PROFINET Infrastructure – Cat-5 Cable


At its heart, PROFINET is based on standard Ethernet IEEE 802.3 Physical layers using 802.3 supporting components. PROFINET will work on copper Ethernet cable, Fiber Optical (FO) cable, Power Over Ethernet (PoE) cable and Wireless. The components available for your PROFINET infrastructure depend on the harshness of the environment and whether or not you are using PROFINET IRT.

PROFINET Infrastructure

PROFINET has to work in several distinct environments, from the front office, to the control room, to the factory floor. As you might guess, the front office environment is not very stressful as far as electronic communications go; standard Ethernet components usually work just fine here. The control room and factory floor environments are much tougher on communications. There, complications like EMC, cross-talk, mechanical stress,  and vibrations can each add their own brand of misery to your network stability.

Ethernet Cable for PROFINET

Ethernet cable is pretty generic. Most Ethernet installations are usually designed for a simple office environment. One of the common questions asked about PROFINET is, “Will it work over Cat-5 cable?” The answer is – maybe!  Standard Cat-5e cable is usable in PROFINET office environment installations.  However, potential transmission speeds available with Ethernet  depend on the type of cable being used. The following table shows the cable types and their transmission speeds. 

 Length
(meters)
Transmission speed
10 Mb/s
Transmission speed 100 Mb/sTransmission speed
1 Gb/s
Transmission speed 10 Gb/sPower Over Ethernet
(POE)
  
Cat-5100XXX
Cat-5e100XXXX
Cat-6100
55 for 10 Gb/s
XXXXX
Cat-6a100XXXXX

EMC protection measures

Basic Ethernet cables use twisted pair techniques to help eliminate cross-talk. Cables for harsher environments often have more twists per inch than basic cables. In PROFINET, the main technique for hardening against EMC is adding shielding to the cable. PROFINET cables have both a foil shield and a braided shield to protect against interference. In a factory floor environment PROFINET cable (along with PROFINET connectors) are strongly recommended.

PROFINET Cable

PROFINET network infrastructure choices should depend on the operating environment. You can use regular Ethernet cable in PROFINET installations, but only in an office type environment . In order to take advantage of the increased robustness that PROFINET can provide, you should use PROFINET cable and PROFINET connectors to create your network.  You can access the complete PROFINET cable technology guideline here https://www.profibus.com/download/profinet-cabling-and-interconnection-technology/