Active resource control of added functionality in a numerical control process having at least one resource is provided. It can occur during run-time of the numerical control process, that an added functionality uses at least a portion of the resource. On-line checking of the added functionality detects during run time whether the added functionality causes the numerical control process to reach a resource limit. Error handling handles errors upon reaching a resource limit. Off-line checking detects off-line, before the run time of the numerical control process, whether the added functionality causes the numerical control process to reach a resource limit of the resource. Multiple layers are provided that check at multiple layers of the numerical control process whether the added functionality causes the numerical control process to reach a resource limit of the resource. A flexible response to resource limit errors based on a degree of importance of the added functionality is provided.