JPS6326640B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for measuring the time difference from the time when a stop signal of a stepping motor is generated to the time when the stepping motor actually stops.

Stepping motors are excited and driven by pulse signals and are easy to control, so they are widely used in various fields.

By the way, a stepping motor is stopped by stopping the oscillation of excitation pulses in response to a stop signal, but stopping a rotating motor at the same time as a stop signal is input will cause the motor to rotate at a constant speed or higher. If so, it's almost impossible. Particularly when the motor is rotating at high speed, a sudden stop may cause vibrations, which may cause damage to the driven device and the motor itself.

Therefore, the stepping motor is stopped by gradually decreasing the excitation pulse after inputting a stop signal to smoothly stop the motor. Figure 2 shows an example of pulse changes from the time the stop signal is input to four phases (A phase,
(phase, B phase, phase) excitation methods are shown below. A stop signal is input at (t ₁ ), after which the pulse width and pulse interval gradually become longer until finally no pulses are emitted.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device that measures the time from when such a stop signal is input to when the stepping motor actually stops.

Next, the function realizing means of the apparatus of the present invention will be explained based on FIG.

1 is a stepping motor excitation pulse generating means, and the excitation pulse generated by the pulse generating means 1 is sent to the stepping motor 2 and excitation pulse input means a. The input means a performs waveform shaping of the excitation pulse, and sends its output to the excitation pulse measurement means b.

The excitation pulse measuring means b measures the pulse width and/or pulse interval of the excitation pulse. This measurement is constantly performed for each pulse. Further, the object to be measured may be only the pulse width, only the pulse interval, or both.
Note that, unless otherwise specified, the case where the pulse interval is measured will be described as a typical example.

Denoted at step c is a stepping motor stop signal detecting means, which detects a stop signal generated by the operation of the stop switch 3 and sends the signal to the measuring means b.

The pulse interval measured by the measuring means b is stored in the storage means d. The contents stored in the storage means d may be updated for each pulse, or if there is only one pattern of excitation pulses during steady driving of the stepping motor, the contents stored in the storage means d may be updated for each pulse. The pulse interval of the excitation pulse is set to 1
It may be something that has been memorized twice. In the latter case, a predetermined pulse interval may be stored in the storage means d.

When the stop switch 3 is activated, a stop signal is sent to the stop signal detection means c and also to the pulse generation means 1, which reduces the frequency of the oscillation pulse as described above (see Fig. 2, hereinafter this pulse will be referred to as a stop pulse). ).

Similarly, the stop pulse is inputted to the measuring means b through the pulse input means a, and its pulse interval (D) is measured.

The measurement result of the pulse interval of the stop pulse is sent to the stop determination means e. The contents stored in the storage means d (hereinafter referred to as the pulse interval (DS) of the reference pulse) are also input to the stop determination means e. The stop determination means e compares the pulse interval (D) of the stop pulse with the pulse interval (DS) of the reference pulse, and determines when the pulse interval (D) of the stop pulse becomes a predetermined times the pulse interval (DS) of the reference pulse. It is assumed that the stepping motor has already stopped, and an output is sent to timer f.

A stop signal is inputted to the timer f from the stop signal detection means c, and the timer f is started by the input and stopped by the input from the stop determination means e. Therefore, the content of timer f is longer than the actual stopping time of the stepping motor by a predetermined times the reference pulse interval (DS) (hereinafter referred to as error time (DE)).

Therefore, the contents of timer f are sent to correction means g,
Subtract the error time from the content sent from the timer. The output of the correction means g is sent to the display means h, and the time difference from the generation of the stop signal to the actual stop of the stepping motor is displayed. As the display means h, for example, a digital display, a universal counter, an oscilloscope, etc. are suitably used.

In this way, the device of the present invention compares the reference pulse when driving the stepping motor with the stop pulse after the stop signal is input, and detects when the pulse interval of the stop pulse becomes a predetermined times the pulse interval of the reference pulse. ,
A major feature of this method is that the stepping motor is assumed to have already stopped, and the time from the time when a stop signal is generated to the time when the stepping motor temporarily stops is measured and then corrected.

It is clear that similar effects can be obtained even if the object of measurement is not the pulse interval but the pulse width or both the pulse interval and the pulse width. Furthermore, in order to obtain accurate measurement results, it is preferable to measure not only one phase but also two or more phases.

Further, the content stored in the storage means d may be the pulse interval of each pulse, the pulse interval of a typical pulse, or the pulse interval of a predetermined pulse, as described above. .

Storing and updating each pulse is particularly suitable when the excitation pattern of the stepping motor can be changed. In this case, a stop signal is input from the stop signal detecting means c, and updating of the stored contents is stopped by inputting the stop signal, and the contents immediately before the input of the stop signal are adopted as the reference pulse.

The stop determination means e may constantly compare the measurement results of the measurement means b and the contents of the storage means d, or may start the comparison when a stop signal is input.

How many times the pulse interval of the reference pulse should be used for the time required for stop observation (error time), which is the standard for determining the temporary stop of the stepping motor, depends on the excitation method of the stepping motor, the object to be driven, and the required This can be selected appropriately depending on the accuracy, etc., but in most cases, when the stopping pulse reaches a pulse interval in the range of 2 to 5 times, usually 3 to 4 times, the pulse interval of the reference pulse, the stepping motor will stop. It can be assumed that it has already stopped.

For example, in FIG. 2, the pulse interval (DS) of the reference pulse is 1, and if a stop signal is input at _t1 , the pulse interval (D) of the stop pulse becomes gradually longer. If the measurement target is phase (A) and the stop judgment criterion is when the pulse interval (D) of the stop pulse becomes three times or more the pulse interval (DS) of the reference pulse, that is, a temporary stop, then the stop At the time of signal input, the second pulse P from t ₁ is the pulse interval D ₃ from 1 to _the next pulse (not shown; there may be no next pulse) at a point t that is three times (DS). ₃
exceeds. Therefore, the error time (DE=
3DS) is subtracted from point _t2 , which is the point at which the stepping motor actually stops. In addition, in a stepping motor, the pulse usually changes (for example, the point
Even after t ₂ ), current continues to flow for a certain period of time, and mechanical movement may occur. Therefore, in such a case, the error time can be estimated to be one pulse shorter, for example, to be 2DS. In that case, the point at which the stepping motor actually stops is point _t4 .

Measurement in measuring means b involves, for example, detecting the pulse state (“HIGH” or “LOW”) at intervals much shorter than the pulse width and/or pulse interval, and counting the time that the same state continues. It may be expressed as such, but it is not limited to this method.

Next, FIG. 3 shows a schematic block diagram of an embodiment of hardware for implementing the apparatus of the present invention.

10 is the stepping motor excitation pulse (A phase,
This is a waveform shaping section that adjusts the waveforms of phase A, phase B, and stop signals, and is connected to the input port 12 of the microcomputer via the voltage comparison section 11. Reference numeral 13 denotes a reference voltage generation section, which sends a reference voltage to the voltage comparison section 11. 14 and 15 are a stamper switch and a reset switch, respectively.

Each signal input to input port 12 is sent to the CPU
16. The above processing in ROM 17 and RAM 18,
It makes a judgment and outputs the output from the output port 19. The output is a digital output and a segment output when a dedicated digital display 20 such as an LED is used as a display means, and is output via an output buffer 21 when a general-purpose universal counter or oscilloscope (not shown) is used. Count start signal (corresponds to stepping motor stop signal)
and a count stop signal (corresponding to the output of the correction means g).

The device of the present invention may be incorporated into a driven device or its control device, or may be configured as an independent measuring device by providing connection terminals at the input section and output section.

Next, an embodiment of a flowchart of a program for operating the apparatus of the present invention is shown in FIG.

In this embodiment, processing and judgment are performed under the following conditions.

(i) There are two stepping motors: 3 msec and 4 msec.
Driven by excitation pulses with switchable stages (ii) Measurement targets are both pulse width and pulse interval (iii) Phases of pulses to be measured are A phase and B phase (iv) Pulse width (“HIGH”) and pulse interval ("LOW") measurement is counted every 400 μsec (v) The count is updated every pulse. Each symbol shown in FIG. 4 represents the following processing and judgment, respectively.

(100): Set the CPU to the initial state (101): Reset switch ON (102): Is the standby switch ON? (103): Is the A phase input pulse “HIGH”? (104): Has the A phase input pulse become “LOW”? (105): Has the A phase input pulse become “HIGH”? (106): Count every 400 μsec until it becomes “HIGH” (107): Has the A phase input pulse become “HIGH”? (108): Update the previous count number (reference pulse interval DS) in RAM to the measured count number (reference pulse interval DS) (109): Has a stop signal been input? (110): Count every 400μseo until it becomes "LOW" (111): Has the A phase input pulse become "LOW"? (112): Update the previous count number (standard pulse width WS) in RAM to the measured count number (standard pulse width WS) (113): Was a stop signal input? (114): Stop updating count number (115): Error time calculation (DE and pulse width error time WE) (116): Start timer (117): Is the A phase input pulse “HIGH”? (118): Has the A phase input pulse become “LOW”? (119): Count the length of “LOW” (stop pulse interval D) every 400 μsec (120): D>3DS? (121): Has the 1A phase input pulse become “HIGH”? (122): Counts the length of “HIGH” (stop pulse width W) every 400 μsec (123): W>3WS? (124): Does the pulse interval or pulse width of the B-phase input pulse exceed three times the pulse interval or pulse width of the reference pulse? (125): Stop timer (126): Error time (DE or
When using the device of the present invention, the time difference between when the stop signal is input and when the stepping motor actually stops must be calculated accurately within the required precision. The measurement results provide important data for correcting the moving position and distance of the driven device, or for inspecting stepping motors.

In a special field, it can be used as a device for displaying the time from the stop signal for the reels (rotationally driven by a stepping motor) of an electric slot machine, which is a game machine, to the time when the reels actually stop. In electric slot machines, it is stipulated that the reel stop time difference must not exceed a predetermined time, and the time difference is required to be displayed.

As described above, the device of the present invention is highly effective in controlling and inspecting stepping motors in various fields where stepping motors are used.

[Brief explanation of drawings]

Fig. 1 is a schematic block diagram of the function realizing means of the device of the present invention, Fig. 2 is a schematic waveform diagram of an example of a stopping pulse of a stepping motor, and Fig. 3 is an example of an electronic circuit of the device of the present invention. Schematic block diagram of 4th
The figure is a flowchart of an embodiment of a program for operating the device of the present invention. (Main symbols in the drawing), 1: Stepping motor excitation pulse generation means, 2: Stepping motor,
3: Stop switch, 10: Waveform shaping section, 12: Input port, 16: CPU, 17: ROM, 18:
RAM, 19: Output port, 20: Digital display, a: Excitation pulse input means, b: Measurement means,
c: stop signal detection means, d: storage means, e: stop determination means, f: timer, g: correction means, h: display means.

Claims (1)

[Claims] 1 (a) stepping motor excitation pulse input means, (b) means for constantly measuring the pulse width and/or pulse interval of the excitation pulse, (c) stepping motor stop signal detection means, (d) means for storing the pulse width and/or pulse interval of the stepping motor excitation pulse before inputting the stop signal; (e) means for storing the pulse width and/or pulse interval of the stepping motor excitation pulse before inputting the stop signal; pulse width and/or
The pulse interval is compared with the pulse width and/or pulse interval of the reference pulse stored in the storage means d, and the pulse width and/or pulse interval of the stopping pulse are compared with the pulse width and/or pulse interval of the reference pulse. (f) A timer that measures the time from inputting a stop signal to inputting an output from the stop determining means; (g) Determining the pulse width of the reference pulse from the contents of the timer; and (or) a correction means for reducing the pulse interval by a predetermined multiple; and (h) a means for displaying the content of the correction means. 2 (a) stepping motor excitation pulse input means, (b) means for constantly measuring the pulse width and/or pulse interval of the excitation pulse, (c) stepping motor stop signal detection means, (d) the stop signal means for storing the pulse width and/or pulse interval of the stepping motor excitation pulse before input; (e) the pulse width and/or pulse interval of the stop pulse measured by the measuring means b after input of the stop signal;
The pulse interval is compared with the pulse width and/or pulse interval of the reference pulse stored in the storage means d, and the pulse width and/or pulse interval of the stopping pulse are compared with the pulse width and/or pulse interval of the reference pulse. (f) A timer that measures the time from inputting a stop signal to inputting an output from the stop determining means; (g) Determining the pulse width of the reference pulse from the contents of the timer; and (or) a predetermined times the pulse interval - a stepping motor stop time difference measuring device having a correction means for reducing the pulse width of the reference pulse and/or the time of the pulse interval; and (h) means for displaying the content of the correction means.