4 Installations with safety technology (PROFIsafe)

PROFIBUS DP supports the operation of safety relevant devices (such as light curtains, remote I/O, drives with integrated safety, etc.) via the safe communication protocol "PROFIsafe". Special care must be taken with these applications with assembling, cabling and commissioning due to potential hazards for people and equipment.

The following provides some general rules on how to proceed in these cases:

1. Each and every device on PROFIBUS DP (standard and safety) shall provide a PROFIBUS test certificate or at least a corresponding manufacturer declaration.
   
   
2. Each and every safety device shall provide a safety certificate by a “Notified Body" (e.g. TÜV, BIA, HSE, INRS, UL, etc.).
   
   
3. The 24V power supplies in use shall be one-error proof and provide SELV / PELV only. In the USA the power supplies shall provide a current limitation of 8A (UL508C).
   
   
4. No spurs or branch lines are permitted in a RS485 segment.
   
   
5. Ensure effective cable shielding especially after bending the cable or after changing connectors. In case of doubt, a more flexible and robust cable type should be used.
   
   
6. Sub-D connectors shall have multi contact features at the connector housing in order to provide an optimal contact between the cable shield, the cable connector and its counterpart at the PROFIBUS device. Please take care to achieve a good (low impedance) contact between the cable shield and connector housing.
   
   
7. Use only M12 connectors that guarantee a good contact between cable shield and connector housing. Certain instruction manuals require wiring from the cable shield to the connector PIN 5. In case of doubt, it is more important to connect the cable shield to the connector housing using the largest possible contact area.
   
   
8. The power cabling for drives and motors shall be carried out using 5 wire cables that keep the "N" line and the "PE" lines separate (so-called TN power networks). Thus currents due to potential differences and electro-magnetic inference can be avoided as much as possible.
   
   
9. A cabinet of protection class IP54 (dust, shower water) is normally used for safety devices that are offering a lower protection class such as IP20. Cabinets with a lower protection class may only be used if safety devices explicitly permit other environments according to the manufacturer's information (e.g. heat problems).
   
   

It is highly recommended to create records after a visual check of the plant. Whenever possible the quality of the network shall be documented: no double addressing, no reflections, no repeat telegrams, etc.