Methods for Protecting a Personal Computer and Data Acquisition Electronics Installed on Mobile Equipment

Successful data acquisition on mobile platforms, such as tractors, requires the provision of protection for the sensitive electronics, as these platforms are inherently rife with electrical transients that have sufficient energy to cause damage to unprotected instrumentation. Unfortunately, though there are many protection options for industrial applications (i.e., those installed at 120VAC), off-the-shelf products for mobile protection are extremely limited and, after a survey, were determined to provide insufficient protection. The objective of this study was to identify the requirements for the protection of mobile platform instrumentation and equipment, and/or identify circuits that can perform this function. A literature review of electrical transients typical to automotive electronics was performed and circuit simulations were performed using open source software. Off-the-shelf circuit components were tested, via simulation, in various configurations until a design emerged that provided adequate protection from all surge classes. To ensure protection of valuable data, one of the design criteria was to ensure the circuit would continue to supply power to the personal computer (PC), and electronics, even during a load-dump event. The circuit was also designed to provide protection from electrical fast transients and electrostatic discharges. The reported circuit is capable of protecting a computer and data acquisition electronics installed on 12 VDC mobile equipment. This simple, inexpensive design meets Automotive Electronics Council requirements and uses readily available components without a specially fabricated circuit board.