Returns the value of the type of a Discrete Measurement Source. This is a read-only property. Possible values for this property are 1 - wstScada: SCADA, 2 - wstOperator: Operator, 3 - wstCCLink: Control Center, 4 - wstBilling: Billing, 5 - wstCalculated: Calculated, 6 - wstDatabase: Database, or 100 - wstTopologyProcessor: Topology Processor.