Refs #9155. Updating DgsConvertToEnergyTransfer wiki docs.

Code/Mantid/Framework/WorkflowAlgorithms/src/DgsConvertToEnergyTransfer.cpp

@@ -1,7 +1,35 @@
 /*WIKI*
 
 This algorithm is responsible for making the conversion from time-of-flight to
-energy transfer for direct geometry spectrometers.
+energy transfer for direct geometry spectrometers. The diagram below shows the
+workflow for the algorithm. The SNS instruments have a log called EnergyRequest
+which allows the IncidentEnergyGuess parameter to be left blank. Also, SNS
+instruments need to pass a monitor workspace to GetEi since they are separate
+from the sample workspace. Parameters in italics are controlled by the
+[[InstrumentParameterFile|instrument parameter file (IPF)]] unless provided to
+the algorithm via a property manager. The mappings are given below.
+
+{| class="wikitable"
+|-
+! Parameter !! IPF Mapping
+|-
+| TibTofRangeStart || bkgd-range-min
+|-
+| TibTofRangeEnd || bkgd-range-max
+|}
+
+Parameters in italics with dashed perimeters are only controllable by the IPF
+name given. All underlined parameters are fixed and not controllable.
+The EnergyTransferRange parameter takes the canonical Mantid notation of
+(start, step, stop). However, it can be left blank and the following values
+will be used
+<math>(-0.5E^{Guess}_{i}, 0.01E^{Guess}_{i}, 0.99E^{Guess}_{i})</math>.
+
+The use of the SofPhiEIsDistribution parameter in the last Rebin call is used
+to set the Rebin algorithm parameter PreserveEvents.
+
+==== Workflow ====
+[[File:DgsConvertToEnergyTransferWorkflow.png]]
 
 *WIKI*/