JPS6289497A - Controller for stepping motor - Google Patents

Abstract

PURPOSE:To smoothly rotate a stepping motor at exciting pattern switching time of a controller by providing means for storing the exciting pattern of an output pulse. CONSTITUTION:When one stepping motor 14 is controlled by two controllers 40, 50, the pulse output from the first controller 40 is input to the second controller 50 so that all pulses are applied from the controller 50 to the motor 14. The controller 50 has a means for storing the exciting pattern of the pulse output at previous time, a means for judging whether there is a variation in the pattern, and pulse generating means for outputting the pulse of the pattern continued to the previous pattern stored when the variation is judged. Thus, when new drive pulse is output from the controller 40, the pulse matched to the pattern of the pulse output finally from the controller 50 is again output from the controller 50.

Description

[Detailed description of the invention]

SUMMARY OF THE INVENTION There is a first device and a second device each generating pulses for driving a step motor. The pulses output from the first device are input to the second device, and the arrangement is such that all pulses are applied from the second device to the stepper motor. The second device monitors changes in the excitation pattern of the pulses input from the first device, and when there is a change, outputs pulses with an excitation pattern that is continuous to the excitation pattern of the previously output pulse that is stored. Output. 1-1 (1) Background of the invention (2) Outline of the invention (2, 1) Purpose of the invention (2, 2) Structure and effects of the invention (3) Description of embodiments (3, 1) Magnetic recording and reproducing device (3, 2) Electrical configuration of the video signal reproducing device (3, 3) Principle of high-speed random access (3, 4) High-speed random access
An example of access processing and the necessity of phase matching of driving pulses (3, 5) Phase matching processing of driving pulses (3, 6)) About fixing the count values of rack No. and counter CN (1) The backbone of the invention The present invention relates to a technique for controlling one step motor with two control devices. Two controllers each generate pulses to drive the stepper motors. After one controller drives the step motor, the other controller subsequently drives the motor during the same step. In such a case, the last excitation pattern of the series of drive pulses output from the control device of the controller matches the first excitation pattern of the series of drive pulses subsequently output from the other control device. It is preferable (7) because if the drive pulses are not phase aligned when switching from control by one control to control by the other, the step motor will be output from the other control. This is because the first drive pulse causes the motor to rapidly rotate by an angle corresponding to the phase difference. (2) Summary of the invention (2,1) Purpose of the invention It is an object of the present invention to enable a step motor to be smoothly rotated at the same time when the control device that performs control is switched when the control device is controlled by a control device of a stand. A step motor control device according to the present invention includes a first device and a second device that generate pulses for driving the step motor, and the pulses output from the first device generate pulses for driving the step motor. The device is configured such that all pulses are inputted to the second device and sent from the second device to the step motor, and the second device stores the excitation pattern of the previously output pulses. , means for determining whether or not there has been a change in the excitation pattern of pulses input from the first device, and when it is determined that there has been a change, outputting a pulse of an excitation pattern following the stored previous excitation pattern; It is characterized by being equipped with a pulse generating means. When rotating the step motor in forward and reverse directions, -1-
The determining means is configured to determine whether the change in the excitation pattern of the pulse inputted from the first device is in the forward or reverse direction, and the pulse generating means is configured to determine whether the change in the excitation pattern of the pulse inputted from the first device is in the forward or reverse direction, and the pulse generating means is configured to determine whether the change in the excitation pattern of the pulse inputted from the first device is in the forward or reverse direction. The previous excitation pattern that was memorized is correct/
The device is configured to output pulses of an excitation pattern that are continuous in opposite directions. With the configuration described in -1- below, when a new drive pulse is output from the first device, a pulse that matches the excitation pattern of the pulse last output from the second device is output from the second device again. Because it will be output. The step motor will now rotate smoothly. (3) Description of Embodiments Hereinafter, an embodiment in which the present invention is applied to an l-rack random access device in a magnetic recording/reproducing device will be described. (3,1) The need for random access processing of one track in a magnetic recording/reproducing device Recently, imaging devices such as solid-state image sensors and image pickup tubes, and magnetic disks, which are inexpensive and have a relatively large storage capacity as recording media, have become popular. The electronic still image is combined with a recording device using a digital camera to electronically photograph the subject, record the still image on a magnetic disk, and reproduce the seven images using a separately installed television system or printer. Mela system has been developed. In addition, 1 Ij of ordinary film and photographic paper, etc.
r Stillness 1 recorded on the visual recording medium! - A single-image magnetic recording system that photographs an image and records it on a magnetic disk, and a video reproduction system that reads a video signal from the magnetic disk and displays it on a television or the like have also been realized. In such a conventional magnetic recording + RR recording device. Magnetic disk! - Rack access was only possible one track at a time. That is, the conventional device is equipped with a forward switch and a reverse switch, and when the forward switch is pressed, the magnetic head moves one position inside!・
Proceed to the rack, and when the reverse switch is pressed, it will move to the next outer track. Therefore, in order to jump through several tracks and access a desired track (random access), you have to press the forward or reverse switch many times, which is a tedious operation. Ta. Also, each time the forward or reverse switch is pressed, the device controls the magnetic head to position it at the center of the next track (tracking control), which takes time, and it is difficult to do this for multiple tracks. If it were to be performed sequentially, a considerably long access time would be required. Especially when it comes to advanced recording and reproducing devices. While moving the magnetic head in the radial direction of the magnetic disk, the envelope of the read signal is detected, and the magnetic head is positioned f1'/ at a position where the envelope shows a peak. Because so-called mountain climbing control is being carried out,
The problem arises that tracking becomes very slow. Therefore, it is rare to realize a device capable of high-speed random access. There are probably two ways to implement a device capable of high speed random access. One is to create a device from scratch with the purpose of enabling high-speed random access, and the other is to add some (-J addition circuits to the conventional device) to provide high-speed random access. - Adding an access function.The latter method is more useful in saving development costs and time.This embodiment achieves high speed by adding some circuits etc. (=J) to the conventional device. This device is designed to have a random access function, and in order to realize this random access processing, the step Φ motor is driven and controlled by the control device according to the present invention without moving the magnetic head. It includes both a recording device and an "I!Ki" 11-r generating device (this is a new model).In order to make the description of the embodiment more concise, only the device that generates the video signal 11-r recorded on the magnetic disk will be described below. (3,2) Electrical configuration of the video signal reproducing device The magnetic disk loaded in the video signal reproducing device contains a plurality of magnetic disks (for example, 5
0) Book track (e.g. track pitch 1001
+m) are provided concentrically, and one field or one frame of FM-modulated color video signals (including brightness signals, chroma signals, etc.) is magnetically recorded on each track. . A magnetic reproducing head for reading these video signals is movable in the radial direction of the magnetic disk, accesses a designated track, and reads the video signal of that track from the rotating magnetic disk. FIG. 1 shows an example of the electrical configuration of a video signal reproducing device. ? ] The part surrounded by the chain line indicated by No. 1O is a conventional video signal reproducing device. This part of the device lO and the circuitry excluding the color television system 39, i.e. the second control device 50. Numeric keypad 51. New additions include a motor drive circuit 52 and switching transistors 55 and 5G. The first control device N40 provided in the conventional video signal reproducing device IO has a forward switch 15. It performs reading processing of the states of various switches including the reverse feed switch 16, tracking control described later, control of video signal reproduction, warning processing, etc. 2 central processing units, preferably microprocessors (hereinafter referred to as CPUs), their programs and It consists of a memory that stores necessary data and interfaces with each peripheral element circuit, device, etc. The control device 40 is also provided with a counter CN that counts the number of tracks 1-L of the magnetic head in normal magnetic head transfer and racking control other than random write access processing. A predetermined area of the memory may be used as the counter CN. A forward switch for inputting a command to move the magnetic head 12 one track from the outside to the inside of the magnetic disk 11, which will be described later.+5. A reverse feed switch 18 for sending the magnetic head 12 in the opposite direction; a load switch for detecting that the bucket (1:) is closed and locked; 111 Detects that the magnetic disk 12 is contained in the
pack switch. A home position switch (all shown in the figure), a power switch, and other switches, which will be described later, are connected to the first control device 40, and their on/off states are read in the Giesgian routine, which will be described later. A warning indicator light (illustrated path) is also provided, and is turned on by a display command from the control device 40 when a predetermined condition is met. The forward switch 15 and reverse switch 1G can be substituted by a numeric keypad 51, which will be described later, and therefore do not necessarily need to be provided. Magnetic disk 11 is mounted on the spindle of disk motor 21 when it is contained within the packet and the packet is closed and locked. The magnetic 11 is in contact with the magnetic recording surface of the magnetic disk 11.
The f-read head 12 is disposed so as to be movable in the half i% direction of the magnetic disk 11. Further, the core of the magnetic disk 11 is in contact with a phase detector 13 that detects a magnetic material provided in the core and generates one pulse for each rotation of the magnetic disk 11. The disk motor 21 is provided with a frequency generator 22 that generates a signal with a frequency proportional to its rotational speed, and its output frequency signal is fed back to a servo control circuit 23. The detection pulses from the nine-phase detector 13 are also input to the servo control circuit 23 and the control device 11-40. The standard lock contest pulse generator 24 generates a 60 Hz 1.0 kHz signal which is the same as the field frequency table of the rask scan video signal recorded on the magnetic disk 11. (Generates q signal) 7 Sends this to →Novo control circuit 23,
The control unit F740 has a high speed, for example 3.58 MHz.
clock pulses. 1 Node control circuit 2
3 drives the disk motor 21 based on these input signals.
at a constant rotation speed, for example 3. [100r, p, m. control to rotate at a constant speed. The motor 21 is also started and stopped in accordance with commands from the control device 40. The magnetic head 12 is supported movably in the radial direction of the magnetic disk 1.1 by a transfer drive device including a step motor 14, and is controlled to be transferred in the same direction. The control of the motor 14 during the step for transporting the magnetic head I2 will be described later.2 This step motor 1
4 has four phases A, A, and B by the drive circuit 52. B's drive pulse! I can get it. Drive pulse I) P is generated from the second control device 50 and given to the drive circuit 52 =
12 = Ru. During stepping, the direction in which the magnetic head 12 is moved is determined by the rotation direction of the motor 14, and the distance the magnetic head 12 is moved is proportional to its rotation angle. For example, step - [
- evening shift φ pulse per pulse this motor is approximately 3
The magnetic head 12 rotates approximately 8.4μ.
m is transferred. therefore. Almost one track (10
0 μm) transfer is performed. Here, one shift pulse means one change in the excitation pattern by four-phase drive pulses consisting of A phase, A phase, B phase, and B phase, as shown in FIG. When moving the magnetic head ■2 in the forward direction, one shift
Excitation pattern for each pulse is 1001→1100→01
10 → 0011, and when transferring in the opposite direction, the excitation pattern changes in the reverse order. The 4-phase drive pulse can be generated by hardware using the shift pulse as the clock ψ pulse.
0 and the shift pulse can be generated by the program of the CPU in the second control device 50, so the shift) pulse may not actually exist, but for the convenience of explanation, it is
The concept of a 1-shift pulse is used. The magnetic head 12 reads the video signal recorded on the i-rack of the tilted disk 11-1- at the (1°l position A or (I''! position). In this embodiment, the magnetic disk 11 is 3,600 r, p, m
, -C rotates at a constant speed, so one rotation is 1/[i 1 track worth of video signal every 0 seconds, i.e. 1 film).
An FM modulated video signal of %3 is reproduced from the magnetic head 12. Kone is i (NT by being toned)
SC) 1 standard color television system and both r
'f. (magnetic head) 2 (7) '+fi Riki Ikuyama power amplifier 31 is sent to the video signal processing circuit: (4 and envelope detection circuit 32. The video signal processing circuit 34 is
Signal processing (
7. For example, the circuit 34 extracts the vertical synchronizing signal VSYNC from the 8-demodulated N'rS (combined color video signal of the NTSC format) and outputs it as a combined color video signal of the NTSC format. 'lN4
It has the function of supplying this to D. Further, when receiving the signal MUTE from the control device 40, the scanning period of the video signal is set to a blank signal, and a muting operation is performed. The color video signal output from the circuit 34 is sent to a color television system 39 comprising a cathode ray tube display (referred to as CRT) 36 and its control circuit 35.
The video signal recorded on the magnetic disk II is visually displayed on the CRT 3B-1-t. The envelope detection circuit 32 detects signals 41 read from the magnetic head 12 and recorded on the tracks of the Zunawaji magnetic disk 11.
This is a detection circuit that detects the envelope of the FM modulated video signal that has been detected and outputs a voltage signal corresponding to the envelope. The voltage signal representing the envelope is sent to an analog/digital converter (A/D converter) 33 41. For example, it is converted into an 8-bit digital signal representing 256 quantization levels and input to the control device 40. The envelope detection signal is used to search for tracks on the magnetic disk 11. When the magnetic head 12 is moved in the radial direction of the magnetic disk 11, the position where the detected signal peaks is located at the position where the video signal is recorded.
It is the center of the rack. il, ll The ill device 40 controls the magnetic head transport drive device FI based on the input 8-bit digital signal to position the magnetic head 12 over the center of a predetermined track IH. This is called tracking control. In addition, the second control device 50 is also newly added. It is composed of a CPU (preferably a microprocessor), a memory for storing its programs and necessary data, and interfaces with each peripheral element circuit, device, etc. This memory contains the TI of the magnetic head 12.
, +7+: (: is placed (]・Rack No., ). There is an area for storing rack No., The second control device 50 also performs a key scan Φ routine.The second control device 50 controls the first control device 40 according to the state of the switch read in this key scan routine. = 16 - In the initial tracking control and forward and reverse feed processes described later, the drive path Jl/speed of the step motor 14 output from the first control device 4o is DP is input to the second control device 50. The second control device 50 receives this input pulse and sends the drive pulse DP to the step motor 14 via the drive circuit 52. This is for inputting the target track number ([1 mark track number, ), and the signal representing this track number is sent to the second control device 5.
Enter 0. In response to this, the second control device 50 outputs a required number of drive pulses for the step motor 14 in a one-shot feed process to be described later. 2. When this -feed processing is completed, a forward feed signal or a reverse feed signal is output. These signals cause switching transistor 5
5.5B are respectively turned on. The transistor 55 is connected in parallel to the forward switch 15, and the transistor 5G is connected to the reverse switch 16 in parallel. therefore,
When the transistor 55 is turned on by the forward signal outputted from the second control device 50, the same effect as if the forward switch 15 was pressed is returned to the first control device 40. If reverse feed signal is output, reverse feed switch 1
This is equivalent to pressing 6. FIG. 3 shows the relationship between the tracks provided on the magnetic disk 11 and the home position HP (original position or standby Rt, f&) of the magnetic head 12. Fifty tracks are provided concentrically on the magnetic recording surface 1 of the magnetic disk, and are numbered 1 to 50 in order from the outermost track.
Track No. 3 up to is attached. The home position HP is outside the track No. ]. This home position HP is not attached to the magnetic disk 11, but is an extreme position allocated to the movement path 1- of the magnetic head 12. The home φ position HP is detected by the home position switch described in ①-. The movement of the magnetic head I2 from the outside to the inside of the magnetic disk 11 is forward feeding, and the movement in the opposite direction is called reverse feeding. (3,3) Principle of high-speed random access FIG. 4 shows the principle of high-speed random access of any track according to the present invention. The magnetic head 12 is located at track No. TK,
Use the numeric keypad 51 to select the track number and T.
Suppose N is given as a target track to be accessed. For now, let us consider the case where N≧2. First, target track No. I is one track before T.
Up to N racks (N-1)), four forward air feeds are performed on the racks. 12 pulses to the step motor 14! By moving the magnetic head 12 by one track, +2X (N-1) pulses are applied to the step motor 14. With this, the magnetic head 12!・Transferred to the truck with rack No. T up to +N-1. This pneumatic feed is performed by the second control device w5.
This is done under the control of 0. Thereafter, a sequential feed signal is given from the second control device 50 to the first control device 40. As a result, the first control device 40 performs normal forward tracking control, moves the magnetic head 2I in the forward direction to an adjacent track (track No. -19=T), and positions it at its center IN. 1. Description

[7] In this control unit, the drive pulse of the step motor 14 output from the first control device (N40) is applied to the step motor 14 by passing through the second control device 50. When N≦-2 , the second control device 50 performs one-shot feeding in the reverse feed direction, and then the first control device 4
0 is given a reverse feed signal and the second
Needless to say, reverse tracking is performed through the control device 50. In the case of N-1 or -1, the second control device 50 does not need to feed the second one at once, and the first control device 40
Only racking (forward or reverse feeding through the control device 50) takes place. When N=0, there is no need to move the magnetic head I2, so no processing is performed. In a conventional video signal reproducing device, if the magnetic head is
If 0 tracks are to be transferred, the above tracking control must be repeated 50 times. Tracking control to an adjacent track takes 0.4 seconds, so even a simple calculation would require 20 seconds. Using the high-speed random access method described above, it takes only 0.6 seconds to feed 501 racks at a time, so 0. [Access becomes possible in about i+0.4-1.0 seconds. It will be appreciated that very fast random access can be achieved. (3, 4) An example of high-speed random access processing and the necessity of phase matching of drive pulses First, the order, reverse feed, and tracking control of the first control device 40 will be explained. This control includes an initial racking process, forward feed control, and reverse feed control process. The initial tracking process is performed when a reset signal is applied from the second control device 50. Reset when the device is powered on, when the magnetic disk contained in the packet is replaced, when a reset signal is input from the numeric keypad 51, or when the Ryuteki 2 control device 50 determines that it is necessary. A signal is provided to the first controller 40 . As mentioned above, the first control device E40 performs key scans at regular intervals, but the required switches (power switch, rotor switch, pack switch, etc.) are scanned during the key scan by the second control device 50. except,
These switches are connected to ground, for example, so that a change in the state of these switches cannot be detected by key scanning by the first control device 40. In this initial tracking process, the magnetic head 12 is first returned to the A1' device at the home position HP, and the magnetic head 12 is moved in the forward direction from the home position HP to track No. 1. The magnetic head 12 is positioned at the center of the track while searching the center. As a result, the track number and the count value of the counter CN become 1, but in order to further advance the value of this counter CN to an appropriate value in the range of 2 to 49, a sequential feed signal is output from the second control device 50. Ru. As a result, the first control device 40 starts a sequential feed process to be described later, and a drive pulse for the step motor 14 is output, but the second control device N50 ignores this drive pulse and outputs a drive pulse to the step motor 14. not give. Therefore, the magnetic head 12 does not actually move, and only the counter CN is incremented. By repeating this forward empty feed several times, the value of the counter CN is set to the above-mentioned appropriate value. The technical meaning of this will be discussed later. FIG. 5 conceptually shows an overview of forward and reverse processing and tracking processing. The first control device 40 senses the states of the forward feed signal (switch 15), reverse feed signal (switch 16), etc. at a constant cycle. As a result, when the forward feed signal is sensed (YES in step 101), the following forward feed and tracking processing is performed. If the track No. and the value of the counter CN are not 50 (NO in step 111), in order to move the magnetic head 12 to the vicinity of the center of the adjacent track in the forward direction, the shift pulse corresponds to 11 shift pulses in the forward direction. The change in the drive pulse is applied to the middle motor 14 via the second control device 50 (Step 112). Then, the output of the envelope detection circuit 32 at this time is read in. Subsequently, one more forward shift pulse is output and the envelope level is similarly sensed. If there is no significant difference between the previous and current envelope levels, search the envelope levels in the vicinity many times while switching the transport direction of the magnetic head 12 between forward and reverse directions to find a significant difference between the respective envelope levels. After confirming that there is no track, the position is determined to be the center of the track, and the magnetic head 12 is positioned there. If there is a significant difference between the previous and current envelope levels, the envelope
Shift the magnetic head 12 one more time to the higher level.
Repeat the same process by moving the pulse. This is the tracking control process in step 113. Note that the envelope level is a predetermined threshold φ
If the level is below F, it is determined that no video signal is recorded on that track. Finally, if the track number and the value of the counter CN are 1, they are incremented (step 114). If the values of the track number and counter CN have reached 50, sequential forwarding is impossible, so a warning process is performed by lighting two warning indicator lights, sounding a buzzer, etc. (step 115). If a reverse feed signal is detected (Y in step 102)
ES), a process similar to the two series of processes for the reverse direction is performed (steps 122 and 123). Counter CN is decremented by 1 (step 124
). Furthermore, when CN=1, a warning process is performed (steps 121, 125). Next, an example of processing by the second control device 50 will be explained. The processing of the second control device 50 includes reset processing and random access processing. The reset process returns the current position storage area of the memory in the second control device 50 to the initial state, that is, track No. 1.
is stored as the current position. As described above, this process is started when the reset key in the numeric keypad 51 is input, when the magnetic disk 12 is replaced, when the power is turned on, and at other times. The second control device #5+1 sends a reset signal to the first control device 40. In response to this reset signal, the first control device 40
- The initial tracking process described above is performed, and the magnetic head 1
2 is positioned on track N091. Further, in the second control device 50, track number 1 is set in the current position storage area of the memory. Thereafter, the sending of the sequential feed signal described above is repeated [by step 7, the track number of the first control device 40 and the value of the counter CN are set to appropriate values between 2 and 49]. FIG. 6 shows an outline of an example of random access processing by the second control device 5( ). It is assumed that the current position storage area stores l, rack No., and Ig. 1-1 mark track number to be accessed from numeric keypad 51
, and when the value (K+N) is input, this is read (step +31), and it is first checked to see if it is a number between 1 and 50 (step 132). If it is within this range, the track number of the next key input,
The operation of subtracting the track number of the current position storage area from (K + N) - K is performed, and the result is N
is 0 or not (steps 133, 13
4). If the key-input track number is not within the range of 1 to 50, or if the subtraction result N is 0, no processing is performed. Subsequently, it is determined whether N-1, N=-1, or something else (step 135). If N≧2 or N≦-2, it is further checked whether N>0 or N<0 (step 136). If N>O, forward random access processing is performed, and if N<0, reverse random access processing is performed. In the forward random access process, first, in the forward direction (N
-1) In order to transfer the l-rack dividing magnetic head [2], drive pulses corresponding to 12 (N-1) shift pulses are output from the second control device 50 and passed through the drive circuit 52 [7]. is applied to the step motor 14 (step 141). Thereafter, a sequential feed signal is given from the second control device 50 to the first control device 40 (step 142). Then, the first control device 40 starts the forward tracking process (steps 101, 111 to 114) shown in FIG. 5, and outputs a series of drive pulses. Second control device 50
receives this drive pulse and outputs it as is to the step motor 14, and the process is carried out in the following four steps. First, it is determined whether the excitation pattern of the drive pulse input from the first control device 40 to the second control device 50 is 0000 (step I43). The excitation pattern is 1OQ1, 11... of A, A, B, B phases explained using FIG.
It is in a state such as 00. The fact that this excitation pattern is 0000 means that the first control device 40 is not outputting any driving pulses. Therefore, step 14
Processing 3 is to wait for a drive pulse to be sent from the first control device 40 after sending a forward feed signal. When it is output (step 143 - NO), the second control device 50 reads the excitation pattern (step +44) and outputs a drive pulse of the same excitation pattern to the drive circuit 52 of the step motor 14. (Step 146).This means that the drive pulse outputted from the first control device 40 remains as it is and the second control device 5
This is equivalent to passing through 0. By repeating this process, progressive tracking is performed, and the magnetic head 12 is at the center of the target track.
When positioned at -, the first control device 40 no longer outputs drive pulses. Therefore, the second control device 5
The excitation pattern read at 0 becomes 0000 (YI home S at step 145). Thereafter, a reverse feed signal is sent to the first control device 40 (step 147), and the key-input target track number, (K
+N) is stored in the memory (current (17 position storage area)) of the second control device 50 as the current position of the magnetic head 12 (step 148).In response to the reverse feed signal of step 147, the first control device 40 The reverse tracking process (steps 102.121 to 1) shown in FIG.
24). From the first control device 40 to the second control device 5
A drive pulse is input to the step motor 14, but the second control device 50 ignores the input of this drive pulse and does not output a drive pulse to the step motor 14. Did you? Therefore, the magnetic head 12 does not actually move. That is, in the tracking control at step 123 in FIG. 5, it is determined that there is no significant difference between the previous and current envelope fist levels, so the first control device 40 (+111) always ends the reverse tracking process. Step +51-1.57,148 backward random
Access is also performed in the same manner as the forward random access described in -1-. However, in step +51, drive pulses equivalent to 12X (N-1) shift pulses in the reverse direction of C are sent out, in step 152 a reverse feed signal is sent out, and in step 157 in the forward direction. They differ in the way the signals are sent. If N=1, since there is no need for the second control device 50 to feed all at once, step +41 is skipped and the process moves to step 142, where the first control device 40 performs sequential feeding. In the case of N--1, step 151 is skipped and the process moves to step 152. As shown in FIG. 2, the excitation pattern of drive pulses provided to the stepper motor 14 always changes in a fixed order, thereby causing the stepper motor 14 to rotate smoothly. However, in the random access processing described in -1-, - the driving pulse for pneumatic feeding is generated from the second control device 50, and - the driving pulse for the forward or backward processing performed after pneumatic feeding is generated. is generated from the first controller 40 and passed through the second controller 50 as it is to the step motor 14. Therefore, the last excitation pattern in the air-feeding process and the first excitation pattern in the forward-feeding or reverse-feeding process are not necessarily in the fixed order relationship described in 1-1, and in many cases, the relationship between these two processes is The excitation pattern changes discontinuously during switching. In this case, there is a possibility that the step motor 14 suddenly rotates by a certain angle, or rotates by a certain angle in the reverse direction even though it is forward feeding. For example, when rotating in the reverse direction, the magnetic head I2 reaches near the peak of the envelope level on the target track even after sending out the first 11 shift pulses in forward or reverse processing. However, it is possible that the envelope fist level read at the time is lower than the predetermined threshold level. In this case, the first control device 40 determines that no video signal is recorded on the [-1 mark] rack. (3,5) Phase matching processing of drive pulses In order to eliminate the possibility of such a situation occurring,
According to the invention, the second control device 50F7)Illll
Phase matching with the 141 force drive pulse of the dynamic drive pulse 1 controller 40 is performed. This phase matching process is illustrated in FIG. 8 for the case of forward random access. In this figure, the same processes as those shown in FIG. 6 are given the same reference numerals. The memory of the second control device 50 is provided with an area Po for storing output excitation patterns. This area Po stores the excitation pattern last output from the second control device N50 in the previous process (step 1
67). Now, when forward random access is determined (6th
(YES in step 136), the process moves to the process shown in FIG. Written on! 1.2 (N-
1) drive pulses corresponding to shift pulses are output from the second control device 50 (step 141A). For example, referring to FIG. 2, if the excitation pattern stored in area Po is 1001, the excitation pattern output first in step 141A is 1100, followed by the order 0110.0011. Drive pulses are output. This process allows you to step from the angular position where it was stopped at the end of the previous process.
The forward rotation of the motor 14 begins smoothly. When the transfer of the magnetic head 12 for the forward direction (N-1) track is completed, the excitation pattern of the drive pulse output last in this transfer process is stored in the area Po (step 16).
1). Then, a sequential feed signal is sent from the second control device 50 to the first control device 40 (step +42), and the second control device 50
waits for the first control device 40 to start the forwarding process (
Step 143). When the first control device 40 starts the sequential feeding process, a drive pulse of an excitation pattern other than pattern 0000 is sent from the first control device 40 to the second control device 50, so step 1
43 is NO. The second control device 50 is the first control device 4
Regardless of the excitation pattern of the drive pulse input from 0, the drive pulse of the excitation pattern next to the excitation pattern stored in the area Po is output to the step motor I4 (step 162). Then, it is monitored whether or not the excitation pattern of the drive pulses input from the first control device 40 has changed. (Step 163). As described above, in the sequential processing, the first control device 40
After sending out drive pulses equivalent to 11 shift φ pulses in the forward direction, tracking control is started, and the step motor 14 is set to iE according to the output of the envelope detection circuit 32.
, search for the peak of the envelope while rotating in the opposite direction. Therefore, the excitation pattern of the drive pulses output from the first control device 40 changes in the forward direction for at least the first 11 pulses, but thereafter changes in either the forward or reverse direction. In any case, the second control device 50 is the first control device 40
The change in the excitation pattern input from the controller is monitored, and if there is a change, it is checked whether it is a change in the forward direction, a change in the reverse direction, or whether the excitation pattern has become 0000 (step 164). Since the first 11 shift pulses change in the forward direction, the process proceeds to step 165, where the second control device 50 selects an excitation pattern that is next to the excitation pattern of the drive pulse output last time, that is, one step forward in the excitation pattern. Output to step motor 14. When the first controller 40 enters the tracking fist routine, the input excitation pattern changes in either the forward or reverse direction. If the change 17 is in the forward direction, an excitation pattern that is one step forward in the excitation pattern output last time is output as described above (step 165).
If the change is in the opposite direction, an excitation pattern obtained by returning the previously output excitation pattern by one step in the opposite direction is output (step 166). Input 1 from the first control device 40 to the second control device 50. No drive pulses are sent directly to motor 14 during stepping. The excitation pattern of the drive pulse inputted from the first control device 40 is used only to detect whether there is a change in the excitation pattern and whether the change is in the forward or reverse direction. The drive pulses to be sent to the step motor 14 are generated in the second control device 50 so as to be consistent with those applied previously, that is, to be continuous with the previously output excitation pattern. In this way, step motor 14 always rotates smoothly. The excitation pattern input from the first control device 40 is 0000.
Then, since the forward processing in the first control device 40 is completed (7), the last excitation pattern output from the second control device 50 is stored in the area Po (step 187), and the reverse feed signal is sent and the magnetic Head position storage processing is performed (steps 147 and 148).It goes without saying that the I'I phase matching of the drive pulses is performed in almost the same way in the reverse J direction random access.Steps 147 and 148. 141^ as ``Area P.
) Pulse output", step +42 is rRE
Step 162 is changed to the process of ``sending V signal'', step 162 is changed to the process of ``outputting the excitation pattern that is one step back in the opposite direction of the excitation pattern of the storage area Po'', and step 147 is changed to the process of ``sending out the V signal''.
What is necessary is to change the processing to "FWD signal transmission". (3, 8) About fixing the l-rack No. and the run I value of the counter CN In the flowcharts of FIGS. 6 and 8, in the case of forward random access, the first control device 40 Forward tracking is performed by tilting the signal (step +42), and a reverse signal is further applied to perform pseudo reverse tracking (step 147).
). The same is true for reverse random access (
FIG. 6, steps 152 and 157). This is it, the first
This is to fix the track number and the value of the counter CN of the control device 40. As described above, when forward processing is performed in the first control device 40, the track number and counter CN are incremented over and over, and when backward processing is performed, 1j is again incremented.
Deku 1 is nominated (Steps 114 and 124 in Figure 5)
). However, if steps 147 and 157 in FIGS. 6 and 8 were not provided, the following problem would occur. Referring to FIG. 7, it is assumed that the current position of the magnetic head I2 is track No. n ['), l.rack No., and the value of the counter CN is 1. On the numeric keypad 51 (n
+2) is input and forward random access is performed, the current f1'/position becomes (n+2) and the value of the counter CN becomes (m+1). Next track N
o, when a random access is made to (n+4), the current position is (n+4) and the value of counter CN is (m+2).
becomes. When such small forward random access is repeated a total of four times and the current position reaches (n+11), the value of the counter CN becomes (m+4). After this, n is specified using the numeric keypad 51 and the reverse direction random
When access is performed, the current position returns to n, but the value of the counter CN returns only to (m+3). If the quantum-like operation is repeated many times, the value of the counter CN gradually increases until it reaches 50. When the value of the counter CN reaches 50, forward processing is no longer performed (steps 111 and 115 in FIG. 5). A similar problem occurs when the value of the counter CN decreases as desired, and when the value of the counter CN reaches 1, reverse feed processing becomes impossible. In order to avoid such a situation, in the processing shown in FIGS. 6 and 8, in the case of forward random access, a forward direction signal is sent to the first control unit w40 to perform sequential forwarding. Later (step 142, CN increases by 1 IJI
I), the reverse direction signal is Q and the reverse direction is skipped (
Step +47. CN decreases by 1), and the value of the counter CN is fixed. The same applies to reverse random access. It is necessary to set the track number and counter CN values in the first control device 40 to appropriate values between 2 and 49, which is -11 in advance. In the processing), the value of the counter CN is set to an appropriate value within the range of 2 to 49 by performing forward null feeding from 1 to 48 times.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of the video signal i17 generation device. FIG. 2 is a waveform diagram showing four-phase drive pulses and excitation patterns for the step motor. Figure 3 shows the track arrangement of the magnetic disk and the home
It is a figure which shows the position of a position. FIG. 4 is a diagram for explaining the principle of random track access. = 40 - FIG. 5 is a flow chart showing the conventional processing procedure in the first control device. FIG. 6 is a flow chart showing an example of a random access processing procedure by the second control device. FIG. 7 is a diagram for explaining the necessity of fixing the track number and counter of the first control device. FIG. 8 is a flow chart showing a random contention access processing procedure improved by applying the present invention. 14... Ste-tsubu competition motor. 40...First control device. 50...Second control device. Patent applicant: Fuji Photo Film Co., Ltd. Agent
Patent Attorney Asami Kato (External 1)
given name)

Claims (1)

[Claims] (1) There is a first device and a second device that each generate pulses for driving the step motor, and the pulses output from the first device are input to the second device, and all pulses are is configured to be applied to the step motor from the second device, and the second device has means for storing the excitation pattern of the pulses output last time, and means for storing the excitation pattern of the pulses input from the first device. Control of a step motor, comprising means for determining whether or not there has been a change, and pulse generation means for outputting a pulse of an excitation pattern following a stored previous excitation pattern when it is determined that there has been a change. Device. (2) The determination means determines whether the change in the excitation pattern of the pulse inputted from the first device is in the forward or reverse direction, and the pulse generation means determines whether the change in the excitation pattern of the pulse inputted from the first device is in the forward or reverse direction, and the pulse generation means The step motor control device according to claim 1, wherein the step motor control device outputs pulses of an excitation pattern that are continuous in the forward/reverse direction to the stored previous excitation pattern.