Siemens SIMATIC NET PROFIBUS manual Layout of the Repeater Function

Active Components for RS-485 Networks

Table 5-1 Description and Functions of the RS-485 Repeater

Layout of the Repeater

No.

Function

	DC	L+ M PE M 5.2
10	24 V

À

Á

Â

ÀTerminal for connecting the power supply of the RS 485 repeater (pin “M5.2” is the reference ground if you want to measure the voltage between terminals “A2” and “B2”).

ÁShield clamp for strain relief and grounding the LAN cable of bus segment 1 or bus segment 2

ÂTerminal for the LAN cable of bus segment 1

A1	B1	A1	B1	Ã	Terminating resistor for bus segment 1	)1
			ON	Ä	Switch for OFF state
				Ã	(= Disconnect bus segments 1 and 2, for example, during
			DP1	11
È	PG			Ä	commissioning)
			OFF
	OP		DP2	12	Terminating resistor for bus segment 2	)1
				Å Å
			ON	Æ	Terminal for the LAN cable of bus segment 2
SIEMENS
RS 485-REPEATER				Ç	Catch for mounting and removing the RS-485 repeater on a
A2	B2	A2	B2

Æstandard rail

ÈInterface for PG/OP on bus segment 1

Á

10 LED 24 V power supply

Ç	LED indicating bus activity on segment 1
11

12

LED indicating bus activity on segment 2

)1 If the terminating resistor is activated, the right-hand bus attachment is disconnected (see

Figure 5-3) !

Note

Terminal M5.2 of the power supply (see Table 5-1, no. À) is used as the reference ground for signal measurements if problems occur and must not be wired up.

PROFIBUS Networks SIMATIC NET	5-3
6GK1970-5CA20-0AA1 Release 2 05/2000