When a significant change has been made to a product, then the Woodward process calls for a part number change. Minor hardware change like resistor manufacturer, production procedure changes, software bug-fixes and application software changes are reflected in revision letter updates in the sequence: NEW, A, B, C, ….

The revision changes are described in the beginning pages of the product manual.  Many of the revision changes are triggered by changing grid codes, worldwide, for the utility paralleled operations. 

Settings files, the user configured parameters, may be shared between the various part numbers and revisions.  As product changes are made, parameters are added or removed.  Loading settings files will load all the parameters that are commonly numbered.  New settings must then be updated manually.

History example on the easYgen3000 family:
The 8440-1831 to 8440-1923 transition included hardware changes including power supply and analog outputs that improved the device in marine and oilfield applications.  These units had a grey-scale display.  Several years ago, the earth quake and resulting tsunami in Japan, destroyed the plant where the grey scale displays were made.  The Easygen-3500 control (complicated system controller, including multiple mains and tie breakers) had just been released with a color display.  Rather than sourcing and redesigning a new grey-scale display for the easYgen3200, the color display from the easYgen3500 was adopted.  The change from grey to color display changed the part number from 8440-1923 to 8440-2050. 

The 8440-2050 has a parameter to present the color display in grey-scale for backward compatibility.

All of the Easygen-3000 line will operate with each other.