JP5539090B2 - Encoder with noise level detection function - Google Patents

Description

  The present invention relates to an encoder, and more particularly to an encoder capable of detecting noise that affects an internal signal of the encoder.

  An encoder is used as a sensor for detecting the position of a driven body driven by an electric motor such as a motor. The encoder includes a rotary encoder and a linear scale. The former detects a rotation angle and a rotation amount, and the latter detects a position and a displacement amount from a reference position on the path.

  The operation principle of the rotary encoder will be briefly described. A disc provided with a slit is attached to the rotary shaft of the rotary encoder. On the other hand, a fixed slit is fixed to the rotary encoder body so as to face this disk. A light-emitting element such as a light-emitting diode and a light-receiving element such as a phototransistor serving as detection means are arranged with two slits therebetween. The light emitted from the light emitting element is incident on the light receiving element when the two slits are overlapped by the rotation of the rotating shaft. Therefore, the light incident on the light receiving element repeats the bright state and the dark state by the number of times proportional to the amount of rotation of the rotating shaft. The light receiving element as the detecting means outputs two-phase approximate sine waves having phases different from each other by 90 degrees. The rotational direction can be determined from the phase relationship of the two phases, and the number of rotations can be obtained by counting the signals of the two phases.

  Generally, an encoder is used by being attached to a housing of a driving device such as a motor that drives a driven body.

  FIG. 10 is a schematic diagram for explaining a method of attaching a drive device such as a motor of a conventional encoder to a housing. The encoder 100 is attached to a housing 113 of a driving device such as a motor via an encoder flange 103a included in the encoder 100. The encoder flange 103a is fixed to the motor casing 113 by a flange fixing screw 103b, and the circuit board 106 is fixed to the encoder flange 103a by a circuit board fixing screw 103d. A rotating slit 103c connected to the shaft 114 is provided between the circuit board 106 and the encoder flange 103a.

  FIG. 11 is a schematic diagram of a configuration of a conventional encoder. In FIG. 11, an encoder 201 includes a detection unit 202 that detects a moving state of a driven body (not shown) driven by an electric motor 210, and a circuit board 205. A signal processing circuit 203 for generating an encoder signal by processing the detection signal 202 is formed.

  The moving state of the driven body is detected by the detection unit 202, an encoder signal is generated by the signal processing circuit 203, and output as output data 206 to the outside of the encoder 201. Here, when noise 200 is mixed into the electric motor 210, a noise signal 207 is generated in the output signal 206 of the signal processing circuit 203.

  As described above, the encoder 100 includes the circuit board 205 including the signal processing circuit 203 therein. The circuit board 205 is not directly electrically connected to the housing of the driving device to which the encoder is attached, but is indirectly electrically connected by stray capacitance.

  In this case, if the potential fluctuates due to noise generated on the housing side of the driving device, the circuit board 205 in the encoder 100 is affected via the stray capacitance, and the output data 206 output from the encoder 100 includes an error. There is a fear.

  Conventionally, in order to measure noise, it has been necessary to attach an external noise measurement device or mount a dedicated circuit for noise detection in the encoder. (For example, patent document 1).

  FIG. 12 is a schematic diagram of a configuration of a conventional encoder provided with noise detection means in the encoder. An encoder 201 shown in FIG. 12 includes a detection unit 202 that detects a moving state of a driven body driven by an electric motor 210, a signal processing circuit 203 that processes a detection signal of the detection unit 202 and outputs an encoder signal, Noise detection means 204 for detecting noise included in the detection signal is provided, and the noise detection means 204 introduces the detection signal via the coupling capacitor 204a. The noise detection means 204 detects only the noise 200 by introducing only the noise components 207 and 208 in the detection signals 206 and 206 ′ through the coupling capacitor 204 a.

JP-A-2005-172523

  As shown in FIG. 10, in a conventional encoder, when an external noise measuring device is attached to measure the noise state of the encoder, a point 120 where the potential becomes 0 [V] in the circuit in the encoder and the motor It is necessary to measure the potential difference between the case 113 and the case 113 using the potential measuring means 104, and it is difficult to always measure it.

  Further, when a dedicated circuit for noise measurement is mounted in the encoder, it is disadvantageous in terms of cost and outer shape. In addition, the method of installing the dedicated noise detection means in the encoder as shown in FIG. 12 requires a dedicated circuit for separating the noise from the detection signal and measuring the noise, in terms of circuit area and cost. It is disadvantageous.

  An object of the present invention is to provide a low-cost and small encoder that can always measure a noise level and does not require a dedicated circuit for noise detection.

  An encoder with a noise level detection function of the present invention is an encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor, and periodically according to the moving state of the driven body. Detection means for outputting a detection signal composed of two-phase sinusoidal analog signals generated at different 90-degree phases, an AD converter for converting the detection signal into a digital value at a constant time interval, and outputting it as output data, and output And a noise level detector that calculates a fluctuation component based on a temporal change in data and outputs the fluctuation component as a noise level.

  In the encoder with a noise level detection function of the present invention, it is preferable that the noise level detection unit calculates a differential value obtained by differentiating the output data at least once, and uses the calculated differential value as a fluctuation component.

  In the encoder with a noise level detection function of the present invention, the noise level detection unit calculates a moving average value based on a plurality of differential values calculated in the past and a differential value calculated this time for the output data, and the moving average value Is preferably a variable component.

  In the encoder with the noise level detection function of the present invention, the noise level detection unit performs filtering on the differential value calculated this time, using the differential values calculated in the past for the output data. It is preferable to use the performed differential value as a fluctuation component.

  In the encoder with a noise level detection function of the present invention, the noise level detection unit, for the output data, based on the absolute value of the differential value calculated in the past and the absolute value of the differential value calculated this time, the moving average value It is preferable to calculate the moving average value as a fluctuation component.

  In the encoder with the noise level detection function of the present invention, the noise level detection unit uses the absolute value of the differential value calculated in the past for the output data, with respect to the absolute value of the differential value calculated this time, It is preferable to perform filtering and use the filtered differential value as a fluctuation component.

  In the encoder with a noise level detection function of the present invention, the noise level detection unit, for the output data, based on the absolute value of the differential value calculated in the past and the absolute value of the differential value calculated this time, the moving average value It is preferable to calculate the difference between the moving average value and the absolute value of the differential value calculated this time, and use the difference as a fluctuation component.

  In the encoder with the noise level detection function of the present invention, the noise level detection unit uses the absolute value of the differential value calculated in the past for the output data, with respect to the absolute value of the differential value calculated this time, It is preferable that the difference between the filtered differential value and the absolute value of the differential value calculated this time is used as the fluctuation component.

  In the encoder with a noise level detection function according to the present invention, the noise level detection unit is configured to output the output data based on the absolute value of the differential value calculated a plurality of times in the past and the absolute value of the differential value calculated this time. The moving average value is calculated, the difference between the first moving average value and the absolute value of the differential value calculated this time is calculated, the difference calculation is performed on the absolute values of the differential values for the past multiple times, and the past plural It is preferable to calculate the second moving average value based on the difference calculated for the absolute value of the differential value of the batch and the difference calculated this time, and use the second moving average value as the fluctuation component.

  In the encoder with the noise level detection function of the present invention, the noise level detection unit uses the absolute value of the differential value calculated in the past for the output data, with respect to the absolute value of the differential value calculated this time, The first filtering is performed, the difference between the differential value subjected to the first filtering and the absolute value of the differential value calculated this time is calculated, and the difference is calculated with respect to the absolute value of the differential value for a plurality of past times. Using the difference calculated for the absolute value of the differential value for a plurality of past times, the difference calculated this time is subjected to the second filtering, and the differential value that has been subjected to the second filtering is used as the fluctuation component. preferable.

  In the encoder with a noise level detection function of the present invention, the noise level detection unit calculates a differential value for a plurality of times calculated in the past and a maximum peak value among the differential values calculated this time for the output data. The value is preferably a variable component.

  In the present invention, an external circuit is used to obtain the noise state from the fluctuation state of the output data of the AD converter that converts the A / B phase analog signal into a digital value in order to calculate the position data in the encoder. Unlike the case of measuring the noise level, it is possible to always measure the noise level, and there is no influence due to the addition of a circuit.

  Further, since the noise level is calculated by the signal processing circuit for obtaining the position data, a dedicated circuit for noise detection is not required, and a small encoder can be provided at low cost.

It is the schematic of the structure of the encoder with a noise level detection function which concerns on Example 1 of this invention. It is a figure showing the time dependence of the output data of AD converter. FIG. 3 is an enlarged view of a time dependence graph of output data of the AD converter shown in FIG. 2. It is the schematic of the structure of the encoder with a noise level detection function which concerns on Example 2 of this invention. It is the schematic of the structure of the encoder with a noise level detection function which concerns on Example 3 of this invention. It is the schematic of the structure of the encoder with a noise level detection function which concerns on the other example of Example 3 of this invention. It is the schematic of the structure of the encoder with a noise level detection function which concerns on Example 4 of this invention. It is the schematic of the structure of the encoder with a noise level detection function which concerns on Example 5 of this invention. It is the schematic of the structure of the encoder with a noise level detection function which concerns on Example 7 of this invention. It is a schematic sectional drawing for demonstrating the attachment state of the encoder in the conventional noise detection method. It is the schematic of the structure of the conventional encoder. It is the schematic of the encoder in the conventional noise detection method.

  An encoder with a noise level detection function according to the present invention will be described below with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to these embodiments, but extends to the invention described in the claims and equivalents thereof.

  FIG. 1 shows a schematic diagram of a configuration of an encoder with a noise level detection function according to a first embodiment of the present invention. The encoder 1 according to the first embodiment is an encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor, and has a period corresponding to a moving state of the driven body (not shown). Detecting means 3 for outputting a detection signal composed of two-phase sinusoidal analog signals having different 90-degree phases, and an AD converter for converting the detection signal into a digital value at a constant time interval and outputting it as output data 5 and a noise level detector 8 that calculates a fluctuation component based on a temporal change in output data and outputs the fluctuation component as a noise level.

  The signal processing circuit 4 is disposed on a circuit board 2 in the encoder 1, and a transmission unit 9 for transmitting position data of the driven body to the external controller 11 is disposed on the circuit board 2. .

  The signal processing circuit 4 includes an AD converter 5 that converts the A-phase signal 21 and the B-phase signal 22, which are analog signals output from the detection unit 3, into digital signals. The signal processing circuit 4 further includes a position data calculation unit 7 for calculating position data from the output data from the AD converter 5 and a temporal change in the output data of one or both phases of the output signals. And a noise level detector 8 that calculates a fluctuation component and outputs the fluctuation component as a noise level.

  As shown in FIG. 1, the encoder with the noise level detection function according to the first embodiment outputs a two-phase sinusoidal analog signal having a phase difference of 90 degrees from the detection means 3, and the AD converter 5 converts the digital value at regular intervals. Convert to FIG. 2 shows an example of a graph of a temporal change in output data in which the A-phase signal 21 that is an analog signal output from the detection means 3 is changed to a digital signal by the AD converter 5. It can be seen that the output data fluctuates in a sine wave shape with time, and a component that fluctuates in a cycle shorter than the sine wave cycle is superimposed.

  This output data is input to the position data calculator 7 to output the position data of the driven body, and the noise level is calculated in the noise level detector 8. Here, the noise level calculation method will be described with reference to FIG. FIG. 3 is an enlarged view of a part of the graph of the temporal change of the output data in FIG. The values of the output data 51 to 54 at time t (n-2), t (n-1), t (n), t (n + 1) are respectively AD (n-2), AD (n-1), Let AD (n) and AD (n + 1). At this time, the fluctuation component of the output data from time t (n-1) to t (n) is obtained by AD (n) -AD (n-1), and similarly from time t (n-2) to t (n The fluctuation component of the output data up to n-1) is obtained by AD (n-1) -AD (n-2). In the first embodiment, this fluctuation component is a noise level. Here, an example in which the noise level is calculated from the A phase signal among the detection signals has been shown, but the noise level may be calculated from the B phase signal, and the noise level is calculated from both the A phase and the B phase. You may do it.

  After the fluctuation component is calculated by the noise level detection unit 8, the fluctuation component 30 is output from the noise level detection unit 8 to the transmission unit 9 and transmitted from the transmission unit 9 to the external controller 11 as illustrated in FIG. 1. By warning the external controller 11 when the noise level exceeds a predetermined value, it becomes possible to cope in advance before the system detects an abnormality due to the noise and stops. In addition, by displaying the noise level on the external controller, the effect of the noise countermeasure can be confirmed when the noise countermeasure is taken.

  As described above, in the encoder with a noise level detection function according to the first embodiment of the present invention, the A / B phase analog signal is converted into a digital value in order to calculate the position data in the encoder. Since the noise state is obtained from the state of fluctuation of the output data, it is possible to always measure the noise level, unlike the case of measuring the noise externally, and there is no influence due to the addition of the circuit.

  Further, since the noise level is calculated by the signal processing circuit for obtaining the position data, a dedicated circuit for noise detection is not required, and a small encoder can be provided at low cost.

  Next, a second embodiment of the encoder with noise level detection function of the present invention will be described. FIG. 4 shows a schematic diagram of a configuration of an encoder with a noise level detection function according to the second embodiment of the present invention. The encoder with the noise level detection function according to the second embodiment is characterized in that the noise level detection unit calculates a differential value obtained by differentiating the output data at least once and uses the calculated differential value as a fluctuation component. The difference from the encoder of the first embodiment is that a differential value calculation unit 81 is further provided in the noise level detection unit 8. Since other configurations in the encoder 1 are the same as those in the first embodiment, a detailed description thereof will be omitted.

  The output data of the AD converter 5 output at regular intervals fluctuates slightly as shown in FIG. 2 due to the influence of noise and the like. In the second embodiment, the fluctuation component of the value X (n) obtained by differentiating the fluctuation component of the output data of the AD converter 5 once or more times from the output data AD (n) converted by the AD converter 5 at regular intervals. And

  As shown in FIG. 3 in which a part of the position data in FIG. 2 is enlarged in the time axis direction, the one-time differentiation is the output data AD (n) of the AD converter and the output data AD (n−1) of the immediately preceding AD converter. ) Difference data X (n). For example, when differentiating once, the fluctuation component is obtained by X (n) = (AD (n) −AD (n−1)) / (t (n) −t (n−1)). The same calculation can be performed when differentiating twice or more.

  Since the A / B phase detection signal becomes a sinusoidal analog signal when the driven body moves, the sine wave component remains in the value obtained by differentiating once or more times. Since the noise component is several MHz, the separation is possible. Further, it is possible to eliminate the influence of the sine wave component by performing the evaluation when the driven body is stopped.

  Next, a third embodiment of the encoder with noise level detection function of the present invention will be described. 5 and 6 are schematic diagrams showing the configuration of an encoder with a noise level detection function according to Embodiment 3 of the present invention. In the encoder with a noise level detection function according to the third embodiment, the noise level detection unit calculates a moving average value based on a plurality of differential values calculated in the past and a differential value calculated this time for the output data. It is characterized in that the value is a variable component. Also, instead of calculating the moving average value, the differential value calculated this time is filtered using a plurality of differential values calculated in the past, and the filtered differential value is used as a fluctuation component. It may be. The difference from the encoder of the second embodiment is that the noise level detection unit 8 further includes a moving average value calculation unit 82 or a filtering unit 83. Since other configurations in the encoder 1 are the same as those in the second embodiment, a detailed description thereof will be omitted.

  First, a method for obtaining a moving average using the moving average value calculation unit 82 will be described. In the same manner as in the second embodiment, the differential value calculation unit 81 is used to obtain a past value X (n) obtained by differentiating the output data AD (n) output from the AD converter 5 at regular intervals one or more times. m are calculated, and using this value, the moving average value calculation unit 82 in the noise level detection unit 8 calculates m averages, and this moving average value is used as the noise level.

Further, instead of calculating the moving average value, filtering may be performed by the filtering unit 83. As an example of filtering, the following equation can be used.
Y (n) = X (n) / m + Y (n-1) x (m-1) / m
Where Y (n): Noise level required this time
Y (n-1): Noise level obtained one time before
X (n): Value obtained by differentiating the current position data AD (n) twice or more times The data filtered by the above equation is used as the noise level.

  The noise level calculated by the moving average value calculation unit 82 or the filtering unit 83 is transmitted to the external controller 11 via the transmission unit 9, and the noise level can be monitored.

  According to the present embodiment, the fluctuation component can be smoothed by moving average or filtering. Specifically, when processing and displaying on a computer numerical control (CNC) machine tool or the like, an effect of making the value of the fluctuation component easy to see is obtained.

  Next, a fourth embodiment of the encoder with noise level detection function of the present invention will be described. FIG. 7 shows a schematic diagram of a configuration of an encoder with a noise level detection function according to a fourth embodiment of the present invention. In the encoder with the noise level detection function according to the fourth embodiment, the noise level detection unit has a moving average based on the absolute values of the differential values calculated in the past and the differential values calculated this time for the output data. It is characterized in that a value is calculated and the moving average value is a fluctuation component. Also, instead of calculating the moving average value, the absolute value of the differential value calculated in the past is filtered using the absolute value of the differential value calculated in the past, and the filtered differential value is filtered. May be a variable component. The difference from the encoder of the third embodiment is that an absolute value calculation unit 84 is further provided in the noise level detection unit 8. Since the other structure in the encoder 1 is the same as that of Example 3, detailed description is abbreviate | omitted.

  As shown in FIG. 7, with respect to the output data AD (n) of the AD converter 5 output at regular intervals, a differential value calculation unit 81 is used to calculate a value X (n) that has been differentiated once or more times. Then, after the absolute value is calculated using the absolute value calculator 84, the moving average is calculated using the moving average calculator 82, and the calculated value is set as the noise level. Here, instead of moving average, filtering may be performed in the same manner as in the third embodiment.

  The noise level calculated by the moving average value calculation unit 82 or the filtering unit 83 is transmitted to the external controller 11 via the transmission unit 9, and the noise level can be monitored.

  According to the present embodiment, when the noise swings negatively, the value may be 0 when the moving average or filtering is performed. Therefore, the noise level can be obtained correctly by obtaining the moving average or filtering of the absolute value. Can do.

  Next, a fifth embodiment of the encoder with noise level detection function of the present invention will be described. FIG. 8 shows a schematic diagram of a configuration of an encoder with a noise level detection function according to a fifth embodiment of the present invention. In the encoder with the noise level detection function according to the fifth embodiment, the noise level detection unit has a moving average based on the absolute value of the differential value calculated in the past and the absolute value of the differential value calculated this time for the output data. A difference is calculated between the moving average value and the absolute value of the differential value calculated this time, and the difference is used as a fluctuation component. Also, instead of calculating the moving average value, the absolute value of the differential value calculated in the past is filtered using the absolute value of the differential value calculated in the past, and the filtered differential value is filtered. And the difference between the absolute value of the differential value calculated this time may be used as the fluctuation component. The difference from the encoder of the fourth embodiment is that a noise level detector 8 further includes a difference value calculator 85. Since the other structure in the encoder 1 is the same as that of Example 4, detailed description is abbreviate | omitted.

  As shown in FIG. 8, with respect to the output data AD (n) of the AD converter 5 output at regular intervals, a differential value calculation unit 81 is used to calculate a value X (n) that has been differentiated once or more times. . With respect to this differential value, an absolute value is obtained using the absolute value calculation unit 84, and then a moving average is calculated using the moving average calculation unit 82. Thereafter, the difference value calculation unit 85 is used to calculate the difference between the moving average value and the absolute value of X (n), and this difference value is set as the noise level. Here, instead of moving average, filtering may be performed in the same manner as in the third embodiment.

  A sine wave component appears in the output data AD (n) of the AD converter 5 during movement. This sine wave component is at most several hundred kHz, but the desired noise level is several MHz or more, so the sine wave component can be obtained by moving average or filtering the absolute value of X (n) several times in the past. Can be obtained. By making the difference between this value and the absolute value of X (n) the noise level, it is possible to remove the influence of the sine wave component.

  The noise level calculated by the difference value calculation unit 85 is transmitted to the external controller 11 via the transmission unit 9, and the noise level can be monitored.

  According to this embodiment, since the sine wave component is superimposed on the output of the AD converter during movement, the sine wave component is obtained by moving average or filtering, and the noise level can be obtained more accurately by subtracting from the fluctuation component. it can.

  Next, a sixth embodiment of the encoder with noise level detection function of the present invention will be described. In the encoder with a noise level detection function according to the sixth embodiment, the noise level detection unit first outputs the output data based on the absolute value of the differential value calculated a plurality of times in the past and the absolute value of the differential value calculated this time. The moving average value is calculated, the difference between the first moving average value and the absolute value of the differential value calculated this time is calculated, the difference is calculated for the absolute values of the differential values for the past multiple times, and the past The second moving average value is calculated based on the difference calculated for the absolute value of the differential value for a plurality of times and the difference calculated this time, and the second moving average value is used as a fluctuation component. Also, instead of calculating the moving average value, the first filtering is performed on the absolute value of the differential value calculated this time using the absolute value of the differential value calculated in the past, and the first filtering is performed. The difference between the filtered differential value and the absolute value of the differential value calculated this time is calculated, the difference is calculated for the absolute value of the past differential value, and the absolute value of the past differential value is obtained. The difference calculated this time may be used to perform the second filtering on the difference calculated this time, and the differential value obtained by performing the second filtering may be used as the fluctuation component. The configuration of the encoder with a noise level detection function according to the sixth embodiment is the same as that of the fifth embodiment.

  As shown in FIG. 8, with respect to the output data AD (n) of the AD converter 5 output at a constant interval, a differential value calculation unit 81 is used to calculate a value X (n) that has been differentiated once or more times. . For this differential value, an absolute value is obtained using the absolute value calculation unit 84, and then a first moving average value is calculated using the moving average calculation unit 82. Thereafter, a difference between the first moving average value and the absolute value of X (n) is calculated using the difference value calculating unit 85, and the second moving average value is calculated using the moving average calculating unit 82 for this difference value. This value is calculated as the noise level. Here, instead of performing the first and second moving averages, the first and second filtering may be performed.

  The noise level calculated by the moving average value calculation unit 82 or the filtering unit is transmitted to the external controller 11 via the transmission unit 9, and the noise level can be monitored.

  According to the present embodiment, the fluctuation component can be smoothed by moving average or filtering. Specifically, when processing and displaying on a CNC machine tool or the like, an effect of making the value of the fluctuation component easy to see is obtained.

  Next, a seventh embodiment of the encoder with noise level detection function of the present invention will be described. FIG. 9 shows a schematic diagram of a configuration of an encoder with a noise level detection function according to a seventh embodiment of the present invention. In the encoder with a noise level detection function of the seventh embodiment, the noise level detection unit calculates a differential value for a plurality of times calculated in the past and a peak value which is the maximum among the differential values calculated this time for the output data, It is characterized in that the peak value is a fluctuation component. The difference from the encoder of the second embodiment is that a noise level detector 8 further includes a peak value calculator 86. Since other configurations in the encoder 1 are the same as those in the second embodiment, a detailed description thereof will be omitted.

As shown in FIG. 9, a value X (n) obtained by differentiating the output data AD (n) output from the AD converter 5 at regular intervals once or more times by using a differential value calculation unit 81 is calculated. The peak value calculation unit 86 holds the peak value. A value indicating a peak in a predetermined period is defined as a noise level. Here, although the peak value is held for a certain period, the peak value held at every certain period _Tph is reset so as to cope with the fluctuation of the cause of noise generation. This certain period _Tph needs to be sufficiently longer than the update interval of the output data of the AD converter 5.

  The noise level calculated by the peak value calculation unit 86 is transmitted to the external controller 11 via the transmission unit 9, and the noise level can be monitored.

  According to the present embodiment, in the case of moving average or filtering, since the value of the fluctuation component is low with respect to sudden noise, taking the peak value can make it easy to grasp sudden noise. .

DESCRIPTION OF SYMBOLS 1 Encoder 2 Circuit board 3 Detection means 4 Signal processing circuit 5 AD converter 7 Position data calculation part 8 Noise level detection part 81 Differential value calculation part 82 Moving average value calculation part 83 Filtering part 84 Absolute value calculation part 85 Difference value calculation part 86 Peak value calculation unit 9 Transmitting means 10 Electric motor 11 External controller

Claims (9)

An encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor,
Detecting means for outputting a detection signal composed of two-phase sinusoidal analog signals that are periodically generated and differing in phase by 90 degrees corresponding to the movement state of the driven body;
An AD converter that converts the detection signal into a digital value at regular time intervals and outputs the digital value as output data;
A noise level detector that calculates a fluctuation component based on a temporal change in the output data and outputs the fluctuation component as a noise level;
The noise level detection unit calculates a differential value obtained by differentiating the output data at least once , and calculates a moving average value for the output data based on a plurality of differential values calculated in the past and a differential value calculated this time. An encoder with a noise level detection function , characterized in that the moving average value is calculated and used as a fluctuation component. An encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor,
Detecting means for outputting a detection signal composed of two-phase sinusoidal analog signals that are periodically generated and differing in phase by 90 degrees corresponding to the movement state of the driven body;
An AD converter that converts the detection signal into a digital value at regular time intervals and outputs the digital value as output data;
A noise level detector that calculates a fluctuation component based on a temporal change in the output data and outputs the fluctuation component as a noise level;
The noise level detection unit calculates a differential value obtained by differentiating the output data at least once, and using the differential value for a plurality of times calculated in the past for the output data, An encoder with a noise level detection function , characterized by performing filtering and using the filtered differential value as a fluctuation component. An encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor,
Detecting means for outputting a detection signal composed of two-phase sinusoidal analog signals that are periodically generated and differing in phase by 90 degrees corresponding to the movement state of the driven body;
An AD converter that converts the detection signal into a digital value at regular time intervals and outputs the digital value as output data;
A noise level detector that calculates a fluctuation component based on a temporal change in the output data and outputs the fluctuation component as a noise level;
The noise level detection unit calculates a differential value obtained by differentiating the output data at least once, and for the output data, the absolute value of a plurality of differential values calculated in the past and the absolute value of the differential value calculated this time are calculated. An encoder with a noise level detection function, wherein a moving average value is calculated based on the moving average value as a fluctuation component. An encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor,
Detecting means for outputting a detection signal composed of two-phase sinusoidal analog signals that are periodically generated and differing in phase by 90 degrees corresponding to the movement state of the driven body;
An AD converter that converts the detection signal into a digital value at regular time intervals and outputs the digital value as output data;
A noise level detector that calculates a fluctuation component based on a temporal change in the output data and outputs the fluctuation component as a noise level;
The noise level detection unit calculates a differential value obtained by differentiating the output data at least once, and uses the absolute value of a plurality of differential values calculated in the past for the output data. An encoder with a noise level detection function, wherein the absolute value is filtered, and the filtered differential value is used as a fluctuation component. An encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor,
Detecting means for outputting a detection signal composed of two-phase sinusoidal analog signals that are periodically generated and differing in phase by 90 degrees corresponding to the movement state of the driven body;
An AD converter that converts the detection signal into a digital value at regular time intervals and outputs the digital value as output data;
A noise level detector that calculates a fluctuation component based on a temporal change in the output data and outputs the fluctuation component as a noise level;
The noise level detection unit calculates a differential value obtained by differentiating the output data at least once, and for the output data, the absolute value of a plurality of differential values calculated in the past and the absolute value of the differential value calculated this time are calculated. An encoder with a noise level detection function, wherein a moving average value is calculated, a difference between the moving average value and an absolute value of a differential value calculated this time is calculated, and the difference is used as a fluctuation component. An encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor,
Detecting means for outputting a detection signal composed of two-phase sinusoidal analog signals that are periodically generated and differing in phase by 90 degrees corresponding to the movement state of the driven body;
An AD converter that converts the detection signal into a digital value at regular time intervals and outputs the digital value as output data;
A noise level detector that calculates a fluctuation component based on a temporal change in the output data and outputs the fluctuation component as a noise level;
The noise level detection unit calculates a differential value obtained by differentiating the output data at least once, and uses the absolute value of a plurality of differential values calculated in the past for the output data. An encoder with a noise level detection function, wherein the absolute value is filtered, and the difference between the filtered differential value and the absolute value of the differential value calculated this time is used as a fluctuation component. An encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor,
Detecting means for outputting a detection signal composed of two-phase sinusoidal analog signals that are periodically generated and differing in phase by 90 degrees corresponding to the movement state of the driven body;
An AD converter that converts the detection signal into a digital value at regular time intervals and outputs the digital value as output data;
A noise level detector that calculates a fluctuation component based on a temporal change in the output data and outputs the fluctuation component as a noise level;
The noise level detection unit calculates a differential value obtained by differentiating the output data at least once, and for the output data, the absolute value of a plurality of differential values calculated in the past and the absolute value of the differential value calculated this time are calculated. Based on the first moving average value, the difference between the first moving average value and the absolute value of the differential value calculated this time,
The calculation of the difference is performed on the absolute value of the differential value for the past multiple times,
And the difference calculated for the absolute value of the past plurality of times of differential values, based on the difference calculated this time, and calculates a second moving average values, characterized in that said second moving average value and the variation component Encoder with noise level detection function. An encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor,
Detecting means for outputting a detection signal composed of two-phase sinusoidal analog signals that are periodically generated and differing in phase by 90 degrees corresponding to the movement state of the driven body;
An AD converter that converts the detection signal into a digital value at regular time intervals and outputs the digital value as output data;
A noise level detector that calculates a fluctuation component based on a temporal change in the output data and outputs the fluctuation component as a noise level;
The noise level detection unit calculates a differential value obtained by differentiating the output data at least once, and uses the absolute value of a plurality of differential values calculated in the past for the output data. A first filtering is performed on the absolute value, and a difference between the differential value subjected to the first filtering and the absolute value of the differential value calculated this time is calculated.
The calculation of the difference is performed on the absolute value of the differential value for the past multiple times,
By utilizing the difference calculated for the absolute value of the past several times of the differential value, with respect to the difference calculated this time, performing a second filtering, in that the differential value of performing a second filtering and variation component noise level detecting function encoder characterized. An encoder with a noise level detection function for obtaining position data of a driven body driven by an electric motor,
Detecting means for outputting a detection signal composed of two-phase sinusoidal analog signals that are periodically generated and differing in phase by 90 degrees corresponding to the movement state of the driven body;
An AD converter that converts the detection signal into a digital value at regular time intervals and outputs the digital value as output data;
A noise level detector that calculates a fluctuation component based on a temporal change in the output data and outputs the fluctuation component as a noise level;
The noise level detection unit calculates a differential value obtained by differentiating the output data at least once, and for the output data, a differential value for a plurality of times calculated in the past and a peak value that is the largest among the differential values calculated this time. An encoder with a noise level detection function , characterized by calculating a value and using the peak value as a fluctuation component.

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