B&B Electronics GW-7552 - Manual - Manual (Page 13)

GW-7552 PROFIBUS/MODBUS GATEWAY User Manual (Version 1.40, Apr/2012) PAGE: 13
rate and range for a cable with the following properties:
1. Impedance :135~165Ω
2. Capacity : lower than 30 pF/m
3. Loop resistance : lower than 110Ω/Km
4. Wire diameter : greater than 0.65mm
5.
Core cross-section : greater than 0.34mm 2
Table 7 Transmission rate decreasing with increasing transmission distance
Transmission Rate(Kbps) Transmission Distance per Segment (meter)
9.6; 19.2; 45.45;93.75 1200
187.5 1000
500 400
1500 200
3000; 6000; 12000 100
In order to minimize the reflection effect of signal transmission, both ends (first
node and last node) of a PROFIBUS segment needs to be equipped with an
active terminal resistor as shown in figure10. A standard PROFIBUS connector
is usually already equipped with a terminal resistor. The user therefore only has
to switch on the resistor of the devices stationed at the ends of a segment as
shown in figure11.
Figure 10 PROFIBUS connection