Explain SetTagWordWait() & GetTagWordWait()

It reads a word variable (16 bits) from the tag database. The use of ..Wait() methods forces to create a read request to the Plc (or whatever is the source of the tag) to get the latest value, and not the value from the cache (last read). The "OR" operation with "|" and the value 256 = 2 to the power of 9 sets bit 9 in the word (the other bits keep it's state, and writes the complete word back to to the plc.

This is often used if you have for example a control-word (to spare the usage of tags in WinCC) to operate a valve, and the bits in the word have functions like Bit9 = OpenValve, Bit10 = CloseValue, Bit11=ManualOperation, Bit12=AutoOperation.