Siemens FS720 - Page 194

Installing, exchanging and connecting modules
RS232 / RS485 module
7
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Building Technologies
A6V10210390_m_en_
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Fire Safety
2018
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08
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29
7.19.2.2 X2 on RS485 module
Pin Designation Description
4 RS485_A Line A
3 RS485_B Line B
2 Not connected
1 Not connected
Admissible cable cross-section: 0.2…1.5 mm²
T1 First participant
Tn Last participant
*) Stub lines must not exceed 20 m!
● Consider the polarity A, B!
● Terminate the line after the last participant (Tn) with 120 Ω!
3
4
X2
RS485_B
RS485_A
T1
Tn
2
1
*)
A
B