JPH08333087A - Crane control equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] Even if the control unit itself that controls the inverter that drives the crane motor fails, the motor can be reliably detected and the motor stopped to prevent accidents such as crane runaway. Prevent. [Structure] A monitoring unit 14B having the same components as the control unit 14A is provided, and various operations are performed by a signal conversion circuit 18A (18B) based on a command signal S2 (S2 ') and a frequency signal S3 (S3') in both units. Signal S2
a, S2a ', etc. are created. When a difference occurs between the two operation signals, the comparison circuit 19 detects the difference, and when this difference continues for a predetermined time, the contactor 12 shuts off the AC power supply 10 and the motor 1 stops.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane controller for driving a motor with an inverter, and more particularly to a technique for detecting an abnormal operation thereof.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional crane controller disclosed in, for example, Japanese Unexamined Patent Publication No. 2-84090, in which 1 is a motor for driving the crane to hoist, traverse or travel. Reference numeral 2 is an inverter control device for driving the motor 1, 3 is a discharge resistor for absorbing regenerative energy, 4 is a microcomputer having a braking effect determination means built therein, 5 is an alarm device, and 6 is a mechanical braking device for stopping the motor 1. is there.

Next, the operation, especially the protection operation when an abnormality occurs in the device, will be described. The output frequency signal from the inverter control device 2 is input to the microcomputer 4, and the microcomputer 4 compares the predetermined deceleration curve previously stored by the software program of the microcomputer with the output frequency signal to determine whether or not a predetermined braking effect is produced. If it is determined that the braking effect is insufficient, an alarm signal is output and the mechanical braking device 6 is operated to stop the motor 1.

[0004]

Since the conventional crane controller is constructed as described above, if the output frequency of the crane controller does not drop due to the failure of the inverter controller itself, the runaway of the crane will not be noticed at all. become.
In addition, there is a problem that the microcomputer cannot be protected even if it runs out of control or fails.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a crane control device capable of surely detecting an abnormality regardless of the state of an output signal due to a device failure. To aim.

[0006]

A crane control device according to a first aspect of the present invention creates an input operation means for inputting an operation command for a crane, and a drive signal for a switching element based on an operation signal from the input operation means. A crane control device that includes a control unit that drives a crane motor by controlling an inverter based on a drive signal from the control unit, and operates by using the operation signal as an input, and configures the same components as the control unit. A monitoring unit that has, a signal conversion circuit that creates an operation signal that represents an operation state during control operation based on signals in the control unit and the monitoring unit for each unit, and an operation signal of both units from the signal conversion circuit. The comparison circuit that outputs an abnormal signal when both signals are compared and an error signal from this comparison circuit Hazuki those having a motor stopping means for stopping the motor the crane.

According to a second aspect of the present invention, there is provided a control unit for a crane control apparatus, wherein a command signal creating circuit for converting an input operation signal into a binary command signal and a frequency signal based on the command signal from the command signal creating circuit. Is provided, and the signal conversion circuit is adapted to generate an operation signal based on the command signal or the frequency signal.

A control unit of the crane control device according to a third aspect of the present invention comprises a frequency signal creating circuit for creating a frequency signal based on the input operation signal, and the signal converting circuit operates as an operating signal based on the frequency signal. Create a running signal indicating whether it is in the middle, an acceleration signal indicating whether it is accelerating, and a deceleration signal indicating whether it is decelerating, and the comparison circuit outputs one of the above operation signals from both units. When a difference occurs, an abnormal signal is output.

In the crane controller according to the fourth aspect, a delay circuit is inserted between the comparison circuit and the motor stopping means, and the motor stopping means is operated when the abnormal signal from the comparison circuit continues for a predetermined time. It is the one.

A crane control device according to a fifth aspect is a crane control device in which two sets of a control unit, an inverter and a motor for a crane are provided, and the crane control device is operated based on the same operation signal. One of the control units is a monitoring unit. Is treated as

[0011]

In the crane controller according to claim 1,
Regardless of the types of operation signals from the control unit and the monitoring unit, if a difference occurs between the two signals, it is determined that the device has failed and the crane motor is stopped.

In the crane control device according to the second aspect of the present invention, the operation signal is generated from the command signal and the frequency signal handled in the control unit (and hence the monitoring unit), and the failure is judged from the difference between the operation signals. .

In the crane controller according to the third aspect of the present invention, the operating signal, the accelerating signal and the decelerating signal are created as the operating signals from the frequency signals handled in the control unit (and therefore the monitoring unit as well). Then, if a difference occurs between any of these operation signals, it is determined that a failure has occurred.

In the crane control device according to the fourth aspect, even if a difference occurs in the operation signal, it does not immediately cause a failure, but after the difference for a predetermined time set by the delay circuit continues, it is judged as a failure. Therefore, it is possible to prevent an erroneous detection operation due to a slight difference in characteristics between the control unit and the monitoring unit.

In the crane control device according to the fifth aspect, one of the two sets of control units performs the original function as a control unit and at the same time as the other control unit, as a monitoring unit for detecting a mutual failure. Function. Therefore, since it is not necessary to separately provide hardware as a monitoring unit, the cost of the device can be reduced.

[0016]

【Example】

Example 1. 1 is a block diagram showing a crane controller according to a first embodiment of the present invention. In the figure, 10 is an AC power supply having a commercial frequency, 11 is an AC power having a commercial frequency from the AC power supply 10, and is converted into electric power having a predetermined frequency.
An inverter device 12 for supplying electric power to the inverter device 11 is a contactor inserted between the AC power source 10 and the inverter device 11 as a motor stopping means, and operates based on a failure detection signal described later to cut off the power supply to the inverter device 11. Then, the motor 1 is stopped urgently.

Reference numeral 13 denotes an operation push button (hereinafter, simply referred to as a push button) as an input operation means by which an operator inputs an operation command of the crane. In this embodiment,
It is assumed that the motor 1 is a traveling motor for a crane, and correspondingly, the push button 13 includes a traveling button and a high-speed button operated on the assumption that the traveling button is in the pushed position. There is.

Reference numeral 14A is a control unit composed of a microcomputer, which has a command signal generating circuit 15A for binarizing the operation signal S1 by the push button 13 and converting it into a command signal S2 suitable for the following arithmetic processing, and a command signal. Frequency signal generating circuit 1 for generating a frequency signal S3 for determining the number of revolutions of the motor 1 by a software program stored in advance based on S2.
6A and a PWM generation circuit 17A that generates a drive signal S4 for the switching element by PWM control based on the frequency signal S3.

Reference numeral 14B is the same component as that of the control unit 14A, here, a command signal generating circuit 15 having the same structure as the command signal generating circuit 15A and the frequency signal generating circuit 16A.
B is a monitoring unit including a frequency signal generating circuit 16B, and an operation signal S1 from the push button 13 is input to the monitoring unit 14B, and operates in the same manner as the control unit 14A. 18A and 18B are the signals S in the control unit 14A and the monitoring unit 14B, respectively.
1, S2 and S1 ', S2' are the operation signals S2 described later.
a, S3a to S3c and S2a ', S3a' to S3
This is a signal conversion circuit for converting into c '.

Reference numeral 19 is a comparison circuit which compares the operation signals from both signal conversion circuits 18A and 18B and outputs an abnormal signal P1 when a difference occurs between the two signals. 20 is an abnormal signal P1 from the comparison circuit 19 for a predetermined set time. (For example, about several μsec)
When the above continues, a delay circuit that outputs an abnormality determination signal P2, and 21 is a protection control circuit that outputs a stop signal P3 to the contactor 12 when the abnormality determination signal P2 is input from the delay circuit 20 and also displays an alarm. .

Next, referring to FIG. 2 showing the states of various signals associated with the push button operation, the protection operation in the event of an abnormality in the device will be described. First, FIG. 2A shows the operating states of the two types of push buttons 13. That is, when the travel button is operated to be turned on at time t1, the operation signal S
1 is input to the command signal generating circuit 15A and the travel command signal rises to the H level (FIG. 2 (2)). Based on this, the frequency signal generation circuit 16A executes a calculation by a program stored in advance and outputs a 6 Hz frequency signal S3 for low speed running (FIG. 2 (3)).

Next, when the operator operates the high speed button at time t2, the high speed command signal from the command signal generating circuit 15A rises to the H level (FIGS. 2 (1) and 2 (2)). Along with this, the frequency signal generation circuit 16A linearly increases the frequency value of the frequency signal S3 from 6 Hz at a predetermined time gradient during acceleration, and when this frequency value reaches the maximum of 60 Hz at time t3, Hold that value (Fig. 2
(3)). Therefore, after time t3, the driving pattern becomes a high-speed constant traveling.

Next, when approaching the target stop position of the crane,
When the operator operates the high speed button to turn it off at time t4 (FIG. 2 (1)), the high speed command signal from the command signal generating circuit 15A falls to L level (FIG. 2 (2)), and the frequency signal generating circuit is generated. 16A receives this and sets the frequency value of the frequency signal S3 to 60 Hz with a predetermined time gradient during deceleration.
Then, the frequency value is linearly decreased, and when it reaches the minimum value of 6 Hz at time t5, the value is held thereafter (FIG. 2 (3)). Then, when the stop position is estimated and the travel button is operated to turn it off at time t6 (see FIG. 2).
(1)), the travel command signal falls to L level (see FIG. 2).
(2)), and accordingly, the frequency signal S3 becomes 0 Hz, and the motor 1 stops. The above is the control unit 1
4A is operating normally, the monitoring unit 14B also outputs the same signals S2 'and S3'.

Next, the operation of the signal conversion circuit 18A (18B) will be described mainly with reference to FIGS. That is, first, based on the command signal S2 (S2 ') from the command signal creating circuit 15A (15B), the running signal S2a (S2a') indicating whether or not the vehicle is running is created (FIG. 2 (4)). This is a signal obtained by inputting the running command signal and the high speed command signal shown in FIG. 2B into the OR circuit and obtaining the output thereof.

Further, the frequency signal generating circuit 16A (16
Three types of operation signals are generated from the frequency signal S3 (S3 ') from B). First, the in-operation signal S3a (S3a ') indicating whether or not the operation is in progress is as shown in FIG.
It is obtained as an output signal of the comparator 22 which determines whether or not the frequency signal S3 is larger than 0 (the upper stage of FIG. 2 (5)). Next, an accelerating signal S3b (S3b ') indicating whether or not accelerating
Is a comparator 24 that determines whether or not the current value of the frequency signal S3 is larger than the immediately preceding value S4 from the sample hold 23 (for example, sampling is performed at intervals of several hundreds of microseconds), as shown in FIG. 3B. Obtained as an output signal (Fig. 2
(5) Middle row). Further, a deceleration signal S indicating whether or not deceleration is being performed.
3c (S3c ') is obtained as an output signal of the comparator 26 which determines whether or not the immediately preceding value S4 of the frequency signal from the sample hold 25 is larger than the current value S3, as shown in FIG. Fig. 2 (5) bottom).

The operation signals S2a, S3a to S from the control unit 14A and the monitoring unit 14B described above are used.
3c and S2a ', S3a' to S3c 'are comparison circuits 1
9 is constantly compared, and, for example, if a failure occurs inside the control unit 14A or the monitoring unit 14B and a difference occurs in either of the operation signals,
Immediately, the abnormal signal P1 is output. Therefore, in FIG.
Although the comparison circuit 19 is illustrated by one comparator, in reality, comparison elements corresponding to the number of types of operation signals to be compared are required.

When the abnormal signal P1 continues for the time set by the delay circuit 20 or longer, the abnormal determination signal P2 is output, the stop signal P3 is sent to the contactor 12 via the protection control circuit 21, the AC power supply 10 is cut off, and the motor is turned off. 1 makes an emergency stop. The delay circuit 20 is provided for the following reason. In other words, both units 14A and 14B are manufactured with the same specifications, but there are some differences in characteristics, especially speed response, etc. An instantaneous difference may occur in the generated driving signal. Therefore, in order to prevent such an erroneous operation due to the instantaneous output, the presence / absence of abnormality is determined after a necessary time factor in consideration of an assumed characteristic difference.

In the above description, both units 14
Even if any one of the operation signals from A and 14B has a difference between the two signals, the motor stop protection operation is performed. However, for safety of operation, the most serious condition is a failure during deceleration operation. Therefore, when a difference occurs between the deceleration signals S3c and S3c ', the motor stop operation is performed, and when a difference occurs in another operation signal, only the alarm display may be performed. In this case, there is an advantage that the influence of the protection operation on the operation can be reduced.

Example 2. In the first embodiment, an operation signal is created based on the command signal S2 (S2 ') from the command signal creation circuit 15A (15B) and the frequency signal S3 (S3') from the frequency signal creation circuit 16A (16B) and compared. However, the drive signal S4 from the PWM generation circuit 17A
It is also possible to create an operation signal including this and add it to the comparison target. In this case, the monitoring unit 14B has a PWM
Although it is necessary to provide the PWM generation circuit 17B (shown by a dotted line block in FIG. 1) having the same configuration as the generation circuit 17A, the abnormality detectable range is widened and a more complete protection system can be obtained.

Example 3. In the above embodiment, the monitoring unit 14B, which is not necessary for the original crane operation, is provided for detecting an abnormality. However, for example, in a large crane device, two sets of a control unit, an inverter device, and a motor are provided to perform the same operation. In the case of the method of operating based on signals, one of the two control units is regarded as a monitoring unit, various operation signals are created from the signals in both units with the other control unit, and these are compared to detect an abnormality. It may be configured to perform. In this case, there is an advantage that the cost is reduced because there is no need to newly provide a monitoring unit.

Example 4. In the above embodiments, the control device for the traveling motor of the crane has been described as an example, but the present invention can be applied to the control device for the hoisting and traversing motors in the same way, and is equivalent. Of course, it has an effect. Also, as the motor stopping means, the contactor 1
The method is not limited to the method of shutting off the power source by 2 and may be another method such as a mechanical braking method.

[0032]

As described above, the crane control device according to the first aspect of the present invention is provided with the predetermined monitoring unit, the signal conversion circuit, the comparison circuit, and the motor stopping means. Therefore, the control for controlling the inverter for driving the crane motor is performed. Even when a failure occurs in the unit itself, the failure is surely detected and the motor is stopped, so that an accident such as a crane runaway can be prevented.

Further, the control unit of the crane control device according to the present invention comprises a predetermined command signal generating circuit and a frequency signal generating circuit, and generates an operation signal based on the command signal and the frequency signal from them. Therefore, it is possible to detect an abnormal operation of the control unit in a wide range.

The control unit of the crane controller according to the third aspect of the present invention is provided with a predetermined frequency signal generating circuit so as to generate a predetermined operating signal, an accelerating signal and a decelerating signal based on the frequency signal from the circuit. Therefore, it is possible to detect an abnormal operation in each crane operation mode.

Further, since the crane control device according to the fourth aspect is provided with the predetermined delay circuit, it is possible to prevent an erroneous detection operation due to a slight characteristic difference between the control unit and the monitoring unit.

Further, since the crane control device according to the fifth aspect is configured so that one of the two control units existing is regarded as a monitoring unit to detect an abnormality, it is not necessary to separately provide hardware as a monitoring unit. Therefore, the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a crane controller according to a first embodiment of the present invention.

FIG. 2 is a time chart showing states of various signals associated with the push button operation of FIG.

FIG. 3 is a diagram showing an internal configuration of the signal conversion circuit of FIG.

FIG. 4 is a block diagram showing a conventional crane control device.

[Explanation of symbols]

1 motor, 10 AC power supply, 11 inverter device,
12 contactor, 13 push button, 14A control unit, 14B monitoring unit, 15A, 15B command signal generation circuit, 16A, 16B frequency signal generation circuit, 18
A, 18B signal conversion circuit, 19 comparison circuit, 20 delay circuit, 21 protection control circuit, S1 operation signal, S2
S2 'command signal, S3, S3' frequency signal, S2
a, S2a 'running signal, S3a, S3a' running signal, S3b, S3b 'accelerating signal, S3c, S3
c'Deceleration signal, P1 abnormality signal, P2 abnormality determination signal, P3 stop signal.

Claims (5)

[Claims] 1. An input operation means for inputting an operation command for a crane, and a control unit for generating a drive signal for a switching element based on an operation signal from the input operation means. The drive signal from the control unit is provided. In a crane control device that controls an inverter based on this to drive a crane motor, a monitoring unit that operates using the above operation signal as an input and has the same components as the above control unit, and based on the above control unit and the signals in the monitoring unit A signal conversion circuit that creates an operation signal representing the operation state during control operation for each unit, and a comparison circuit that compares the operation signals of both units from this signal conversion circuit and outputs an abnormal signal if a difference occurs in both signals. , And stop the motor for the crane based on the abnormal signal from this comparison circuit. Crane control apparatus characterized by comprising a stage. 2. The control unit controls the input operation signal to 2
A command signal creating circuit for converting the command signal into a digitized command signal and a frequency signal creating circuit for creating a frequency signal based on the command signal from the command signal creating circuit are provided, and the signal converting circuit is based on the command signal or the frequency signal. The crane control device according to claim 1, wherein an operation signal is generated in the crane control device. 3. The control unit comprises a frequency signal creating circuit for creating a frequency signal based on the input operation signal, and the signal converting circuit uses the frequency signal as an operation signal to indicate whether or not the operation is in progress. Create a medium signal, an in-acceleration signal indicating whether or not acceleration is in progress, and a deceleration signal indicating whether or not deceleration is in progress.
The crane control device according to claim 1, wherein the comparison circuit outputs an abnormality signal when a difference occurs in any of the operation signals from both units. 4. A delay circuit is inserted between the comparison circuit and the motor stopping means, and the motor stopping means is operated when an abnormal signal from the comparison circuit continues for a predetermined time. Item 4. The crane control device according to any one of Items 1 to 3. 5. A crane control device in which two sets of a control unit, an inverter and a crane motor are provided and operated based on the same operation signal, wherein one of the control units is regarded as a monitoring unit. A crane control device to which the configuration described in (1) is applied.