Siemens SIMATIC NET PROFIBUS User Manual

Infrared Link Modul (ILM)

6ZB5530–3AC30–0BA1

51

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

 by Siemens

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