The function ReadPointValue (_ReadPointValue@8
in the Stdcall call convention) is optional and it is called to get the value
I/O tag after writing a new value using the function WritePointValue.
Request executed OK.
An error occurred (the device does not communicate or is
out of service, or there is any
error), the station changes into the state COM_ERR, or HARD_ERR after
returning from the function.
The function was ignored and the station status is not changed.