JPH08159809A - Transmission method for multi-rotary type absolute value encoder and device provided with this encoder - Google Patents

Abstract

PURPOSE: To greatly reduce the number of electric wires by providing a selection means for selecting the transmission of all of an absolute position data, rotational speed data and the other data or only always required data to allow the data processing time close to the prompt processing and reduce incremental signal and origin signal. CONSTITUTION: By a selection signal processing circuit 8 having the selecting function for transmitting all data bits DB0 to DB29 or transmitting only data bits DB0 to DB2 which are always required, when data receiving side data of a serial signal Rx at the time of turning on a power supply or the like is different from data inside an encoder, all data port sides DP0 to DP29 of data selector circuit 6 and transfer synchronization TL of a serial signal conversion circuit 7 are selected by the output 0 of the circuit 8 and transmitted from the data output TX of the circuit 7. After that, the once or are times transmission of all data bits is determined at the input I1 of the circuit 8, and the data bit side of the circuit 6 and the transfer synchronization TS of the circuit 7 are selected by the output 0 and transmitted from the output TX of the circuit 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission method of a multi-turn absolute value encoder, and more particularly, to reduce the number of transmission signal wires by minimizing the amount of data transmitted by a serial signal. And a device therefor.

[0002]

2. Description of the Related Art A transmission method of a multi-rotation absolute value encoder that outputs data by a conventional serial signal (for example, an asynchronous start-stop synchronous serial data transfer method including start bits, data bits, stop bits, etc.) 1
Absolute position data within rotation, rotation speed data, and other data (information data inside the encoder) are all transmitted in a batch with a serial signal, so the amount of data increases, so the serial signal transmission time Since the processing time of the data processing on the data receiving side (control device etc.) of the serial signal becomes long, the incremental signal (phase difference 2 signal) and the origin signal that can be immediately processed are included in addition to the serial signal. It is transmitting.

That is, the encoder used here is a serial signal type multi-rotation absolute value encoder for transmitting absolute position data by a serial signal, and speed control, position control, etc. are considered for feedback of a servo motor. It was done.

A serial signal of absolute position data is generated by, for example, a pure binary code, and one rotation resolution is 2
¹¹ (2048 divisions / revolution), the number of revolutions required for total weighing is 8
191 (2 ¹³ -1) rotation, when measuring the increase direction counterclockwise rotation as viewed from the time of the encoder input (CCW), adapted to increase sequentially output form the line driver (e.g. EIA standard, RS-422 Compliant) serial data communication.

The information data of the encoder includes, for example, a revolution counter overflow and alarm information inside the encoder such as an overspeed alarm.

Further, in serial communication (for example, Rx specification) from the encoder, transmission standards are, for example, EIA standard and RS.
In accordance with the −422 standard, the specification modem corresponds to, for example, DN1811 manufactured by Mitsubishi Cable Industries.

In the transfer format formed by 32 bits of 16 bits × 2, as shown in Table 1 below, the first data (1st data) is formed by 16 bits of data DO0 to DO15. Data DO0-10 is 1
It is the absolute rotation position data, and the following data DO11 to DO
14 is multi-rotation data, and the next data DO15 is for L fixing.

[0008]

[Table 1]

Data D of the second data (2nd data)
It is formed by 16 bits of O0 to DO16, the first data DO0 to DO8 is multi-rotation data, and the next data DO
9 to DO14 are information data, and the next data DO
15 is fixed to H.

In the serial signal transmission mode in the absolute position encoder having such operations and functions, for example, serial signals are alternately transferred with 1st data and 2nd data, and the transfer cycle Tcyc thereof is 84 μs (42 μs × 42 μs).
2). The number of transmission signal electric wires used for transmission of the serial signal is 14 in this conventional example, and is composed of the electric wire group shown below. 1: Main power supply EXT-Vcc 2: Zero volt common COM 3: Battery VBAT 4: Zero volt common COM 5: Clear signal CLR 6: Frame ground FG 7, 8: Serial signals RX, RX '9 to 12: Incremental signals A, A ', B, B' 13, 14: Origin signal Z, Z '

As shown in Table 1, these 14 transmission signal wires have 1st data and 2nd data superimposed on serial signals Rx and Rx '(inverted signals of Rx when a line driver is used). In addition, the incremental signals A, A ', B, B'which consist of binary numbers provided with a phase difference for distinguishing the forward and reverse rotations and the origin signals Z, Z'generated when the encoder is at the origin position are transmitted. To do.

That is, FIG. 8 is a timing chart showing a transmission mode in the case where a serial signal is transmitted after the power is turned on and cleared during the transmission. First, 1st data and 2nd data of the serial signal Rx are transmitted based on the cycle of the transfer cycle Tcyc after a time Tin which is stable after the power is turned on. When the clear signal CLR is generated during the transmission, the transmitted serial signal Rx is reset at the time TCL generated by the clear signal CLR, and after a lapse of a stable time Tin after the completion of the clear signal CLR, the serial signal Rx is again generated. (1st data, 2nd data)
Will be transmitted and predetermined data will be transmitted.

[0013]

However, the transmission method of the multi-rotation type absolute value encoder which outputs the serial signal according to the above-mentioned prior art discriminates the origin position and forward / reverse rotation of the data transmitted by the serial signal. Therefore, in addition to the serial signal, the incremental signals (phase difference 2 signals) A, A ′, B, B ′ and the origin signals Z, Z ′ are inevitable.
Is transmitted separately as necessary. Therefore, transmission signal wires for that amount are required, and especially when many encoders are used in control devices with many driving parts, such as robots, the signal wires are broken, and the area for arranging the signal wires is large. There is a problem that it ends up.

Therefore, in order to solve the above problems, 1
By providing a function to select whether to transmit all absolute position data within rotation, rotation speed data, and other information data, or to output only the data that is always required, the transmission time is shortened and the serial signal By making the data processing on the data receiving side closer to the time when it can be processed immediately,
For example, an incremental signal (phase difference 2 signal) A,
It is an object of the present invention to provide a multi-rotation absolute value encoder in which signal wires for A ′, B, B ′ and origin signals Z, Z ′ are deleted.

[0015]

In order to solve the above-mentioned problems, a transmission method and an apparatus for a multi-rotation absolute value encoder according to the present invention include a data receiving side of a serial signal at power-on and data information of the encoder. Therefore, the absolute position data (pure binary code, binarized decimal code, etc.) within one rotation, rotation speed data and other information data inside the encoder are all transmitted at once, and after that it is always necessary. Only transmit data.

The data which is always required is first 1st.
Since all the data including the data and the 2nd data is transmitted, it suffices if the amount of change in the absolute position and the rotation direction can be determined. In other words, the number of bits from the least significant bit that can transmit a data amount that is greater than twice the amount of change in absolute position at the maximum rotation speed within the transfer period of the serial signal is sufficient. However, it is 2 bits or more in the case of pure binary code and 4 bits or more in the case of binary coded decimal code.

Therefore, when the data amount is D, the change amount is L, the resolution per rotation is N, the maximum rotation speed per second is V, and the serial signal transfer synchronization is T, D> 2L (L = N × V × T) and the transfer synchronization of the serial signal can be determined in advance in consideration of the processing time on the data receiving side, so that the processing time on the receiving side can be shortened.

From the above, a function for selecting whether to transmit all data or only required data at all times is provided, and when the data of the encoder is lost at power-on or the data receiving side of the serial signal, etc. In addition, since all the data to be transmitted are selected and then only the data that is always necessary in the normal operation state is selected, the data processing time can be approached to the immediate processing, so that an incremental signal (phase difference 2 signal) and The origin signal can be reduced and the number of transmission signal wires can be significantly reduced.

[0019]

When the data on the serial signal receiving side such as when the power is turned on is different from the absolute position data within one rotation, the rotation speed data, and other information data, all the data inside the encoder is transferred from the encoder. Transmit,
The data receiving side stores the data in the memory, then transmits only the data that is always required, compares the data that is always required with the data stored in the memory, calculates the absolute position change amount and the rotation direction, and stores it in the memory. By rewriting the stored data, the absolute position data and the rotation speed data within one rotation inside the encoder can be reproduced at the data receiving side in a time close to the immediate processing, and thus the incremental signal (phase difference 2
Signal) and the origin signal are unnecessary, and the number of transmission signal wires can be reduced.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [1] Transmission mode, [2] Transmission method and device for multi-rotation absolute value encoder according to the present invention
The theoretical basis for reducing the amount of data to be transmitted and [3] circuit configuration will be described below in this order with reference to the drawings. It should be noted that the tables and drawings adopted in the prior art are appropriately cited.

[1] Transmission mode The transmission mode is basically a method of transmitting only the minimum required 1st data out of the transfer format consisting of 1st data and 2nd data (see Table 1 of the prior art). There are (1) a method of transferring only the 1st data after transferring a predetermined transfer format, and (2) a method of transferring only the 1st data after transferring the 1st data and the 2nd data under the control of the outside. The number of transmission signal electric wires used is eight as shown below. 1: Main power supply EXT-Vcc 2: Zero volt common COM 3: Battery VBAT 4: Zero volt common COM 5: Clear signal CLR 6: Frame ground FG 7, 8: Serial signals Rx, Rx ′

(1) Method of transferring only the 1st data after transmitting a predetermined transfer format FIGS. 1, 2 and 3 are timing charts showing operations under various conditions by this method, Alternate the serial signal Rx to 1st data and 2nd data by 1
Transfer more than once (one cycle 52μs x 16 times), then 1s
By continuously transferring t data (one cycle of 26 μs), the transfer cycle is made faster. As described below, the operation that differs depending on the various conditions is as follows: (a) When the main power source EXT-Vcc is turned on, (b) Clear signal C
When LR is input, it is roughly divided into (c) operation when an alarm is generated. In addition, 1 cycle 52μs, 26μs,
It goes without saying that it can be changed appropriately, and the specific numerical value of the period value quoted in the following description can also be changed appropriately.

(A) When the main power source EXT-Vcc is turned on As shown in FIG. 1, when the main power source EXT-Vcc is turned on, the serial signal Rx has a predetermined value which is stable after the main power source EXT-Vcc is turned on. 1st data, 2nd after time Tin has passed
The data transfer cycle Tcyc (52 μs in the embodiment)
It is transferred once or more each time. After that, the transfer cycle Tcyc1
The 1st data is continuously transferred every (26 μs in the embodiment), and is continued while the main power source EXT-Vcc is supplied.

(B) When the clear signal CLR is input FIG. 2 shows the clear signal CL during the continuous transfer of the 1st data.
FIG. 3 is a timing chart when R is turned on, and the main power supply EXIT-Vcc shown in FIG. 1 is supplied for 1 s.
If the clear signal CLR is generated during transfer of t data,
After the elapse of a predetermined time TCL, the serial signal Rx is stopped,
After a lapse of a fixed time Tin after the clear signal Rx disappears, the serial signal Rx composed of 1st data and 2nd data is transferred once or more again at the transfer cycle Tcyc, and then only the 1st data is continuously transferred at the transfer cycle Tcyc1.

(C) When an alarm occurs The serial signal Rx transfers only the 1st data of the transfer cycle Tcy.
When an alarm (information data inside the encoder) occurs during the transfer at c1 (26 μs in the embodiment), the transfer cycle Tc
1st data consisting of yc (56 μs in the embodiment) and 2
Switching to alternate serial communication Rx of nd data.

(2) A method of transmitting only the 1st data after transmitting the 1st data and the 2nd data under the control of the outside. In this method, only the 1st data is transferred in the transfer cycle Tcyc1.
The continuous transfer at (26 μs) can be controlled by a control signal CTRL from the outside. FIG. 4 is a timing chart showing the state of switching by the control signal CTRL from the outside and the state of the serial signal Rx when the clear signal CLR is input on the way, and when the main power supply EXT-Vcc is turned on. , The serial signal Rx has a transfer cycle Tcyc (56 μ
serial signal R of 1st data and 2nd data in s)
External control signal CT when x is being transferred
When RL is received, 1 in transfer cycle Tcyc1 (26 μs)
The serial signal Rx is transferred to transfer only the st data. When the clear signal CLR is received in the switched state, after transferring the serial signal Rx of the 1st data and the 2nd data having the transfer cycle (56 μs),
The serial signal Rx of only the 1st data having the transfer cycle (26 μs) is transferred. When an alarm occurs, the method is the same as that described with reference to FIG.

[2] Theoretical basis for reducing the amount of data to be transmitted For the theoretical basis of the amount of data to be transmitted, it is easy to understand that the absolute position data within one revolution of the encoder is a pure binary code. An example of the next condition in the case will be described.
The actual transfer format is composed of data D00 to DO15 that form 1st data and 2nd data. (1) Resolution of absolute position data within one rotation N = 204
Divided into eight. (2) Number of bits of absolute position data within one rotation = 11 bits (DB0 to DB10). (3) Number of bits of rotation speed data = 13 bits (DB11
~ DB23). (4) Number of bits of other information data = 6 bits (DB2
4 to DB29). (5) Maximum rotation speed V = 100 rotations / second. (6) Transfer cycle Ts when always transmitting only necessary data
= 10 × 10 ⁻⁶ seconds. (7) Serial signal transmission rate = 500 Kbits /
Seconds.

First, the transfer period Ts of the serial signal when transmitting only necessary data at all times and the number of bits of data to be transmitted will be described. Explaining the number of bits of data, the change amount L of the absolute position is L = N × V × Ts = 2048 × 100 × 10 × 10 ⁻⁶ =
Since the data amount D to be transmitted has a value larger than twice the change amount L, D> 2L = 2 × 2.048 = 4.096.

Therefore, in this embodiment, since the pure binary code is explained, the data transmitted from the data amount D may be selected from the least significant bit (LSB) of 3 bits or more. This will be described with reference to FIG.

FIG. 5 is a timing chart showing rectangular wave signals of data bits DB0 to DB10 generated when the encoder rotates clockwise (CW) and counterclockwise (CCW). For example, if the encoder rotates from the point P1 to the point P2 or P3, the value of 2 bits (data bits DB0 to DB1) from the LSB is P
Since the data values at the points 2 and P3 are the same, it can be understood that the amount of change in the absolute position can be determined but the rotation direction cannot be determined by comparing with the data value at the point P1. Therefore,
Value of 3 bits or more from LSB (for example, data bit DB
By selecting (0 to DB2), the data values at points P1, P2, and P3 are all different, and it is possible to determine the amount of change in absolute position and the rotation direction. Therefore, it is possible to know the absolute position data and the rotation direction without depending on the origin signal for informing the origin position of the encoder and the incremental signal for identifying the forward and reverse rotations.

Next, the transfer cycle will be described. what if,
If the serial signal Rx is composed of a start bit (1 bit), a data bit, and a stop bit (1 bit), the transmission rate is from 500 Kbit / sec to 1
The number of bits per bit is 2 × 10 ^-6 seconds, and the serial signal that always transmits only the necessary data is (start bit number + data bit number + stop bit number) x 2 x 10 ^-6 seconds = (1 + 3 + 1) x 2 x 10 ^-6 seconds =
It becomes 10 × 10 ⁻⁶ seconds, and it can be seen that the serial signal transfer cycle TS = 10 × 10 ⁻⁶ seconds is possible.

Further, a transfer cycle TL for transmitting all data
Since the absolute position data within one rotation has 11 bits, the rotation speed data has 13 bits, and the other information data has 6 bits, the total data has 30 bits, and TL = ( Start bit number + data bit number + stop bit number) x 2 x 10 ^-6 seconds = (1 + 30 + 1) x 2 x 1
0 ⁻⁶ seconds = 64 × 10 ⁻⁶ seconds, which requires 64 × 10 ⁻⁶ seconds or more.

[3] Circuit Configuration [2] The circuit configuration based on the theoretical basis that the amount of data to be transmitted can be reduced is (1) the circuit configuration by the encoder internal switching method shown in FIG. 6, and (2) There is a circuit configuration according to the encoder external switching system shown in FIG.

(1) Circuit Configuration According to Encoder Internal Switching Method (See FIGS. 1, 2 and 3) FIG. 6 is a block diagram showing the circuit configuration according to the encoder internal switching method. The circuit configuration is such that a serial signal generation unit 5 which is a serial signal conversion unit is provided between the serial signal (Rx) output terminal and the serial signal (Rx) output terminal.

The encoder generator 1 generates and outputs one-rotation absolute position data, rotation speed data, and other information data (see Table 1 of the prior art) forming a transfer format in the multi-rotation absolute value encoder. And its configuration is data bit D of absolute position data within one rotation.
Absolute position data section 2 which outputs 11 bits of B0 to DB10 in parallel, and data bit DB1 of rotation speed data
Rotation speed data section 3 for outputting 13 bits of 1 to DB23 in parallel, and data bit DB2 representing information data
4 to the information data section 4 for outputting the DB 29.

The serial signal generator 5 is interposed between the encoder data generator 1 and the serial signal (Rx) output terminal, and is always required to know the amount of change in the absolute position of the rotating encoder and the rotation direction. Data selector circuit 6 that generates a serial signal Rx that transmits only data that has a parallel input port that is switched to the data port DP0 to DP2 or DP0 to DP29.
And a serial signal conversion circuit 7 for converting parallel data into serial data, all data bits DB0 to DB29 from the encoder, or a data bit DB that is always required.
A selection signal processing circuit 8 for selecting 0 to DB2,
Each connection status is as follows.

The output sides of the parallel data bits DB0 to DB2 of the absolute position data section 2 within one rotation are connected to the data ports DP0 to DP2 of the data selector circuit 6.

The output sides of the parallel data bits DB11 to DB23 of the rotation speed data section 3 and the output sides of the data bits DB24 to DB29 of the information data section 4 are connected to the data ports DP0 to P29 of the data selector circuit 6. .

The parallel output port Y of the data selector circuit 6 is connected to the data input DX of the serial signal conversion circuit 7, and the data output side TX of the serial signal conversion circuit 7 is connected to the serial signal (Rx) output terminal. .

One input side I1 of the selection signal processing circuit 8
Is connected to the data output TX of the serial signal conversion circuit 7, the other input side I2 is connected to the output side of the data bits DB24 to DB29 of the information data section 4, and its output O is the switching gate of the data selector circuit 6. It is connected to G.

A trigger portion 9 may be provided as shown in FIG. 6 so that the trigger portion 9 is connected so as to be automatically switched when the power is turned on.

The operation of the circuit according to the encoder internal switching system having such a configuration and connection state transmits all the data bits (DB0 to DB29) or only the always required data bits (DB0 to DB2). The selection signal processing circuit 8 having a function of selecting whether the output O of the selection signal processing circuit 8 when the data on the data receiving side of the serial signal Rx when the power is turned on and the data inside the encoder are different. , All data port sides (DP0 to DP29) of the data selector circuit 6 and the transfer cycle TL of the serial signal conversion circuit 7 are selected and transmitted from the data output TX of the serial signal conversion circuit 7. After that, at the input I1 of the selection signal processing circuit 8, all data bits (DB0 to DB0
DB29) is transmitted once or more, and the data bit (DB
0 to DB2) side and the transfer cycle TS of the serial signal conversion circuit 7 are selected, and the output TX of the serial signal conversion circuit 7 is selected.
Better transmit.

(2) Circuit configuration according to encoder external switching system (see FIG. 4) FIG. 7 is a block diagram showing the circuit configuration according to the encoder external switching system. The encoder internal switching system described with reference to FIG. 6 is used. Similarly, the circuit configuration is such that the serial signal generation unit 5 is provided between the encoder data generation unit 1 and the serial signal (Rx) output terminal.

The configuration is the same, and different connection states are that one input side of the selection signal processing circuit 8 is connected to a terminal for inputting the external switching signal CTRL,
Others are the same as the circuit configuration shown in FIG. 6, and the description thereof will be omitted.

The operation of the circuit according to the external switching system having such a configuration and connection state is the external selection system in which the output O of the selection signal processing circuit 8 is selected by the outside of the encoder (for example, the data receiving side of the encoder). It is possible to select whether to transmit all the data bits (DB0 to DB29) or only the always required data bits (DB0 to DB2) according to the external timing of the encoder.

In this way, according to the internal and external methods, in this embodiment, the transfer cycles TL and TS described above are used.
From TL-TS = 64 × 10 ⁻⁶ seconds−10 × 10 ⁻⁶ seconds = 54 ×
It is possible to shorten the processing time by 10 ^-6 seconds or more.

Further, when there is a change in the information data (eg, alarm signal) value inside the encoder, the input I2 of the selection signal processing circuit 8 makes a judgment, and the output O makes the data selector circuit 6
By selecting the transfer cycle TL of all the data ports (DP0 to DP29) and the serial signal conversion circuit 7 and transmitting from the output TX of the serial signal conversion circuit 7, the information data is transmitted to the data reception side of the serial signal Rx. Can be sent.

In this way, by transmitting only the minimum required data, it is possible to eliminate the transmission wires of, for example, the incremental signal (phase difference 2 signal) and the origin signal, and reduce the number of transmission wires. You can do it.

[0049]

As described above, the transmission method for a multi-rotation absolute value encoder and the apparatus equipped with the encoder according to the present invention transmit all absolute position data, rotation speed data and other information data. By providing a function to select whether to transmit only the data that is always needed or not, and by including the information such as the amount of change in absolute position and the rotation direction in the minimum data that is always needed, and transmitting it. The transmitted data can be processed immediately and the number of transmission signal wires used for incremental signals, origin signals, etc. can be reduced, which is an extremely excellent effect.

[Brief description of drawings]

FIG. 1 is a timing chart showing a method of transmitting only 1st data of a serial signal Rx according to the present invention.

FIG. 2 is a timing chart when the clear signal is generated.

FIG. 3 is a timing chart diagram when the alarm is generated.

FIG. 4 is a timing chart of a switching signal CTRL and a clear signal from the outside.

FIG. 5 is a timing chart showing the reason why the amount of data to be transmitted can be reduced.

FIG. 6 is a block diagram schematically showing a circuit configuration according to the internal switching method.

FIG. 7 is a block diagram schematically showing a circuit configuration according to the external switching method.

FIG. 8 is a timing chart diagram for transmitting a serial signal of an encoder in the related art.

[Explanation of symbols]

 1 Encoder Generation Unit 2 Absolute Value Position Data (within 1 Rotation) 3 Rotation Speed Data Unit 4 Information Data Unit 5 Serial Signal Generation Unit 6 Data Selector Circuit 7 Serial Signal Conversion Circuit 8 Selection Signal Processing Circuit

Claims (5)

[Claims] 1. A multi-rotation absolute value encoder for converting a plurality of signals consisting of absolute position data within one rotation, rotation speed data, and other data generated by forward or reverse rotation into serial signals and outputting the serial signals. The transmission method is provided with a selection means for selecting whether to transmit all of the absolute position data, rotation speed data and other data, or to transmit only necessary data at all times. Encoder transmission method. 2. The selecting means for transmitting only the necessary data, after transmitting the plurality of signals at least once,
The method of transmitting a multi-rotation absolute value encoder according to claim 1, wherein only the data that is always required is transmitted. 3. The always required data is formed by a signal capable of determining the amount of change in the absolute position from the least significant bit side of the absolute position data within one rotation and the rotation direction. 2. The transmission method of the multi-rotation absolute value encoder according to 2. 4. An absolute position data section 2 for outputting data bits of absolute position data within one rotation in parallel, a rotation speed data section 3 for outputting data bits of rotation speed data in parallel, and data representing information data. An encoder generation unit 1 including an information data unit 4 that outputs bits, and a serial signal conversion unit that converts each data bit into a serial signal and outputs the serial signal. The absolute position data and the rotation speed data are included. Switching between transmitting all the data of the information data or transmitting only the data which is always necessary so that the amount of change in the absolute position and the rotation direction can be judged is performed by the serial signal Rx from the serial signal converting means.
An apparatus equipped with a multi-rotation absolute value encoder, characterized in that 5. An absolute position data section 2 for outputting data bits of absolute position data within one rotation in parallel, a rotation speed data section 3 for outputting data bits of rotation speed data in parallel, and data representing information data. The absolute position data and the rotation speed data are composed of an encoder generation unit 1 including an information data unit 4 that outputs bits, and a serial signal conversion unit that converts each data bit bit into a serial signal and outputs the serial signal. It is characterized in that switching between sending all data of the information data and information data, or sending only the data that is always necessary to determine the amount of change in absolute position and the rotation direction is performed based on an external switching signal. A device equipped with a multi-turn absolute encoder.