Siemens Welding System ST PCS 7 User Manual

PROFIBUS DP

Siemens ST PCS 7 · November 2007

9

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The PROFIBUS DP fieldbus enables the SIMATIC PCS 7 auto-

mation systems (controllers) to communicate with distributed 

I/Os from the ET 200 range (remote I/Os) as well as with 

field/process devices, CPUs/CPs and operator terminals that 

have a PROFIBUS DP interface. It is possible to route the 

PROFIBUS DP into Ex zone 1 by using a fieldbus isolating trans-

former (RS 485-iS coupler) and the RS 485-iS transmission tech-

nology. Connection of the intelligent, distributed field/process 

devices and operator terminals on PROFIBUS PA to the automa-

tion system takes place likewise through PROFIBUS DP.
Depending on the type of automation system and the number of 

available slots, up to 4 PROFIBUS DP lines can be connected to 

a SIMATIC PCS 7 automation system through internal interfaces 

in the CPU, and up to 10 PROFIBUS DP lines through additional 

CP 443-5 Extended communications processors. On a 

PROFIBUS DP line it is possible to operate up to 125 devices, 

and on a bus segment up to 31 devices with PROFIBUS DP in-

terface (32 stations). 
Electrical and optical transmission technologies offer many dif-

ferent configuration options for PROFIBUS DP networks. Electri-

cal networks can span up to approx. 10 km. With optical trans-

mission systems, the total size of the network is governed 

primarily by the cycle times as a result of the almost loss-free 

transmission.
With SIMATIC PCS 7, PROFIBUS DP topologies are always im-

plemented through the standard electrical PROFIBUS DP con-

nection on the automation system in the form of electrical or 

mixed (electrical/optical) networks. In the case of mixed net-

works, the transition between the two media is implemented by 

an optical link module (OLM). As regards communication be-

tween the stations, there is no difference between electrical two-

wire technology and fiber optic technology. 
Electrical networks can be configured with a line or tree topol-

ogy. Mixed electrical/optical networks with OLMs as routers can 

be configured with a line, ring or star topology.

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1)

According to PROFIBUS installation guideline 2.262

RS 485

RS 485-iS

Fiber-optic

9.6 kbit/s ... 12 Mbit/s

9.6 kbit/s ... 1.5 Mbit/s

9.6 kbit/s ... 12 Mbit/s

2-wire shielded

2-wire shielded

Plastic as well as multi-mode and 

single-mode glass-fiber

EEx(ib)

Line, tree

Line

Ring, star, line

32

32 

1)

–

126

126

126

1200 m at max. 93.75 kbit/s
1000 m at 187.5 kbit/s

400 m at 500 kbit/s

200 m at 1.5 Mbit/s

100 m at 12 Mbit/s

1000 m at 187.5 kbit/s

1)

400 m at 500 kbit/s

1)

200 m at 1.5 Mbit/s

1)

Max. 80 m (plastic) 
2-3 km (multi-mode glass-fiber) 
>15 km at 12 Mbit/s (single-mode 

glass-fiber)

Max. 9

Max. 9

1)

Not relevant

© Siemens AG 2007