JP3931830B2 - Pulse generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, an external output pulse having a total number of pulses set in advance by a pulse transmission start command is actually transmitted from a pulse generator for transmitting to a pulse train input means such as a pulse train servo motor that performs a positioning operation of a machine tool. More particularly, the present invention relates to a pulse monitoring device for a pulse generator capable of preventing a problem that occurs when a forced stop command is given to the pulse generator during an external output pulse sending operation.
In the following drawings, the same reference numerals denote the same or corresponding parts.
[0002]
[Prior art]
FIG. 3 shows a configuration example of a main part of a conventional positioning control system applied to a machine tool or the like. In this figure, 1 is a pulse generator, 2 is a means for inputting a pulse train. In this example, a pulse train servo having a function that the rotation angle (and hence the movement amount) per pulse of the input pulse train is constant. Motors 3 are output pulses sent to the outside from the pulse generator 1 and given to the pulse train servomotor 2.
In the pulse generator 4 of the pulse generator 1, the total number of output pulses 3 (therefore, in this example, the total movement amount as the total rotation angle of the pulse train servo motor 2) is set in advance, and the pulse generator 4 starts from the outside. When the signal 7 is input, the pulse generator 1 generates and sends out the number of output pulses 3 equal to the set total number of pulses. At this time, the frequency of the output pulse 3 is changed over time according to the total number of pulses. At the same time, it varies with a predetermined acceleration / constant speed / deceleration pattern as shown in FIG.
[0003]
In the pulse generator 1, when the pulse generator 4 is preset with a total number of pulses and receives a start signal 7 from the outside, a timing pulse that is the basis of the output pulse 3, that is, one pulse of the output pulse 3. A timing signal 4a indicating the rising point and falling point of each time is output.
The latch circuit 5 holds a signal indicating the rising point of the timing signal 4a, and clears the held output by a signal indicating the falling point of the timing signal 4a, whereby a wide pulse 5a having the same waveform as the output pulse 3 is obtained. The buffer circuit 6 amplifies the wide pulse 5a to produce an output pulse 3.
[0004]
FIG. 4 shows an example of a normal operation waveform of FIG. When the total number of pulses is set in advance in the pulse generator 4 of the pulse generator 1 and the external start signal 7 is turned ON at time t0, the pulse generator 1 sets the frequency of the output pulse 3 to linear in this example from time t0 to t1. The servo motor 2 is accelerated to a constant speed, and the servo motor 2 is operated at a constant speed with the frequency of the output pulse 3 kept constant from time t1 to time t2.
Further, from the time t2, the frequency of the output pulse 3 is linearly decreased in this example to decelerate the servo motor 2, and the servo motor 2 is stopped at the time t3 when the total number of output pulses 3 reaches the set number of pulses.
[0005]
[Patent Document 1]
JP 2002-43914 A [0006]
[Problems to be solved by the invention]
FIG. 5 shows an example of an operation waveform when the forced stop signal 8 is inputted from the outside to the pulse generator 4 of the pulse generator 1 at the time t2 ′ during the output of the output pulse 3.
As shown in the figure, when the forced stop signal 8 to the pulse generator 4 is turned on at the time t2 ′, the pulse generator 4 immediately reduces the timing signal 4a, and thus the frequency of the output pulse 3, to decelerate the servo motor 2. And the servo motor 2 is stopped at time t3 ′.
As described above, the conventional pulse generator 1 has a mechanism that gives the highest priority to the transmission stop of the timing signal 4a generated by the pulse generator 4 at the forced stop by the forced stop command (forced stop signal 8) from the outside. Therefore, the timing signal 4a that is the final output of the pulse generator 4 at the time of forced stop is not the timing signal of the fall of the output pulse 3, and the waveform of the time t3 ′ of the output pulse 3 shown in FIG. Thus, even if the servo motor 2 is stopped, the output pulse 3 may not fall and remain ON. In this case, since the final output of the output pulse 3 is not completed, there is a problem in that the control is troubled and the servo motor 2 is adversely affected by the continued energization of the pulse.
[0007]
An object of the present invention is to provide a pulse monitoring device for a pulse generator capable of solving the above-described problems that occur when transmission of an output pulse 3 from the pulse generator 1 is stopped by a forced stop command.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the pulse monitoring device of the pulse generator according to claim 1 is configured to output pulses (3) to be output to the outside for a preset total number of pulses based on a pulse transmission start command (start signal 7). ), The rising timing signal (4a) indicating the rising timing and the falling timing signal (4a) indicating the falling timing do not always exceed at least the predetermined maximum time width (pulse maximum width Wmax). Based on the timing signal sending means (pulse generating unit 4) that sends out sequentially while making a pair at intervals and the paired timing signal, a pulse having a time width from the rising timing of the pair to the falling timing ( Width pulse generation means (latch circuit 5) for generating a wide pulse 5a) (via the buffer 6) and sending it as the external output pulse; In the pulse generator equipped (1),
When the duration from the rising timing of the external output pulse sent from the width pulse generating means exceeds the predetermined maximum time width (by outputting the clear signal 10a), the external output pulse is lowered. A state monitoring unit and a timer, and a self-output pulse total number monitoring unit that counts the total number of external output pulses (3) actually generated and transmitted from the pulse generator (1) based on a pulse transmission start command (start signal 7) ( 12), and a self-monitoring circuit (9) is provided.
[0009]
The pulse generator according to claim 2 is the pulse generator according to claim 1, and rises for every one of the output pulses sent through the state monitoring unit (11) and the timer (10). The duration from the point in time is measured, and when the duration exceeds a predetermined maximum length, a clear signal is given to the pulse generator (1) to reset the output pulse (3) to fall. And
[0010]
The operation of the present invention is as follows. That is, the conventional pulse generator 1 is provided with a self-monitoring circuit 9 including a timer 10, a state monitoring unit 11, and a self-output pulse total number monitoring unit 12,
(1) The duration from the rising point is measured for each output pulse 3 sent from the pulse generator 1 via the state monitor 11 and the timer 10, and this duration is a predetermined maximum length. When Wmax is exceeded, a clear signal 10a is given to the pulse generator 1 to reset it, and the output pulse 3 is lowered, so that the final output of the output pulse 3 does not fall at the time of forced stop as in the prior art, and remains ON. Thus, it is possible to prevent the pulse output from being completed and causing a malfunction of the control or adversely affecting the servo motor 2.
(2) Output pulse 3 generated at the time of forced stop by counting the total number of output pulses 3 actually sent from pulse generator 1 after input of start signal 7 through self-output pulse total number monitoring unit 12 The difference from the set value of the total number is clarified, and the process of correcting this difference is facilitated.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a configuration of a main part of a positioning control system as an embodiment of the present invention. In FIG. 1, compared to FIG. 3, a self-monitoring circuit 9 including a timer 10, a state monitoring unit 11, and a self-output pulse total number monitoring unit 12 is added in the pulse generator 1.
2 shows that during the positioning operation of the system shown in FIG. 1 (that is, the total number of output pulses 3 to be sent from the pulse generator 1 is preset in the pulse generator 4, and the pulse generator 4 receives a start signal from the outside at time t0. 7 is a waveform diagram showing the operation when the forced stop signal 8 is input from the outside at time t2 ′ during the operation of the system of FIG. 1 after 7 is input. This figure corresponds to FIG. .
[0012]
Next, each functional unit in the self-monitoring circuit 9 will be described with reference to FIGS.
Here, the state monitoring unit 11 always determines whether the output pulse 3 is ON (H level in this example) or OFF (L level in this example).
The timer 10 always measures the ON state duration (that is, the pulse width of the output pulse 3) from the time when the state monitoring unit 11 determines the start of the ON state of the output pulse 3, and this pulse width is a predetermined longest width. Monitor not to exceed Wmax.
Therefore, as shown in the deceleration section of FIG. 2, when the forced stop signal 8 is input at the time t2 ′, the pulse generator 4 immediately decreases the frequency of the timing signal 4a (and hence the output pulse 3), and the pulse train. When the servo motor 2 is decelerated and the output pulse 3 is stopped at the time point t3 ′, the worst is the final output state of the output pulse 3. At the time tb when the duration time reaches the predetermined maximum width Wmax, the clear signal 10a is output to the pulse generator 4 and the latch circuit 5, the pulse generator 1 is reset to the initial state, and the output pulse 3 is turned OFF.
[0013]
On the other hand, the self-output pulse total number monitoring unit 12 self-outputs the output pulse 3 itself output to the outside by the pulse generator 1 after the start of the positioning operation of the system of FIG. 1, that is, after the time t0 when the start signal 7 is input. Count.
As a result, even if the pulse generator 1 stops sending the output pulse 3 during the positioning operation, the output pulse 3 physically sent by the pulse generator 1 to the external pulse train servomotor 2 before the stop of the sending. The total number can be known, and the difference between the forced stop position of the pulse train servo motor 2 and the original positioning position can be accurately managed.
[0014]
【The invention's effect】
According to the present invention, a self-monitoring circuit 9 is provided in the pulse generator 1,
(1) Always determine the ON / OFF state (H / L in this example) of the output pulse 3 and measure the pulse width (ON duration) of the output pulse 3, and the pulse width is a predetermined longest width Wmax. Since the clear signal 10a is given to the pulse generator 4 and the latch circuit 5 when the signal exceeds the value, the pulse generator 1 is reset to the initial state.
Worst case in the final output state of the output pulse 3 after the input of the forced stop signal 8 to the pulse generator 4, the output pulse 3 is lowered and turned OFF even if the output pulse 3 keeps rising. As in the past, the final output of the output pulse 3 does not fall at the time of forced stop and remains ON, and the pulse output is not completed, resulting in a control failure, or the servo motor 2 is adversely affected by continued energization of the pulse. Can be prevented. Also,
(2) Since the pulse generator 1 counts the total number of output pulses 3 actually sent to the outside for each positioning operation,
By inputting the forced stop signal 8, even if the pulse generator 1 stops sending the output pulse 3 during the positioning operation, the total number of output pulses 3 sent can be known, and the pulse train servo motor 2 is forcibly stopped. Since the difference between the position and the original positioning position can be accurately grasped, the subsequent correction of the difference becomes easy.
[Brief description of the drawings]
FIG. 1 is a block diagram of a main part of a positioning control system as an embodiment of the present invention. FIG. 2 is a waveform diagram showing an operation at a forced stop in FIG. 1. FIG. 3 is a conventional block diagram corresponding to FIG. 4 is a waveform diagram showing an operation in a normal state in FIG. 3. FIG. 5 is a waveform diagram showing an operation in a forced stop in FIG.
1 Pulse generator 2 Pulse train servo motor 3 Output pulse 4 Pulse generator 4a Timing signal 5 Latch circuit 5a Wide pulse 6 Buffer 7 Start signal 8 Forced stop signal 9 Self-monitoring circuit 10 Timer 10a Clear signal 11 Status monitoring unit 12 Self-output pulse Total number monitoring unit Wmax longest pulse width

Claims (2)

Based on the pulse transmission start command, a rising timing signal indicating a rising timing and a falling timing signal indicating a falling timing for each of the pulses output to the outside for a preset total number of pulses are always at least at least. Timing signal transmission means for sequentially transmitting while pairing at intervals not exceeding a predetermined maximum time width;
A pulse generator comprising: a width pulse generating means for generating a pulse having a time width from a rising timing to a falling timing of a pair based on the paired timing signal and transmitting the pulse as the external output pulse ,
A state monitoring unit and a timer for lowering the external output pulse when the duration from the rising timing of the external output pulse sent from the width pulse generating means exceeds the predetermined maximum time width; and the pulse sending A pulse generator comprising a self-monitoring circuit including a self-output pulse total number monitoring unit for counting the total number of external output pulses actually generated and transmitted from the pulse generator based on a start command.   2. The pulse generator according to claim 1, wherein the duration from the rising point is measured for each one of the output pulses transmitted via the state monitoring unit and the timer, and the duration is a predetermined time. When the maximum length is exceeded, the pulse generator is reset by giving a clear signal to the pulse generator to cause the output pulse to fall.

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