JP2758324B2 - Encoder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a relates to the encoder, on the switching means of the particular main power mode and a backup power supply mode.

[0002]

2. Description of the Related Art In an encoder for detecting the absolute position of an external device to be detected , for example, an absolute encoder, it is necessary to always detect the movement of the external device even when the device is not in a normal use state, for example, during transportation. .
Therefore, when the device is not in the original use state, power is supplied from the backup power supply to the external signal detecting means for detecting the position of the external device, and the position of the external device is always detected.

In a general encoder, for example, a magnetic rotary encoder, the peripheral surface of a magnetic drum that rotates integrally with an external device is magnetized with different polarities at a constant interval in the circumferential direction, and the magnetic sensor is opposed to the peripheral surface of the magnetic drum. For example, a magnetoresistive element (hereinafter, referred to as “MR element”) is arranged, and a detection output of the MR element is shaped into a waveform and input to a signal processing circuit. The signal processing circuit includes a counter and other various logic circuits. Generally, these logic circuits use a gate array. Hereinafter, the term “gate array” is used, but the gist of the present invention is not lost in a logic circuit created by constructing a logic element. Since signal processing by the gate array requires a clock pulse of a constant frequency, an oscillator is connected to the gate array in the conventional encoder to obtain the required clock pulse.

In a conventional absolute encoder, one oscillator is used to obtain a clock pulse to be supplied to a gate array. It is necessary to set the frequency of the clock pulse to a high frequency in advance so that the gate array can cope even when the external device operates at the highest possible speed. Therefore, the oscillation frequency of the oscillator is set to a high value, for example, 4 Mz. Need to be kept.

[0005]

Considering that there are various situations in which backup is required in the encoder device, it is desirable that backup can be performed for as long a time as possible. However, according to the conventional absolute encoder, a clock pulse is obtained by one oscillator in both the main power supply mode and the backup power supply mode, and the backup cannot be performed for a long time. Because, as described above, the oscillation frequency of the oscillator is set high in advance and the frequency of the clock pulse is set high so that the gate array can respond even when the external device moves at the highest possible speed as described above. Since the current consumption of the logic elements such as the gate array increases as the frequency of the clock pulse increases, the current consumption is large even in the backup power supply mode as in the main power supply mode. Because it will be faster.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem. At the time of backup, attention has been paid to the fact that the movement of an external device is generally slow. Using a high-oscillation frequency oscillator allows the gate array to respond sufficiently to rapid movements of external devices, while using a low-oscillation frequency oscillator in the backup power mode. by reducing the current consumption by the array, and to provide the possibility to <br/> the encoder to back for a long time.

Another object of the present invention is to stop driving the oscillator having the higher oscillating frequency when the external device is moving at a low speed, irrespective of the power supply mode. to provide a reduced the encoder current.

Still another object of the present invention is to provide a detection method that follows the high-speed movement of an external device when an oscillator having a lower oscillation frequency is operating despite the external device moving at a high speed. can not, because it is impossible to detect the absolute position of the external device, in such a case it is to provide a encoder which is adapted inform the user with an error information signal.

[0009]

According to the first aspect of the present invention,
A power supply having a backup power supply mode and a main power supply mode, a first oscillator, and being constantly activated by the power supply
At the same time, a pulse having a lower frequency than the first oscillator is generated.
A second oscillator for raw, a power supply mode discriminating means for discriminating the power mode of the power source, external to detect movement of the external device
A Department signal detecting means, based on a detection signal inputted from the discrimination signal and the external signal detecting means is inputted from the power supply mode determining means, determines that the power supply is a main power mode
Or when the above external signal is set to a certain value except zero.
If it is determined that the first oscillation has occurred, the first oscillation
A determination unit for activating the child .

[0010] The invention described in claim 2 is an invention according to claim 1.
In the judgment part of the encoder, the external device
Power mode.
Regardless, the start of the first oscillator is stopped
And then, the third aspect of the present invention, the encoder according to claim 1, wherein
External device moves faster than a certain set value
Is detected by the external signal detection means, and
Error information signal when the first oscillator is not operating.
An error information generating section for outputting a signal.
You.

[0011]

According to the first aspect of the present invention, in the main power supply mode, the determination section activates the oscillator having the higher oscillation frequency. In the backup mode, the determination unit activates the oscillator having the lower oscillation frequency to suppress the consumption of the backup power. Even in the backup mode, when the external device moves at a high speed, the determination unit starts the oscillator having the higher oscillation frequency based on the detection signal input from the external signal detection unit,
A detection operation corresponding to the high-speed movement of the external device is performed.

According to a second aspect of the present invention, the driving of the oscillator having the higher oscillation frequency is stopped when the external device is moving at a low speed, irrespective of the main power mode or the backup power mode. As a result, the oscillator having the lower oscillation frequency is driven, thereby saving current consumption.

According to the third aspect of the present invention, if the oscillator having the lower oscillation frequency operates even though the external device is moving at a high speed, the detecting operation corresponding to the high speed movement of the external device is performed. Since this cannot be performed and the absolute position of the external device cannot be detected, an error information signal is output. Based on the error information signal, the user can take a necessary action.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an absolute encoder. In FIG. 1, a rotating shaft 11 coupled to a rotating shaft of an external device such as a motor is integrally provided with a magnetic drum 12 as a signal source. A plurality of signals are recorded on the magnetic drum 12 by being magnetized with different polarities at regular intervals in the circumferential direction. An MR element 1 which is a magnetic sensor and faces the peripheral surface of the magnetic drum 12
3 is provided to detect the magnetic pole of the magnetic drum 12. Two-phase detection signals are output from the MR element 13, and these detection signals are subjected to waveform shaping by the waveform shaping circuit 14 to become rectangular wave signals A and B. The circuit portion including the MR element 13 and the waveform shaping circuit 14 detects the movement of the external device to which the magnetic drum 12 is coupled, and detects the movement of the external device.
It constitutes an external signal detecting means for detecting the moving speed (rotation speed) . The waveform shaping circuit 14 can be composed of a comparator and other appropriate circuits.

The rectangular wave signals A and B from the waveform shaping circuit 14
Is input to a line driver 28 which is a signal transmission device via a gate array 20 and
, And is output as an absolute signal Ab and input to the line driver 28. The output signal of the line driver 28 is input to a higher-level device via a cable, and the position control, speed control,
It is also used for various other controls. The rectangular wave signals A and B are also input to the speed detector 23 in the gate array 20. The speed detector 23 outputs a rectangular wave signal A per unit time,
B is always counted, and the result is input to the judgment unit 24 and the error information generation unit 36 in the gate array 20.

Power is supplied to the gate array 20 from a power supply circuit described below. A power supply circuit 31 provided in the host device constitutes a main power supply, and generates a DC power supply of, for example, about 5 V from the commercial AC power supply 30. The main power generated by the power circuit 31 is input to the main power monitor 22 via the main power line, and is also supplied to the gate array 20 via the diode 34 after passing through the main power line. The commercial AC power supply 30 cannot be used when the external device is in a state other than the intended use, for example, when being transported. Therefore, in order to constantly detect the absolute position of the magnetic drum 12 integrated with the external device, power is supplied from the backup power supply 32 provided in the host device to the gate array 20 via the diode 33 and the backup power supply line. The diode 33 is for preventing the main power supply from flowing into the backup power supply 32. The diode 34 connected between the main power supply line and the backup power supply line is for preventing the backup power supply 32 from flowing into the main power supply line. Power is also supplied from the power supply circuit 31 and the backup power supply 32 to the MR element 13, the waveform shaping circuit 14, and the line driver 28, but they are not shown.

In the above-mentioned power supply circuit, in a normal use state, the commercial AC power supply 30 is converted from a power supply circuit 31 into a DC of a predetermined voltage (for example, 5 V) and supplied as power. This is the main power mode. When the commercial AC power supply 30 cannot be used in a normal use state, for example, during transportation, there is no output from the power supply circuit 31 and power is supplied from the backup power supply 32 instead. Further, even in a normal use state, when the commercial AC power supply 30 loses power or the voltage of the power supply
3. Power is supplied via the backup power line.

The main power supply monitoring unit 22 constantly monitors the voltage of the main power supply line and determines whether the power supply is in a main power supply mode or a backup mode. More specifically, when the voltage of the main power supply line is equal to or higher than a predetermined value, for example, the voltage of the backup power supply 32, a signal is input to the determination unit 24 assuming that the main power supply mode is set. Has become. The determination unit 24 outputs a signal based on the determination signal input from the main power supply monitoring unit 22 and the detection signal input from the speed detection unit 23, and the gate circuit 3
Gate 7 is opened and closed. The main power supply monitoring unit 22 constitutes a power supply mode determination unit that determines a power supply mode.

There are two oscillation circuits in the gate array 20, and a first oscillator 25 and a second oscillator 2 for generating a pulse of a predetermined frequency in each oscillation circuit.
6 is externally attached to the gate array 20. The oscillation frequency of the first oscillator 25 is high so that it can cope with the external circuit moving even at the maximum speed. On the other hand, the oscillation frequency of the second oscillator 26 is a low oscillation frequency. The second oscillator 26 is always started and its oscillation output is input to the clock switching circuit 35. The first oscillator 25 is activated when the gate of the gate circuit 37 is opened, and its oscillation output is input to the clock switching circuit 35. The condition for outputting a signal from the determination unit 24 to open the gate of the gate circuit 37 is as follows: the determination signal from the main power supply monitoring unit 22 is a signal indicating that the main power supply mode is set; This is a case where the signal is a signal indicating that the speed is higher than a certain speed. However, the gate circuit 37 may be opened only when the detection signal from the speed detection unit 23 is a signal indicating that the speed is equal to or higher than a certain speed.

The clock switching circuit 35 receives a clock signal generated by the first oscillator 25 or the second oscillator 26, and when the first oscillator 25 is activated, the first oscillator 25 is activated. The high frequency clock signal generated in step (1) is input to each circuit section in the gate array 20 and the error information generating section 36, and when the first oscillator 25 is not activated, the low frequency generated in the second oscillator 26 is output. The clock signal of the frequency is input to each circuit unit in the gate array 20 and the error information generating unit 36. Error information generator 36
Is determined by the signal from the speed detector 23 that the external device is moving at high speed, and the second oscillator 26 having a low oscillation frequency operates without the first oscillator 25 operating. When an oscillation signal is input, an error signal is output. This error signal is input to the host device via the line driver 28, and is transmitted to the user through a display, various alarms, and the like.

In the above embodiment, assuming that the main power supply voltage is normally supplied from the main power supply line,
Since the voltage of the main power supply line is equal to or higher than a certain value, the main power supply monitoring unit 22 outputs a signal corresponding to the main power supply mode of the power supply and inputs the signal to the determination unit 24. In response to this signal, the determination unit 24 opens the gate of the gate circuit 37, activates the first oscillator 25, generates a high-frequency clock pulse, and supplies it to each unit of the gate array 20. When the frequency of the clock pulse is high, it can cope with a high moving speed of the external device, but the current consumption by the gate array 20 is large. However, in the main power supply mode, a sufficient current is supplied from the main power supply.

When the commercial AC power supply 30 cannot be used, for example, during transportation, when the encoder is not in its original use state, or when the commercial AC power supply 30 is cut off,
Since the voltage of the main power supply line is lower than the voltage of the backup power supply 32, the power supply line enters the backup power supply mode in which power is supplied from the backup power supply 32. As described above, when the voltage of the main power supply line becomes lower than the voltage of the backup power supply 32, the main power supply monitoring unit 22 outputs a signal corresponding to the backup mode and inputs the signal to the determination unit 24.
In response to this signal, the determination unit 24 closes the gate of the gate circuit 37, stops the operation of the first oscillator 25, and operates only the second oscillator 26 to generate a low-frequency clock pulse. Supply to each part. When the frequency of the clock pulse is low, it is possible to cope only with the case where the moving speed of the external device is slow, but since the external device generally moves slowly during backup,
No problem. When the frequency of the clock pulse is low, the current consumption by the gate array 20 is reduced, and thus there is an advantage that the backup power supply 32 allows the backup to be performed for a long time.

However, even at the time of backup, when a large shock is applied to the external device, the external device may move rapidly. In such a case, if only the second oscillator 26 having a low oscillation frequency is operating, it may not be possible to detect a rapid movement of the external device, and may function as an absolute encoder. You can't. However, in the embodiment shown in FIG. 1, when the moving speed of the external device becomes equal to or higher than a predetermined value, the speed detecting unit 23 detects the moving speed and opens the gate of the gate circuit 37 according to the judgment of the judging unit 24. Since one oscillator 25 is activated, the gate array 20 can cope with a high-speed movement of the external device, and can accurately detect the position of the external device. When the moving speed of the external device falls below a certain value, the judging unit 24 sets the gate circuit 3
7, the operation of the first oscillator 25 is stopped, and only the second oscillator 26 is operated.

The signal from the speed detector 23 determines that the external device is moving at a high speed, and the first oscillator having a high oscillation frequency does not operate and the second oscillator 26 having a low oscillation frequency operates. When the oscillation signal is input during operation, the gate array 20 cannot cope with the high-speed movement of the external device and cannot function as an absolute encoder. However, in such a case, the error information generating section 36 outputs an error signal and is transmitted to the user side, so that the user can take necessary measures.

[0025] Thus, according to an embodiment of the Rue encoder written present invention, provided two different oscillator oscillation frequency, a second lower oscillation frequency is the backup mode
Is used, the current consumption is reduced, the consumption of the backup power supply 32 is suppressed, and the backup period by the backup power supply 32 can be lengthened. Further, even during the backup, if the moving speed of the external device becomes higher than a certain value for some reason, the speed is detected by the speed detector 23 and the first oscillator 25 having the higher oscillation frequency is started. Therefore, the position of the external device can be accurately detected.

Although the embodiment described above is for a magnetic encoder, it can be applied to an optical encoder. Further, the present invention can be applied to not only a rotary encoder but also a linear encoder. Regardless of the type of encoder, the effects described above can be obtained by applying the present invention.

The technical idea of the present invention requires an oscillator,
In addition, as long as the device can safely lower the oscillation frequency in the backup mode, it can be applied to devices other than the absolute encoder.

The moving speed of the external device is divided into, for example, three stages of stopping, moving at a low speed, and moving at a high speed, and each of the oscillators having a different oscillation frequency corresponding to each stage has one oscillator.
It may be provided individually. Also, backup power supply, main power supply
Is not limited to those provided in the host device. In addition,
Power supply voltage in backup power mode and main power mode
Are different, the voltage on the cathode side of the diode 34 is
The power may be monitored by the power monitoring unit 22.

[0029]

According to the first aspect of the present invention, the back
A power source having an up power mode and a main power mode;
Oscillator and the above-mentioned power supply,
A pulse generating a lower frequency pulse than the first oscillator
And a power supply mode for determining the power supply mode of the power supply.
Mode determination means and an external signal detection for detecting the movement of an external device.
Output means and a determination input from the power mode determination means.
Signal and the detection signal input from the external signal detection means.
If the above power source is determined to be in the main power mode,
Or the above external signal is above a certain set value excluding zero
If it is determined that the first oscillator is moving, the first oscillator is started.
The main power supply mode determines
Section activates the first oscillator having the higher oscillation frequency, and
In the backup power supply mode, the judgment unit
To activate the second oscillator to reduce the consumption of backup power.
Can be suppressed and the backup period lengthened
Is possible. And in backup power mode
External device moves faster than a certain set value.
Then, the first oscillator is activated by the judgment of the judgment unit,
Perform detection operation corresponding to high-speed movement of external devices.
Can be.

According to the second aspect of the present invention, the first aspect is provided.
In the determination unit of the described encoder, the external device is fixed
If it is determined that it is moving at a speed lower than the set value,
Since the activation of the first oscillator is stopped regardless of the mode , the power consumption of the power supply can be reduced regardless of whether the power supply mode is the main power supply mode or the backup mode.

If the external device moves at a high speed and the oscillator having the higher oscillation frequency is not operating at that time, the encoder cannot cope with the high speed movement of the external device. In the present invention, the engine described in claim 1 is used.
In the coder, the external device is faster than a certain set value.
The movement is detected by the external signal detection means, and
At that time, when the first oscillator is not operating, an error message is displayed.
The provision of the error information generating section for outputting the information signal allows the user to take necessary measures based on the error information signal .

[Brief description of the drawings]

Block diagram illustrating an embodiment of Rue encoder written to the present invention; FIG.

[Explanation of symbols]

 Reference Signs List 13 MR element as external signal detecting means 14 Waveform shaping circuit as external signal detecting means 22 Main power monitoring section as power mode determining means 24 Judging section 25 Oscillator 26 Oscillator 31 Main power supply 32 Backup power supply 36 Error information generating means

Claims (3)

(57) [Claims] And 1. A power supply with backup power mode and the main power supply mode, the first oscillator, with which constantly activated by the power source, the first origination
A second oscillator that generates a lower frequency pulse than the pendulum
When a power supply mode discriminating means for discriminating the power mode of the power source, an external signal detecting means for detecting a movement of an external device, the determination signal and the <br/> external signal detecting means which is inputted from the power supply mode judging means Based on the detection signal input from
If the power supply is determined to be in main power mode, or
The external signal is moving above a certain set value excluding zero.
If it is determined that the first oscillator is activated,
And an encoder comprising: Wherein said determination unit, the external device is above a certain
If it is determined that the robot is moving at a lower speed than
2. The encoder according to claim 1, wherein the activation of the first oscillator is stopped regardless of a power supply mode . Wherein said external device than the predetermined set value
High-speed movement is detected by the external signal detection means.
And at this time the first oscillator is not operating
2. The encoder according to claim 1, further comprising an error information generating unit that outputs an error information signal when the error occurs.