Siemens SIMATIC S5 Manual page 14

System Description
Definitions
• Planning Level
This is where you plan orders, production strategies and production guidelines, and where the
information from the production process is monitored.
• Process Control Level
This is where you decide how the production will take place and how the function groups will be
coordinated.
• Cell Level
This level receives requests from the process control level. It consists, as a rule, of assembly
cells. Each assembly cell is controlled by at least one programmable controller.
• Field Level
This is where the field devices such as sensors and actuators are. The task of these units is to
make the exchange of information between control and technical process possible.
Communication Tasks Required from the Different Networks
The requirements for the planning and process control level networks differ from the requirements
for the cell and field level networks as follows:
• Communication in the planning and control levels
- Large amounts of data ( range >100 bytes)
- Often no time-critical requirements
- Electromagnetic compatibility requirements matched to office environment
(with additional specific measures, also for industrial environment)
- Large network expansion
- Large number of stations
- Higher connection costs acceptable
• Communication in the cell and field levels
- Smaller amounts of data (range <100 bytes)
- Time-critical requirements (real-time requirements)
- High electromagnetic compatibility requirements (industrial environment)
- Small network expansion
- Small number of stations (range <100)
- Low connection costs
The SINEC L2 network is optimally adapted to the requirements of the cell and field levels".
1-2
S5-95U, SINEC L2
EWA 4NEB 812 6112-02