Installation and Upgrade > Windchill ESI > Installing and Configuring Windchill ESI in an SAP Environment > Object Number Lengths in SAP > Exceptions for Process Plan numbers
  
Exceptions for Process Plan numbers
The following are exceptions to the object numbering criteria specified:
Routing group number must fall within the defined external number range.
Maximum number of characters supported is 8.
By default Routing groups should be alphanumeric and must start with a letter. To have numeric values only, the external range needs to be created in SAP.