JPS5814155B2 - Milmo-tano-sokudo-setsutei-souchi - Google Patents

Description

[Detailed Description of the Invention] The present invention is a control circuit for a mill drive motor in a steel rolling plant, in which all motor speed settings are made stationary so that high-speed, stable, and inexpensive speed settings can be performed. This invention relates to a speed setting device for a mill motor.

FIG. 1 shows a conventional speed setting device, in which a voltage-to-frequency converter (hereinafter referred to as V/F converter) 1 generates a frequency proportional to an input voltage Vi, and when a control human power F is applied, The pulse motor 3 is controlled by this setting device, and a signal for accelerating the rotational speed of the pulse motor 3 is outputted from the motor drive circuit 2 to the pulse motor 3.

Further, when the control input R is applied to the V/P converter 1, a signal for decelerating the rotational speed of the pulse smoke 3 is outputted to the motor drive circuit 2.

This motor drive circuit 2 receives the acceleration or deceleration signal and drives the pulse motor 3 with a pulse output.

The rotational motion of the pulse motor 3 is transmitted to the slider of the potentiometer 6 via the reduction gear 4 and the slip mechanism 5, and a voltage VR applied to the potentiometer 6 corresponds to the position at point b of the slider. voltage can be obtained.

Furthermore, when the control input S is applied to the V/F converter 1, the pulses generated in the V/F converter stop, and the series of rotational movements transmitted by the pulse motor 3 stops.

In this way, the voltage set is used as a reference signal in the speed setting circuit of the mill motor.

By the way, in such a conventional speed setting device, mechanical rotational movement, that is, the reduction gear 4, the slip machine 5,
Since it relies on the movement of the upper limit switch 7, lower limit switch 8, etc., it has the following drawbacks.

(1) Short life span (2) Slow response speed (3) Requires large space (4) Poor resolution etc.

This invention was made to eliminate the above-mentioned conventional drawbacks, and does not rely on mechanical rotational or moving movements.
The present invention provides a speed setting device for a mill motor that is fast, stable, and inexpensive due to a completely stationary circuit.

Next, an embodiment of the speed setting device for a mill motor according to the present invention will be described with reference to the drawings. FIG. 2 is a block diagram showing the principle of one embodiment, and 11 is a V/F converter.

This V/F converter 11 generates a pulse with a frequency proportional to the electric signal Vi introduced to its input side, and sends this pulse to a first gate 12 and a second gate 13.

The first gate 12 is controlled by a signal F, and when this signal F is introduced, pulses from the output side of the V/F converter 11 are sent to the third gate 14.

This third gate 14 is controlled by a signal S and a first detection circuit 18, which will be described later.

Further, a signal R is introduced into the second gate 13, and the signal R is used to control the signal R.

Then, the output of this second gate 13 is transmitted to the fourth gate 1.
5, and this fourth gate 1
The signal S mentioned above is also introduced into the circuit 5, and is controlled by the output of the second detection circuit 19.

The pulse train sent out from the output side of the third gate 14 and the fourth gate 15, that is, the V/F converter 11
The pulses generated from the output side are introduced into a reversible counter 16 and counted there.

The output of the reversible counter 16 is sent to a first detection circuit 18, a second detection circuit 19, and a D/A conversion circuit 17 (digital-to-analog conversion circuit). When becomes equal to a preset value T, the first detection circuit 18 gives a close signal to the third gate 14.

Similarly, when the output of the reversible counter 16 becomes equal to the preset value B°, the second detection circuit 19 detects the fourth
A close signal is given to the gate 15 of.

The D/A conversion circuit 11 uses VR as a reference voltage and outputs an analog output VOUT proportional to the number of pulses counted by the reversible counter 16.

Next, the operation of the mill motor speed setting device of the present invention configured as described above will be explained. The V/F converter 11 generates a pulse with a frequency proportional to the magnitude of the input signal Vi, and its output is The signal is sent to the first gate circuit 12 and the second gate circuit 13.

Now, when the control signal F is applied to the first gate circuit 12,
The first gate 12 opens the gate, ■↑ converter 11
The pulses from are introduced into the reversible counter 16 through this first gate 12 and third gate 14.

As a result, the reversible counter 16 starts counting.

Conversely, if the control signal R is applied to the second gate 13, the second gate 13 opens the gate in the same way as above.
The pulse from the V/F converter 11 passes through the second gate 13 and the fourth gate 15 to the reversible counter 16.
will be introduced in

As a result, the reversible counter 16 now performs a subtraction count.

In this way, when counted to add by the reversible counter 16, the number of pulses counted is
It is converted into an analog output VOUT by the conversion circuit 17, and when a control signal F is applied, an output VOUT is outputted so that the rotational speed of the mill motor controlled by the speed setting device of the present invention is accelerated.

Conversely, when the reversible counter 16 performs a subtractive count (when the control signal R is applied to the second gate 13), an output VOUT is output that reduces the rotational speed of the mill motor. , Furthermore, when the mill motor is moved at a constant speed, the signal S is sent to the third gate 14.
and the fourth gate 15.

Then, this third gate 14 and fourth gate 15
closes its gate, the pulse from the V/F converter 11 is no longer introduced into the reversible counter 16, the reversible counter 16 keeps the counted value stable, and the D/A conversion circuit 17 changes according to the stable value. An analog signal is output from the output side, and the mill motor is controlled at a constant speed.

Further, when the reversible counter 16 is incrementing, the first detection circuit 18 sends a signal to close the third gate 14 when the count value of the reversible counter 16 reaches a predetermined value T. Send to third gate, reversible counter 1
Preventing the introduction of pulses into 6.

Similarly, when the reversible counter 16 is decrementing, when the count value of the reversible counter 16 reaches a preset value B, the second detection circuit 19 detects it and outputs the signal to the fourth gate 15. The gate sends a signal to close automatically.

Therefore, in a state where the third gate 14 is automatically closed, even if the control signal F is applied to the first gate 12, since the third gate 14 is closed, the reversible counter 16 has a V/F value. No pulses from converter 11 are introduced.

Similarly, when the fourth gate 15 is closed,
Even when the control signal R is applied to the second gate 13, the output pulse of the V/F converter 11 is not introduced to the reversible counter 16 because the fourth gate 15 is closed.

The respective gate close signals described above are canceled by applying control signals in opposite directions.

That is, the first detection circuit 18 and the second detection circuit 1
9 are upper limit switches 7 shown in FIG.
It also plays the role of a lower limit switch 8.

Now, FIG. 3 is a block diagram showing the configuration of another embodiment of the present invention constructed based on the principle of the present invention shown in FIG. 2. In this FIG. 3, the same parts as those in FIG. In this Figure 3, V
/F converter 11, first gate 12, second gate 13, third gate 14, fourth gate 15, reversible counter 16, D/A converter 17, first detector 18, second
The structural relationship of the detector 19 is almost the same as in the case of FIG. 2, so its explanation will be omitted.

However, in FIG. 2, the control signals F, R, and S are applied from outside, but in FIG. 3, the control signals F, R, and S are automatically controlled.

20 is a subtraction circuit, which is a circuit for increasing the operational stability of the reversible counter 16.

The output of the reversible counter 16 is introduced into the subtraction circuit 20.

A digital bias K is applied in advance to the reversible counter 16 and the subtraction circuit 20, and this bias amount K is subtracted by the subtraction circuit 20.

The output of the subtraction circuit 20 is sent to the first detection circuit 18, the second detection circuit 19, the comparison circuit 21, and the D/A conversion circuit 17.

The output of the buffer memory 22 is introduced into the comparison circuit 21, and the output of the comparison circuit 21 is sent to the first gate 12 and the second gate 13.

The output of the quantity setter 23 and the signal RI are introduced into the buffer memory 22.

The operation of the embodiment shown in FIG. 3 will be described with reference to FIG. 4. Now, if the required capacity of the reversible counter 16 is N counts, the reversible counter 16 will be able to move from O to N counts, that is, the solid line A It will go back and forth between point P2 and point Q2 in .

Therefore, when the reversible counter 16 is provided with a capacity for only the necessary minimum number of N counts, the reversible counter 16 operates on the same polygonal line as the solid line A due to the original operation of the reversible counter 16.

In other words, there is only a difference of one count between points P2 and Q1 and between points Q2 and P3, and if the reversible counter 16 is stationary at point P2 or point Q2, an error will occur. The signal causes point P2 to become point Q1, and point Q2 to point P.
There is a risk of jumping to 3, which is extremely dangerous.

Therefore, as shown by the dotted line B, if the reversible counter 16 is given a margin, a digital bias K is given in advance, the 0 point is moved to the P point, and the reversible count is actually performed between the P point and the Q point, the lower limit value P Even if a subtraction signal is mistakenly applied while the point is stationary, the count value will only be subtracted from point P2 toward point P.
Do not jump to one point.

Similarly, it is possible to prevent a jump from point Q2 to P3 due to an addition signal that is erroneously applied while stationary at point Q2, and the above-mentioned instability can be eliminated.

In addition, a value corresponding to the speed of the mill motor is set in advance using the quantity setter 23, and this value is sent to the buffer memory 2 using the signal RI.
When the contents of 2 are read and given to the comparator circuit 21, the comparator circuit 2
1 is this set value and the value output from the subtraction circuit 20,
That is, it compares the count value of the reversible counter 16 with a value obtained by subtracting a constant value, and if the set value is large, outputs the first gate opening command.

Conversely, if the count value is larger, the second gate 13
Outputs an open command to.

In addition, if both are equal, the third gate 14, the fourth gate
Both gate circuits 14 and 15 are automatically closed so that the comparator circuit 21 outputs a signal that the gates 15 close simultaneously, and the signal given to the D/A conversion circuit 17 is always equal to the value set by the setting device 23. control.

As described above, according to the present invention, the part that conventionally controlled the speed of the mill motor using mechanical rotational motion or moving motion is now controlled by a stationary circuit, thereby eliminating the drawbacks of the conventional method. Not only can it be removed, it is fast, stable, and inexpensive, but it is also easy to maintain.
It is possible to obtain a speed setting device for a mill motor that has many advantages such as low power consumption.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional mill motor speed setting device, FIG. 2 is a block diagram showing the basic configuration of the mill motor speed setting device of the present invention, and FIG. 3 is a block diagram of a mill motor speed setting device of the present invention. FIG. 4 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 4 is a diagram for explaining the operation of the mill motor speed setting device shown in FIG. 3. 11...V/F converter, 12...
First gate, 13...Second gate, 14.
...Third gate, 15...Fourth gate, 1G...Reversible counter, 17...
D/A conversion circuit, 18...first detection circuit, 1
9...Second detection circuit, 20...Subtraction circuit, 21...Comparison circuit, 22...Buffer memory, 23...Quantity Setting device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1 Pulse generator or voltage-frequency converter, a first gate through which the pulses obtained by the pulse generator or voltage-frequency converter are passed when increasing the rotation speed of the mill motor to be controlled, rotation of the mill motor a second gate through which the pulses pass when reducing the speed; a reversible counter that counts the pulses that have passed through the first or second gate and to which a predetermined digital bias amount is applied in advance; and a counter for this reversible counter. a subtraction circuit that subtracts the digital bias amount from the numerical value, and when the first gate passes a pulse, detects when the output of the subtraction circuit reaches a first predetermined amount, and closes the first gate; a first detection circuit that detects this and closes the second gate when the output of the subtraction circuit reaches a second predetermined amount when the second gate passes a pulse; a detection circuit, a D/A conversion circuit that converts the output of the subtraction circuit into an analog quantity, a quantity setter that sets a quantity corresponding to the rotational speed of the mill motor, and a buffer memory that stores the quantity set by the quantity setter. , a comparison circuit that compares the quantity stored in the buffer memory with the output of the subtraction circuit;
and between the second gate and the reversible counter, and when the result of comparison by the comparison circuit is equal to the output of the subtraction circuit and the quantity, the gate is closed by the output of the comparison circuit. A speed setting device for a mill motor, comprising third and fourth gates.