vijeo scada

hi, now i am working with citect scada .in my logic i have two set points in scada itself and have to manipulate it to be sent to plc for one PID we using. in this case i want to know whether that two set points in the scada itself to be considered as a tag or local variables . and please give some idea how to do it.

anything that you want to send to PLC or read back from PLC must be a tag