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2 How to Install
2.1 Cabling
2.1.1 Cable Lengths and Number of Codes
The maximum cable length allowable in one segment is dependent on the transmission speed. The total cable length includes drop cables if any. A drop cable
is the connection from the main network cable to each node if a T-connection is used instead of permissible cable length and maximum number of nodes/
adjustable frequency drives with 1, 2, 3 and 4 network segments.
Drop cable connection (i.e., T-connection) beyond the cable lengths indicated is not recommended, due to the increased risk of reflection occurring. Instead, GE
recommends direct connection of the adjustable frequency drive.
Note that a repeater is a node in both of the two segments it connects. The number of adjustable frequency drives is based on a single master system. If there
are two or more masters (e.g., PC tools), the number of adjustable frequency drives must be reduced correspondingly.
Maximum total network cable length:
Transmission speed
9.6–187.5 kBaud
500 kBaud
1.5 Mbaud
3–12 Mbaud
Total drop cable length limit per segment:
The length statements in the tables above are valid for network cable with the following properties:
-
Impedance: 135 to 165 ohm at a measuring frequency from 3 to 20 MHz
-
Resistance: <110 ohm/km
-
Capacitance: <30 pF/m
-
Damping: max. 9 dB over the whole wire length
-
Cross-section: max. 0.00053 in2 [0.34 mm2], corresponding to AWG 22
-
Cable type: twisted in pairs, 1 x 2, or 2 x 2, or 1 x 4 wires
-
Shielding: Copper-braided shield or braided shield and foil shield
Use of the same cable type throughout the entire network is recommended to avoid impedance mismatch.
1 segment:
2 segments:
32 nodes
64 nodes
(31 drives)
(1 repeater, 61 drives)
[m]
[m]
1000
2000
400
800
200
400
100
200
DET-624
AF-650 GP/AF-600 FP Profibus DP Instruction Manual
3 segments:
96 nodes
(2 repeaters, 91 drives)
[m]
3000
1200
600
300
Transmission speed
9.6–93.75 kBaud
187.5 kBaud
500 kBaud
1.5 Mbaud
3–12 Mbaud
4 segments:
128 nodes
(3 repeaters, 121 drives)
[m]
4000
1600
800
400
Max. drop cable length per
segment
[m]
96
75
30
10
None
2
2-1
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