Sinec L2 Network With Rs 485 Technology; Distance Table For Rs 485 Technology - Siemens SIMATIC S5 Manual

System Description
PLC
PLC
PLC
PLC
e.g., S5-95U programmable controller
SINEC L2 bus connector
SINEC L2 bus connector with switched-on terminating resistor
RS 485 repeater with switched-on terminating resistor
Figure 1-15. SINEC L2 Network with RS 485 Technology
The conditions for installing the network are as follows:
• You can connect a maximum of 127 stations (TLN 0 is reserved for a programmer).
• A maximum of 32 bus loads is permitted per segment (a bus load is either a station or a
repeater).
• You can connect a maximum of 7 repeaters in series.
Table 1-7 shows the possible distances between stations calculated on the basis of the expansion
of a bus segment and of the condition specified above that a maximum of 7 repeaters is allowed
between two stations.
Baud Rate in
Kbits/s
1
9.6; 19.2; 93.75 1.2 km
187.5 1.0 km
500 0.4 km
1500 0.2 km
Caution
!
In extensive networks, the potential difference between two stations may be more than
± 7 V. In such a case, take the necessary equipotential bonding measures, otherwise
the SINEC L2 interface will be destroyed.
1-22
PLC
PLC
Table 1-10. Distance Table for RS 485 Technology
Number of Segments Connected in Series
2 3
2.4 km 3.6 km
2.0 km 3.0 km
0.8 km 1.2 km
0.4 km 0.6 km
4 5 6
4.8 km 6.0 km 7.2 km
4.0 km 5.0 km 6.0 km
1.6 km 2.0 km 2.4 km
0.8 km 1.0 km -
S5-95U, SINEC L2
PLC PLC
PLC PLC
7 8
8.4 km 9.6 km
7.0 km 8.0 km
2.8 km 3.2 km
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EWA 4NEB 812 6112-02