices.clear()
+    def _compile(self):
+        self._outputByUri = self._compileOutputByUri()
+        self._outputMap = _outputMap(self.graph, set(self._outputByUri.keys()))
 
-        self._outputByUri.clear()
-        for out in self.outputs:
-            self._outputByUri[OutputUri(out.uri)] = out
-
-        self.outputMap = _outputMap(self.graph, set(self._outputByUri.keys()))
-        self.deviceType: Dict[DeviceUri, DeviceClass] = {}
-        self.remapOut: Dict[Tuple[DeviceUri, OutputAttr], OutputRange] = {}
+        self._deviceType.clear()
+        self.remapOut.clear()
         for dc in self.graph.subjects(RDF.type, L9['DeviceClass']):
             dc = cast(DeviceClass, dc)
             for dev in self.graph.subjects(RDF.type, dc):
                 dev = cast(DeviceUri, dev)
-                self.allDevices.add(dev)
-                self.deviceType[dev] = dc
+                self._deviceType[dev] = dc
+                self._compileRemapForDevice(dev)
 
-                for remap in self.graph.objects(dev, L9['outputAttrRange']):
-                    attr = typedValue(OutputAttr, self.graph, remap, L9['outputAttr'])
-                    start = typedValue(float, self.graph, remap, L9['start'])
-                    end = typedValue(float, self.graph, remap, L9['end'])
-                    self.remapOut[(dev, attr)] = OutputRange((start, end))
+    def _compileOutputByUri(self) -> Dict[OutputUri, OutputInstance]:
+        ret = {}
+        for output in self.outputs:
+            ret[OutputUri(output.uri)] = output
+        return ret
+
+    def _compileRemapForDevice(self, dev: DeviceUri):
+        for remap in self.graph.objects(dev, L9['outputAttrRange']):
+            attr = typedValue(OutputAttr, self.graph, remap, L9['outputAttr'])
+            start = typedValue(float, self.graph, remap, L9['start'])
+            end = typedValue(float, self.graph, remap, L9['end'])
+            self.remapOut[(dev, attr)] = OutputRange((start, end))
 
     def _forgetStaleClients(self, now):
         staleClientSessions = []
@@ -114,14 +119,14 @@ class Collector:
         for devUri, devAttr, val in settingsList:
             if (devUri, devAttr) in out:
                 existingVal = out[(devUri, devAttr)]
-                out[(devUri, devAttr)] = resolve(self.deviceType[devUri], devAttr, [existingVal, val])
+                out[(devUri, devAttr)] = resolve(self._deviceType[devUri], devAttr, [existingVal, val])
             else:
                 out[(devUri, devAttr)] = val
         return out
 
     def _warnOnLateRequests(self, client, now, sendTime):
         requestLag = now - sendTime
-        if requestLag > .1 and now > self.initTime + 10 and getattr(self, '_lastWarnTime', 0) < now - 3:
+        if requestLag > .1 and now > self._initTime + 10 and getattr(self, '_lastWarnTime', 0) < now - 3:
             self._lastWarnTime = now
             log.warn('collector.setAttrs from %s is running %.1fms after the request was made', client, requestLag * 1000)
 
@@ -176,15 +181,10 @@ class Collector:
         deviceAttrs = self._merge(iter(self.lastRequest.values()))
 
         outputAttrs = cast(Dict[DeviceUri, Dict[OutputAttr, OutputValue]], {})
-        for d in self.allDevices:
-            try:
-                devType = self.deviceType[d]
-            except KeyError:
-                log.warn("request for output to unconfigured device %s" % d)
-                continue
+        for d, devType in self._deviceType.items():
             try:
                 outputAttrs[d] = toOutputAttrs(devType, deviceAttrs.get(d, {}))
-                self.listeners.outputAttrsSet(d, outputAttrs[d], self.outputMap)
+                self.listeners.outputAttrsSet(d, outputAttrs[d], self._outputMap)
             except Exception as e:
                 log.error('failing toOutputAttrs on %s: %r', d, e)
 
@@ -209,7 +209,7 @@ class Collector:
 
         for device, attrs in outputAttrs.items():
             for outputAttr, value in attrs.items():
-                outputUri, _index = self.outputMap[(device, outputAttr)]
+                outputUri, _index = self._outputMap[(device, outputAttr)]
                 index = DmxMessageIndex(_index)
                 outArray = pendingOut[outputUri]
                 if outArray[index] != 0: