Radical 7 series Effects of EMI and Liquids on Capacitive Touchscreens Rev A

TECHNICAL SERVICE BULLETIN Effects of EMI and Liquids on Capacitive Touchscreens

Revision: A

STT-0378

Product Name: Radical-7 2012, Radical-7 Touchscreen Symptoms: The touchscreen display may change erratically when exposed to uncontrolled electromagnetic fields or liquids. Cause: The subject devices’ touchscreen utilize capacitive or P-CAP technology which have distinct advantages in the clinical setting compared to touchscreens that utilize resistive technology. The use of capacitive technology allows for more responsive user interface interactions even when used with gloved fingers. Touchscreens using resistance technology in contrast can be more difficult to use especially with a gloved finger. The capacitive touchscreen technology operates by generating an electrostatic field across the surface of the touchscreen. Touching the screen with a finger creates a distortion of the electrostatic field that is registered as a “touch”. Based upon how the technology works, other factors that may disrupt the electrostatic field may also register as a “touch”. Some factors we have identified are as follows: • •

Exposure to cleaning liquids on the surface of the device; Exposure to high amounts of electromagnetic interference (EMI) created by lighting ballasts. Both factors are addressed in the operator’s manual for the subject device. Corrective Action: Both issues are extremely unlikely to affect the patient monitoring; however, it can be a source of concern if customers are not aware of what is occurring. To minimize the likelihood of any issues, do the following: - Always turn off and disconnect the Radical-7 from the patient before cleaning - Keep the Radical-7 away from sources that may be a source of EMI (such as ungrounded lighting ballasts)