Properties of zones
You will find an overview of the zone divisions in the following table:
Table 4-1 Classification of zones - hazardous areas
Areas Explosion hazard
Zone 2 Rare or short-term presence of potentially explosive gas atmosphere
Zone 22
1)
Rare or short-term presence of potentially explosive dust atmosphere
1)
Use the CFU only with approved housing
For additional information, refer to the Fundamentals of Explosion Protection (
https://
support.industry.siemens.com/cs/ww/en/view/12521844) system manual.
Component areas
CAUTION
Use in hazardous area of Zone 2/22
● Any CFU can be used as a bus node in Zone 2 hazardous areas.
● All CFU bundles with aluminum housing can be used as bus nodes in Zone 2 and Zone 22
hazardous areas.
Products:
– Compact Field Unit PA Bundle with Aluminum housing
– Compact Field Unit DIQ with Aluminum housing
● CFU PA: Only intrinsically safe electrical field devices of equipment category 3G and 3D
for Zone 2 and 22 may be connected to spur lines FB0 to FB7.
Read the information on approval in the product information.
The following can be used in Zone 2/22 hazardous areas:
● PROFINET cables to the CFU
● Cables to PROFIBUS PA field devices, sensors and actuators
● 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.
Operation planning
4.9 Use in hazardous areas
SIMATIC CFU
30 Commissioning Manual, 08/2019, A5E39252870-AD
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