JP5804447B2 - Pulse counting device - Google Patents

Description

  The present invention relates to a pulse count device applicable to a servo amplifier, an inverter, or the like that counts command pulses output from a command device to control the speed and position of a motor.

FIG. 4 shows the configuration of a servo system that drives the servo amplifier 300 by command pulses from the command device 100.
In FIG. 4, reference numeral 100 denotes a command device including a sequencer provided with a DC power source 101 and a transistor 102 constituting an open collector circuit. A command pulse generated by turning on and off the transistor 102 is transmitted via a command cable 200. Send to servo amplifier 300.

  The servo amplifier 300 includes a pulse transmitting photocoupler 5 connected to terminals a, b, and c via current limiting resistors 2, 3, and 4, respectively, a noise filter 7 connected to the output side thereof, and a counter circuit. 9 and CPU 10 are provided. The terminals a and c are used when an open collector type command device 100 is used as shown in the figure, and the terminals b and c are used when a line driver type command device (not shown) is used. is there.

Next, the circuit operation of FIG. 4 will be described.
When the transistor 102 in the command device 100 is turned on, a pulse current flows through the path of the DC power source 101 → terminal a → current limiting resistor 2 → light emitting element in the photocoupler 5 → current limiting resistor 4 → terminal c → transistor 102, The light emitting element in the coupler 5 is turned on. Next, when the transistor 102 is turned off, the current in the path is cut off and the light emitting element is turned off.

While the light emitting element of the photocoupler 5 is on, a pulse voltage is generated on the output side of the light receiving element, and this pulse voltage is input to the noise filter 7. Here, the noise filter 7 is for removing the high frequency component of the pulse voltage waveform, and prevents unnecessary counting of the high frequency component by the counter circuit 9.
The counter circuit 9 counts the number of pulses output from the noise filter 7 and outputs it to the CPU 10. The CPU 10 executes a control operation for rotating a motor (not shown) according to the input count value.

A positioning control device described in Patent Document 1 is known as a pulse input device that can respond to both open collector and line driver output command pulses like the servo amplifier 300 of FIG.
FIG. 5 is a circuit diagram showing the main part of this prior art. In FIG. 5, 400 is a Z-phase pulse output circuit having a line driver 401 (reference pulse output every rotation of the motor), 500 is a Z-phase pulse output circuit having an open collector output transistor 501, and 600 is a positioning control. 610 is a pulse input circuit to which a pulse from the pulse output circuit 400 or 500 is input, 611 is a DC power supply, 612 to 614 are resistors, 615 is a photocoupler, 401a, 401b, 501a, 501b, 601a to 601d are terminals It is.

  In the Z-phase pulse output circuit 400, the line driver 401 outputs the normal signal of the input signal to the terminal 401a and the inverted signal of the input signal to the terminal 401b. In the Z-phase pulse output circuit 500, when the transistor 501 is turned on in response to the input signal, the terminals 501a and 501b are turned on, and when the transistor 501 is turned off, the terminals 501a and 501b are turned off.

  When the line driver type Z-phase pulse output circuit 400 is used, the terminals 401a and 401b are connected to the terminals 601b and 601c of the positioning control device 600, respectively, as indicated by solid lines. As a result, a current flows through a path from the terminal 401a → the light emitting element of the photocoupler 615 → the terminal 401b, and a pulse is sent to the internal circuit of the positioning control device 600 by the current flowing through the light receiving element.

  On the other hand, when the open-collector type Z-phase pulse output circuit 500 is used, the terminals 501a and 501b are connected to the terminals 601c and 601d of the positioning control device 600 as shown by the broken lines, and the terminals 601a and 601b are connected to each other. Connecting. Thus, when the transistor 501 is turned on, a current flows through the path of the DC power supply 611 → the light emitting element of the photocoupler 615 → the transistor 501, and a pulse is sent to the internal circuit of the positioning control device 600 by the current flowing through the light receiving element.

JP-A-8-69325 (paragraphs [0028] to [0031], FIG. 1, etc.)

  Now, when controlling the speed of the motor and the amount of rotation per unit time using pulses from the command device, the number of command pulses whose frequency changes within a range of, for example, 0 to several [MHz] is accurately counted. Although necessary, the apparatus applicable to both the output of the open collector and the line driver as shown in FIGS. 4 and 5 has the following problems.

That is, the servo amplifier 300 shown in FIG. 4 does not use the terminal b when the command device is an open collector output, and does not use the terminal a when the command device is a line driver output. The photocoupler 5 may malfunction due to noise current generated by the wiring portion including the use terminal as an antenna, and the counter circuit 9 may erroneously count pulses (noise) other than the original command.
Further, the intruding noise is removed by the noise filter 7 subsequent to the photocoupler 5. However, since it is necessary to count pulse commands having a wide frequency as described above, the cutoff of the noise filter 7 is performed. The frequency must be set to the upper limit value of the frequency of the command pulse, and it has no effect on noise with a frequency lower than that.
In general, since the line driver method operates at a higher frequency than the open collector method, the cut-off frequency of the noise filter 7 is set to the upper limit value of the line driver method. The noise filter 7 cannot be removed by the noise filter 7.

Thus, due to noise that cannot be removed by the noise filter 7, an error occurs between the number of pulse commands output from the command device 100 and the count value by the counter circuit 9, and as a result, position control is performed. There has been a problem such as causing the motor to be displaced.
In the prior art of FIG. 5, wiring work for short-circuiting between the terminals 601a and 601b is necessary when the open collector type Z-phase pulse output circuit 500 is connected.

In the prior art shown in FIG. 4, in order to prevent the erroneous counting due to the noise described above, methods such as grounding both shield ends and unused terminals of the command cable 200 can be considered. In addition, wiring work outside the positioning control device 600 is required, and in the prior art shown in FIG. 5, the wiring work for short-circuiting the terminals 601a and 601b is complicated.
Therefore, a problem to be solved by the present invention is to enhance the noise removal effect without requiring a complicated operation in a pulse counting device that can handle both the open collector and line driver output pulse commands.

In order to solve the above-mentioned problem, the invention according to claim 1 is a pulse counting device having a function of counting pulses of a predetermined frequency output from an open collector type or line driver type command device.
First and third input terminals connected to an open collector type command device;
Second and third input terminals connected to a line driver type command device;
A first changeover switch for switching the connection destination of the common contact to the first and second input terminals;
Pulse transmission means for receiving an output pulse of an open collector type or line driver type command device from the common contact of the first changeover switch and a third input terminal;
An output pulse of the pulse transmission means is applied to a common contact, and a second changeover switch for switching the connection destination of the common contact to the first and second filter input contacts;
A first noise filter connected to the first filter input contact and having a cutoff frequency for an open collector output;
A second noise filter connected to the second filter input contact and set with a cutoff frequency for line driver output;
Counting means for counting pulses output from the first and second noise filters;
When a signal indicating whether the command device is an open collector method or a line driver method is set from the outside, the command device is connected to the first or second noise filter according to the set circuit method. Switch switching means for switching the first and second selector switches so that an output pulse is input.

The invention according to claim 2 is a pulse counting device having a function of counting pulses of a predetermined frequency output from an open collector type or line driver type command device,
First and third input terminals connected to an open collector type command device;
Second and third input terminals connected to a line driver type command device;
A first changeover switch for switching the connection destination of the common contact to the first and second input terminals;
Pulse transmission means for receiving an output pulse of an open collector type or line driver type command device from the common contact of the first changeover switch and a third input terminal;
The output pulse of the pulse transmission means is applied to a common contact, and the connection destination of the common contact is an input contact of a noise filter in which a cutoff frequency for an open collector output or a line driver output is set among a plurality of noise filters A second changeover switch for connecting to
Counting means for counting pulses output from each noise filter;
When a signal indicating whether the command device is an open collector method or a line driver method and a maximum operating frequency of the circuit are set from the outside, a predetermined value is set according to the set circuit method and the maximum operating frequency. Switch switching means for switching the first and second switch so that the output pulse of the command device is input to the noise filter.

The invention according to claim 3 is the pulse counting device according to claim 1 or 2,
The pulse transmission means is a photocoupler in which a light emitting element is connected to the first changeover switch side and a light receiving element is connected to the second changeover switch side.

  According to the present invention, both the open collector and the line driver type command device are used, and the troublesome wiring work is performed by switching the pulse input circuit and the cutoff frequency of the noise filter while sharing the parts other than the noise filter. Therefore, the noise removal effect can be enhanced without the need for and the erroneous counting of command pulses can be prevented.

It is a circuit block diagram at the time of connecting the pulse counting device which concerns on 1st Embodiment of this invention to the command device of an open collector system. It is a circuit block diagram at the time of connecting the pulse counting device which concerns on 1st Embodiment of this invention to the command device of a line driver system. It is a circuit block diagram at the time of connecting the pulse counting device which concerns on 2nd Embodiment of this invention to the command device of an open collector system. It is a circuit block diagram of the servo system of a prior art. It is a circuit block diagram of the prior art described in patent document 1. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the pulse count device of the present invention is applied to a servo system.
FIG. 1 is a circuit configuration diagram when the pulse counting device according to the first embodiment of the present invention is connected to an open collector type command device 100, and FIG. 2 is a line driver type command device 100A. It is a circuit block diagram at the time of connecting. In these drawings, the same components as those in FIG. 4 are denoted by the same reference numerals, and the following description will focus on the differences from FIG.

In FIG. 1, 300A is a servo amplifier, and the first input terminal a connected to the command device 100 with an open collector output and the second input connected to the command device 100A (see FIG. 2) with a line driver output. A terminal b and a third input terminal c connected in common to both command devices 100 and 100A.
The input terminal a is connected to the switching contact 1 of the first changeover switch S1 via the current limiting resistor 2, the input terminal b is connected to the switching contact 2 of the changeover switch S1 via the current limiting resistor 3, and the input terminal c is a current limiting resistor. 4 is connected to the output terminal of the light emitting element of the photocoupler 5 as pulse transmission means. The common contact 3 of the changeover switch S1 is connected to the input terminal of the light emitting element of the photocoupler 5.

The output terminal of the light receiving element of the photocoupler 5 is connected to the common contact 3 of the second changeover switch S2, and the first filter input contact 1 of the changeover switch S2 is connected to the first noise filter 7 for the open collector. The two filter input contacts 2 are connected to a second noise filter 8 for line drivers, respectively. The pulses output from the noise filters 7 and 8 are input to the counter circuit 9.
Here, the cutoff frequency of the first noise filter 7 is set for an open collector output, and the cutoff frequency of the second noise filter 8 is set for a line driver output.
The photocoupler 5 uses a common mode voltage pulse input from the switching contact 1 or the switching contact 2 of the first changeover switch S1 via the common contact 3 to generate a normal mode voltage based on the circuit ground. Has the function of converting to pulse and outputting.

  The count value counted by the counter circuit 9 is output to the CPU 10, and the CPU 10 executes a control operation for rotating a motor (not shown) according to the input count value. Further, the circuit system (open collector system or line driver system) of the command device set by the user can be set to the I / F (interface) circuit 11 from the outside, and shows the circuit system set by the user. A signal is input to the register of the CPU 10 via the I / F circuit 11.

The CPU 10 operates as a switch switching unit in accordance with the set circuit system, and outputs the switching signal C1 to the switching switch S1 and the switching signal C2 to the switching switch S2. As shown in FIG. 1, the switching signals C1 and C2 are connected to the switching switches S1 and S2 on the contact 1 side and the output pulse of the photocoupler 5 is input to the noise filter 7 (when the open collector method is set). As shown in FIG. 2, the switch S1, S2 is connected to the contact 2 side to switch the operation of inputting the output pulse of the photocoupler 5 to the noise filter 8 (when the line driver method is set). is there.
Further, a switch setting signal indicating whether the changeover switches S1 and S2 are set to the open collector method or the line driver method is input from the CPU 10 to the counter circuit 9, and the counter circuit 9 responds to the switch setting signal. Either of the output signals of the noise filter 7 or 8 is selected and inputted.

As shown in FIG. 1, an open collector output command device 100 is connected to the input terminals a and c of the servo amplifier 300A via the command cable 200, and the user uses the I / F circuit 11 to connect the servo amplifier 300A. When the circuit method is set to the open collector method, the connection state of the changeover switches S1 and S2 is as shown in FIG. 1, and an open collector circuit is formed.
When a command pulse (current pulse) is input from the command device 100 to the servo amplifier 300A in this state, noise generated in the wiring portion of the input terminal b is blocked by the changeover switch S1 and does not reach the photocoupler 5. The circuit after the coupler 5 does not enter. In addition, noise entering from the input terminals a, c, etc. is sufficiently removed by the noise filter 7 whose cutoff frequency is set for the open collector, so that the counter circuit 9 accurately counts the number of command pulses. And no malfunction occurs.

  On the other hand, FIG. 2 is a circuit configuration diagram when the command device 100A for line driver output is used. In this case, the command device 100A is connected to the input terminals b and c of the servo amplifier 300A via the command cable 200, and when the user sets the circuit method of the servo amplifier 300A to the line driver method via the I / F circuit 11. The connection state of the changeover switches S1 and S2 is as shown in FIG. 2, and a line driver circuit is formed.

  When a command pulse is input from the command device 100A to the servo amplifier 300A in this state, noise generated in the wiring portion of the input terminal a is blocked by the changeover switch S1 and does not reach the photocoupler 5. Does not enter the circuit. Further, since the noise that has entered from the input terminals b, c, etc. is sufficiently removed by the noise filter 8 in which the cutoff frequency is set for the line driver, the counter circuit 9 has a command pulse as in the case of FIG. Can be accurately counted, and no malfunction occurs.

Next, FIG. 3 is a circuit configuration diagram when the pulse counting device according to the second embodiment of the present invention is connected to an open collector type command device 100.
In FIG. 3, reference numeral 300B denotes a servo amplifier, and the circuit configuration from the input terminals a, b, c to the photocoupler 5 is the same as that in the first embodiment.

The second embodiment includes a total of n (n is a plurality of 3 or more) noise filters 12 (noise filters 12 _{1 to} 12 _n ) for open collectors and line drivers, and each of the filters 12 _{1 to} 12. _n is set so that the cut-off frequency varies in small increments. Here, for example, of the n noise filters 12 _{1 to} 12 _n , m (m is a plurality, m <n) filters are for open collectors, and (n−m) filters are for line drivers. It has become.

The output terminal of the light receiving element of the photocoupler 5 is connected to the common contacts 3-1, 3-2,..., 3-n in the second changeover switch S3, and the filter input contact 4- corresponding to each common contact. 1, 4-2,..., 4-n are connected to noise filters 12 _{1 to} 12 _n , respectively. The output side of these noise filters 12 _{1 to} 12 _n is connected to the counter circuit 9.
The circuit configuration after the counter circuit 9 is the same as that of the first embodiment, but in this second embodiment, the switching signal C3 from the CPU 10 is input to the second changeover switch S3 and the user is the maximum of the circuit. The operating frequency can be set in the I / F circuit 11.

Hereinafter, the operation of the second embodiment will be described.
As shown in FIG. 3, when the user sets the circuit system of the servo amplifier 300B to the open collector system via the I / F circuit 11 with the open collector output command device 100 connected, the changeover switches S1, S3 The connection state is as shown in FIG. 3, and an open collector circuit is formed. Here, in the changeover switch S3, for example, the contacts 3-n and 4-n are connected to each other by the changeover signal C3, so that the cut-off frequency is lowest than the maximum operating frequency of the circuit set in the I / F circuit 11. noise filter 12 _n with is adapted to be selected.

When a command pulse is input from the command device 100 to the servo amplifier 300B in this state, the noise generated in the wiring portion of the input terminal b is blocked by the changeover switch S1 and does not reach the photocoupler 5, and after the photocoupler 5 Does not enter the circuit. In addition, noise entering from the input terminals a, c, etc. is sufficiently removed by the noise filter 12 _n having the lowest cut-off frequency above the maximum operating frequency of the circuit, so that the counter circuit 9 accurately determines the number of command pulses. Thus, malfunction can be prevented.

Although not shown in the figure, when a command device for line driver output is used, the command device is connected to the input terminals b and c in the same manner as in FIG. 2, and the selector switch S1 is switched by switching signals C1 and C3 from the CPU 10. , S3 are switched to form a line driver circuit. At this time, the changeover switch S3 is made to turn on the contacts so that the noise filter is selected to have a higher cutoff frequency than the noise filter 12 _n.

2, 3, 4: Current limiting resistor 5: Photocoupler 7, _8, 12, 12 _{1 to} 12 _n : Noise filter 9: Counter circuit 10: CPU
11: I / F circuit 100, 100A: Command device 101: DC power supply 102: Transistor 103: Line driver circuit 200: Command cable 300A, 300B: Servo amplifiers a, b, c: Input terminals S1, S2, S3: Changeover switch

Claims (3)

In a pulse count device having a function of counting pulses of a predetermined frequency output from an open collector type or line driver type command device,
First and third input terminals connected to an open collector type command device;
Second and third input terminals connected to a line driver type command device;
A first changeover switch for switching the connection destination of the common contact to the first and second input terminals;
Pulse transmission means for receiving an output pulse of an open collector type or line driver type command device from the common contact of the first changeover switch and a third input terminal;
An output pulse of the pulse transmission means is applied to a common contact, and a second changeover switch for switching the connection destination of the common contact to the first and second filter input contacts;
A first noise filter connected to the first filter input contact and having a cutoff frequency for an open collector output;
A second noise filter connected to the second filter input contact and set with a cutoff frequency for line driver output;
Counting means for counting pulses output from the first and second noise filters;
When a signal indicating whether the command device is an open collector method or a line driver method is set from the outside, the command device is connected to the first or second noise filter according to the set circuit method. Switch switching means for switching the first and second selector switches so that an output pulse is input;
A pulse counting device comprising: In a pulse count device having a function of counting pulses of a predetermined frequency output from an open collector type or line driver type command device,
First and third input terminals connected to an open collector type command device;
Second and third input terminals connected to a line driver type command device;
A first changeover switch for switching the connection destination of the common contact to the first and second input terminals;
Pulse transmission means for receiving an output pulse of an open collector type or line driver type command device from the common contact of the first changeover switch and a third input terminal;
The output pulse of the pulse transmission means is applied to a common contact, and the connection destination of the common contact is an input contact of a noise filter in which a cutoff frequency for an open collector output or a line driver output is set among a plurality of noise filters A second changeover switch for connecting to
Counting means for counting pulses output from each noise filter;
When a signal indicating whether the command device is an open collector method or a line driver method and a maximum operating frequency of the circuit are set from the outside, a predetermined value is set according to the set circuit method and the maximum operating frequency. Switch switching means for switching the first and second changeover switches so that the output pulse of the command device is input to the noise filter of
A pulse counting device comprising: In the pulse counting device according to claim 1 or 2,
The pulse counting device, wherein the pulse transmission means is a photocoupler in which a light emitting element is connected to the first changeover switch side and a light receiving element is connected to the second changeover switch side.

Images