In DynaSys we take the production volumes at "Production line" level (Resource / Workcenter level is more destined to Costing, Quality and Scheduling in tools like SAP MF50, Ortems or Aspen).
In SAP:
> 1 Planned Order is linked to 1 'Production version', this last linked in turn to one 'Production line'
> However, 1 Production version 'can be linked to several resources
This decision is based on SAP Design: the 'Production line' in the 'Production version' corresponds to the bottleneck resource among all resources used in the production version.
By SAP Design, this 'Production line' should be always defined.
In some cases, the resources can have the same name than the 'Production line' (when we have only one resource linked to the Prod line).
SAP Transaction C223 allow the user to view the Production line defined for the Material / Plant.
In some cases, as there is no specific blocking control to guarantee it's defined, users might need to maintain it in SAP.