Siemens Welding System ST PCS 7 User Manual

ET 200M distributed I/O

Siemens ST PCS 7 · November 2007

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The safety functions of the AS 414F/FH and AS 417F/FH automa-

tion systems are matched to the safety-related I/O modules 

(F-modules) of the ET 200M distributed I/O system. The F-signal 

modules (DI/DO/AI) in the ET 200M remote I/O stations are able 

to guarantee plant safety even in the event of a CPU failure. They 

are of redundant design, and can diagnose both internal and ex-

ternal faults. They carry out self-tests for this purpose, e.g. for 

short-circuit or wire breakage, and automatically monitor the dis-

crepancy time defined in the parameter settings. They comply 

with the requirements up to SIL 3 (IEC 61508) or AK 6 

(VDE 0801). 
The input modules operate internally with single-channel evalu-

ation (SIL 2 sensors), 2-out-of-2 evaluation (SIL 3 sensors) or 

2-out-of-3 channel evaluation (only F-AI module). A safety re-

sponse is triggered immediately there are any differences. The 

type of evaluation influences the number of usable inputs (chan-

nels). For example, only half of the existing inputs are available 

in the case of 2-out-of-2 channel evaluation. 
The digital output modules enable safe disconnection through a 

second disconnect path in the event of a faulty output.

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Order No.

Electrically isolated in groups 

of 12

Redundant design possible 

(module redundancy)
• 4 short-circuit-proof sensor 

power supplies, each for 

6 channels, isolated in groups 

of 3

• External sensor power supply 

possible

• SIL 2: single-channel evaluation, 

24 channels

• SIL 3: 2-out-of-2 evaluation on 

the module, 12 channels 

(adjustable discrepancy time)

• Short-circuit monitoring to L+
• Discrepancy monitoring
• Supports time stamping (SOE)
• Diagnostics inside module
• PROFIsafe telegram
• Front connector required: 

40-contact

Isolated by channel

Redundant design possible 

(module redundancy)
• 8 short-circuit-resistant sensor 

power supplies, each for 

1 channel, mutually isolated

• SIL 2: single-channel evaluation, 

8 channels

• SIL 3: 2-out-of-2 evaluation on 

the module, 4 channels 

(adjustable discrepancy time)

• Wire break and short-circuit 

monitoring (for contacts with 

external resistor circuit)

• Discrepancy monitoring
• Diagnostics inside module
• PROFIsafe telegram
• Front connector required: 

40-contact

© Siemens AG 2007