Theodor Friedrichs COMBILOG 1020, Hardware Manual

Page: 90 / 170

Hardware Manual COMBILOG 1020
90
‰ Line length:
depends on the transmission speed, max. 1.2 km (0.75 miles)
per bus segment, max. 4.8 km (3 miles) via a physical bus
string with 3 repeaters.
‰ Number of bus users:
max. 32 bus users per bus segment, max. 127 bus users via
a physical bus string.
10.1 Bus Interface
The bus interface in the datalogger is an RS485 interface. Its ad-
vantages compared with RS232 connections are a larger number
of users, its higher transmission speed, its higher immunity from
interferences and the extended line length.
transmission speed
1 K 10 K 100 K
187,5 K
1 M 10 M
[bps]
10 m (32.5 ft)
100 m (325 ft)
1000 m (3.250 ft)
1200 m (3.900 ft)
transmission
600 m (1.950 ft)
RS 232
RS 422
RS 485
route
Figure 10.1 Interrelation between transmission speed and line length