JPH0681097U - Encoder device - Google Patents

Abstract

(57) [Abstract] [Purpose] Supplying power from the control unit to the encoder and transmitting position data from the encoder to the control unit
A simple circuit configuration is used with a pair of common lines. [Configuration] DC power is intermittently supplied to the encoder 15 from the control device through the common lines 13 and 14 at predetermined time intervals. In the encoder 15, the voltage detector 7 detects the presence or absence of power supply and controls the switch circuits 5 and 6.
During the period when power is supplied, the encoder is operated by the supplied power and the battery 3 is charged. During a period in which power is not supplied, the encoder is operated by using the power storage device 3 as a power source, and the detected position data of the moving body is transmitted from the signal transmission circuit 2 to the control device through the common lines 13 and 14.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an encoder device used for controlling industrial robots, numerically controlled machine tools and the like.

[0002]

[Prior art]

 Conventionally, in this type of encoder device, an encoder is installed on a controlled moving body, and power is supplied to the encoder through a power supply line from a power supply provided on the side of the control device that is located away from the moving body. However, the position data of the moving body detected by the encoder is transmitted to the control device through the transmission line. Then, the control device outputs a control signal for controlling the moving body based on the position data obtained from the encoder. However, if the power supply line and the transmission line are separately provided, there arises a problem that the number of wirings between the encoder and the control device increases when the number of encoders increases. Therefore, the applicant previously proposed that power supply and data transmission be performed using a common line. The technology previously proposed by the applicant is a rectification circuit that arranges an AC power supply on the control device side and continuously supplies AC power for encoder power supply to a pair of common lines, and rectifies the alternating current to DC on the encoder side. In addition, the encoder output was converted into alternating current and position data was transmitted to the control device through a common line.

[0003]

[Problems to be solved by the device]

 However, such a method has a problem that the circuit configuration is complicated because, for example, a transformer or a transmitter is required as a means for carrying electric power and data on the common line.

An object of the present invention is to provide an encoder device that can supply electric power and transmit data through a common line with a relatively simple circuit configuration.

[0005]

As shown in FIG. 1, an encoder device to be improved by the present invention is an encoder for transmitting detected position data of a moving body by a serial signal transmission circuit 2 through a transmission line. 15 and a control device that supplies power to the encoder through a power supply line and outputs a control signal used for controlling the moving body based on the position data transmitted from the encoder, and forms a pair as a transmission line and a power supply line. Common lines 13 and 14 are used.

In the encoder device of the present invention, the control device includes a DC power source for supplying DC power to the encoder 15 through the common lines 13 and 14 at predetermined time intervals, and the encoder 15 detects the voltage of the common lines 13 and 14. And a voltage detector 7 for detecting a period during which DC power is being supplied from the DC power supply and a period during which DC power is not being supplied, and switches 5 and 6 that perform switching operation according to the detection output of the voltage detector. A capacitor 3 is provided which is charged through the switches 5 and 6 while the voltage detector 7 detects the supply of the direct current power and operates as a power source of the encoder 15 while the DC power is not supplied. Then, the serial signal transmission circuit 2 is configured to transmit the position data to the common lines 13 and 14 through the switches 5 and 6 during the period when the voltage detector 7 does not detect the supply of the DC power.

The serial signal transmission circuit 2 may be configured to operate with the fall of the voltage of the DC power supply as a transmission start timing signal.

[0008]

[Action]

 In the encoder device of the present invention, DC power is intermittently supplied to the encoder 15 from the control device through a pair of common lines 13 and 14 at predetermined time intervals. The voltage detector 7 detects the presence or absence of power supply, and operates the serial signal transmission circuit 2 and the switches 5 and 6 based on the detected output. During the period in which the voltage detector 7 detects the supply of electric power, the DC power is supplied to the circuits of the respective parts of the encoder through the switches 5 and 6, and the battery 3 is charged. In addition, while the voltage detector 7 does not detect the supply of DC power, the circuit of each part of the encoder 15 operates with the battery 3 as a power source, and the encoder 15 transmits the detected position data of the moving body to the serial signal transmission circuit. 2 to the common lines 13 and 14 via the switches 5 and 6 and transmit them to the control device. Therefore, in the present invention, the pair of common lines 13 and 14 are shared by the power supply line and the signal transmission line by time division. As a result, it is possible to perform power supply and data transmission using a common line by using a simple circuit configuration without the need for a transformer and a transmitter as in the conventional case.

In the encoder device of the present invention, when the serial signal transmission circuit 2 is configured to operate with the fall of the voltage of the DC power supply as the timing signal of the transmission start, the supply of the power supply power is stopped and the position data Good transmission.

[0010]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an outline of the circuit configuration on the encoder side used in the encoder device of the present invention, and a controller and a DC power supply arranged on the controller side for supplying DC power to the encoder are not shown. In FIG. 1, reference numeral 1 is an encoder signal detection circuit that outputs a binary signal based on a change in the position of a moving body. Although not shown in the figure, a detection signal detected by the encoder body fixed to the moving body is input to the encoder signal detection circuit 1. Reference numeral 2 denotes a serial signal transmission circuit that converts the binary signal output from the encoder signal detection circuit 1 into a serial signal and transmits the serial signal. In this embodiment, as the encoder signal detection circuit 1 and the serial signal transmission circuit 2, those whose current consumption is reduced by the recent progress of semiconductor technology are used, and the serial signal transmission circuit 2 uses a serial signal. The one that can transmit at high speed is used.

Reference numeral 3 denotes a condenser having a relatively large capacity, which is provided in parallel with the encoder signal detection circuit 1 and the serial signal transmission circuit 2 and is charged through the power supply lines 8 and 9. In the present embodiment, A large-capacity capacitor is used as the storage battery 3. By the way, when using a low current consumption encoder signal detection circuit 1 and serial signal transmission circuit 2 and a serial signal transmission circuit 2 capable of high-speed transmission of serial signals, when using a capacitor as this capacitor It is preferable that the capacitance of the capacitor is 1F or more. As will be described later, this capacitor 3 is charged while DC power is being supplied from a DC power supply (not shown), and while DC power is not being supplied, the power supply for each circuit of the encoder including the serial signal transmission circuit 2 is supplied. Acts as

Reference numeral 4 is a voltage regulator that appropriately converts a DC voltage supplied from a control device (not shown) through the common lines 13 and 14 and supplies an appropriate power supply voltage to the encoder signal detection circuit 1 and the serial signal transmission circuit 2. is there. This voltage regulator 4 makes the voltage applied to the capacitor 3 smaller than the voltage of the DC power supply. Accordingly, it is possible to prevent the voltage detector 7 to be described later from detecting the charging voltage of the battery 3 during the period in which the DC power is not being supplied from the DC power supply and erroneously recognizing that the DC power is being supplied.

Reference numerals 5 and 6 denote switch circuits that form a switch, and these switch circuits 5 and 6 perform a switching operation according to the detection output of the voltage detector 7. These switch circuits 5 and 6 are in a state of connecting the common lines 13 and 14 to the power supply lines 8 and 9 while the voltage detector 7 detects the supply of the DC voltage from the DC power supply. , The voltage detector 7 is configured to connect the output of the serial signal transmission circuit 2 to the common lines 13 and 14 during the period in which the supply of DC power from the DC power supply is stopped. . It should be noted that these switch circuits may be configured using either a contact type analog switch or a semiconductor switch. In the embodiment, a contact switch is used for illustration.

The voltage detector 7 is connected to the common lines 13 and 14, and determines whether or not the DC power is supplied from the DC power supply, that is, the period during which the DC power is supplied from the DC power supply and the DC voltage. Not detect for a period. In this embodiment, it is determined that DC power is being supplied while the voltage of 5 V or higher is being detected. The voltage regulator 4 adjusts the voltage (for example, to 3 V) so that the charging voltage of the battery 3 becomes less than 5 V. Reference numerals 10 and 11 are signal transmission lines, and reference numeral 12 is wiring for transmitting the detection output of the voltage detector 7 to the serial signal transmission circuit 2 and the switch circuits 5 and 6. The encoder 15 of the embodiment is configured as described above.

Next, the operation of the embodiment will be described. In this embodiment, a so-called Manchester encoding synchronous transmission system is used as a means for transmitting a serial signal to a control device (not shown) arranged at a position apart from the encoder 15. This is, for example, a transmission method in which an encoder signal can be transmitted if 82 μs is required for one data transmission. In this case, if the control device can receive the encoder signal in the sampling time of 500 μs to 1 ms, it can effectively control the moving body such as the robot without any trouble. Therefore, in the present embodiment, as shown in FIG. 2, the pair of common lines 13 and 14 are used as a DC power supply line having a voltage of 5 V for 500−8 2 = 418 μs, and the encoder signal detection circuit is controlled by the controller. 1 and the serial signal transmission circuit 2 is supplied with power and the capacitor 3 is charged. Then, during the next 82 μs, the DC power supply from the control device is interrupted, and the encoder signal detection circuit 1 and the serial signal transmission circuit 2 with low current consumption are operated by the electric charge stored in the large-capacity electric storage device 3. Now, the pair of common lines 13 and 14 are used as transmission lines for serial signals to transmit the position data to the control device. That is, the common lines 13 and 14 are shared by the power supply line and the signal transmission line by time division. In order to perform the above operation, the voltage detector 7 detects the presence or absence of the power supply voltage 5V supplied between the lines 13 and 14, and as shown in FIG. In the case, the data transmission control signal having the signal value HIGH is output to the wiring 12, and when the voltage 5V is not supplied, that is, when the signal is OFF, the data transmission control signal having the signal value LOW is output to the wiring 12. The switch circuits 5 and 6 respectively connect the common lines 13 and 14 to the contact a and supply the power supply to the voltage regulator 4 while the control signal having the signal value HIGH is input. Next, when a control signal having a signal value LOW is output from the voltage detector 7, the switch circuits 5 and 6 are switched to the contact b side, and the lines 13 and 14 are connected to the signal transmission lines 10 1 and 11, respectively. . Further, the serial signal transmitting circuit 2 operates by using the timing when the control signal changes from HIGH to LOW, that is, the fall of the power supply voltage as the timing signal for starting transmission, and outputs the serial signal indicating the position data of the moving body. In this embodiment, position data immediately before the fall of the power supply voltage is transmitted. After the transmission is completed, the serial signal transmission circuit stops the transmission operation. As described above, the serial signal is transmitted to the control device through the common lines 13 and 14.

During the signal transmission period, the encoder signal detection circuit 1 and the serial signal transmission circuit 2 operate by the stored power of the battery 3 even if the power supply from the control device is stopped. However, both circuits 1 and 2 described above are designed for low current consumption, and since the transmission operation is not performed after the completion of transmission, even if the power supply on the control device side is interrupted, the encoder will not operate due to the electric charge of the power storage device 3. It will be backed up for quite a long time. Therefore, even if the DC power supply fails for a long time, the encoder can store and retain the information of the origin position, and the work of determining the origin position again after the power failure is restored becomes unnecessary. Although a capacitor is used as the storage battery 3 in this embodiment, it goes without saying that a secondary battery such as a lithium battery can be used as the storage battery.

[0017]

[Effect of device]

 As described above, according to the encoder device of the present invention, the pair of common lines are shared by the power supply line and the signal transmission line by time division, so that the transformer, the transmitter, etc. are used as in the conventional case. There is an advantage that the power supply and the data transmission can be performed using the common line without the need of the above and with a simple circuit configuration.

According to the second aspect of the invention, the encoder can favorably transmit the position data at the same time when the supply of the power source power is stopped.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a main part of an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the operation of the embodiment.

[Explanation of symbols]

 1 Encoder signal detection circuit 2 Serial signal transmission circuit 3 Condenser 4 Voltage regulator 5, 6 Switch circuit (switch) 7 Voltage detector 13, 14 Common line 15 Encoder

Claims (2)

[Scope of utility model registration request] 1. An encoder for transmitting the detected position data of the moving body through a transmission line by a serial signal transmission circuit, and an electric power is supplied to the encoder through a power supply line and based on the position data transmitted from the encoder. A control device that outputs a control signal used to control the moving body, wherein the control device is a encoder device that uses a pair of common lines as the transmission line and the power supply line, A direct-current power supply for supplying direct-current power to the encoder at time intervals, wherein the encoder detects a voltage of the common line and provides a period in which direct-current power is supplied from the direct-current power supply and a period in which the direct-current power is not supplied, respectively. A voltage detector that detects the voltage; a switch that performs a switching operation according to the detection output of the voltage detector; and the voltage detector Is charged through the switch during a period in which the supply of the DC power is detected, and includes a capacitor that operates as a power source of the encoder during a period in which the DC power is not supplied, and the serial signal transmission circuit, An encoder device configured to transmit the position data to the common line through the switch during a period in which the voltage detector does not detect the supply of the DC power. 2. The encoder device according to claim 1, wherein the serial signal transmission circuit is configured to operate with a fall of the voltage of the DC power supply as a transmission start timing signal.