System Overview
CP
523
Communications Mode
In “Communications
mode”, the
523 can communicate over the
interface with an
unit
(terminal,
523, CPU 944, etc.) equipped with a V.24 (RS 232C) or TTY interface. This mode
enables the transfer of data frames between the CPU and an
device connected to the CP 523.
The CP 523 provides a total of three communication control procedures, i.e. two protocol-free
procedures and one with a standardized protocol:
. Protocol-free data transmission
- Transparent mode, i.e. data transmission without receiver-side end identifier sequence
- Interpretive mode, i.e. data transmission
end identifier sequence.
. Data transmission with protocol
-3964 (R) mode
Your application program determines the modes you want to use.
You can also evaluate the module’s real-time clock in your program for date and time-dependent
tasks.
The FE 200 “SEND” and FB 201 “RECEIVE” function blocks allow user-friendly bidirectional
transfer of message frames with a length of up to 256 bytes. A thorough description, with
examples, is given of how to use the function blocks.
If you decide to forego the convenience of the FB 200 and
201 function blocks in
of
higher data transmission speeds, you can communicate with the CP 523 direct from the user
program. This method of data exchange is also described in detail with examples.
Figure 1-2. S5-115U Programmable Controller with
523 and Terminal
1-2
EWA4NEB811 6044-02a