JPH0670639B2 - Directional Discrimination Circuit for Polyphase Square Wave - Google Patents

Description

The present invention relates to a directional discriminating circuit for a polyphase rectangular wave, and more particularly to a polyphase rectangular wave for discriminating the rotational direction of a servomotor used for controlling a machine tool. The present invention relates to a direction discriminating circuit.

[Conventional technology]

Generally, the direction of rotation of a servo motor used for controlling a machine tool is discriminated by a direction discriminating circuit from an output from a phase detection signal generator (encoder) connected to the servo motor.

FIG. 4 shows a conventional direction discriminating circuit, in which A and B are 90 degrees apart from each other by an encoder (not shown) connected to a servomotor.
Input terminals for A-phase and B-phase outputs having different phases, 1 to 4 are delay flip-flops (DFFs), 6 and 7 are respectively exclusive OR circuits (EXOR), 8 is a NOT circuit (NOT), and 9 to 12 is a negative OR circuit (OR), 13 and 14 are NAND circuits (NAN)
D).

[Problems to be Solved by the Invention]

In such a conventional direction discriminating circuit, the A-phase and B-phase output signals from the encoder are added to the input terminals A and B, respectively, to generate pulse signals according to the rising and falling edges of each signal, and the timing of each pulse signal. However, the output corresponding to the rotation direction of the servomotor is obtained from the NAND circuits 13 and 14, but the circuit is complicated because there are many components and the area of the mounting board for these components is large, which is expensive. was there.

[Means for Solving the Problems]

The direction discriminating circuit of the multi-phase rectangular wave of the present invention is configured such that the output signals of the first and second phases having different phases of the multi-phase rectangular wave obtained from the position detection signal generator of the rotating body are input to each phase. And a group of data selection circuits corresponding to the first and second phases and a group of first and second delay flip-flops connected in series corresponding to each other. The normal phase output of the delay flip-flops is commonly input to the upper select terminals of each of the data select circuits, and the normal phase output of the second delay flip-flop of the second phase is the lower select of each of the data select circuits. Common input to the terminals, the positive phase output and the negative phase output of the first delay flip-flop of the first phase are commonly input to the first and second data terminals of each of the data select circuits, and Phase 1 of 2
The positive-phase output and the negative-phase output of the delay flip-flop are commonly input to the third and fourth data terminals of each of the data select circuits, and the negative data corresponding to the rotation direction of the rotor is output from each of the data select circuits. It is characterized in that an output that changes from positive to positive or negative is obtained.

[Action]

The multiphase rectangular wave direction discriminating circuit of the present invention can reduce the number of its components.

〔Example〕

In the present invention, as shown in FIG. 1, two layers of rectangular wave signals having different 90 ° phases from an encoder connected to a servomotor are connected in series via input terminals A and B, respectively corresponding to each phase. In addition to the input terminals of the first and second delay flip-flops (DFFs) 15, 16 and 17, 18,
The positive phase outputs of the second delay flip-flops 16 and 18 are respectively
1, common to the upper and lower select terminals of the second data select circuits 19 and 20.

The positive phase output and the negative phase output of the first delay flip-flop 15 of the A phase are set to the first and second data select circuits.
In addition to the common first and second data terminals 19 and 20, the positive phase output and the negative phase output of the B phase first delay flip-flop 17 are used for the first and second data select circuits 19, 20. Are added to the third and fourth data terminals of.

Since the direction discriminating circuit of the multi-phase rectangular wave of the present invention is configured as described above, the first and second data select circuits 19 and 20 can obtain outputs corresponding to the rotation directions of the servo motors. .

That is, the output obtained from the encoder is, for example, as shown in FIG.
In the case of two-phase rectangular waves 90 ° out of phase with each other, the positive-phase outputs obtained from the first delay flip-flops 15 and 17 are slightly delayed, respectively, and the negative-phase outputs become, The positive phase outputs of the delay flip-flops 16 and 18 of 2 are further delayed by a little and become as shown in.

If the input is regarded as binary data, (a) in Fig. 2
The outputs of (d) are shown as 10, 11, 01, 00, respectively.

The data select circuits 19 and 20 are the data corresponding to the values specified by the input, that is, Y ₂ , Y ₃ , Y ₁ , Y ₀ , Y ₂ ...
.. During reverse rotation, the values of Y ₀ , Y ₁ , Y ₃ , Y ₂ , Y ₀ ... Will be sequentially output.

If the inputs to the data select circuits 19 and 20 are connected as shown in Fig. 3 here, the data select circuits will be in the normal rotation.
Since the signal is output from the data select circuit 20 during reverse rotation from 19, the rotation direction can be discriminated and the L0 active quadruple signal is obtained.

The above is applicable not only to two-phase output but also to multi-phase output of three or more phases with a phase difference other than 90 °.

〔The invention's effect〕

As described above, according to the present invention, the initial object can be achieved with a small number of parts, and there is a great advantage that the cost and the occupied area can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a directional discriminating circuit of a polyphase rectangular wave of the present invention, FIG. 2 is a waveform diagram of each part thereof, FIG. 3 is an explanatory table, and FIG. 4 is a block diagram of a conventional directional discriminating circuit. . A, B ... Input terminals, 1-4 ... Delay flip-flop (D
FF), 6 to 7 ... Exclusive OR circuit (XOR), 8 ... Negative circuit (NOT), 9 to 12 ... Negative OR circuit (OR), 13, 14
...... NAND circuit (NAND), 15,16,17,18 …… Delay flip-flop, 19,20 …… Data select circuit.

Claims (1)

[Claims] Claims: 1. A multi-phase rectangular wave obtained by a position detection signal generator for a rotating body, which is connected in series to each other corresponding to respective phases to which output signals of first and second phases having different phases are inputted. A group of first and second delay flip-flops, and
A group of data select circuits corresponding to the second phase, the positive phase output of the second delay flip-flop of the first phase is commonly input to the upper select terminals of each data select circuit, and The positive phase output of the second delay flip-flop of the second phase is commonly input to the lower select terminals of the data select circuits, and the first phase of the first phase
The positive-phase output and the negative-phase output of the delay flip-flop of are commonly input to the first and second data terminals of each of the data select circuits, and the positive-phase output of the first delay flip-flop of the second phase and An output in which a reverse phase output is commonly input to the third and fourth data terminals of each of the data select circuits, and which changes from negative to positive or from positive to negative corresponding to the rotating direction of the rotating body from each of the data select circuits. Directional discriminating circuit for multi-phase rectangular waves characterized in that