This article describes what EMI is and methods to mitigate its effects on touchscreen devices.

EMI: Electromagnetic interference. This interference in the operation of a device is caused by incompatibility with ambient signals. Common sources of EMI include transmitters and receivers (radio, TV, cell phone), power mains (lightning, surges, brownouts), appliances, computer oscillators, and electrostatics. Many countries have established laws (such as FCC and CE) governing EMI source limits.

To test for EMI, products must undergo EMC testing. This testing measures the ability of equipment or systems to function satisfactorily in their electromagnetic environment without introducing intolerable electromagnetic disturbance to anything in that environment.

All Elo products have EMC testing performed and certification can be found on each individual product spec page in the resources section. An example declaration of Conformity is shown below:




Even though a product undergoes testing and is in compliance with EMC standards, there may be times when EMI is present due to environmental conditions. Below are suggested methods to mitigage EMI in Elo touchscreen devices.

Mitigation Methods
There are basically three methods to mitigate EMI in electronic devices; shielding, grounding, filtering. See below for more information.

1. Shielding - this is perhaps the best method for mitigating EMI. This method uses a coupling device to encase electronic wiring. You may notice ferrite beads on the ends of computer cabling (VGA, HDMI, Power, etc.). A ferrite bead is a type of choke that suppresses high-frequency electronic noise in electronic circuits. Adding a ferrite bead to existing cabling will greatly reduce EMI on electronic devices.



2. Grounding - electronic devices should be properly grounded to prevent stray voltages from being introduced or emitted from the device. Make sure the electrical circuit and outlet being used is properly grounded. You can also add an additional grounding strap to most electronic devices. Using an ESD mat grounded to earth and placed beneath electronic equipment will help mitigate EMI.

3. Filtering - use a power line conditioner to help mitigate electromagnetic interference through the AC line. These can be found in something as simple as a power outlet or special devices such as the Tripp-Lite LS604 shown below: