JPS598163Y2 - Edge position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an edge position detection device, and can be applied, for example, to optically measuring the width of a strip in a rolling mill.

As a method for measuring the strip width of a rolling mill using an optical position detector disposed at an edge position, there is a method having a structure as shown in FIG.

In FIG. 1, reference numeral 1 denotes a measuring optical sensor consisting of a photomultiplier tube arranged, for example, on the axis of a slit drum 2 having eight slits 2A. 4, and the light from the light source 4 passes through the lens 5 and further enters the optical sensor 1 via the slit 2A of the slit drum 2.

In addition, a reference light sensor 6 is provided inside the slit drum 2, and a reference light source 7 is provided outside the drum 2, facing the reference light sensor 6.

When the slit drum 2 rotates in the direction of the arrow 8 in the configuration shown in FIG. 1, the slit 2A first comes to the position of the reference light source 7, so that a detection output is obtained at the reference light sensor 6.

This reference light detection output is output from the preamplifier 1 as shown in FIG.
1. It is applied to the waveform shaping circuit 13 via the main amplifier 12, and for example, its falling edge triggers the monostable multi-bi break 14, thus monostable multi-bi break 1.
At the output end of 4, a reference detection pulse P1 synchronized with the rotation of the slit drum 2 is obtained as shown in FIG. 3B.

In this way, when each slit 2A of the slit drum 2 passes through the reference optical sensor 6 position and reaches the measuring optical sensor 1 position,
First, the light from the light source 4 in the area where the plate 3 does not exist passes through the slit 2A and enters the measurement optical sensor 1, and then the slit 2A enters the area where the plate 3 exists, so that the light is transmitted to the measurement optical sensor 1. is no longer incident.

In this way, a detection output S1 corresponding to the amount of incident light is obtained from the measurement optical sensor 1, and this detection output S1 is sent to the waveform shaping circuit 17 via the preamplifier 15 and the main amplifier 16.
As shown in FIG.
It is possible to obtain a photodetection output S1 which rises at time t1 when the slit 2A enters the field of view of the measurement optical sensor 1, and then falls at time t2 when the slit 2A passes the edge position of the plate 3.

This photodetection output Se is given to the width signal circuit 18, and the rising width Wl (=
tl to t2) as a logic 1 width signal S2.

This width signal S2 triggers the monostable multivibrator 19 when it falls, thereby obtaining an edge detection pulse train P2 generated in response to the fall of the photodetection output S1 as shown in FIG. 3D.

However, each pulse of the edge detection pulse train P2 is given as a set input to the edge signal output flip-flop circuit 20, and each pulse of the reference detection pulse train P1 is given as a reset input.

As a result, after the slit 2A passes the position of the reference optical sensor 6, it is possible to obtain the edge signal S3 (FIG. 3E) that falls to logic 0 until the slit 2A passes the edge position of the plate material 3.

Therefore, if the width of the plate material 3 changes and the edge position changes, the logical 0 section of the edge signal S3 changes accordingly, resulting in the width W to the edge.

can be determined. By the way, according to such a structure, in the light path (for example, the lens 5, the slit drum 2),
When water, steam, dirt, dust, etc. adhere, light refraction or scattering occurs, and Figure 4A corresponds to Figures 3A-E.
-E, if a disturbance such as a decrease in the detection output of this spectral sensor 1 is mixed in, and the degree of decrease is large, it will be mistakenly recognized that the detection output has fallen to the L level, and this will cause the detection plate width WOX
There is a risk of an error.

? The present invention is intended to propose an edge position detection device that can obtain an output from which the influence of disturbance mixed in such a photodetection output is removed.

An example of the present invention will be described below in detail with reference to the drawings.As shown in FIG. (FIG. 6A) is applied to the monostable multivibrator 25, and a trigger pulse for the timer 26 is obtained by the rising edge of the signal.

At this time, the timer 26 inverts the logic O gate output in the inverter 27 and applies it to the three-man NAND gate 28 during the time limit operation time.

Also, the output S1 of the waveform shaping circuit 17 is this NAND gate 2.
8 as a gate signal, and is configured to open the NAND gate 28 during the rising edge W1 of the output S1.

Here, the gate level of the NAND gate 28 is the detection output S1
is set to a level lower than the falling level of the defective part X,
As a result, even if there is a defective portion X, the NAND gate 28 is opened without being affected by the defective portion X.

Thus, the NAND gate 28 is opened from the time t1 when the time limit τ of the timer 26 has elapsed to the time t2 when the output S1 of the waveform shaping circuit 17 falls, and inputs the clock pulse CP to the first counter 29.

On the other hand, the counter 29 is supplied with a load signal LD1 generated at the rising edge of the output S1 by the load signal circuit 30 receiving the output S1 of the waveform shaping circuit 17, and is quantized.
As a result, as shown in FIG. 6D, a number of clock pulses corresponding to the time width between time points tll and t2 are counted by the falling edge of the clock pulses.

The output S1 of the waveform shaping circuit 17 is a two-person AND gate 33.
is given as a gate signal to the output S1, and the rise time t of the output S1
The clock pulse CP that arrives between 1 and t2 is input to the second counter 34 as a down count input.

However, the counter 34 receives the load signal LD generated by the load signal circuit 30 at the falling time t2 of the output S1.
2 is given, and at this time, the counter 2 is given as shown in FIG. 6E.
The count contents of 9 are preset in the counter 34.

Thus, as shown in FIG. 6A, in the waveform shaping circuit 17, when the photodetection pulse outputs S1 arrive one after another, while one photodetection pulse output S1 arrives (particularly from time tll to
t2), the first counter 29 performs a counting operation, and the count contents are calculated based on the light detected? At the falling edge of Lus S1, the second
(at time t2), and then when the next photodetection pulse S1 arrives (at time t3),
At the same time as the first counter 29 performs a counting operation, the second counter 34 counts down.

When the content of the second counter 34 decreases beyond 0, a borrow signal (carry down signal) BOR is generated (FIG. 6F),
This borrow signal BOR is applied to the edge signal output circuit 35.

The edge signal output circuit 35 includes an edge signal output flip-flop circuit 36 and a control flip-flop circuit 37.
The output flip-flop circuit 36 is set by the rising edge of the output pulse P1 (FIG. 6B) of the waveform shaping circuit 13 on the side of the reference optical sensor 6, and for example, as shown in FIG. 6J from the Q output terminal. A width signal S1 rising to 1 is sent out.

The control flip-flop circuit 37 is connected to the second counter 34.
is set by the borrow signal BOR of the waveform shaping circuit 13, and reset by the fall of the output pulse P1 of the waveform shaping circuit 13,
Thus, a condition signal S1 as shown in FIG. 6G is input from the Q output terminal to the two-person canand circuit 38 as its first condition signal.

This NAND circuit 38 has a second condition signal as its second condition signal.
The output S13 (FIG. 6C) of a width signal circuit 39 having the same structure as the edge signal circuit 18 shown in the figure is applied, and the output terminal shown in FIG.
A NAND output S14 as shown in is obtained.

This NAND output S14 drives the monostable multivibrator 40 with its falling edge to obtain a control pulse Sl5 as shown in FIG. 6I, and this control pulse B15 is applied to the reset terminal of the output flip-flop circuit 36.

In the above structure, based on the output of one measurement photodetector 1, at time t1 in FIG. (FIG. 6A) Once this is obtained, the timer 26 starts a time-limited operation, and the first counter 29 starts counting from the time tl+ when the time limit τ has elapsed (FIG. 6D).

The counting operation of the first counter 29 continues as long as the photodetector 1 is sending out the detection output, and when the waveform shaping output S1 eventually falls at time t2, the gate 28 closes and the counting operation of the first counter 29 starts. stops, and
The count contents are loaded into the second counter 34 (FIG. 6D and E).

This state remains until the next waveform shaping output S1 arrives? When the waveform shaping output S1 rises at time t3, the gate 33 opens and the second counter 34 starts counting down (FIG. 6E).

Eventually, at time t3, the content of the second counter 34 becomes 0.
When the value exceeds the value, the borrow signal BOR is sent (Fig. 6F).
, the control flip-flop 37 is set by this borrow signal BOR (FIG. 6G).

Therefore, the output of the NAND circuit 38 is generated (FIG. 6H), and when this NAND output falls at time t4, the output flip-flop circuit 36 receives the reset pulse S1. (6th
1) (FIG. 6J).

On the other hand, since the output flip-flop circuit 36 is previously set by the output of the reference optical sensor 6 at time P1 (FIG. 6J), the falling part of the output Sll of the output flip-flop circuit 36 ends up being the edge. It is sent out as an edge signal representing the position.

Here, the falling edge signal Sll is obtained by the output P1 of the reference optical sensor 6 in synchronization with the rotation of the slit drum 2, whereas the rising edge signal So is obtained from the measuring optical sensor 1.
This occurs at a time corresponding to the edge position of the plate material 3 due to the output of .

According to the configuration shown in FIG. 5, when determining the edge position, a relatively narrow signal portion of the photodetection signal close to the edge (in other words, the count value of the counter 29 by the timer 26) is used. By using only the reference position and not using other signal parts between the relevant edge signal parts, even if disturbances such as water, steam, dirt, dust, etc. occur in other signal parts, the influence of the disturbances will be minimized. It is possible to detect the edge without being affected, and the measurement accuracy can be improved accordingly.

FIG. 7 shows another embodiment of the present invention, in which a timer 51 and a monostable multivibrator 52 are connected to the output end of the monostable multivibrator 40 provided on the output side of the control flip-flop circuit 37 in FIG. A timer 53 and an inverter 54 are connected to the output side of the waveform shaping circuit 13 provided on the output side of the reference optical sensor 6.
A series circuit is provided, and the output of this series circuit is given to the two-man NAND gate 55 as an open control signal.

This NAND gate 55 is inserted in the path of the Q output of the output flip-flop circuit 36, and the edge signal S20 is sent out through this gate 55. There is.

In the structure of Fig. 7, the structure shown in Fig. 8 corresponds to Fig. 6 A-J.
As shown in Figures A-J, when an output pulse S15 is obtained at the output end of the monostable multivibrator 40 in the same way as in the case of Figure 5, the timer 51 is driven by the rising edge of the output pulse S15.
(K) in FIG. 8, an output pulse S16 is obtained at the output end of the monostable multivibrator 52 after a time limit τ2 (L in FIG. 8).
).

By resetting the output flip-flop circuit 36 with this output pulse S16, a rectangular wave output S1 as shown in FIG. 8J can be obtained from the control flip-flop circuit 36.

On the other hand, the timer 35 is triggered by the output pulse P1 of the waveform shaping circuit 13, and a gate signal S17 that falls for 2 times is obtained at the output end of the inverter 54 (FIG. 8M), and thus the NAND gate 55 An edge signal S20 as shown in FIG. N is sent out.

Even in this case, the edge signal can be reliably obtained as in the case of FIG.

As described above, according to the present invention, even if the output of the optical sensor 1 is mixed with a notch-like disturbance, the edge signal that reliably corresponds to the edge position of the plate material 3 to be measured can be obtained without being affected by the disturbance. can be obtained.

Note that in the above example, the borrow signal B is processed by two timers.
Although OR is obtained, an up/down counter may be used instead.

In addition, in the above, the output flip-flop circuit 3
6's Q output was obtained as the edge position signal, but instead of this, Q
The output may be obtained as an edge position signal.

[Brief explanation of drawings]

1 and 2 are optical system diagrams and block diagrams showing conventional edge position detection devices, and FIGS. 3A-E and 4A-
E is a signal waveform diagram for explaining its operation, FIG. 5 is a block diagram showing an example of the edge position detection device according to the present invention, FIGS. 6A-J are signal waveform diagrams for explaining its operation, 7
The figure is a block diagram showing another example of the present invention, and FIGS. 8A to 8N are signal waveform diagrams for explaining its operation. 1... Measuring optical sensor, 2... Slit drum, 3... Plate material, 4... Light source, 6
・・・・・・Reference light sensor, 11, 12, 15.16・
...Amplifier, 13.17...Waveform shaping circuit, 14,19,25.40...Multivibrator, output flip-flop circuit, 26...
...Timer, 27.54...Inverter, 2
9.34...Counter, 30...Load signal circuit, 35...Edge signal output circuit, 36
...Output flip-flop circuit, 37...
...Control flip-flop circuit, 39...
Width signal circuit.

Claims (2)

[Scope of utility model registration request] (1) A measurement light detection output is generated by applying the measurement light coming from the plate material to be measured to the measurement light sensor through the slit of the slit drum, and a reference pulse synchronized with the rotation of the slit drum is generated by the reference light sensor. In the edge position detection device, the edge position of the plate to be measured is determined based on the period from when the reference pulse is generated until the measurement light detection output is no longer obtained. After the measurement light detection output is generated, a first timer is triggered by the leading edge of the measurement light detection output, and the output of the first timer starts counting up after the time limit elapses. ,
Counting means that then stops counting at the trailing edge of the measurement detection output, starts counting down at the leading edge of the next measurement light detection output that arrives thereafter, and generates a borrow signal when the count exceeds 0; a control flip-flop circuit that is set by the borrow signal to generate a first condition signal; and a control flip-flop circuit that is set (or reset) by the reference pulse and generates a first condition signal after the measurement detection output. 1. An edge position detection device comprising: an output flip-flop circuit that is reset (or set) at the edge, and the edge position is determined by the output of the output flip-flop circuit. (2) a first timer provided at the output end of the control flip-flop circuit to delay the generation of the first condition signal; and a first timer provided at the output end of the output flip-flop circuit to delay the generation of the output. An edge position detecting device according to claim 1, further comprising a second timer for detecting a second timer.