II - DCE FEL ČVUT v Praze

Mechanical Configuration of an Automation System with SIMATIC S7 Ex Modules
1.1 Fundamental Guidelines and Specifications
Approval
FM approval
Safety Extra-Low
Voltage
1-2
Note
Ex systems may only be installed by authorized personnel!
SIMATIC S7 Ex modules have [EEx ib] IIC approval. This means they are
classified as associated apparatus and must therefore be installed outside
hazardous areas. Intrinsically safe electrical apparatus for Zone 1 and 2 may
be connected. The approval applies to all explosive gas mixtures of Groups
IIA..IIC (see Manual: “Principles of Intrinsically-Safe Design“, Chapter
“Secondary Explosion Protection”, “Marking of Explosion- Protected
Electrical Apparatus” and The Intrinsic Safety ”i” Type of Protection“)
Refer to the Certificates of Conformity (Appendix A) for the safety-relevant
limits. In Appendix A you will also find explanations of the designations
used.
SIMATIC S7 Ex modules feature the following FM approvals (see Manual:
“Principles of Intrinsically-Safe Design“, Chapter “Regulations for
Explosion Protection Outside the CENELEC Member States”) :
FM CL I, DIV 2, GP A, B, C, D, T4
In compliance with these approvals, the modules can be used in areas which
contain volatile flammable liquids or flammable gasses which are normally
within closed vessels or systems, from which they can only escape under
abnormal operating or fault conditions. The approval applies to all test gasses.
A surface temperature no higher than 135 C (T4) occurs at ambient
temperatures of 60 C.
SIMATIC S7 Ex modules must be operated with a ”safety functional
extra-low voltage”. This means that only a voltage of U 60 V must be
applied to the modules even in the event of a fault.You will find more
detailed information on the safety extra-low voltage in the specifications for
the power supplies to be used.
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04