Technical data

An FMA request consists of an 8-byte header. Depending on the service,
the confirmation consists of a maximum of 250 bytes, of which the first 8
bytes are occupied by the confirmation header (FMA header).
Fig. 12.4 shows the structure of a block of data to be transmitted or
received. The designations of the header bytes are taken from the
PROFIBUS standard.
The FMA header contains the following parameters which are not
completely evaluated by all functions.
com_class
user_id
service_code
link_status
Byte
1
2
3
4
0
Header
service_class
DSAP/RSAP
rem_add_station
rem_add_segment
data
5
6
7
8
249
Fig. 12.4 Structure of the FMA Header for Request and Confirmation
B8976060/02 Service and Diagnostics using FMA Functions
12 - 7 Volume 1