Bernard INTELLIBUS FF - Terminator

INTELLIBUS
Number : NR 1157
Revision : B
Page 8/19
Instructions for start-up
The number of devices possible on the fieldbus will vary depending on the power
consumption of each device. The INTELLIBUS FF consumption is 20mA and the
minimum voltage allowable is 9V. It is necessary to check the available voltage at each
actuator.
Example:
With a cable type Belden 3076F 23 ohm/km at 70°C ( 46 ohm for 2 wires)
INTELLIBUS consumption 20mA, minimum voltage 9V.
Fieldbus supply voltage 24V
The drop in voltage due to the consumption is summarized in the following table.
Drop in voltage = cable resistance x current
• Total fieldbus length (1 to 7) is less than 1900m.
• Spurs length (3 + 6) is less than 120m
The last actuator has a supply voltage of:
24V - 1 - 2 - 4 - 5 - 7 = 22V (> 9V) that is enough to work.
4.2.3 Terminator
A terminator must be connected at each end of the main trunk
cable (note: there is no end of line terminator inside the actuator)
This terminator is made with a capacity in series with a resistor.
Length
Nb of actuators
current Drop in
segment
m ft supplied mA voltage
1
200
656 5 100
0,92
2
50
164 4 80
0,18
3
50
164 1 20
0,05
4
70
230 3 60
0,19
5
70
230 2 40
0,13
6
60
197 1 20
0,06
7
700
2297 1 20
0,64
total 1200
3937
PLC
Spurs
End of line
Terminator
Note:The PLC is also at
the end of the main trunk
cable and needs a
terminator
1
2
3
4
5
6
7
100 Ohms
1 µF
Main truck Main truck