Returns the value of the type of a Discrete Measurement Source. This is a read-only property. Possible values for this property are 1 - stScada: SCADA, 2 - stOperator: Operator, 3 - stCCLink: Control Center, 4 - stBilling: Billing, 5 - stCalculated: Calculated, 6 - stDatabase: Database, 100 - stTopologyProcessor: Topology Processor, 101 - stPowerFlow: Power Flow, 102 - stStateEstimator: State Estimator, 103 - stLoadShedding: Load Shedding, 105 - stSelfHealing: Self-Healing, or 106 - stExternalReader: External Reader.