The 3 Biggest Killers of the PROFINET Industrial Network

Our engineers perform diagnostics of industrial networks in hundreds of manufacturing companies. They travel across the country to find the causes of failures. We have asked them what problems they have most frequently diagnosed in customers' PROFINET networks recently. What have they told us?

Introduction: What PROFINET Network Monitoring Is All About

PROFINET diagnostics related to a customer's problematic production line are usually performed by a FOXON technician, who connects to the production line's control cabinet using a laptop equipped with diagnostic software. The software displays the topology of the PROFINET network and provides a lot of information about the stations. If it is possible to disconnect the network for a while, the technician will also connect the TAP adapter to get an extended overview of the network, such as port utilisation, alarms, lost packets and more. Some faults can be seen immediately by the technician, while others may only become apparent after monitoring the network for a longer period of time.

For long-term monitoring, we usually rent the customer the so-called yellow suitcase. It contains not only a network analyser but also an Ewon router that allows the technician to connect to the network remotely. We usually monitor the network for 14 days with our technician continuously monitoring the network's behaviour remotely. He communicates with maintenance staff and together they test various changes in the network and their impact. What faults would our technicians currently classify as the most frequent?

Replace a Cable

A problem in the cabling is one of the most common causes of faults that are difficult to detect without diagnostic tools. The tricky part is that if you connect the cable incorrectly, for example by not connecting all the pins or swapping the coloured wires, communication will usually still go through. So the cable often behaves as if it is working, but it can cause occasional network failures. This problem can be easily avoided by testing each cable at installation with the NAVITEK tester.

Change Stations' Update Times

The communication cycle of PROFINET stations (update time) is often set too low by the production line supplier for all stations in the network, e.g. 2 ms. Increasing the value of the update time reduces excessive network overload and increases the robustness of the network.

Change the Topology

The topic of network topology would be a separate article. After all, it is also one of the main topics of our two-day PROFINET training courses at the FOXON Academy. Network analysis software allows a technician to view the topology and quickly find out where the problem is, provided that managed switches are used in the network. If we were to pick the three most common problems in topology, they would be depth, loops and camera images.

• Too much depth in topology, i.e. too many stations connected in series, reduces the health of the network and increases the likelihood of failure.
  
  
• Our engineers have troubleshot loops in the network on a number of occasions. Some stations were accidentally or incorrectly connected in a ring and the stations were not set to the ring.
  
  
• Special care must be taken with native camera images. If this data-intensive communication goes through PROFINET stations, it can easily overload the network. In practice, we know of cases where an overloaded network caused delays or dropped packets, resulting in occasional failures of the entire production line. 

Once a diagnosis has been made, a FOXON technician will suggest a treatment – i.e. changes that need to be made to keep PROFINET running smoothly.

Get Rid of All the Killers Before You Start the Production Line

Our engineers often encounter problems even with brand new production lines. Some either fail to start or experience repeated downtime. Sometimes once every two days, sometimes several times a day. The worst failures are the ones that happen just once a month. At first it looks like the supplier delivered a perfectly good production line, but after a few weeks problems start to appear.

That is why our technicians recommend that you have everything measured when your production line is installed, so that you do not have to worry about anything during actual production.

To Ensure the Reliability of Your PROFINET, Our Engineers Also Recommend:

• Order a diagnosis of your network and check its condition. Even if there have been no failures yet, this does not mean that network faults are not slowly accumulating. Networks are getting older and preventive checks are a way of avoiding bigger problems.
• Talk to us about choosing an analyser for your networks. We use testers and diagnostic software in the field and are happy to recommend the best solution for you.
• Sign up for our PROFINET network diagnostics training course and learn directly from our experienced engineers.