[opc]

Settings for the OPC client

[opc] enableGeneralQuery

Type
string
Default
Yes
Range
Yes|No
You can deactivate the automatic general query during a redundancy switch. This can be done by setting the config file entry enableGeneralQuery to "No". If this config file entry is set to "No", also the general query via the _DriverCommon.GQ DPE is deactivated. The deactivation does not regard the general queries activated via internal _OPCServer.ServerGA or _OPCGroup.Refresh data point elements. Thus, these DPEs can further be used to manually execute general queries although the automatic general query is deactivated.

[opc] ioReadBack

Type
string
Default
Yes
Range
Yes|No
"Readback" is a feature to make the IOTransitionTimeout compatible with the OPC update mechanism: When an I/O address is written, the driver waits for a value for this address from the periphery for IOTransitionTimeout seconds. If no value arrives within this time the driver concludes that the write did not succeed. OPC Servers on the other hand do not immediately reply to a value but only after update rate Milliseconds. So if IOTransitionTimeout is smaller than update rate, there will be no callback and the driver assumes that the IOTransaction did not succeed (although it may have gone well). To prevent this situation the OPC Driver starts a read operation immediately after the write to read the value back (hence "readback") from the periphery. The readback functionality can be deactivated using the ioReadBack = "NO" entry.

[opc] mapInvalidAdressToDrvInvalidBit

Type
string
Default
yes
Range
yes|no
If this config entry is set, the quality mapping or at least invalid mapping has to be activated in the OPC server panel (Panel OPC server). If 

[opc]
mapInvalidAdressToDrvInvalidBit = "yes"
is set in the config file, the invalid bit of the driver is set if the address (OPC item) cannot be found in the server. The bit is reset as soon as the address exists in the server and the system tried to use the address using_OPCGRoup.retryCorruptItem. If this is successful, the address is available in the server and the server sends an update. Thus, a value from the driver is sent to WinCC OA and DRV_INVALID is reset. Thus, the DP is not invalid anymore. Note that the same OPC group must not be used for two different OPC drivers.

[opc] priorityClass

Type
int
Default
0
Range
Linux: -20-19 Win:-1-2
Controls the priority of managers under Windows and Linux (see also Entries for different sections).

[opc] server

Type
string string
With this entry, the symbolic server name used in the peripheral address is assigned the ProgID (program identification from the registry), and possibly a path to a remote server. 

Example:
server = "server1" "www.foo.com/ETM.OPC.Simulation.1"
If a OPC client establishes a connection to several servers, a datapoint has to exist for each sever (for each server config entry). You can create the datapoint via the OPC parameterization panel. See chapter Panel OPC server. Assigns the ProgID ETM.OPC.Simulation.1 to the symbolic name server1. The path is optional. If a path is given, it must be separated by a "/" from the ProgID. When a path is given, the server is automatically started as a remote server on the specified computer. All UNC names ("//server" or "server") and all DNS names ("server.com", "www.foo.com", or "135.5.33.19") can be given as path names. At least one server must be specified, and a maximum of 20 servers can be started at the same time. The symbolic names of these servers must differ. This is necessary because for each server there has to be a datapoint of type _OPCServer, whose name includes the symbolic name (see chapter _OPCServer (OPC Client)).

[opc] timeStampFromServer

Type
string
Default
Yes
Range
Yes|No
By default the timestamps are generated by the OPC server. If this config entry is set to "No", the timestamps are generated by the OPC client.