Siemens Simatic CFU Commissioning Manual page 25

● Intrinsically safe field devices connected to fieldbus connections FB<n> (spur line to the
field device)
● Sensors and/or actuators connected to freely configurable channels DIQ<n> (spur line to
sensor/actuator)
Intrinsic safety of the CFU PA
The CFU PA limits the energy on the fieldbus line to the intrinsically safe PA field devices, and
electrically isolates them from the live parts of the CFU PA (for example, power supply).
Fieldbus connections of the CFU PA are designed in Ex [ic] type of protection.
You can find additional information on intrinsic safety in the product information.
Labeling of the CFU
The CFU is equipped with markings for the explosion-prone area. These markings indicate in
which explosion-prone environments the equipment can be used.
Certificates for the CFU
The EU prototype test certificate and the EU certificates of conformity for the CFU are available
under Service & Support on the Internet (https://support.industry.siemens.com/cs/us/en/).
Connecting and disconnecting the cables to the CFU during operation
Explosion hazard
It is forbidden to open the enclosure during operation in the Zone 22 hazardous area.
De-energize the CFU before carrying out any work on it.
Explosion hazard
In the Zone 2 hazardous area, it is forbidden to connect or disconnect the following cables
to/from a CFU during operation:
● Power supply
● PROFINET cable (BusAdapter)
● Cable to freely configurable channels
De-energize the CFU before carrying out work on these cables.
Hazardous area - zone 2:
In a CFU PA, fieldbus connections are implemented as intrinsically-safe connections (Ex ic)
and may be inserted or removed during operation.
SIMATIC CFU
Commissioning Manual, 07/2018, A5E39252870-AC
DANGER
DANGER
Operation planning
5.4 Use in hazardous areas
25