Siemens SIMATIC S7-400 Manual page 97

Device-Related Diagnostics
Device-related diagnostics provides detailed information on a DP slave. Device-related
diagnostics starts at byte x and can include up to 20 bytes.
The figure below illustrates the structure and contents of the bytes for a configured address
area of the transfer memory.
Byte x
Byte x +1
Byte x +2
Byte x +3
Byte x +4
to
Byte x +7
Figure 5-5
Starting at byte x +4
The meaning of the bytes starting at byte x+4 depends on byte x +1 (see figure "Structure of
device-related diagnostics").
In byte x +1, the code stands for...
Diagnostic interrupt (01
The diagnostic data contains the 16 bytes of status
information of the CPU. The figure below shows the
allocation of the first four bytes of diagnostic data. The
following 12 bytes are always 0.
S7-400 Automation System, CPU Specifications
Manual, 10/2006, 6ES7498-8AA04-8BA0
6
7 0
0 0
Length of the station diagnosis incl. byte x (=
maximum 20 bytes)
Code for station diagnosis
7 0
0 0 0 0 0 0 0 0
Structure of the device-related diagnostics
)
H
5.1 CPU 41x-3 PN/DP as DP master / DP slave
Bit no.
01H: Code for diagnostic interrupt
02H Code for process interrupt
Number of the configured address area
of the intermediate memoryThe
following applies:
General rule: Number+3
(Example: CPU = 02H
1st. adress area = 04H
2nd Address area = 05H and so on)
(Fixed to 0)
Diagnostics data
and
interrupt data
Hardware interrupt (02
You can program 4 bytes of interrupt information any way
you wish for the process interrupt. You transfer these 4
bytes to the DP master in
PROFIBUS DP
)
H
STEP 7
using SFC7 "DP_PRAL".
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