As industrial automation becomes more digitized, the susceptibility of equipment to electromagnetic interference (EMI) increases. Filtering and/or shielding these devices against EMI is vital to ensure uninterrupted operation and intended output. This is especially critical because due to interference, controls can malfunction, resulting in faulty output. This can cause serious accidents and/or line-down conditions resulting in loss of productivity.
There are two existing types of electrical interference:
In an industrial setting, machines operate close to each other making them vulnerable to interference. EMI filters can play a key role in preventing noise propagation and interruptions.
Settings like factories are full of potential sources of interference. Now that automation is becoming more common, it's more important than ever to protect machines against unwanted EMI. Common industrial sources of EMI include:
While they aren't a source of EMI themselves, long wires can act as antennas and transmit EMI — the longer a wire is, the better an antenna it becomes for a wider frequency spectrum. When it comes into contact with noise, it'll transmit that signal through either conduction or parasitic capacitance.
Another source is noise coupling, which happens when the current moving through one wire induces a similar voltage on another parallel wire. Keep parallel wires apart by three or more inches to avoid noise coupling. When isolation is not possible, using shielded wires can help.
The EOS acronym refers to a failure state triggered by overwhelming heat, power, or current. One well-known cause of EOS is electrostatic discharge (ESD) — static electricity. However, EMI can also be a major contributor to EOS.
High-frequency noise is present in most modern-day automation and manufacturing tools such as robotic arms, automated fasteners, pick-and-place machines, lead trimmers, and wire bonders. This can be a significant source of EOS in industrial automation equipment. The presence of unwanted high-frequency noise in a production environment can cause potentially damaging exposure to sensitive devices.
The tools and equipment are generally protected against the foreseeable stresses due to line voltages, however, the impact of low amplitude high-frequency noise is often overlooked. At high frequencies, conductors behave differently. A straight wire becomes an inductor with noticeable impedance and a phase shift. While DC and 50/60Hz require a metal-to-metal contact for current flow, at higher frequencies currents can flow without a direct contact because of the low impedance path provided by the parasitic capacitance between conducting metals. This can give rise to unexpected current paths and phase shifts. The problem at high frequencies is compounded by the fact that the repetition rate is much higher due to the higher frequency of the noise signal.
Following tools and devices are highly likely to be exposed to EMI caused EOS:
EOS is the leading cause of damage to integrated circuit (IC) components. An interrupted use of automation processes in operations greatly depends on the prevention and suppression of EMI within the facility. To minimize EOS, the origin and propagation of EMI within the tool/equipment, facility, and protective earth (ground) level must be fully evaluated, understood, and mitigated.
Many devices, such as servo drives and rotating machinery, consume high amounts of energy in short intervals, which causes high spikes in voltage. These peaks create high levels of EMI, which overwhelms nearby devices by interrupting their normal functions. These high-frequency interruptions can be especially damaging when they happen in close proximity to sensitive devices. If the voltage produced by the EMI is too high for the exposed devices to handle, they're at risk of EOS.
EOS is the leading cause of damage to integrated circuit (IC) components. If you use automation in your processes, the sustained daily function of your operation depends on your ability to prevent and suppress EMI within your facility. To minimize EOS as much as possible, you need to understand the origins of EMI on both a facility level and a ground level.
Consider which machines tend to generate the most noise and which parts of each machine cause internal interference. This information can help you to strategize the best method of implementing EMI-suppression equipment like filters.
Working to reduce the amount of EMI exposure for industrial machines is a smart move, especially now that wireless local-area networks (WLANs) are becoming more and more common in industrial facilities. When manufacturing an electric tool, you want to do more than filter out externally-created EMI — you also want to mitigate noise propagation within the device to prevent interference within itself.
Considering said factors in the early design phases typically allows for more cost-effective options moving forward. Here are a few design suggestions for reducing and preventing EMI in industrial automated technology:
Most of the time, it's difficult and expensive to go back and fix a vulnerable design or problematic machine in the field. EMI prevention is often a design afterthought, which makes fixing pre-existing machinery expensive and time-consuming. It is a good idea to do EMI due diligence upfront to avoid potentially more expensive field issues later.
It's crucial to pick the right filter for your operation. After all, you want to make sure your filter can handle the demands of the device and will be enough to suppress the EMI down to acceptable levels. What filter do you need for your machinery?
Please read our Step-by-Step Process for Selecting An EMI Filterfor factory automation and other industrial systems.
Astrodyne TDI has over 60 years of experience in manufacturing top-notch EMI filters, so you can trust in the quality and performance of your products. If you know what you need, you can browse our online selection of EMI filters for off-the-shelf solutions.
If you need something a little more specific, or you want to know where to start — we can help! Astrodyne TDI offers custom solutions for specialized products. Get started by requesting a free quote or finding a representative near you to get more information on our products.