JPH0468579B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an inspection device for an automobile that inspects devices such as electrical components mounted on an automobile and their systems, and particularly relates to an oscilloscope and its operation. The present invention relates to an automobile inspection device equipped with an oscilloscope operation support device to facilitate inspection.

[Conventional technology]

In recent years, the use of car electronics in automobiles has been remarkable, and electronic fuel injection control systems are one example. When inspecting and maintaining this control system, for example, crank angle sensor signals, ignition control signals, fuel, injector drive signals, etc. have pulse waveforms, and conventionally it was possible to inspect them using an ECCS checker. Many modern cars do not have checker terminals, and as a result, it has become necessary to use an oscilloscope to check the electrical system. This is because inspection using an oscilloscope has the advantage of being able to measure all input and output signals and extending the detection range compared to conventional checkers.

[Problem that the invention seeks to solve]

However, it is difficult for maintenance personnel to master the oscilloscope in a short period of time, especially when setting the oscilloscope's vertical axis setting knob to an optimal value that does not overscale, or when the measurement target changes one after another. There have been problems such as operations such as changing the setting of the optimum vertical axis value are time consuming and inefficient, and mistakes can occur in setting the vertical axis value, making it impossible to perform proper inspection.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to provide an automobile inspection device equipped with an oscilloscope operation support device that allows easy operation of an oscilloscope.

[Means for solving problems]

To achieve the above object, the present invention includes an oscilloscope and an oscilloscope operation support device connected to the oscilloscope, and receives measurement signals such as an ignition system output signal, a fuel injection system output signal, or a charging system output signal from on-vehicle equipment. The present invention is intended for an automobile inspection device that inspects in-vehicle equipment by inputting data to the oscilloscope and the oscilloscope operation support device, respectively.

The oscilloscope operation support device includes the following means. That is, a signal attenuation means having, for example, a group of resistors and a group of switches, whose attenuation ratio can be changed over multiple stages by inputting the measurement signal, and a measurement signal outputted at a predetermined level by the signal attenuation means. signal holding means, such as a peak value hold circuit or (as well as) an average value hold circuit, which holds the value of the signal holding means, a quantity conversion means which converts the held signal of the signal holding means into a quantity, and an initial setting of the signal holding means. and selects the attenuation ratio of the signal attenuation means, controls the signal holding means to hold a predetermined level value, reads the converted value of the held signal through the quantity conversion means, and calculates the converted value from this and the signal attenuation ratio. data processing means for calculating the measured signal value and comparing it with a pre-stored setting value of the vertical axis setting knob of the oscilloscope to obtain a setting value at which the ratio of the two is within a predetermined range; and display means for displaying the set value of the knob on the display section.

[Effect]

The oscilloscope operation support device detects the peak value or average value of the input signal, and automatically calculates and selects the optimum vertical axis setting value of the oscilloscope that does not overscale based on the detected value.
By displaying this vertical axis optimal value,
Since the user only has to operate the vertical axis setting knob of the oscilloscope according to this display, it is easy to set and change the vertical axis knob, thereby shortening the operation time and reducing operational errors.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 is a front view of the inspection device according to the embodiment, Fig. 2 is an enlarged plan view of the vertical setting knob in the inspection device, Fig. 3 is an internal wiring diagram of the oscilloscope operation support device, and Fig. 4 is the oscilloscope operation. It is a flowchart for explaining the operation of the support device.

First, the entire automobile inspection device will be explained with reference to FIG. In the figure, 10 is a known oscilloscope that can use two channels, and 21 is a signal measurement probe. 20 is an oscilloscope operation support device, which has a channel 1 display section 30 on the front;
A channel 2 display section 40 is provided separately.

The channel 1 display section 30 has a display mode changeover switch 31 for selecting display of a signal peak value or average value, a vertical axis setting value display 32 of the oscilloscope 10, and a V or mV changeover display section 33. are doing. Channel 2 display section 40
Similarly, the display mode changeover switch 41 and the vertical axis setting value display 42 of the oscilloscope 10
and a V or mV switching display section 43.

The probe 21 is connected to the oscilloscope 10 and the oscilloscope operation support device 20 so that measurement signals can be supplied to each. The oscilloscope 10 includes a display section 11, an initial setting section 12,
It has a trigger control section 13, a time axis setting section 14, vertical axis setting knobs 15 and 16, and the like. An example of the vertical axis setting knobs 15, 16 is shown in FIG. In this example, the vertical axis setting knobs 15 and 16 are
It can be set in the range from 5mV to 5V per minimum scale on the display screen.

FIG. 3 is an internal wiring diagram of the oscilloscope operation support device 20. As described above, one side is connected to the resistor group 51 of the oscilloscope operation support device 20 and the other side is connected to the input section of the oscilloscope 10 so that the measurement signal from the probe 21 can be inputted.

A resistor group 51 in which a plurality of resistors having different electrical resistance values are connected in parallel is connected in series with a switch group 52, and the voltage is divided through a resistor 53. 54 is an operational amplifier, and its output is connected to diode 5 on one side.
5, to a peak value hold circuit 64 consisting of a capacitor 56 and a switch 57, and the other to a resistor 5.
8 and a capacitor 59, respectively.

60, 62 are comparators, 61 is a digital/
The analog (D/A) converter 63 is a microcomputer. The comparator 60 uses the output of the peak value hold circuit 64 as one input, the other input as the output of the D/A converter 61, and inputs the output to the microcomputer 63. The comparator 62 uses the output of the average value holding circuit 65 as one input, the other input as the output of the A/D converter 61, and inputs the output to the microcomputer 63. The operation of selecting one switch from the switch group 52 and the on/off operations of the selected switch and switch 57 are controlled by a microcomputer 63. D/A
The converter 61 is for converting a digital signal from the microcomputer 63 into an analog signal. The vertical axis optimum setting value calculated and processed by the microcomputer 63 is displayed on the display 32 . The switch 31 is the aforementioned display mode changeover switch, and the display mode (peak value display mode or average value display mode) signal selected by this switch 31 is input to the microcomputer 63.

The operation of the automobile inspection device having the above configuration will be explained.

The procedure for using the oscilloscope 10 is to turn on the power, and then cause the initial setting section 12 to display bright lines for each channel on the display surface 11.
Next, set the trigger control unit 13 appropriately, apply the measurement probe 21 to a device to be measured on the vehicle, such as an ignition system, fuel injection device, or charging device, and measure the time axis setting knob 14 and the vertical axis setting knobs 15 and 16. It is common to set and measure each point.

Here, among the setting knobs 14, 15, or 16 that the operator may have to change the setting every time the measurement point is changed, the vertical axis setting value is not appropriate especially for the vertical axis setting knobs 15 and 16. The waveform may not be displayed on the display surface 11, or even if it is displayed, the waveform may be too large or too small, making the display unsuitable for inspection.

Therefore, in order to display an appropriate vertical axis setting value to the operator at all times, the present invention provides an oscilloscope operation support device 20 when the probe 21 is placed on a measurement point.
Appropriate vertical axis setting values are displayed on the displays 32 and 42, respectively.

Oscilloscope operation support device 2 shown in Figure 3
The operation of 0 will be explained in conjunction with FIG.

When the probe 21 shown in FIG. 3 is connected to a signal source (for example, an ignition device, a fuel injection device, a charging device, etc.) and the power is turned on, the microcomputer 63 in the oscilloscope operation support device 20 operates as shown in FIG. A sequence control operation is performed.

In other words, when you start, the step (hereinafter, S
It is abbreviated as ) 1, the display mode changeover switch 31 of the channel 1 display section 30 or the display mode changeover switch 4 of the channel 2 display section 40
1 switch state, that is, peak value display mode or average value display mode, a signal indicating the mode setting contents is taken into the microphone computer 63 and stored in a predetermined RAM address.

Next, in S2, one switch is selected from the switch group 52 so that the measurement signal from the probe 21 is attenuated to the maximum value determined by the resistor group 51 and the resistor 53.
Select one switch and turn it on. In S3,
It is determined whether the mode setting by the aforementioned mode changeover switch 31 or 41 is the peak value display mode or the average value display mode, and if it is the former, then in S4,
If it is the latter, proceed to the first stage of S5.

Next, switch 5 of the peak value hold circuit 64
By temporarily closing capacitor 56
is discharged (S4), N=0 in S5, and then waits for a certain period of time (time for capacitor 56 to complete charging even when the input value is at its maximum) in S6, and D/A converter 6
1, first output from N=0 (S7). Then, the mode setting is determined in S8, and if the determination result is the peak value display mode, the process proceeds to the next S9,
If it is the average value display mode, the process advances to S10, where it is determined whether or not there is an output to the comparator 62. If it is determined that there is an output, the process advances to the previous stage of S11.

The output of the D/A converter 61 is an analog value,
This output and the output of the capacitor 56 are compared by the comparator 60 (S9), and if the output of the D/A converter 61 equal to the potential at the end of the capacitor 56 is given, the comparator 60 outputs a match signal and goes to the next step S11. move on. If a match signal is not output, input a value from 0 to N+1→N to the D/A converter 61 (S10), update it until a match output is obtained from the comparator 60, and obtain the digital conversion value N when there is a match. . Here, as an example, when the maximum value that can be input to the D/A converter 61 is Nmax, 80%Nmax>
30%...N is valid if it satisfies [Equation (1) (S11)], and the absolute value of the peak voltage of the input signal is calculated from this and the attenuation ratio (SS12).

On the other hand, if the above formula (1) is not satisfied, select the switch of the circuit whose resistance attenuation ratio is one step lower than the previous one from the switch group 51 and turn it on (S13), and repeat from S3 to S11. This series of operations is repeated until the above equation (1) is satisfied.

Next, in S12, after calculating the absolute value of the peak voltage of the input signal, this voltage value is
Voltage value per division on the vertical axis at 0 (Vr)
(S14). On the other hand, the pre-memorized vertical axis setting value (Vm) of the oscilloscope 10 that can be set is loaded in S15, compared with the aforementioned converted voltage value Vr, and starting from the minimum value (or maximum value) of Vm. 90%＞Vm／Vr＞50%……[(2)
(S16)], and if the minimum value does not satisfy the above formula (2), update the Vm value (S17), repeat until formula (2) is satisfied, and (2) The Vm value when the formula is satisfied is displayed on the vertical axis set value display 32 or 42 (S18).

The operator only has to set the vertical axis setting knob 15 according to the display 32 or 42.

Furthermore, even if the item to be measured changes, by performing the series of operations described above, the optimal vertical axis setting value of the oscilloscope is automatically calculated and displayed.

〔Effect of the invention〕

Since the present invention is configured as described above,
The vertical axis setting value of the oscilloscope can be appropriately and easily set, which makes it extremely easy to use the oscilloscope, reduces setting time, and provides a highly reliable automobile inspection device.

[Brief explanation of the drawing]

Fig. 1 is a front view of an inspection device according to an embodiment of the present invention, Fig. 2 is an enlarged plan view of a vertical setting knob in the inspection device, Fig. 3 is an internal wiring diagram of an oscilloscope operation support device, and Fig. 4 is a flowchart of the oscilloscope operation support device. 10... Oscilloscope, 15, 16... Vertical axis setting knob, 20... Oscilloscope operation support device, 21... Probe, 30... Channel 1
Display section, 31...Display mode changeover switch, 32
... Vertical axis setting display, 33 ... Switching display section, 40 ... Channel 2 display section, 41 ... Display mode changeover switch, 42 ... Vertical axis setting display, 43 ... Switching display section, 51 ... Resistance group, 52... switch group, 63... microcomputer, 64... peak hold circuit, 65
...Average value hold circuit.

Claims (1)

[Claims] 1. An automobile inspection system comprising an oscilloscope and an oscilloscope operation support device connected to the oscilloscope, and inspecting the on-vehicle device by inputting measurement signals from the in-vehicle equipment to the oscilloscope and the oscilloscope operation support device, respectively. In the apparatus, the oscilloscope operation support device includes a signal attenuation unit that can input the measurement signal and change the attenuation ratio over multiple stages, and a signal attenuation unit that can input the measurement signal and change the attenuation ratio over multiple stages, and a signal attenuation unit that outputs the measurement signal at a predetermined level by the signal attenuation unit. a signal holding means for holding a value; a quantity converting means for quantifying and converting the signal held by the signal holding means; and initial setting of the signal holding means and selection of an attenuation ratio of the signal attenuation means, and the signal holding means control to hold a predetermined level value, read the converted value of the held signal through the above-mentioned quantity conversion means, calculate a measured signal value from this and the above-mentioned signal attenuation ratio, and calculate the measured signal value from this and the above-mentioned oscilloscope stored in advance. The data processing means compares the setting value of the vertical axis setting knob to obtain a setting value at which the ratio of the two falls within a predetermined range, and the display means displays the knob setting value obtained by the data processing means on a display unit. An automobile inspection device characterized by: 2. An inspection device for an automobile according to claim 1, wherein the signal holding means comprises a peak value holding circuit. 3. The automobile inspection device according to claim 1, wherein the signal holding means comprises an average value holding circuit.