Infrared Link Modul (ILM)6ZB5530–3AC30–0BA1
51
Copyright by Siemens
12 Appendix
Electrical parameters of the RS 485 LAN cables
You can use the following cables to attach an RS 485 bus segment and individual DTEs to the PROFIBUS ILM:
â Cable Type A complying with PROFIBUS DP; (DIN 19 245 Part 2)
â Cable Type B complying with DIN 19 245 Part 1; 04.91; Section 3.1.2.3
Remember the restricted distance and transmission rate possible with the Type B cable (according to Table 2).
Cable Parameters
Type A Type B
Characteristic resistance 135 to 165 ohms
(3 to 20 MHz)
100 to 130 ohms
(f →100 kHz)
Capacitance per unit
length
<30 pF/m <60 pF/m
Loop resistance <110 Ohms/km –
Core diameter →0.64 mm →0.53 mm
Core cross-section →0.34 mm
2
→0.22 mm
2
Table 5: Electrical Parameters of the Shielded Twisted Pair LAN Cables
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