Fetch/Write Mode - Siemens S7-300 Configuration Manual

Amounts of data and configuration limits
Refer to the manual supplied with the Ethernet CP /2/ for the number of UDP connections
supported by the specific Ethernet CP. The number of connections per station can be
increased by adding more CPs.
Up to 2042 bytes of user data can be transferred per job buffer. The job header occupies an
additional 6 bytes.
5.8

FETCH/WRITE mode

FETCH/WRITE
The FETCH/WRITE services allow direct access to the system memory areas on the
SIMATIC S7 CPU from SIMATIC S5, SIMATIC PC stations, or from third-party devices:
● FETCH: Read data directly
● Write: Write data directly
Connection types
The FETCH/WRITE services can be configured and used in SIMATIC S7 on the following
connection types:
● ISO transport connections
● ISO-on-TCP connections
● TCP connections
Project engineering
The mode is configured in the "Options" tab of the properties dialog of the connection.
Depending on the station type, the following modes can be configured for the connection
endpoint of a station:
Configuring and commissioning S7 CPs for Industrial Ethernet
Configuration Manual, 09/2013, C79000-G8976-C182-13
Configuring communications connections
5.8 FETCH/WRITE mode
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