Application: Automotive Control Centers

One of the most important steps in the manufacture of automotive engine control centers is the placement of fuses in the control center housing. Fuses are selected and positioned by hand, with an attendant likelihood of fuses being installed in the wrong position. Detecting misplaced fuses in a high-volume production environment is a daunting task. Many manufacturers rely on vision-based error detection schemes to verify correct fuse placement. While straightforward in concept, this technique has not proven to be reliable, as variability in the visual aspects of fuse bodies can lead to both the rejection of good products and the acceptance of bad product.

Electrical measurement of fuse resistance is an ideal alternative to vision-based systems. The main issue with electrical measurements has been the resolution capability of electrical test systems. The fuses typically used for automotive applications are in the 5 to 60 amp range, with nominal resistance from 20 milli-ohms down to 800 micro-ohms. This range has been below the limits of accuracy for most commercial multi-point test equipment.

OmniTester has developed four-wire (Kelvin) algorithms that extend the range of measurement for the Omni2501 system. As a result, accurate and repeatable resistance measurements in the micro-ohm range can now be made. Additionally, we have conducted analyses of the variance in the resistance of fuses, the measurement circuitry, and the effects of fixture contacts. Our overall conclusion is that effective and reliable testing of fuses is feasible, and this feature is available as a low-cost option to the Series 2500 test systems.

Products suitable for automotive control center applications:

The Omni2501 is applicable for continuity, high voltage insulation resistance, capacitance and passive component testing.