CN201796104U - On-board wiring harness continuity tester - Google Patents

Abstract

The utility model discloses a vehicle-mounted wire harness connection and disconnection detector which comprises a single-chip microcomputer, a buzzer, a decoder, a voltage amplification circuit, a voltage division circuit, a switching circuit and a voltage acquisition circuit, wherein the buzzer is connected with the single-chip microcomputer, the signal output end of the single-chip microcomputer is connected with the decoder, the signal output end of the decoder is connected with the input end of the voltage amplification circuit, one circuit of the output end of the voltage amplification circuit is connected with the supporting connector I of a vehicle-mounted wire harness terminal through a triode Q3, and the other circuit of the output end of the voltage amplification circuit is connected with the supporting connector II of the vehicle-mounted wire harness terminal sequentially through the voltage division circuit, a triode Q4 and a light emitting diode D3. The utility model has the advantages that the detection efficiency is improved, the quantity of work is reduced, the detection speed is fast, the error rate is reduced, and all detection including the detection of the contact performance of the connectors at the two ends of the vehicle-mounted wire harness can be conducted.

Description

On-board wiring harness continuity tester

technical field

The utility model relates to a device for on-off detection of a vehicle-mounted wiring harness.

Background technique

The vehicle wiring harness (vehicle signal transfer wiring harness) is used to collect signals such as vehicle speed and engine speed. In order to detect whether the 20 wires in the vehicle wiring harness have poor contact, missing connection, or wrong connection, the inspector should inspect the already produced harness.

At present, the usual tool for on-off detection of vehicle wiring harness is a multimeter. The inspection method is to use the red and black test leads of the multimeter to touch the terminals 1 to 20 at both ends of the vehicle wiring harness respectively, measure the continuity of the 20 wires, and check whether there are missing connections or wrong connections. The above-mentioned detection mainly has the following shortcomings: 1. Low efficiency: the inspection requires the cooperation of 2 personnel, and the work efficiency is slow. The average detection time for one wire harness is 1 to 2 minutes; , which may lead to missed inspection, and the unqualified product is judged as qualified; or wrong inspection, the qualified product is judged as unqualified; 3. The terminals at both ends of the wire harness and the contact of the sheath cannot be detected: the two ends of the wire harness are sheathed The connector is connected to the automobile instrument harness in this way, and this inspection method cannot detect whether the contact of the harness connector is good.

Utility model content

Aiming at the deficiencies in the prior art, the utility model provides a vehicle-mounted wire harness on-off tester which improves the detection efficiency, reduces the labor load, reduces the error rate, and increases the detection function of the connector.

The vehicle-mounted wire harness on-off detector provided by the utility model includes a single-chip microcomputer, a buzzer, a decoder, a voltage amplifier circuit, a voltage divider circuit, a switch circuit and a voltage acquisition circuit; the buzzer is connected to the single-chip microcomputer; the signal output of the single-chip microcomputer The end is connected with the decoder; the signal output end of the decoder is connected with the input end of the voltage amplifying circuit;

The switch circuit includes a triode Q3, a triode Q4, a light-emitting diode D3 and a resistor R50; the output end of the voltage amplifying circuit is connected to the base of the triode Q3, and the output end of the voltage amplifying circuit is also connected to the triode Q4 through a voltage dividing circuit. The base of the triode Q3 is connected to the 12V power supply, and the emitter is connected to the supporting connector I of the vehicle wiring harness terminal; the emitter of the triode Q4 is grounded, and the collector is connected to the negative pole of the light-emitting diode D3. The anode of the light-emitting diode D3 is connected to the matching connector II of the vehicle wiring harness terminal through the resistor R50;

The voltage acquisition circuit includes a resistor R51, a resistor R52, and a Zener diode D4; the positive pole of the Zener diode D4 is grounded, the negative pole is connected to the single-chip microcomputer, and the negative pole is also connected to the supporting connector II of the vehicle wiring harness terminal through the resistor R51, and the resistor R52 is connected in parallel. across Zener diode D4. the

Further, it also includes a key for controlling the single-chip microcomputer to receive the command of inquiring about the on-off of the wiring harness, and the key is connected to the single-chip microcomputer.

Compared with the prior art, the utility model has the following advantages:

1. Improve detection efficiency: The vehicle-mounted wiring harness continuity detector relies on the software in the single-chip microcomputer for self-inspection, which can detect whether there are missing connections or wrong connections in the wiring harness, reducing the workload, and only one person can complete the detection.

2. Fast detection speed: the average detection time for one wire harness is 3-5 seconds.

3. Reduce the error rate: use the single-chip microcomputer for round-robin detection to avoid errors caused by artificial factors, the error rate can be reduced to 0, and the position of the wrong wiring harness can be accurately located.

4. Increase the detection function of connectors: the vehicle-mounted wiring harness on-off detector of the utility model can cover all detections including the detection of the contact of the connectors at both ends of the vehicle-mounted wiring harness. The plug-in can detect whether the contact of the vehicle-mounted wiring harness connector is good while checking the on-off.

5. Two detection methods are provided: fast detection is used to judge whether the wire harness wiring is correct during batch inspection; slow detection is used to find the wrong wire sequence of the wire harness identified as incorrect in the fast detection.

Description of drawings

Fig. 1 is a circuit block diagram of a vehicle-mounted wiring harness on-off detector;

Fig. 2 is the schematic diagram of decoder to voltage amplifying circuit;

Fig. 3 is the schematic diagram of voltage divider circuit, switch circuit and voltage acquisition circuit;

Fig. 4 is a software flow chart of detecting the vehicle wiring harness by the on-vehicle wiring harness on-off detector.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail.

1. Hardware implementation

Figure 1 is the circuit block diagram of the vehicle wiring harness on-off detector, as shown in the figure. The vehicle wiring harness on-off tester includes single-chip microcomputer, buzzer, decoder, voltage amplifier circuit, 20-way switch circuit, 20-way voltage divider circuit, 20-way voltage acquisition circuit, 20 light-emitting diodes (that is, indicator lights) and for control The single-chip microcomputer receives the button for inquiring the on-off command of the wiring harness.

The buzzer is connected to the single-chip computer; the signal output terminal of the single-chip computer is connected with the decoder; the signal output terminal of the decoder is connected with the input terminal of the voltage amplifying circuit. The switch circuit includes a triode Q3, a triode Q4, a light emitting diode D3 and a resistor R50; the output end of the voltage amplifying circuit is connected to the base of the triode Q3, and the output end of the voltage amplifying circuit is also passed through a voltage divider circuit (i.e. attached The resistor R136 in the figure) is connected to the base of the triode Q4; the collector of the triode Q3 is connected to the 12V power supply, and the emitter is connected to the matching connector I of the vehicle wiring harness terminal; the emitter of the triode Q4 is grounded, and the collector is connected to the The negative electrode of the light-emitting diode D3 is connected, the positive electrode of the light-emitting diode D3 is connected to the supporting connector II of the vehicle wiring harness terminal through the resistor R50, and the supporting connector II of the vehicle wiring harness terminal is also grounded through the resistor R49. The voltage acquisition circuit includes a resistor R51, a resistor R52, and a Zener diode D4; the positive pole of the Zener diode D4 is grounded, the negative pole is connected to the single-chip microcomputer, and the negative pole is also connected to the supporting connector II of the vehicle wiring harness terminal through the resistor R51, and the resistor R52 is connected in parallel. At both ends of the Zener diode D4, a capacitor C18 is connected in parallel with both ends of the Zener diode D4.

After the button is pressed, the single-chip microcomputer receives an instruction to inquire about the on-off of the wiring harness, and the single-chip microcomputer sends 20 digital signals in sequence. The following is an example of how one signal is detected through the view (the principle of detection for the other 19 signals is the same): as shown in Figure 2, the single-chip microcomputer selects the decoder at a certain moment, and commands the decoder Y0 to output a signal High-level signal, the signal becomes a 12VDC high-level signal after passing through the voltage amplifying circuit IC3, and is output by 1OUT of IC3. As shown in Figure 3, the 12VDC level signal output by 1OUT at this time can drive the transistor Q3 in the corresponding switch circuit; and the other branch of the 12VDC level signal output passes through the voltage divider circuit R136 to become a voltage signal less than 12VDC , the signal can drive the transistor Q4 in the corresponding switch circuit, that is, one signal can control the transistor Q3 and the transistor Q4 in the switch circuit to be turned on simultaneously. The vehicle wiring harness matching connector I is connected to the vehicle wiring harness to be tested, the other end of the vehicle wiring harness is connected to the vehicle wiring harness matching connector II, and the vehicle wiring harness matching connector II returns to the inside of the tester. At this time, if the transistor Q3 and the transistor Q4 are turned on, the power supply current will flow from the transistor Q3 through the vehicle wiring harness to the transistor Q4, forming a current path. The current path passes through the sampling resistor R51 and the resistor R52 in the voltage acquisition circuit, and a high level of 4.5V~5V is formed between the two resistors. The single-chip microcomputer collects the level TEST1, if the collected level is high, it means that the wire is correct and the connection is good. If the collected non-level is low, the single-chip microcomputer determines that the path does not form a path, and the connection of the wire is abnormal. If there is an abnormality, the buzzer will alarm when the measurement is completed. At the same time, after the above-mentioned path is formed, the current can flow through the light-emitting diode (indicator) D3, and the light-emitting diode D3 lights up, indicating that the wire of this line is correct and the connection is good.

The single chip microcomputer adopts Infineon XC886 controller as the signal output detection. Use the I/O port of the single-chip microcomputer to output the signal, and use another I/O port on the single-chip microcomputer as the level acquisition. The vehicle wiring harness on-off tester is based on the XC886 single-chip microcomputer as the core processor. Its design concept is to simulate the existing detection methods to detect the vehicle wiring harness, that is, to detect the two major problems of the vehicle wiring harness, such as missing connection and wrong connection. detection. Moreover, the use of electronic equipment for detection improves work efficiency and avoids errors. In addition, the vehicle-mounted wiring harness on-off detector is also specially designed to match the corresponding vehicle-mounted wiring harness terminal matching connectors. While detecting the wiring harness on-off, it checks the contactability of the vehicle-mounted wiring harness terminal matching connectors.

Decoder selection: Considering that simultaneous detection of 20 wire harnesses requires 40 I/O ports of the single-chip microcomputer, under normal circumstances, the single-chip microcomputer does not have 40 I/O ports (20 sending, 20 collecting). Then a decoder is introduced, as shown in Figure 2, the 20 outputs are listed in the form of a truth table and selected by the decoder. The utility model adopts 3 pieces of 74LS138 decoders (only 1 piece of decoder is listed in Figure 2) to do composite decoding, that is, only 6 I/O ports of single-chip microcomputer are used (3 I/O ports are used as 3 decoders) The chip selection signal of the coder, 3 I/O ports form the decoding selection) to realize the selection of the 20-way signal output. IC2 is 74LS138, 6-pin chip selection signal, 1, 2, 3 pins are decoding selection pins.

Voltage amplifying circuit: Since the decoder 74LS138 is a low-level active decoding selector (that is, the selected channel level is 0), and the level form is 0/5V, a voltage amplifying circuit is introduced (that is, in Figure 2 IC3, Darlington tube UN2003), which is used to change the 0/5V level from the decoder to 0/12V level and reverse the level at the same time. Each piece of UN2003 has 7 input/output channels, so this detector uses 3 pieces of UN2003 to realize the amplification and inversion of 20-way signals.

20-way voltage divider circuit and switch circuit: This tester contains 20-way voltage divider circuit and switch circuit. Attached Figure 3 only lists one of them, and the other 19 lines are the same. The switching circuit adopts two sets of switching triodes 8050 as the switching circuit. In the accompanying drawing 2, the 1OUT output of IC3 simultaneously drives the transistor Q3 and the transistor Q4 of the switch circuit. As shown in Figure 3, the 1OUT output of IC3 can directly drive the transistor Q3, but when driving the transistor Q4, the signal needs to be stepped down. The purpose of introducing a voltage divider circuit is to change the same driving signal into two signals with a voltage difference, so that the triode Q3 and the triode Q4 can be turned on at the same time. Its key feature is that the current-limiting resistor R136 is connected in series, and the current flows through the resistor to generate a voltage drop. According to the conduction principle of the transistor Q4, when the base voltage of the transistor Q4 is less than 12V, the transistor Q4 is turned on.

Voltage acquisition circuit: This tester contains 20 voltage acquisition circuits, of which only one is listed in Figure 3, and the other 19 circuits are the same. As shown in Figure 3, if the triode Q3 and the triode Q4 are turned on, and the vehicle wiring harness is turned on, the power supply voltage (12V) will reach the upper end of the resistor R51, and the voltage of TEST1 will be 4.8V ( 4.5~5V), TEST1 is directly collected by the I/O port input of the single-chip microcomputer, and it is judged as high level, then the single-chip microcomputer judges that the wire of this line is correct and the connection is good. On the contrary, if the triode Q3 and the triode Q4 are turned on, but the line bundle fails to conduct, then the voltage at the upper end of the resistor R51 is 0V, and the single-chip microcomputer collects a low level, then the single-chip microcomputer determines that there is a problem with this line.

Indicator light: The indicator light is part of the switch circuit, as shown in Figure 3. If the triode Q3 and the triode Q4 are turned on, and the vehicle-mounted wiring harness is turned on, the current will flow through the light-emitting diode (that is, the indicator light) D3, and the light-emitting diode D3 will light up. At this time, it shows that the wire connection of this road is correct and the contact is good; otherwise, there is no current in the light-emitting diode D3, and the light-emitting diode D3 is not bright. This indicates that there is a problem with the wire. The indicator light is for inspection personnel to see visually.

Key detection mode: According to the length of time the operator presses the key, it can enter into two modes of fast and slow detection respectively. ① If the time from pressing the key to popping up does not exceed 1s (inclusive), the tester will enter the quick test mode. The rapid detection is used in the batch inspection process. The inspector does not need to look at the light-emitting diode indication, but only needs to hear whether the buzzer alarms after the inspection is completed, and then it can be concluded whether the wiring harness is correct. ② If the time from pressing the key to popping up does not exceed 1s, the tester will enter the slow test mode. The slow test is used to analyze the incorrect wire harness. The slow test takes 1s to check the continuity of each wire, and the buzzer will alarm in real time (that is, when an incorrect wire connection is detected, the buzzer will alarm immediately). During this process, inspectors can refer to the corresponding indicator light of each channel and hear the buzzer alarm to judge the specific location of the fault in the incorrect wiring harness, so as to avoid blind detection.

2. Software implementation

Figure 4 is a software flow chart of the on-vehicle wiring harness on-off detector to detect the vehicle wiring harness, as shown in the figure. Software function: The software mainly includes the following modules - program initialization module, button press detection module, timer module, fast inspection module, slow inspection module, buzzer alarm module and delay module.

The software is divided into two detection modes by detecting the length of time the button is pressed.

Key time <= 1s, using fast detection mode. Features of this mode: the power-on detection time of each wire harness is 100ms, and all wire harnesses are detected in 2s. After the detection is completed, if any wires are connected incorrectly, the buzzer will alarm. This mode is mainly used for batch detection of the continuity of the wire harness. The inspector only needs to hear whether the buzzer is alarming to determine whether the wire is qualified.

Press the button for >1s, using the slow detection mode. Features of this mode: The power-on detection time of each wire harness is 1s. This mode is mainly used to locate the wrong wire.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present utility model without limitation. Although the utility model has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the utility model can be Modifications or equivalent replacements of the technical solutions without departing from the purpose and scope of the technical solutions of the utility model shall be covered by the claims of the utility model.

Claims (2)

1. A vehicle-mounted wiring harness on-off tester is characterized in that: comprise single-chip microcomputer, buzzer, decoder, voltage amplifying circuit, voltage divider circuit, switch circuit and voltage acquisition circuit; Buzzer is connected on the single-chip microcomputer; Single-chip microcomputer The signal output end of the decoder is connected with the decoder; the signal output end of the decoder is connected with the input end of the voltage amplifying circuit; The switch circuit includes a triode Q3, a triode Q4, a light-emitting diode D3 and a resistor R50; the output end of the voltage amplifying circuit is connected to the base of the triode Q3, and the output end of the voltage amplifying circuit is also connected to the triode Q4 through a voltage dividing circuit. The base of the triode Q3 is connected to the 12V power supply, and the emitter is connected to the supporting connector I of the vehicle wiring harness terminal; the emitter of the triode Q4 is grounded, and the collector is connected to the negative pole of the light-emitting diode D3. The anode of the light-emitting diode D3 is connected to the matching connector II of the vehicle wiring harness terminal through the resistor R50; The voltage acquisition circuit includes a resistor R51, a resistor R52, and a Zener diode D4; the positive pole of the Zener diode D4 is grounded, the negative pole is connected to the single-chip microcomputer, and the negative pole is also connected to the supporting connector II of the vehicle wiring harness terminal through the resistor R51, and the resistor R52 is connected in parallel. across Zener diode D4. the 2 . The vehicle-mounted wire harness on-off tester according to claim 1 , further comprising a key for controlling the single-chip microcomputer to receive and inquire about the wiring harness on-off command, and the key is connected to the single-chip microcomputer.

Images