PC Access is indeed not very easy to use, the stability is also poor, the following three recommended solutions can try the following:
Use other OPC software such as Kepware. The advantage is good stability, the disadvantage is the charge, but it can be pj.
Use Simatic PC NET as OPC server. The advantage is good stability, it is sure that the configuration is troublesome and requires authorization.
Use protocol conversion modules, such as Dalian Dejia ETH-PPI. The advantage is good stability, do not need to do too much configuration, can directly use wincc connection, the disadvantage, is the need for Money.