Siemens Simatic S7-400 - PROFINET IO and CBA

8.4 Diagnostics via the diagnostic bu󹪜er of the CP 440
Diagnostic Bu󹪜er of the CP 440
The CP 440 has its own diagnostic bu󹪜er, in which all the diagnostic events of the CP 440 are
entered in the order in which they occur.
The following are displayed in the diagnostic bu󹪜er of the CP 440:
• Initialization and parameter errors
• Errors during execution of a CPU request
• Data transmission errors (send and receive errors)
The diagnostic bu󹪜er allows the causes of errors in point-to-point communication to be
evaluated subsequently in order, for example, to determine the causes of a STOP of the CP 440
or to trace the occurrence of individual diagnostic events.
Note
The diagnostic bu󹪜er is a ring bu󹪜er for a maximum of 10 diagnostic entries. When the
diagnostic bu󹪜er is full, the oldest entry is deleted when a new entry is made in it. This means
that the most recent entry is always 󹪝rst. The contents of the diagnostics bu󹪜er are lost in the
event of a POWER OFF or when the CP 440 is recon󹪝gured.
It is not possible to display the time.
Reading the Diagnostic Bu󹪜er at the Programming Device
The contents of the diagnostic bu󹪜er of the CP 440 can be read by means of the STEP 7
information functions.
All the user-relevant information in the CP diagnostic bu󹪜er is displayed to you in the "Diagnostic
Bu󹪜er" dialog box on the "Module Information" tab. You can access the "Module Information" tab
under STEP 7 from SIMATIC Manager.
Prerequisite: In order to obtain the status of the module, there must be an on-line connection
from the programming device to the programmable controller (on-line view in the project
window).
To do this, proceed as follows:
1. Open the relevant SIMATIC 400 station (double-click or select menu command Edit > Open).
2. Then open the "Hardware" object (double-click or select menu command Edit > Open).
Result:The window containing the con󹪝guration table appears.
3. Select the CP 440 in the con󹪝guration table.
Diagnostics with the CP 440
8.4 Diagnostics via the diagnostic bu󹪜er of the CP 440
Point-to-point connection CP 440 Installation and Parameter Assignment
104 Equipment Manual, 03/2022, A5E00057742-AE