diff --git a/Code/Mantid/Framework/Algorithms/src/GetAllEi.cpp b/Code/Mantid/Framework/Algorithms/src/GetAllEi.cpp
index 8011b2ce54d38d48b348fe0b0256f32fd8cd7a21..0d86ffe5019a1e62a89062cc7881ef8098c1df3c 100644
--- a/Code/Mantid/Framework/Algorithms/src/GetAllEi.cpp
+++ b/Code/Mantid/Framework/Algorithms/src/GetAllEi.cpp
@@ -861,6 +861,8 @@ namespace Mantid {
           // pointer will not be null as this has been verified in validators
           auto pTimeSeries = dynamic_cast<Kernel::TimeSeriesProperty<double> *>
             (inputWS->run().getProperty(m_FilterLogName));
+          if(!pTimeSeries)throw std::runtime_error("findChopSpeedAndDelay: filtering log: "+
+          m_FilterLogName+" can not be interpreted as time series property of type 'double'");
 
           // Define selecting function
           bool inSelection(false);
diff --git a/Code/Mantid/instrument/MAPS_Definition.xml b/Code/Mantid/instrument/MAPS_Definition.xml
index 1b873e2db094abb729b1d9bfbd5c359f148c59e1..0e6a38f941116f2a1f4866dc102ee6a61cba885b 100644
--- a/Code/Mantid/instrument/MAPS_Definition.xml
+++ b/Code/Mantid/instrument/MAPS_Definition.xml
@@ -45,13 +45,32 @@
  <component type="chopper-position">
     <location z="-1.895"/>
 	<description is="The component provides sample-choper distance, used
-	in conjuction with chopper delay time to estimate average energy of neutrons
-	hitting the sample. This parameter is present until full chopper description 
-	is availibe, which will be then used to estimate this and other choper parameters
-	with better accuracy."/>
+	to estimate chopper delay time and Tobyfit resolution calculations."/>
+	<parameter name="initial_phase">    
+		<value val="130000."/>
+		<description is="The initial rotation phase of the disk used to caluclate the time
+		for neutrons arriving at the chopper according to the formula time = delay + initial_phase/Speed"/>	
+    </parameter>
+	<parameter name="ChopperDelayLog" type="string">
+		<value val="Chopper_delay"/>	
+	</parameter>
+	<parameter name="ChopperSpeedLog" type="string">
+		<value val="Chopper_Speed"/>	
+	</parameter>
+	<parameter name="FilterBaseLog" type="string">
+		<value val="good_uah_log"/>	
+	</parameter>
+	<!-- if the log above should be used as it is or 
+	one should calculate its derivative -->
+    <parameter name="filter_with_derivative" type="bool">
+		<value val="True"/>	
+	</parameter>	
+
   </component>
   <type name="chopper-position" is="ChopperPos"></type>  
-   
+  
+
+  
   
   <component type="monitors" idlist="monitors">
     <location />