JPH0534238Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a circuit that commands the speed of mechanical motion such as rotational speed in a rotating machine, and in particular, when the circuit is used to command the machine to restart, the machine suddenly restarts. This invention relates to a speed command circuit that does not start or endanger the operator.

[Conventional technology]

FIG. 5 is a configuration diagram of a conventional speed command circuit 17. In the figure, 1 is a variable resistor that outputs a voltage signal 1a having a voltage corresponding to the set rotational speed of a motor (not shown). 3 and a speed setting signal 4 as a pulse train signal having a pulse frequency corresponding to the voltage of the signal 1a.
It is starting to be converted to . 5 turns on when the slider of resistor 1 is moved so that the voltage of the output signal 1a becomes zero volts, which represents the above-mentioned set rotational speed of zero, and the slider's voltage of the signal 1a does not become zero volts. In the figure, when the switch 5 is turned on, the L level signal 6a is input to the inverter 7 via the noise filter 6, and when the switch 5 is turned off, the H level signal 6a is input to the inverter 7. The signal is input from the filter 6 to the inverter 7. Reference numeral 8 denotes a speed setting device comprising a resistor 1, an amplifier 2, a converter 3, a resistor R shown in the figure, a capacitor C, a switch 5, a filter 6, and an inverter 7. Setting device 8
Since it is configured as described above, it outputs the speed setting signal 4 according to the set rotational speed of the electric motor, and also outputs the setting state signal 7a according to whether the set rotational speed is zero or not to the inverter 7. It can be said that it is designed to output from.

Reference numeral 9 denotes a starting switch which inputs an L level signal 10a to the inverter 11 via the noise filter 10 when it is in the on state, and inputs an H level signal 10a from the filter 10 to the inverter 11 when it becomes the off state; A NAND circuit 13 receives the output signals 7a and 11a of the inverters 7 and 11, and 13 has a terminal to which the output signal 12a of the NAND circuit 12 is input, and a terminal to which the output signal 14a of the initial reset circuit 14 is input. I made it. A flip-flop circuit is made up of two NAND elements 131 and 132, and 15 is an AND circuit into which a signal 13a output from the Q terminal of the flip-flop circuit 13 and an inverter output signal 11a are input. 16 is an AND circuit to which the output signal of the AND circuit 15 and the speed setting signal 4 are input. The speed command circuit 17 is composed of the above-mentioned parts.

Next, the operation of the command circuit 17 will be explained with reference to FIG. That is, first, switch 5 is turned on so that the voltage of signal 1a becomes zero, and switch 9 is turned off.
Assume that power is turned on to the command circuit 17 at t1. Then, the signal 14a whose voltage increases exponentially and eventually becomes H level is input to the terminal of the flip-flop circuit 13, so that the output signal 13 of the circuit 13
a goes to L level, and output signals 7a and 11a of inverters 7 and 11 go to H level and L level, respectively, so signal 12a goes to H level. At this time, since the signal 11a is at the L level, the signal 15a becomes the L level, and the AND circuit 16 is in a cutoff state.

Next, when the start switch 9 is turned on at time t2, the signal 11a goes to the H level, so the signal 12a goes to the L level.
As a result, the state of the flip-flop circuit 13 is inverted and the signal 13a becomes H level. Therefore, the output signal 15a of the AND circuit 15
becomes H level, and the AND circuit 16 enters a state in which it allows the signal 4 to pass. Therefore, if the value of signal 1a is increased successively at time t3, switch 5 is turned off at this time and signal 7a becomes L level, resulting in signal 12a.
becomes H level, but since the state of the circuit 13 does not change, the signal 15a continues to be at the H level, and the AND circuit 16 outputs a signal 16a corresponding to the value of the signal 1a.
is output. Therefore, the signal 16a allows a speed command to be given to the electric motor according to the aging state of the signal 1a, that is, the speed setting signal 4.

At time t4, when the value of signal 1a is set to zero and switch 5 is turned on, signal 7a becomes H and signal 12a becomes
becomes L, but there is no change in the signal levels of other parts, so the circuit 16 continues to have its gate open.
When the switch 9 is turned off at time t5, the signal 11a becomes L, so the signal 15a becomes L, and the circuit 16 is cut off.

[Problem that the invention attempts to solve]

Although the speed command circuit 17 operates as described above,
This circuit has the following problems.
Next, this problem will be explained with reference to FIGS. 5 and 7. That is, assume that the switch 9 is turned off at time t6 after time t3. Then signal 11
Since a becomes L, the circuit 16 is cut off, and as a result, the motor to which the signal 16a is applied stops. Then, at time t7, it is assumed that the switch 9 is turned on and an attempt is made to restart the electric motor. Immediately, the signal 11a becomes H, and the gate of the AND circuit 16 becomes open. At this time, the signal 4 input to the circuit 16 corresponds to, for example, the rated speed of the motor. When a sudden acceleration is commanded, the machine equipped with the electric motor suddenly starts.

Therefore, in the speed command circuit 17 mentioned above,
Since the AND gate 16 is opened and closed in response to the opening and closing of only the start switch 9, after setting the command circuit 17 to a state in which the speed setting signal 4 is output from the circuit 16, the variable resistor 1 is If the switch 9 is turned off while the mover remains in the same position, and then the switch 9 is turned on again and an attempt is made to restart the electric motor using the signal 16a, for example,
If the electric motor is commanded to accelerate suddenly, a large amount of stress will be generated on the machine including the electric motor, resulting in damage.
This poses a problem in that the operator of this machine may be in danger.

The purpose of the present invention is to prevent damage to the machine and human body by preventing the AND gate 16 from being opened only by operating the switch 9 even if the above-mentioned restart operation is attempted using the start switch 9. The purpose is to prevent danger from occurring.

[Means for solving problems]

In order to achieve the above object, the present invention provides a speed setting device that outputs a speed setting signal corresponding to a set speed of mechanical motion and outputs a high level setting state signal when the set speed signal is zero, and and a stopped state, and outputs a first operating signal at a high level in the stopped state, and outputs a second operating signal at a high level in a starting state and has a polarity opposite to the first operating signal. a switch section, an AND circuit that receives the setting state signal and the second operating signal and outputs a third operating signal at a high level when both input signals are at a high level; 3 is set when the operation signal is at a high level, and when the first operation signal inputted to the R terminal is at a high level, and in the set state, a high level gate open signal is output from the Q terminal.
It is characterized by comprising an SR flip-flop circuit and a gate circuit that allows passage of the speed setting signal only when the gate open signal is at a high level, and the speed of the mechanical movement is commanded by the output signal of the gate circuit. do.

[Effect]

With the above configuration, the gate open signal output from the SR flip-flop circuit will be output in accordance with not only the state of the start switch, but also the state of this switch and the value of the setting state signal. Therefore, when restarting the target machine to which a speed command is given, it is impossible to open and close the gate circuit using only the start switch, and the speed setting signal must be set to a value corresponding to the set speed of zero to set the speed. As a result of no longer being able to output a signal from the gate circuit, the machine is no longer commanded to accelerate rapidly, thereby preventing damage to the machine and danger to the human body.

〔Example〕

FIG. 1 is a block diagram of an embodiment of the present invention. The difference between FIG. 1 and FIG. 5 is that the AND circuit 15 is omitted and the output signal 13a of the flip-flop circuit 13 is directly input to the AND circuit 16, and that the output signal of the NOR circuit 18 is connected to the terminal of the circuit 13. The signal 18a is inputted, and
The NOR circuit 18 receives the output signal 10 of the noise filter.
a and a signal 19a obtained by inverting the output signal of the initial reset circuit 14 with an inverter 19. Reference numeral 20 denotes a speed command circuit made up of the various parts shown in the figure. Since the speed command circuit 20 is configured as described above, the switch 9, the noise filter 10, and the inverter 11,
It has a starting state and a stopped state, and outputs a signal 10a as a first operating signal corresponding to both states, and also outputs an inverter output signal 11a as a second operating signal having a polarity opposite to that of the signal 10a. It can be said that the starting switch section 21 constitutes a starting switch section 21 that performs

In the speed command circuit 20, the output signal 12a of the NAND circuit 12 is input to the terminal of the flip-flop circuit 13, and the output signal 18a of the NOR circuit 18 is input to the terminal of the flip-flop circuit 13. This part is shown in FIG. It is clear that the circuit can be equivalently rewritten as shown. That is, the NAND circuit 12 is represented by an AND circuit 121 and an inverter 122, and the NOR circuit 18 is represented by an OR circuit 181 and an inverter 182. Therefore, inverters 122, 182 and circuit 13
It is clear that an SR flip-flop circuit 22 is formed, and as a result, the setting state signal 7a and the second operation signal 11a are input to the speed command circuit 20, and the AND operation is performed on both input signals and the result is calculated. an AND circuit 121 that outputs a third operation signal 121a according to
When the value of the operation signal 121a and the value of the first operation signal 10a inputted to the R terminal via the OR circuit 181 reach predetermined values, the signal 13a which becomes H level is output from the Q terminal as a gate open signal.
It can be said that an SR flip-flop circuit 22 is provided.

Next, the operation of the speed command circuit 20 will be explained with reference to FIG. That is, when the speed setting device 8 first sets the set speed to zero, and then the switch 9 is turned off and power is applied to the speed command circuit 20, the initial reset circuit 14a is output from the initial reset circuit 14, so that The waveforms of each part at time t1 are as shown in the figure. Further, the output signal 19a of the inverter 19 continues to be at the L level after time t1. Therefore, when switch 9 is turned on at time t2, signal 10a becomes L level, signal 18a becomes H level, and signal 11a becomes H level.
Then, the signal 12a becomes L. However, in this case, the signal 18a is a signal delayed from the signal 10a by the signal transmission time in the NOR circuit 18, whereas the signal 12a is delayed by the signal transmission time in the inverter 11 and the NAND circuit 12.
The signal is delayed. Therefore, the signal 18a is input to the flip-flop circuit 13 earlier than the signal 12a, so when the signal 12a becomes L, the output signal 13a of the circuit 13 becomes H level, and the gate of the AND circuit 16 becomes open. Become.
Therefore, the speed setting signal 4 at time t2 is output from the AND circuit 16 as the output signal 16a. However, signal 4 in this case is a signal corresponding to the set speed of zero.

Next, when the set speed in the setting device 9 is increased at time t3, the switch 5 is turned off, so the signal 7a becomes L and the signal 12a becomes H, but the signals in other parts of the command circuit 20 Since there is no change, the gate of the AND circuit 16 remains open, and the speed setting signal 4 corresponding to the voltage signal 1a is output from the circuit 16. In other words, the output signal 16a
is a signal corresponding to the speed setting command from the setting device 8. Therefore, if the set speed is set to zero at time t4, signal 1
6a becomes a signal corresponding to the set speed of zero and the switch 5 is turned on, so the signal 7a becomes H and the signal 12a becomes L, and the states of the signals of each part in the command circuit 20 are the same as the state immediately before time t3. become.
Therefore, when the start switch 9 is turned off at time r5, the signals 10a and 11a go to H and L levels, respectively, the signal 18a goes to L, and the signal 12a goes to H.
However, for the same reason as mentioned above, the signal 18a is inputted to the flip-flop circuit 13 earlier than the signal 12a, so the signal 13a becomes L and the gate of the AND circuit 16 is closed.

The above explanation was based on the case where the command circuit 20 was operated normally, but as shown in FIG.
When switch 9 is turned off at time t6 while the set speed remains non-zero, signals 10a and 11a
go high and then go low, respectively, so the signal 18a goes low, but the signal 12a remains high and does not change, so the signal 13a goes low and the gate of the AND circuit 16a is closed. Therefore, since the value of the signal 16a becomes zero, the above-mentioned electric motor, which receives a speed command based on the signal, stops rotating. Then, in this state, when time t7 comes and switch 9 is turned on,
Signals 10a and 11a go to L level and H level, respectively, so signal 18a goes to H, but signal 12a
does not change. Therefore, the signal 13a continues to be at the L level, and the gate circuit 16 continues to be in the closed state. Therefore, even if the speed setting signal 4 has a value corresponding to a non-zero setting speed at this time, the electric motor will not be restarted. Therefore, in this case, since no sudden acceleration command is given to the electric motor, no damage is caused to the machine including the electric motor, and no danger to the human body occurs.

In FIG. 4, if a deceleration command is output from the setting device 8 after time t7 and the set speed is set to zero at time t8,
Since the switch 5 is turned on, the gate of the AND circuit 16 is opened, but since the set speed is zero at this time, the motor does not start. When the switch 9 is turned off at time t9, the AND circuit 16 enters the gate closed state.

Although the above description of the embodiment relates to a speed command circuit that commands the rotational speed of an electric motor, the present invention is not limited to such an embodiment, and can also be used to control the speed of mechanical motion other than rotational motion. This can also be applied when giving instructions.

[Effect of idea]

As explained above, the present invention includes a speed setting device that outputs a speed setting signal corresponding to the set speed of mechanical motion and also outputs a high-level setting state signal when the speed setting signal is zero, and and a stopped state, and outputs a first operating signal at a high level in the stopped state, and outputs a second operating signal at a high level in a starting state and has a polarity opposite to the first operating signal. an AND circuit which receives the setting state signal and the second operating signal and outputs a third operating signal at a high level when both input signals are at a high level; and the third operating signal which is input to the S terminal. An RS flip-flop circuit that is set when the operation signal is at a high level, is reset when the first operation signal inputted to the R terminal is at a high level, and outputs a high level gate open signal from the Q terminal in the set state. , a gate circuit that allows passage of the speed setting signal only when the gate open signal is at a high level, and a speed command circuit configured to command the speed of the mechanical movement by the output signal of the gate circuit. By this,
The gate open signal output from the SR flip-flop circuit is not only the state of the start switch, but also
The output will depend on the state of this switch and the value of the setting state signal. For this reason, when restarting the target machine to which a speed command is given, it is impossible to open and close the gate circuit using only the start switch.
As a result, the speed setting signal cannot be output from the gate circuit unless the speed setting signal is once set to a value corresponding to the set speed of zero, and as a result, in the present invention, sudden acceleration is not commanded to the machine. This has the effect of preventing damage to the machine and danger to the human body.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an embodiment of the present invention, Fig. 2 is an equivalent circuit diagram of the main parts in Fig. 1, and Figs. 3 and 4 explain different operations of the embodiment shown in Fig. 1. FIG. 5 is a configuration diagram of a conventional speed command circuit, and FIGS. 6 and 7 are time charts for explaining different operations of the circuit shown in FIG. 5. 4...Speed setting signal, 7a...Setting status signal,
8... Speed setting device, 10a... First operation signal, 1
1a...Second operation signal, 16...AND circuit, 1
7, 20...Speed command circuit, 21...Start switch section, 22...SR flip-flop circuit, 12
1...AND circuit, 121a...Third operation signal.

Claims (1)

[Scope of utility model registration request] a speed setting device that outputs a speed setting signal according to a set speed of mechanical motion and outputs a high-level setting state signal when the set speed signal is zero;
It has a starting state and a stopped state, and outputs a first operating signal at a high level in the stopped state, and outputs a second operating signal at a high level in the starting state and has a polarity opposite to the first operating signal. a start switch unit, an AND circuit which receives the setting state signal and the second operating signal and outputs a third operating signal at a high level when both input signals are at a high level; The SR flip-flop is reset when the third operation signal is at a high level, is reset when the first operation signal inputted to the R terminal is at a high level, and outputs a high level gate open signal from the Q terminal in the set state. circuit, and a gate circuit that allows passage of the speed setting signal only when the gate open signal is at a high level,
A speed command circuit, characterized in that the speed of the mechanical movement is commanded by an output signal of the gate circuit.