JPS644680B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is particularly useful for parts insertion machines and the like, especially for electronic parts with various lead shapes and numbers (for example, electronic parts with different lead shapes for each part, so-called irregularly shaped parts). ) is related to a lead center position detection method for detecting the lead center position.

First, the conventional method will be explained according to the drawings.

FIG. 1 is a system configuration diagram of an example of a conventional lead position detection method, and FIG. 2 is a detection waveform diagram thereof.

First, the lead L moving in the direction of the arrow is connected to the projector 1.
When the irradiation beam light from the light receiver 2 is blocked, the output of the light receiver 2 becomes zero. The position of the lead L at this time can be read by the encoder 5 which is synchronized with its movement.

The output current I of the photoreceiver 2 is transmitted through the current-voltage conversion circuit 3.
The output voltage V is converted into a voltage as shown in Figure 2 A.
is obtained. This output voltage V and the threshold voltage V _TH are compared in the comparator circuit 4, and the output voltage V is the threshold voltage.
Only during the period when V _TH is exceeded, the position detection pulse P as shown in FIG. 2A is outputted from the comparator circuit 4.

This pulse P is applied to the clock terminal CK of register 7.
By inputting , the read position detection output can be obtained from the register 7 which stores the count contents of the counter 6 which counts the output of the encoder 5 indicating the read position at that time.

However, as shown in Figure 2A, in this conventional method, for components with a relatively large lead width, the position detection pulse P does not match the lead width even if there is a delay due to the rise and fall portions of the output voltage V. Although it is detected with a slight deviation from the corresponding waveform change width W, as shown in Figure 2B, for components with small lead widths, the output voltage V is the threshold voltage.
Since V _TH is not reached, there is a risk that detection will not be possible, and it could not be used to detect the lead position when the lead width changes. This is because even if the lead width changes, the threshold voltage V _TH cannot be changed correspondingly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lead center position detection method that eliminates the above-mentioned drawbacks of the prior art and is capable of accurately detecting the center position of leads of various widths.

The structure of the lead center position detection method according to the present invention is such that the irradiation beam light is blocked by a lead moving in a predetermined direction at a predetermined speed, and after converting the amount of beam light into a corresponding voltage, the lead is The threshold voltage specified and generated according to the width is compared with the converted voltage above to generate a lead width pulse corresponding to the lead width, and its leading and trailing edges are synchronized with the movement of the lead. Each count data of the encoder output is obtained, and the average value thereof is outputted as the lead center position data.

In short, by specifying the threshold voltage for position detection pulse generation in advance according to the lead width, the position detection pulse can be reliably generated, and by detecting each edge before and after it, the intermediate point can be detected. The aim is to detect this as the lead center position.

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is a system configuration diagram of an embodiment of the lead center position detection method according to the present invention, FIG. 4 is a detection waveform diagram thereof, and FIG. 5 is a flowchart thereof.

Here, 1 is a light projector, 2 is a light receiver, and 3 is
4 is a comparison circuit; 5 is an encoder; 6 is a counter; 7A and 7B are registers; 8 is a DA conversion circuit for specifying a threshold voltage; 9
A, 9B are edge detection circuits for leading edge and trailing edge, 1
0 is an average value circuit. Note that among these symbols, the same ones as those in FIG. 1 are equivalent.

First, the lead L moves in the direction of the arrow at a predetermined speed.
When the irradiation beam light from the light projector 1 is blocked, the output current I of the light receiver 2 becomes 0, indicating that the lead has passed. This output current I is input to the current-voltage conversion circuit 3, and a voltage V corresponding to the amount of the received beam light is inputted to the current-voltage conversion circuit 3.
(Steps 11 and 12 in FIG. 5).

On the other hand, since a threshold designation signal is externally input to the DA conversion circuit 8 in the form of a digital signal, this is subjected to DA conversion in the same circuit and outputted as a threshold voltage _VTH (steps 13 and 14).

Furthermore, the encoder 5 outputs a pulse with a frequency proportional to the moving speed of the lead L (step 15), and by integrating this pulse with the counter 6 (step 16), the position of the lead L can be determined. You can ask for it.

Next, the output voltage V converted by the current-voltage conversion circuit 3 is compared with the threshold voltage V _TH in the comparison circuit 4, and a lead width pulse P corresponding to the width of the lead L passing through the irradiation beam light is generated. (referred to as a position detection pulse in the conventional example) is output (step 17). As shown in FIG. 4, this pulse P is output for a portion of the output voltage V that is lower than the threshold voltage _VTH . That is, the pulse width of this lead width pulse P represents the width of the lead L. The threshold voltage V _TH that determines the pulse width of the lead width pulse P can be arbitrarily set to a desired value from the outside, so even if the width of the lead L is narrow, the threshold voltage V _TH that determines the pulse width of the lead width pulse P can be adjusted to match the output voltage V. can be supplied.

Next, the edge detection circuits 9A and 9B detect the leading edge and trailing edge of the pulse P corresponding to both ends of the lead L by inputting the lead width pulse P, and output the respective detection pulses F and R ( Same step 18).

The positions of the leading edge and trailing edge detection pulses F and R are determined from the output of the counter 6. That is, the register 7A indicates the position of the lead L when the leading edge detection pulse F is inputted by the cumulative number of outputs from the encoder 5, and therefore outputs the value of the counter 6 at that time as the leading edge position data A. Regarding the trailing edge, trailing edge position data B is similarly outputted from the register 7B (step 19).

Finally, the center position data of the lead L is the average value (A+
B)/2 is calculated by the average value circuit 10 (step 20).

In this way, since the center position of the lead is determined after detecting both edges of the lead, accurate position detection can be performed even for leads of different widths. Also,
By changing the threshold value to a predetermined value according to the lead width, position detection becomes possible even for narrow leads, which was impossible with the conventional method, and performance can be improved.

As described above in detail, according to the present invention, the center position of leads of various widths can be detected accurately and reliably, thereby improving the reliability and efficiency of processes such as component insertion. , a remarkable effect on economicization can be obtained.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram of an example of a conventional lead position detection method, FIG. 2 is a detection waveform diagram thereof, and FIG. 3 is a lead center position detection method according to the present invention.
The figure is a detected waveform diagram, and FIG. 5 is a flowchart of the same. 1... Emitter, 2... Light receiver, 3... Current-voltage conversion circuit, 4... Comparison circuit, 5... Encoder,
6...Counter, 7A, 7B...Register, 8...
...DA conversion circuit, 9A, 9B...edge detection circuit, 10...average value circuit.

Claims (1)

[Claims] 1 The irradiation beam light is blocked by a lead moving at a predetermined speed in a predetermined direction, and after converting the amount of beam light into a corresponding voltage, the threshold voltage specified and generated in advance according to the width of the lead and the above A lead width pulse corresponding to the lead width is generated by comparing the converted voltage, and each count data of the encoder output that is synchronized with the movement of the lead is obtained for the leading and trailing edges, and the average is calculated. A lead center position detection method that outputs the value as the lead center position data.