JPH0731630Y2 - External event count circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an external event counting circuit for detecting, for example, the number of rotations, a rotation angle, etc. of a detected rotating body
Particularly, the present invention relates to a circuit configuration that enables accurate presetting and counting.

[Conventional technology]

FIG. 3 is a diagram showing the configuration of an external event counting circuit of this type. 1 is an encoder directly connected to a rotating body to be detected (not shown), 2 is a waveform shaping circuit, 3 is a programmable counter, and 4 is a microcomputer. , 7 is an inversion buffer,
Reference numeral 8 is a data bus, and 9 is an RW (read / write) signal line.

In FIG. 3, the encoder 1 directly connected to the rotating body to be detected outputs pulses 5, 5'corresponding to the forward and reverse rotation directions of the rotating body. Here, two output pulses from the encoder 1
5, 5'is output. For example, as shown in FIG. 4, a pulse output N pulses later than the M pulse is defined as a forward rotation pulse, and as shown in FIG. The N'pulse that is output first is judged as the reverse pulse. The pulse output from the encoder 1 has a distorted waveform when the transmission distance is long. Therefore, the distorted waveform is corrected by the waveform shaping circuit 2 and then the external event pulse 6 of normal rotation or reverse rotation is output, and this output signal is inverted. It is applied as a count input to the clock terminal of the programmable counter 3 via the buffer 7.

The programmable counter 3 is a microcomputer 4
, The data bus 8 and the R / W signal line 9 are connected to each other. For presetting the preset data to the programmable counter 3, the microcomputer 4 outputs the preset data to the data bus 8 and then the R / W signal line. 9
The preset data is latched when the write pulse is output via the, and then preset by the input pulse which is first count-input to the clock terminal of the programmable counter 3. Such a programmable counter normally has a terminal for receiving a preset command from the microcomputer 4 when presetting preset data, but the programmable counter 3 shown in FIG. The number of terminals is reduced by eliminating the terminals for receiving the preset command, and the preset of the preset data is also used as the count input. The data counted by the programmable counter 3 is transferred to the microcomputer 4 via the data bus 8 by the read pulse from the RW signal line 9.
Is input to the detection target rotating body to detect the number of rotations and the like.

[Problems to be solved by the device]

In FIG. 6, the programmable counter 3 in FIG. 3 is assumed to be a 4-bit binary counter, A / B / C / D is preset data input, Q _A / Q _B / Q _C / Q _D is counter output,
4 is a timing chart of the circuit shown in FIG. 3 when it is considered that four flip-flops are operated at the rising edge a ₁ of the write pulse.

In FIG. 6, the falling edge of the write pulse is drawn as the preset data latch timing a, but this is the case of an expensive programmable counter, and the number of terminals shown in FIG. Programmable
Since the counter 3 cannot be preset without an input pulse to the clock terminal, it does not operate until the first pulse b is input, and the preset data (binary number “0101” in the figure is not shown until the first pulse b is input. = 5) f is preset. Therefore, when counting external event pulses to which pulses are randomly input, preset data cannot be accurately preset because the preset data depends on the external event pulse, that is, reliability is low. Further, in this case, the above-mentioned first pulse b becomes a preset pulse, and is actually counted after the second pulse c. Therefore, the count output g at the time of the fourth pulse e is (binary number “1000” = 8), which is different from the actual count value (preset data “5” + 4 = 9). As described above, the conventional circuit has a drawback that accurate presetting and counting cannot be performed.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of the conventional device and to provide an external event count circuit capable of accurately presetting and counting preset data even when counting external event pulses.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides an encoder that outputs a pulse signal by capturing the movement of a detected rotating body directly connected to the detected rotating body, and a waveform shaping circuit that shapes the pulse signal from this encoder. , The output from this waveform shaping circuit is applied to the clock terminal as an external event pulse, the preset data output from the microcomputer at the final stage is latched by the write pulse, and this preset data is latched first and then to the clock terminal. An external event including a programmable counter whose preset data is preset by an applied pulse, and a microcomputer which inputs the count data of the programmable counter and detects the number of rotations, the rotation angle, etc. of the detected rotating body. In the counting circuit, the microcomputer The data output device outputs a preset command pulse subsequent to the write pulse, and connects the output terminal of a logic circuit that outputs the logical sum of the external event pulse and the preset command pulse to the clock terminal of the programmable counter. To do.

[Action]

The external event count circuit in the present invention outputs a preset command pulse subsequent to the write pulse from the microcomputer, and takes the logical sum of the preset command pulse and the external event pulse to give to the clock terminal of the programmable counter. The preset data can be accurately preset regardless of the external event pulse, and the external event pulse can be reliably counted.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention, in which output pulses 5 and 5'output from an encoder 1 are input to a waveform shaping circuit 2. The external event pulse (P ₁ ) 6 waveform-shaped by the waveform shaping circuit 2 and output is input to the input terminal 10a of the logical sum circuit 10 (hereinafter referred to as NOR circuit), and NO
A preset command pulse (P ₂ ) 11 output from the microcomputer 4 is input to the other input terminal 10b of the R circuit 10. Then, the output pulse (P ₃ ) 1 from the NOR circuit 10
Input 2 to the clock terminal of programmable counter 3. The programmable counter 3 is connected to the microcomputer 4 via a data bus 8. The programmable counter 3 inputs preset data and outputs count data in response to a write pulse and a read pulse output from the microcomputer 4 to the RW signal line 9. To do.

FIG. 2 shows the programmable counter 3 shown in FIG. 1 as a 4-bit binary counter, for example, A / B / C / D is preset data input, Q _A / Q _B / Q _C / Q _D is count output, and the rising edge of the write pulse. 6 is a timing chart of the circuit shown in FIG. 1 when it is considered that four flip-flops are operated at the edge. The falling edge a of the write pulse in FIG. 2 is the latch timing of the preset data, and after the data latch, the preset command pulse (P ₂ )
By outputting 11, the output pulse (P ₃ ) 12 of the NOR circuit 10 becomes “H” level regardless of the external event pulse (P ₁ ) 6. Therefore, after the preset data is latched, the output pulse (P ₃ ) 12 becomes “H” level, whereby the preset data (binary number “0101” = 5 in the case of FIG. 5) can be reliably preset. In addition, since it is preset by the preset command pulse (P ₂ ) 11, the external event pulse (P ₁ )
6 starts counting sequentially from the first pulse b, the count output g at the time of the fourth pulse e is also equal to the count value (preset data “5” + 4 = 9), and the preset data f
Even when the count outputs immediately before presetting are equal, the count outputs surely change from the first pulse b and the pulse inputs can be counted.

[Effect of device]

As described above, in the present invention, an encoder that outputs a pulse signal by capturing the movement of the detected rotating body directly connected to the detected rotating body, and a waveform shaping circuit that shapes the pulse signal from this encoder, The output from this waveform shaping circuit is applied to the clock terminal as an external event pulse, the preset data output from the microcomputer at the final stage is latched by the write pulse, and this preset data is latched and then applied to the clock terminal first. External event count provided with a programmable counter in which preset data is preset by generated pulses, and a microcomputer for inputting the count data of the programmable counter to detect the number of rotations, the rotation angle, etc. of the detected rotating body. In the circuit
The microcomputer outputs a preset command pulse following the write pulse, and the programmable
It is configured to connect the output terminal of a logic circuit that outputs the logical OR of the external event pulse and the preset command pulse to the clock terminal of the counter, and programmable by logical OR of the external event pulse and the preset command pulse by the logical circuit. By giving it to the clock terminal of the counter, the preset data can be preset without depending on the external event pulse, and the external event pulse can be accurately counted.

[Brief description of drawings]

FIG. 1 is a block diagram of an external event count circuit showing an embodiment of the present invention, FIG. 2 is a preset timing chart diagram of FIG. 1, FIG. 3 is a block diagram of a conventional external event counter circuit, and FIG. Is a waveform diagram showing an encoder output forward rotation pulse, FIG. 5 is a waveform diagram showing an encoder output reverse rotation pulse, and FIG. 6 is a preset timing chart diagram of FIG. 1: Encoder, 2: Waveform shaping circuit, 3: Programmable counter, 4: Microcomputer, 8: Data bus, 9: R
-W signal line, 10: OR circuit.

Claims (1)

[Scope of utility model registration request] 1. An encoder for detecting the movement of a detected rotary body directly connected to the detected rotary body and outputting a pulse signal, a waveform shaping circuit for shaping the pulse signal from this encoder, and a waveform shaping circuit for the waveform shaping circuit. Output is applied to the clock pin as an external event pulse, the preset data output from the microcomputer at the final stage is latched by the write pulse, this preset data is latched, and then the preset pulse is first applied to the clock pin. Programmable with preset data
In an external event count circuit provided with a counter and a microcomputer for inputting count data of the programmable counter to detect the number of rotations, a rotation angle, etc. of a detected rotary body, the microcomputer is provided with a write pulse following the write pulse. An external event counting circuit, wherein a preset command pulse is output, and an output terminal of a logic circuit which outputs a logical sum of an external event pulse and a preset command pulse is connected to a clock terminal of the programmable counter.