|WikiProject Computing / Networking||(Rated Start-class, Low-importance)|
Why the Profibus standard says that it has a RS-485 transmission technology (Differential mode)?. If It would be true, Why the terminator of Profibus has voltage (5 Volt)?. What happens if the nodes have different earth?, obviously there will be current between them due different earth.
Profibus does use RS-485. The cable shield is used as RS-485 signal ground to prevent variations in earth potential.(EARTH NR) As an extra precaution Profibus also specifies that a 10mm^2 protective earth cable shall run in parallel with the profibus cable, and bolted to the chasi of every Profibus device. (!)
The 5V pin in the Profibus connector is not used in most cases. It can be used for active termination, or to power profibus diagnostic tools which connect directly to a Profibus device. Brolin (talk) 18:33, 11 September 2009 (UTC)
OSI vs Profibus
Layer 7 is nog used in Profibus DP and PA with the DPV-0 to DPV-2. Layer 7 is only used in Profibus FMS in a special FMS layer. view official literature (book): The New rapid way to Profibus DP (by Manfred Popp & www.profibus.com) —Preceding unsigned comment added by 220.127.116.11 (talk) 20:04, 17 April 2011 (UTC)