W&T 57630 Manual page 73

W&T
Disadvantages:
. Only partial event-controlled programming possible.
This limits its usefulness for time-critical applications.
. Only client applications possible, no server applications.
Binary structures BINARY
In this mode the Web-IO can function as a TCP client, TCP
server or UDP peer. Access can be password-protected.
The Web-IO defines binary structures for the various functions
such as reading inputs, setting outputs, etc. Access takes place
solely by exchanging these structures.
Advantages:
. Flexible in its application, since client and server
applications are possible
. Fast communication through use of structures. The status
values are always at a defined location, and no strings
need to be analyzed for their contents
. Event-triggered communication allows the application to
respond immediately to changes in the inputs
. Password protected access makes a high degree of
application security possible
Disadvantages:
. In higher languages which do not support binary structures
a workaround in the form of binary strings or byte arrays
must be found
Summary: BINARY mode should be used for professional
applications which require a high level of processing speed.
Special forms of BINARY mode
. Box-to-Box
Two Web-IOs can communicate with each other without
involving an application program on a PC
. OPC
Subject to errors and modifications:
Controlling the Web-IO with TCP/UDP Sockets
73