It is not possible to differentiate between the storage area of both TC_SEND commands in the image of the CP 1242-7 in order to also correspond to the relevant variables at the OPC Server. Due to this reason the same data block from the S7-1200 control is used for every TC_SEND command. Therefore all variables are always sent to both sub- connections at the time of transmission (i.e. both TC_SEND commands). Æ It can therefore happen in this application example that there are one or more self-controlled transmitted measured values between two cyclic transmitted measured values at the OPC Server during archiving. This must be taken into consideration when archiving at the Central Station.