Siemens S7-400 - Characteristic Data of the Integrated 4 Port Switch

Performance data
2.10 Characteristic data of the integrated 4port switch
CP 443-1 Advanced
Equipment Manual, 03/2023, C79000-G8976-C256-07
29
Meaning of the memory areas
• Flash area in the CPLUG (nonvolatile memory):
The flash area allows data to be stored and retained if there is a power down.
Note
The flash area of the file system allows a limited number of write cycles (approximately
100 000). You should therefore avoid writing data cyclically.
If you write temporary data often, you should switch to the RAM file system located in the
/ram subfolder. The files of the RAM file system (/ram) are lost if there is power down.
• RAM area (/ram volatile memory):
In contrast to the flash area, the RAM can be written to and read from any number of
times. The data in the RAM is retained as long as the CP is supplied with power.
The RAM is intended to store data that changes during operation and needs to be
recorded (data recording services). The RAM is also suitable for temporary storage.
The RAM area is located in the file system below the "/ram" folder. This means that all files
and folders below this folder are lost when there is a power down.
Note the following configuration limits:
Table 2- 4 Configuration limits
Characteristic
Explanation / values
File names The length of the file names is limited; the following are
permitted: Up to 64 characters for the file name, up to 256
characters for the path. It is possible to make the file name
casesensitive in the "Options" tab of the CP properties dialog.
File size
The file size is limited to a maximum of 8 MB.
Memory area for the file system
• Flash area (nonvolatile memory)
30 MB
• RAM area (volatile memory)
30 MB
2.10 Characteristic data of the integrated 4port switch
Learning addresses / deleting addresses (aging time)
The switch integrated in the CP reads the source addresses included in the data packets. The
switch therefore learns the addresses of the end devices connected via a port.
If the switch receives a data packet, it directs this packet only to the port via which the
appropriate end node can be obtained.