Technical data

PAC RS485
Manual, 02/2008, A5E02091800B-01
67
Technical data
10
10.1 Cable
Requirements
Use a serial, shielded, 3-core interface cable:
● Two twisted cores are required for the signals -A and +B
● The third core is required for the Common signal.
The maximum length of the bus cable depends on the following:
● The baud rate
● The properties of the cable used:
– Thickness
– Capacitance
– Characteristic surge impedance
● Number of stations
● The network configuration, e.g. 2-wire cable with shield
Additional information
You can find more information about the cables in the standard ANSI TIA/EIA-485-A-98 and
in the "MODBUS over Serial Line Specification and Implementation Guide".
10.2 Standards
Description
Table 10-1 The device meets the following standards
Standard Title
ANSI TIA/EIA-485-A-98 (R2003) (RS 485) "Electrical Characteristics of Generators and
Receivers for Use in Balanced Digital Multipoint
Systems"