JPS62235573A - Rotation detector - Google Patents

Abstract

PURPOSE:To always detect a reversion in rotation quickly without variations, by performing a discrimination based on a time sequence relationship of edge pulses of a rotary pulse different in the phase with a pair of rotation sensors. CONSTITUTION:When a capstan motor of a rotor rotates forward, a phase difference of 90 deg. exists between output pulses of rotation sensors 3 and 4 and a pulse equivalent to the phase difference of 90 deg. is applied to a clock terminal CLK of a D type FF 17 through an AND gate 14 to which an edge pulse is applied from exclusive OR circuits 12 and 13. Then, an output of OR gates 15 and 16 to which are separately applied a Q output of the FF and an output of the circuit 12 and a Q output thereof and an output of the circuit 13 go to H while an output of an AND gate 18 goes to H and hence, there is no L output indicating a reversion in rotation. On the other hand, with the occurrence of a reversion, an output pulse of the sensor 3 breads off and output pulses of the sensor 4 are detected twice continuously. Likewise, the output of the gate 18 moves to L immediately after a reversion in rotation. Thus, the reversion in rotation can be always detected quickly without variations.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotation detection device that can accurately detect forward and reverse rotations of rotations 1 and 7.

[Prior Art] A magnetic recording device for long-term recording that intermittently advances a magnetic tape and records still images on the stopped magnetic tape rotates a capstan motor intermittently and applies braking at a predetermined rotational position. A method is adopted in which the magnetic tape is sent one track at a time. Rotation control of the capstan motor requires the rotation angle of the rotor, but since it is necessary to know when to release the braking of the capstan motor, a pair of rotation sensors whose detection phases are shifted are generally used. It will be done.

The conventional rotation detection device 1 shown in FIG. 3 includes a pair of rotation sensors 3, 3 and 3, whose output rotation pulses have a phase difference of about 90 degrees, with respect to a slit disk (not shown) that rotates integrally with the rotor of a capstan motor 2. 4 is provided, and D is provided for reversal discrimination.
The configuration is such that the data input terminal and clock input terminal of the flip-flop 1 circuit 5 are connected to rotation sensors 3 and 4, respectively.

The D-tree flop circuit 5 operates, for example, at time 1. in FIG.
When the rotational direction of the slit disk is reversed, the phase relationship between the output of the rotation sensor 4 and the output of the rotation sensor 3 is reversed, so that the Q output changes from a high level to a low level or vice versa at time t2, Detect rotor reversal.

[Problems to be Solved by the Invention] The above-mentioned conventional rotation detection device 1 has a D flip-flop circuit 5 which uses the output of one rotation sensor 3 as a clock input and the output of the other rotation sensor 4 as a data input. Since the configuration is such that the presence or absence of reversal is determined based on the output, as shown in FIG. 4, D
It may take some time until the time t4 when the output of the flip-flop circuit 5 is reversed, and if the output of the rotation sensor 3.4 has a phase difference of 90 degrees as in this example, in the worst case A time delay of 4 clocks will occur.For this reason, if the rotating body is braked and gradually slows down, there will be a long time delay even with 3/4 clock. There was a problem.

Furthermore, regarding the time lag between when the rotating body actually reverses and when the reversal is detected, (t2 t+
) and (ta ts), the variations are severe, so even if the deviation is corrected, there is a problem that there is no effective decisive method.

[Means for Solving the Problems] The present invention solves the above problems, and includes a pair of rotation sensors that detect the rotation of a rotating body with a predetermined phase difference, and a pair of rotation sensors that detect the rotation of a rotating body with a predetermined phase difference. Edge pulse generation means for forming edge pulses at the leading edge and trailing edge of the sensor output pulses, and the order relationship between the edge pulses obtained from the output pulses of one rotation sensor and the edge pulses obtained from the output pulses of the other rotation sensor. and a reversal determining means for logically determining a change in the rotation direction of the rotating body and determining that the rotational direction of the rotating body has been reversed when the temporal relationship between the two edge pulses is reversed. It is.

[Operation] The present invention generates rotation pulses having different phases with respect to the same rotating body by a pair of rotation sensors, mutually checks the temporal relationship between the edge pulses with respect to the output rotation pulses of these rotation sensors, and calculates this relationship. The reversal of the rotating body is determined when the rotation body is reversed.

[Example 7] Examples of the present invention will be described below with reference to FIG. 1.2. FIG. 1.2 is a circuit configuration diagram and a signal waveform diagram of each part of the circuit, respectively, showing an embodiment of the rotation detection device of the present invention.

In FIG. 1, the rotation detection device 11 is an exclusive-OR gate circuit with delay circuits 12a and 13a connected to one input terminal in order to capture the output pulse of the rotation sensor 3.4 at both its leading and trailing edges. 12 and 13 are connected to the rotation sensors 3 and 4, respectively. The exclusive OR gate circuits 12 and 13 are of a type that inverts the polarity of their outputs, and their respective outputs serve as respective inputs of the AND gate circuit 14 and one input of the corresponding OR gate circuits 15 and 16.

The output of the AND gate circuit 14 is a D flip-flop circuit 17 configured to feed back the true output to the D input terminal.
The Q output and the fourth output of the D flip-flop circuit 17 are used as the other inputs of the OR gate circuits 15 and 16.

Further, the outputs of the OR gate circuits 15 and 16 are input to the AND gate circuit 18.

Note that exclusive OR gate circuits 12 and 13 having delay circuits 12a and 13a constitute edge pulse generating means, and AND gate circuit 14 and OR gate circuit 15
,16. The D flip-flop circuit 17 and the AND gate circuit 18 constitute inversion determining means. By the way, the delay circuit 12a.

The delay time τ of 13a determines the output pulse width of the exclusive OR gate circuits 12.13, and even when the capstan motor 2 rotates at the highest speed, the output pulses of both exclusive OR gate circuits 12.13 However, in order to avoid even a partial overlap in time,
Set it to an appropriate value.

In addition, the clear input terminal of the D flip-flop circuit 17 is supplied with a signal when the capstan motor 2 rotates in the normal direction, or at the rising edge of the output rotation pulse of the capstan motor 2.

An OR gate circuit 19 is connected to input a reset pulse so that the output rises. A motor control circuit 2a that controls the forward or reverse rotation of the capstan motor 2 and a delay circuit 13b that delays the output of the exclusive OR gate circuit 13 are connected to the input terminal of the OR gate circuit 19. A reset pulse of negative polarity is formed by the logical product of a normal rotation pulse outputted when the capstan motor 2 rotates normally and a pulse obtained by delaying the output of the exclusive OR gate circuit 13 by Δτ. In this embodiment, the pulse delay time Δτ by the delay circuit 13b is set to about 1/2 of the minimum value of the pulse width τ.

Hereinafter, the operation of the rotation detection device 11 having the above configuration will be explained with reference to FIGS. 2(A) to 2(J).

First, when the capstan motor 2, which is a rotating body, is rotating in the forward direction, between the output pulses of the rotation sensors 3 and 4,
There is a 90 degree phase difference. In this case, the clock input to the D flip-flop circuit 17 becomes a pulse approximately corresponding to the above-mentioned 90 degree phase difference. Therefore, the outputs of the OR gate circuits 15 and 16 are both at a high level, and a negative pulse indicating the reversal of the rotating body is not obtained from the AND gate circuit 18.

On the other hand, suppose that a reversal occurs at time t5, and after the output pulse of the rotation sensor 3 is interrupted, the output pulse of the rotation sensor 4 is continuously detected.

In this case, the phase relationship between the edge pulse formed at the rising edge (time t6) of the second output pulse of the rotation sensor 4 detected two times in succession and the Q output of the D flip-flop circuit 17 is reversed. Immediately after the inversion, a negative inversion detection pulse is generated via the AND gate circuit 18.

Similarly, when an inversion occurs at time t7, the inversion detection pulse is immediately generated at the point in time (time ta) when the temporal order of the edge pulses output from the exclusive-OR gate circuit 12.13 is reversed (time ta). is formed.

In this way, the rotation detecting device 11 generates rotation pulses having different phases with respect to the same rotating body using the pair of rotation sensors 3 and 4, and determines the temporal precedence of the edge pulse with respect to the output rotation pulses of the rotation sensors 3 and 4. Since the relationship is determined logically and the reversal of the rotating body is determined when this relationship is reversed, the resolution for determining the rotation direction obtained from the output rotation pulses of the rotation sensors 3 and 4 is high, and the rotation direction of the pair of rotations is high. Compared to the conventional rotation detection device 1, which determines the rotation direction by determining the lead or lag in the phase of the rotation pulses output from the sensors 3 and 4, the determination result can be obtained from the point at which the rotating body actually reverses. Since the time it takes for the rotating body to stop at a desired rotational phase is uniformly short without variation and the detection of reversal is quick, it is particularly effective in detecting rotation when braking a rotating body and stopping it at a desired rotational phase.

[Effects of the Invention] As explained above, according to the present invention, rotation pulses having different phases are generated by a pair of rotation sensors regarding the same rotating body, and the temporal precedence of the edge pulse with respect to the output rotation pulse of the rotation sensor is determined. The relationship is determined logically, and the reversal of the rotating body is determined when this relationship is reversed, so the resolution for determining the rotation direction obtained from the output rotation pulse of the rotation sensor is high, and the output of the pair of rotation sensors Compared to conventional rotation detection devices that determine the rotation direction by determining the phase lead/lag of the rotation pulse, the time from when the rotating body actually reverses to when the determination result is obtained varies. Since the length is uniformly short and the detection of reversal is quick, it has excellent effects such as being particularly effective in detecting rotation when braking a rotating body and stopping it at a desired rotational phase.

[Brief explanation of drawings]

1 and 2 are a circuit configuration diagram and a signal waveform diagram of each part of the circuit, respectively, showing an embodiment of the rotation detection device of the present invention, and FIG.
．． FIG. 4 is a circuit configuration diagram and a signal waveform diagram of each part of the circuit, respectively, showing an example of a conventional rotation detection device. 3.4... Rotation sensor, 11... Rotation detection device, 1
2.13... Exclusive OR gate circuit, 14
...AND gate circuit, 15.16...OR gate circuit, 17...D flip Flora 1 circuit, 18°°'and gate circuit.

Claims (1)

[Claims] a pair of rotation sensors that detect rotation of a rotating body with a predetermined phase difference; edge pulse generation means that generates edge pulses at a leading edge and a trailing edge of output pulses of the pair of rotation sensors; A change in the order relationship between the edge pulse obtained from the output pulse of one rotation sensor and the edge pulse obtained from the output pulse of the other rotation sensor is logically determined, and when the temporal relationship between the two edge pulses is reversed, the above-mentioned A rotation detection device comprising a reversal determining means for determining whether the rotational direction of a rotating body has been reversed.