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IDL 101
STRUCTURE OF THE BUS TOPOLOGY
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HB_IDL101_E_V222.doc
Gantner Instruments Test & Measurement GmbH
4. STRUCTURE OF THE BUS TOPOLOGY
The coupling of the
Datalogger IDL 101 to a host computer can be performed via the integrated RS-485 interface or via
the integrated RS-232 interface. The RS-232 interface is suitable only for point-to-point connections over a maximum
distance of 20 m. In the “Normal Mode“ the
Datalogger IDL 101 permanently sends the data to both interfaces,
different are only the physical properties of the interfaces. To arrange a system only the RS-485 interface is useful. In
the “Transparent Mode“ the data are transferred from RS-232 to the RS-485 interface.
Bus interface:
RS 485, half duplex
Bus topology:
line pattern, closed at both ends by the characteristic impedance, stub cable to the party max. 30 cm (12
inch).
Bus medium:
shielded, twisted pair cable
Transmission speed:
ASCII-protocol: 2400 / 4800 / 9600 / 19200 / 38400 bps
PROFIBUS-protocol: 9600 / 19200 bps
MODBUS-protocol: 2400 / 4800 / 9600 / 19200 / 38400 bps
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.