ICP CON I-7550E, Руководство пользователя, Страница: 16 / 102

I-7550E PROFIBUS/Ethernet Converter User Manual
(Version 1.00, June/2014)
PAGE: 16
3. Communication protocol transfer theorem
Before a cyclic communication between a PROFIBUS Master and the converter
can be established it is required to specify the number of input and output bytes
that are to be exchanged in each telegram cycle with the PROFIBUS configuration
program. Once the slave is an active station in the PROFIBUS network the
configured input and output length cannot be changed. A new configuration of the
slave is only possible when it is in an off-line mode.
The Maximum input/output length is 240 Bytes, but the first 20 Bytes of
input/output are reserved for I-7550E(We call it as “System setting module”).The
I-7550E supports the Maximum Ethernet data length is 1460 Bytes, so if the I-
7550E receives the data that its length is greater than configured input length, the
I-7550E will partition data into several sections according to configured input
length. And the information of partition data will be put in input area of “System
setting module”, the user can handle the data depending on the information.
3.1 PROFIBUS Data exchange mode
The I-7550E is a PROFIBUS DP Slave device. The I-7550E is first parameterized
then configured and finally it goes into the data exchange mode (
Figure 11 ).
Figure 11 State machine of PROFIBUS DP Slave device
The I-7550E exchanges data cyclically between internal FIFO memory and