JPS63300911A - Multirotation type absolute value encoder - Google Patents

Abstract

PURPOSE:To obtain a high-reliability encoder by detecting the abnormality of a voltage and transmitting its signal to a receiving device in series. CONSTITUTION:An abnormal voltage detecting circuit 19 is provided to detect a battery voltage and a voltage V1 from a large-capacity capacitor 15 at all times. Then when the voltage V1 drops below a prescribed voltage, the abnormal voltage signal is sent to a control circuit 17. Then the circuit 17 sends an ASCII code as abnormal voltage detection data to the receiver through a balanced line driver circuit 16 with priority to data on a rotational quantity in a normal state. The abnormality of the source voltage for the encoder and a reception-side controller is therefore detected by the reception-side controller and this detection is performed similarly without using any external battery even when an auxiliary battery is used internally. Further, when many encoders are used like an articulated robot, absolute value signals are detected by axes, so which axis is abnormal is detected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for detecting the number of revolutions and the direction of rotation of one revolution or more.
A pulse detector and an absolute value encoder that detects absolute angles within one rotation are combined on the same shaft, and based on their respective detection signals, the absolute angle of multiple rotations of the shaft is detected and supplied to the encoder. If there is no power source, the 1-pulse detector and the electronic circuit that measures the detection amount of the 1-pulse detector will be powered off by an external auxiliary power source such as a battery power source, an internal battery power source, a large capacity capacitor, etc. This invention relates to the supplied multi-rotation type absolute value encoder.

(Prior Art) FIG. 7 is a block diagram of a conventional example (Japanese Patent Application No. 61-230253) of this type of multi-rotation type absolute value encoder.

This multi-rotation type absolute value encoder includes a rotating disk 2 for detecting an absolute angle within one rotation, an LED 4 for projecting light onto the disk, a fixed slit 5, a photodiode array 6 as a light receiving element, and these elements. Waveform shaping circuits 71 to 73. waveform shape the detection signals into rectangular waves. It is composed of
The magnetic encoder that detects multiple rotations has a magnet 82 in the rotating part.
A rotating disk 81 equipped with a rotating disk 81, a magnetoresistive element 9 for detecting the rotation speed, a waveform shaping circuit IO, and a power supply switching circuit that switches to an external battery power source when the power supply is cut off. 14, a large-capacity capacitor 15 that uses stored electricity to drive the circuit when the battery power supply runs out, and a voltage detection circuit 13 that detects the power supply voltage.
It has a built-in microcomputer to count the multi-rotation detection signal and hold the numerical value; An ft+ control circuit 17 including a gate array for serially transmitting signals as A channel, B channel, and Z channel signals, and a balanced line driver for sending these signals to the receiving device. It is composed of a circuit 16.The signal transmission method is that when the power supply voltage is supplied, the voltage detection circuit 13 operates, sends a signal to the IB control circuits 17 and 12, and the control circuit 17 operates. First, an asynchronous signal, which is a multi-rotation detection signal of shaft 1, is transmitted to the receiving device as an A channel signal as serial data.In this conventional example, it is transmitted using an 8-character ASCII (ASC+[) code and 9600 baud. Then, the second absolute value signal detected by the absolute value encoder is transmitted to the receiving device as incremental pulses of channels A and B (Figure 8).
. In the receiving device, the absolute position after multiple rotations can be detected from these two signals. Further, after transmission, positioning can be performed using an incremental encoder by transmitting two-phase pulses of A and B channels as before.

[Problem that the invention seeks to solve]

FIG. 9 shows a configuration in which the multi-rotation type absolute value encoder having the configuration shown in FIG. 7 is connected to a control device on the receiving side by a cable. In this state, the external battery power cable is disconnected (X
) or a contact failure occurs and the power is lost, the memory is stored in the internal large capacity capacitor 15, but if this capacitor 15 continues to discharge, the voltage will drop,
A problem arises in that the rotation amount of the shaft cannot be memorized, and an accurate absolute position cannot be detected when the power is turned on again.

In addition, if an auxiliary battery 18 or the like is built into the multi-rotation absolute value encoder (Figure 10), a similar phenomenon will occur due to the voltage drop of the battery, resulting in the inability to detect an accurate absolute position. do.

In the case of an external battery, it is sufficient to constantly detect the battery current of the multi-rotation type absolute value encoder, but this only applies when a single multi-rotation type absolute value encoder is being driven, such as an articulated robot. In addition, a multi-rotary absolute value encoder (6 pieces for 6 axes) is connected to an external battery, and since there are variations in individual current consumption and fluctuations in battery voltage, it is necessary to constantly detect the battery current. It is not possible to detect lead breakage or poor contact.

[Means for solving problems]

The multi-rotation type absolute value encoder of the present invention includes an external battery power supply,
When the electric f circuit, etc. that measures the detected amount of the l-pulse detector is driven by an internal battery power supply or large-capacity capacitor, etc., it is necessary to determine whether this voltage is normal or abnormal, at least to check whether the voltage is abnormal. It has an abnormality detection circuit that detects W-normal, and when the power is turned on, a failure detection signal is serially transmitted to the receiving device instead of a signal indicating the number of rotations of multiple rotations, so that external or This indicates an internal voltage abnormality.

(Operation) Therefore, a highly reliable absolute value encoder can be obtained.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the multi-rotation type absolute value encoder of the present invention, and FIG. 2 is a diagram showing its A channel output and B channel output.

In this embodiment, an abnormal voltage detection circuit 19 is added to the conventional configuration shown in FIG. 7 to constantly detect the battery voltage and the voltage Vl from the large capacity capacitor I5, and in the unlikely event that the voltage v1 falls below the specified voltage. In this case, the abnormal voltage signal is sent to the control circuit 17, and the control circuit 17 gives priority to the normal rotation amount data and sends it to the ASCII code rB as abnormal voltage detection data through the balanced line driver circuit 16 (TERROR).
Send J to the receiving device.

Therefore, as shown in FIG. 9, if the battery voltage between the multi-rotary absolute value encoder and the control device on the receiving side becomes abnormal, the abnormality can be detected by the control device on the receiving side. . Further, even when an auxiliary battery 18 is used internally as shown in FIG. 10 without using an external battery, abnormal voltage can be detected in the same manner. Furthermore, in cases where many multi-rotary absolute value encoders are used, such as in articulated robots, absolute value signals are detected one by one, so the wiring of the multi-rotary absolute value encoder for which axis, the internal battery etc. It can be detected whether the is bold or not.

In addition, in the case of normality, the multiple rotational speed is sent to the control device on the receiving side in the form of , so it can be clearly distinguished from the case of abnormality.

FIG. 3 is a block diagram of another embodiment of the multi-rotation type absolute value encoder of the present invention.

This embodiment uses a detection element 21 and an abnormality detection circuit 20 to detect abnormal temperature and vibration in addition to abnormal voltage.

Fig. 4 shows an example in which a thermistor for detecting temperature is used as the detection element 21, and the temperature of the thermistor placed on the substrate is -
The internal temperature of the encoder is detected using the characteristic that the resistance value decreases as the temperature rises, and this is detected by the comparator Ill:,
, the comparator I of the abnormality detection circuit 20 consisting of resistors R1 to R3 shapes the waveform, and when the temperature reaches the usage limit, an abnormality detection signal is sent to the control circuit 17, and the control circuit 17 outputs an ASCII code called r TEMERRORJ. Output.

Note that by changing the data content for each abnormality, a large amount of detected data can be sent as serial data to the receiving control device. In addition, even when the power is turned on, taking advantage of cases where the encoders of all axes are not moving, such as in robots,
It is also possible to send an abnormality signal for an encoder that is not operating.

FIG. 5 is a circuit diagram of abnormality detection in the case of pulse open phase detection, and FIG. 6 is a time chart thereof.

During operation, this absolute value encoder exhibits the same characteristics as a conventional incremental encoder;
Phase loss of the pulse is detected by looking at the detection signal which shapes the waveform of the phase incremental signal. The two-phase detection signal is shown in FIG. 6 (1).

As shown in (2), A-, which is electrically 180 degrees out of phase with A+, and B+, B+ and 18, which have a 90 degree phase difference from A+.
The four signals B- with a 0° phase shift are the detection signals, and when these detection signals A+, A-1B+, and B- are combined using MP to the amplifier, MP7 to ~, and resistors R4 to R7, the result shown in Figure 6 ( 3
), and if there is a phase loss for some reason, this signal will be smaller than the reference voltage Vi, so the comparator ■C
If the output level of 2 is inverted and this signal is sent to the control circuit 17 as an abnormality detection signal, it is possible to detect an open phase of the pulse.

〔Effect of the invention〕

As explained above, the present invention is capable of detecting temperature and By using a sensor such as a vibration sensor and sending a similar abnormal signal to the control device on the receiving side as serial data, it is no longer driven by a regular absolute value signal, and a highly reliable multi-rotation type absolute value encoder can be obtained. It has the effect of

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the multi-rotation type absolute value encoder of the present invention, Fig. 2 is a diagram showing signal transmission when the battery power supply is defective in the embodiment of Fig. 1, and Fig. 3 is a diagram of the present invention. A block diagram of another embodiment of the multi-rotary absolute value encoder of the invention,
Fig. 4 is a circuit diagram of a specific example of the abnormality detection circuit 20, Fig. 5 is a circuit diagram of another specific example of the abnormality detection circuit 20, Fig. 6 is a time chart of abnormality detection, and Fig. 7 is a multi-rotation type absolute A block diagram of a conventional example of a value encoder, FIG. 8 is a diagram showing an output signal in the conventional example of FIG. FIG. 1O is a block diagram of a conventional multi-rotation type absolute value encoder with a built-in auxiliary battery. 1-----Shaft, 2...Rotating disk for absolute value encoder, 4.
...-LED. 5...Fixed slit, 6---Photodiode array, 7□~7.5
．． 10---Waveform shaping circuit, 81...Magnetic encoder rotating disk. 82... Magnet, 9... Magnetoresistive element 7', 12.17...-it+(I control circuit, 13...
... Voltage detection circuit, 14... Power supply switching circuit, 15... Large capacity capacitor, 16... Balanced line driver circuit, 19.
...Abnormal voltage detection circuit, zO...Abnormality detection circuit, 21...Detection element f, D, ・D2. D3...Diode, R,
, R2,...-, R7-...Resistance. IC,, Ic2---Comparator, ^MP, NAMP 2...Amplifier.

Claims (1)

[Claims] A 1-pulse detector that detects the rotation amount and rotation direction of one rotation or more and an absolute value encoder that detects the absolute angle of one rotation or less are combined on the same shaft. , detects the absolute angle of multiple rotations of the shaft, and when the power is turned on, when the detection circuit that detects the power supply voltage detects a power supply voltage higher than a predetermined voltage, it first transmits the amount of rotation of the multiple rotations to the receiving circuit. Serial transmission, then
It has a control circuit that electrically sends the absolute angle within one rotation as a two-phase rectangular wave signal with a 90° phase difference, and if the power supply to the encoder runs out, it can be connected to an external battery power source, etc. In a multi-rotation absolute value encoder, power is supplied to the electronic circuit, etc. that measures the detected amount of a single pulse detector by an internal battery power supply or a large capacity capacitor, etc. An abnormality detection circuit that determines whether this voltage is normal or abnormal when an electronic circuit, etc. that measures the detection amount of a single pulse detector is driven by a capacitor, etc., or at least detects an abnormality of the voltage. In the case of an abnormality, when the power is turned on, an abnormality detection signal is serially transmitted to the receiving device instead of a signal indicating the number of rotations of the multi-rotation, thereby notifying the external or internal voltage abnormality. Multi-rotation absolute value encoder.