Siemens Simatic S7-300 CPU 31xC Series User Manual

Configuring
4.11 Planning subnets
S7-300, CPU 31xC and CPU 31x: Installation
4-54 Operating Instructions, Edition 08/2004, A5E00105492-05
Note
Update Times for Cyclic Data Exchange
STEP 7 automatically calculates a time within which each PROFINET IO device completes
exchange of its user data with the corresponding IO controller: the update time.
Based on the existing hardware configuration and the resulting cyclic data traffic, STEP 7
automatically calculates an update time that you can extend manually.
If other cyclic services (for example PROFINET CBA) need to be taken into account in
addition to PROFINET IO: Set a percentage in STEP 7/HW Config that will be reserved for
PROFINET IO.
For more detailed information, refer to the STEP 7 online help.
Details on the Possible Uses of the Individual Products
For more information, refer to the documentation of the particular product.
4.11.3.5 PROFINET cable lengths and network expansion
Network expansion options are based on various factors (hardware design used, signal
propagation delay, minimum distance between data packets, etc.)
Prefabricated twisted-pair cord cables
Twisted-pair cables can be used in environments with low EMC loads and with transmission
lines up to 10 m. They employ the TP cord that is designed significantly thinner and more
flexible by using reduced shielding compared to industrial twisted-pair cables. The
connectors used in connecting industrial twisted-pair components are standardized RJ45
connectors and sub-D connectors.

Siemens Simatic S7-300 CPU 31xC Series Specifications

General

Series	S7-300 CPU 31xC
Power Supply	24 V DC
Communication Interfaces	MPI, PROFIBUS DP
Programming Languages	LAD, STL, FBD, SCL
Operating Temperature	0°C to +60°C
Memory	48 KB - 512 KB
Dimensions	40 x 125 x 130 mm (varies by model)