When should I use Undefined Structure?
XCom basically checks the validity of the structure of the send / receive message
and generates an error when a message with an unregistered structure is sent or received.
Therefore, the SML file used by XCom is used. It is necessary to define the format of the message to be used in advance.
In the case of messages used in some SECS-II, if the variable is a subitem, the structure may not be declared in advance. r nIn this case, you need to specify "Undefined Structure".
In this case, if the message has a structure that is not registered in advance, error handling will not occur.