Siemens SIMATIC NET PROFIBUS manual Appendix

6ZB5530–3AC30–0BA1 Infrared Link Modul (ILM)

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:

âCable Type A complying with PROFIBUS DP; (DIN 19 245 Part 2)

âCable 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		100 to 130 ohms
		(3 to 20 MHz)		(f → 100 kHz)
Capacitance per unit		<30 pF/m		<60 pF/m
length
Loop resistance		<110 Ohms/km		–
Core diameter		→	0.64 mm	→	0.53 mm
Core cross-section		→	0.34 mm2	→	0.22 mm2
Table 5:	Electrical Parameters of the Shielded Twisted Pair LAN Cables

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