CHAPTER 8 INSTALLATION AND STARTUP
8-2
8.1.2 Cable installation
For Profibus cable, the Shielded Twisted Pair Cable should be used. Table 8.1 and Table 8.2
shows cable specification and max. transmission distance according to speed and cable type.
Cable characteristic
Type A
Type B
Impedance
135 – 165
Ω
(f= 3 to 20 MHz)
100 – 130
Ω
(f > 100 KHz)
Capacity
< 30 pF/m
< 60 pF/m
Resistance
< 110
Ω
/Km
-
Conductor Area
>= 0.34 mm
2
(22 AWG)
>= 0.22 mm
2
(24 AWG)
Table 8.1 Cable Specifcation
Baud rate
(kbit/s)
9.6
19.2
93.75
187.5
500
1500
3000
6000
12000
Cable
Type
A 1200 1200 1200
1000
400 200 100 100 100
Cable Type B
1200
1200
1200
600
200
70
-
-
-
Table 8.2 Transmission distance according to Cable and Speed
Note) For Transmission distance, assuming that max. signal attenuation is 6dB.
1) General notices
z
Termination treatment of vertical section is needed.
z
In case that the distance is far between stations, it is possible to extend the segment through
repeater. (max. 9 repeater, 10 segment), available to connect 32 stations per segment (incl.
repeater), max. 126 stations.(Repeater does not have station no.). The extended segment
having no station is available.
z
Generally, connect the red cable to no.3 pin TXD/RXD-positive and the green cable to no.8
pin TXD/RXD-negative. Shield shall be connected to the housing of connector.
z
Use the cable that shield density is more than 80%.
z
The ends of cable shield should be grounded.
z
If the ground potential difference between stations is big, a great amount of current may flow
through the shield. In this case, install the cable to make the ground potential difference
equal separately.
For high speed more than 1.5MBps, special cares should be taken.
z
Use the special connector having the inductor inside.
z
Spur Line is not allowed to use.
z
In case of 12Mbps, keep the distance more than 1m between stations.