By Eileen Harvey
Industrial environments are inherently complex, filled with a plethora of machinery, motors, drives and power lines that contribute to a high level of electromagnetic interference (EMI). This interference can manifest in various detrimental ways, especially for systems that rely on PROFINET and other industrial Ethernet protocols. Communication errors may arise, leading to data corruption or loss, which can compromise the integrity of automated processes. The ramifications of such disruptions can be severe, resulting in costly downtime that not only affects production schedules but also increases maintenance expenses as systems may require frequent troubleshooting and repair
One of the most effective strategies to mitigate the effects of EMI is through proper cable routing, which involves careful planning and implementation of cable layouts. By maintaining adequate separation between data cables and power lines organizations can significantly reduce the risk of interference. This includes utilizing shielded cables and following best practices in installation techniques to further enhance protection against EMI.
Understanding EMI in Industrial Networks
Electromagnetic interference (EMI) is a phenomenon that arises when electromagnetic energy emitted by one source interferes with the proper functioning of another device or cable. This disruption can manifest in various ways, leading to signal degradation, distortion or complete loss of communication in affected systems. EMI can emanate from numerous sources, both natural and artificial, including radio towers, power lines, microwaves and even electronic devices like smartphones and computers.
Sources of EMI and Its Effect on PROFINET
Sources of EMI include high-voltage power lines, motors and transformers, variable frequency drives (VFDs) and welding machines and heavy equipment.
EMI has several big impacts on PROFINET communication: data packet loss, increased latency and jitter, and system errors or unplanned downtime. Shielding and grounding reduce EMI effects, but routing and separation are the first lines of defense.
Cable Routing Principles
Before installing PROFINET cables, plan the layout. Best practices for routing are as follows: use dedicated trays, conduits or ducts for network cables; route cables away from high-voltage equipment whenever possible; maintain consistent bend radius to avoid damaging shielding; and if multiple cables run together, ensure bundles are not overly tight. For high-motion applications such as robotics, flexible PUR or TPE jacketed cables are highly recommended.
Separation Guidelines from Power Lines
Keeping data cables separated from power cables significantly reduces EMI risk. Industry guidelines recommend: to maintain at least 20 cm (8 inches) between data and power cables when running in parallel; if cables must cross, do so at a 90-degree angle; use separate trays or conduits for high-voltage and communication cables; and for medium-to-high voltage lines, increase separation to 50 cm or more.
Shielding and Grounding for Added Protection
Shielding and grounding complement routing practices by reducing signal noise. There are several important shielding options for PROFINET cables. Foil shield (F/UTP) protects against high-frequency interference. Braid shield (S/FTP) is excellent for low-frequency EMI and mechanical strength. Combination shield (SF/UTP) provides dual protection for harsh environments.
Grounding best practices include grounding shields at both ends in high-noise environments, grounding at one end to minimize ground loop issues for sensitive systems, and ensuring metal connectors maintain shield continuity.
Common Mistakes in Cable Routing
Even experienced installers sometimes overlook small details that lead to big problems.
Avoid these mistakes:
- Running PROFINET cables parallel to power lines without separation.
- Over-tightened cable ties, which damages shielding.
- Ignoring bend radius recommendations.
- Mixing different categories of Ethernet cables in the same run.
- Forgetting to leave slack for cable movement in robotics or drag-chain systems.
Tips and Recommendations
- Plan: Design cable routes during the engineering phase.
- Use quality materials: Invest in cables with PUR or TPE jackets for harsh environments.
- Separate trays: Dedicate separate ducts for data vs. power cabling.
- Double shielding: Use SF/UTP designs when EMI is a major risk.
- Document installation: Keep maps of cable runs for future troubleshooting.
Industry Standards
We offer four useful facts about industry standards. First, IEC 61784-5-3 defines PROFINET cabling guidelines. Second, EN 50174-2 sets cable routing and separation standards. Third, 60% of industrial downtime is caused by communication failures—often due to poor cabling and EMI. And finally, using shielded PROFINET cables can extend network lifespan by up to 40% in high-noise areas.
FAQs About Cable Routing in PROFINET Installations
Q1: What is the minimum separation distance between PROFINET and power cables?
A: At least 20 cm (8 inches) for parallel runs, 50 cm or more for high-voltage lines.
Q2: Can PROFINET cables and power lines share the same tray?
A: No. Data and power cables should use separate trays to minimize EMI.
Q3: How do shielded cables help against EMI?
A: Shielding prevents electromagnetic fields from disrupting data transmission, ensuring stable communication.
Q4: What happens if EMI is not managed?
A: Unmanaged EMI can cause data loss, jitters, system errors and costly downtime.
Q5: Should grounding be done on one or both ends of the cable?
A: For high-noise environments, both ends should be grounded; for sensitive systems, grounding one end may prevent ground loops.
Reducing EMI in PROFINET networks isn’t just about shielding—it starts with proper routing and separation from power lines. By planning cable paths, following industry standards and investing in shielded cables with durable jackets, industries can ensure long-term performance and reliability. For high-performance installations, brands like TKD Kabel offer industrial-grade solutions designed to handle EMI, chemical exposure and mechanical stress.
Explore the full range of TKD Kabel through L-com. We’ll fill your orders fast, with same-day shipping on all qualified, in stock, online orders received Monday through Friday before 5 p.m. EST. For TKD-related inquiries, connect with our U.S-based TKD expert Eileen Harvey at eharvey@infiniteelectronics.com.
