W&T 57630, Manual

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W&T
Controlling the Web-IO with TCP/UDP Sockets
5.4 Controlling the Web-IO with TCP/UDP Sockets
To access the Web-IO directly from your own applications, two
basic methods are provided for using TCP or UDP sockets to read
inputs and counters and set outputs.
Access via:
.
command strings ASCII
.
binary structures BINARY
5.4.1 Selecting the appropriate access mode
Command strings ASCII
In this mode the Web-IO works as a TCP server or as a UDP peer.
Inputs and counters can be read and outputs set by exchanging
simple command strings.
Inputs are generally read by using polling. Event-controlled
processing is only conditionally possible for imput patters defined
in alarms.
Advantages:
.
Since all higher level languages such as Visual Basic, Visual
Basic for Applications, Delphi, C, C++, etc. allow
uncomplicated handling of string variables, even
inexperienced programmers will have little difficulty
achieving the desired results.
.
Under TCP Port 80 is used (otherwise HTTP), which is
not blocked by most firewalls. This means that mostly
no changes to the netework infrastructure are
necessary.
.
Using string variables together with TCP Port 80 makes
it quite easy to integrate communication with the Web-
IO into PHP and CGI scripts. The Web-IO can also be
accessed from PLCs and other microcontrollers as long
as there is a network connection.