Detection principle of electronic wire harness fault

- Jul 05, 2019-

For different electronic accessories, such as: vending machine wiring harness, the number of wires and the number of colors contained in the electronic wire harness are also different. The number of wires can be from several, several tens to hundreds, and the color can be from several to ten. Several to dozens (including monochrome and two-color), the terminal wire harness fault detector (hereinafter referred to as the detector) should be able to display the type of fault, the color and location of the faulty wire, if an open or short circuit fault is detected, so that The operator immediately discovers and resolves the fault. In order to achieve the above functions, the following detection methods are used:


First number the endpoints of the electronic harness, group the endpoint numbers by color, and then enter the color and endpoint numbers into the detector by group (one model harness is entered once). The detection process of the detector is divided into two steps: short-circuit fault detection and open-circuit fault detection. There are three types of end points: A (red), B (blue) and C (green). The endpoints in the group are connected. Any endpoint in the group is not connected to the endpoint outside the group.


Short-circuit fault detection: firstly detect whether any endpoint in group A is connected to each endpoint in group B and group C. If not, it indicates that there is no short-circuit fault between the endpoint and each endpoint in group B and C; When it is turned on, the detector displays the type of fault, the color of the faulty conductor, and the endpoint number. Short-circuit fault detection can be realized by sequentially detecting whether other endpoints in group A are connected to each of the endpoints in group B and group C.


Open circuit fault detection: Open loop fault detection can be realized by detecting whether the terminals in the group are disconnected by a single loop method.


Under normal circumstances, wire harness processing manufacturers have special wire loop circuit testing equipment to check the wire harness fault, can detect the wrong way of the wire harness and open circuit, generally called the wire loop circuit test bench.


1. The wiring harness is burnt out. This situation usually occurs suddenly, and the burning speed is also relatively fast. In these burnt lines, there is generally no safety device. Wire bundle burnout usually has a certain regularity: in the circuit of the power system, where is the ground iron, where the wire harness will burn, where the junction of the burnt and intact place is the wire of this place Iron; if the wiring harness burns to the wiring of an electrical device, it indicates that the electrical device has failed.


2. The wire bundle is subjected to external compression and impact, which causes the insulation of the wire inside the wire bundle to be damaged, causing a short circuit between the wires, causing some electrical equipment to lose control and the fuse to be blown. If the line is in poor contact, then most of the faults occur in the connector. When the fault occurs, the electrical equipment will not work properly. At the time of judgment, the power of the electrical equipment is turned on, and the relevant connector of the electrical equipment is pulled or touched. When a certain connector is touched, the electrical equipment suddenly works, and suddenly it cannot work, then This shows that the connector has failed.