When Sync Only is chosen as the Communications Mode, the Advantech WebAccess/SCADA SCADA node will use the Scan Time to read data from the OPC Server. If Sync and Async is chosen, the SCAN time is ignored and Advantech WebAccess/SCADA waits for the OPC Server to “advise” the SCADA Node of changes in the values of tags.
The Scan Time is in Milli-seconds (1/1000ths of a second). 1000ms = 1 sec.