diff --git a/src/tempus/Tempus.py b/src/tempus/Tempus.py
index 606a8b3fa7b8009d218726554b14772fdad9e635..fe0075a0bd7a594cfe8f631a8b7eb5c61b127578 100644
--- a/src/tempus/Tempus.py
+++ b/src/tempus/Tempus.py
@@ -370,7 +370,7 @@ class Tempus(Device):
         defaultValue=False,
         allowedStates={State.INIT, State.ON})
 
-    shutterTime = UInt16(
+    shutterTime = UInt64(
         displayedName="Shutter Time",
         unitSymbol=Unit.SECOND,
         metricPrefixSymbol=MetricPrefix.MILLI,