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SIMATIC controllerfor safety-related applications in the process industry

AS 417FH automation system of the SIMATIC PCS 7 process control system

Safety-related SIMATIC controllers are used for critical applica-tions in which an incident can result in danger to persons,plant damage or damage to the environment. The S7-400FHsystem with the safety-related F-IO modules of the ET 200 orthe directly connected fail-safe transmitters on the fieldbusdetects faults in the process plant and system internal. In thecase of a fault the system will set the plant automatically to asafe state.

The SIMATIC S7-414FH and S7-417FH controllers are the rightchoice to implement safety-related applications in the processindustry. They are capable of multitasking: several programscan be executed simultaneously in a CPU. BPCS (standard)applications and safety-related applications can be executedin parallel. The BPCS applications have no effect or influenceon safety-related applications and vice versa. Special taskswith very short response times can also be implemented.

SIMATIC S7-300F controllers can also be used for smallerprocess safety applications, e.g. burner controls. These con-trollers are otherwise primarily used in safety-related controlsin the factory automation.

All mentioned controllers are TV-certified and comply withthe safety integrity levels up to SIL 3 according to IEC 61508.They are able to process BPCS and safety functions parallel inone CPU. Mutual influencing during the processing is pre-vented in that the safety-related and BPCS program compo-nents remain strictly separated and that the data exchange isexecuted by special conversion blocks. The safety functionsare executed twice in different processor sections of one CPUthrough redundant, multi-channel command processing.Potential errors are detected by the system during the sub-sequent comparison of results.

S7-414FH and S7-417FH controllers

The S7-414FH and S7-417FH controllers are based on thehardware of the S7-414H and S7-417H controllers which isextended by the safety functions in the S7 F Systems softwarepackage. Single-channel (only one CPU) or fault-tolerant (tworedundant CPUs) are possible depending on the configura-tion.

In the context of SIMATIC PCS 7, you can obtain the SIMATICS7-414FH and S7-417FH controllers as preassembled andtested automation systems. These product bundles usuallyinclude components such as racks, CPU, power supply, mainmemory, memory card and Industrial Ethernet interface.

They are available in two configuration versions with thefollowing product names:

As single-channel AS 414F or AS 417F (with one CPU,safety-related)

As fault-tolerant AS 414FH or AS 417FH (with two redun-dant CPUs, safety-related and fault-tolerant)

The redundant FH systems are 1 out of 2 systems and consistof two identical subsystems. To achieve optimum EMC, theseare electrically isolated from one another, and are synchro-nized over fiber-optic cables. In the event of a fault, there isa bump-less switchover from the active subsystem to thebackup subsystem. The two subsystems can be located in thesame rack, or separated into different locations with a maxi-mum distance of up to 10 km. The separation into differentlocations provides additional safety gains in the case ofextreme effects in the local environment of the active sub-system, e.g. by fire.

The redundancy of the FH systems only serves to increaseavailability. It is not relevant to processing of the safety func-tions or the fault detection associated with this.

More information on the Internet:www.siemens.com/fh-cpu

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SIMATIC S7-300F controllers

The SIMATIC S7-300F controllers have a very robust and com-pact design. They are only offered in a single-channel versionwith one CPU. Fault-tolerant controllers with redundant CPUsare not available in this series.

The four types of controller result from the combination of thetwo CPUs of different performance (S7-315F or S7-317F) withdifferent fieldbus interfaces (DP or PN/DP):

S7-315F-2 DP S7-315F-2 PN/DP S7-317F-2 DP

S7-317F-2 PN/DPWhereas controllers with the S7-315F-2 DP or S7-317F-2 DPCPUs are designed exclusively for fieldbus communicationover PROFIBUS DP, controllers equipped with the S7-315F-2PN/DP or S7-317F-2 PN/DP CPUs additionally support thePROFINET standard already established in the factory automa-tion.

You can expand the S7-300F CPUs centrally using the safety-related F-modules of the ET 200M I/O system. Distributedexpansion is possible with remote I/O stations and safety-related F-modules of the ET 200M and ET 200S I/O systems.

SIMATIC S7-300F controller

More information on the Internet:

www.siemens.com/f-cpu