GA data and GA requests


When there is a general query (GA) in the remote system all relevant data is forwarded to the control system with the GA bit set. To avoid overloading the system, an internal data point of the general driver can be set to specify how smoothing (filtering) of GA data should be applied (enable/disable filtering of GA). This is specified via the data point defined in the drvSmoothMode entry in the configuration file.


When a GA request is received by the WinCC OA, this is signaled to the Event Manager. The relevant data can then be sent by a Control script, allowing one to configure the response to a GA request received by WinCC OA.


If the SSI driver is being operated in redundant mode, then the failure of one of two mutually redundant connections not only causes an error message, but also initiates a GA automatically, since when switching over connections a potential time difference can lead to data loss. Automatic general query at a driver start or at redundancy switch The driver does not execute a general query when establishing the connection or at a redundancy switch.