An absolute position real-time reading circuit for a servo motor encoder

Abstract

The application discloses a kind of servo motor encoder absolute position real-time reading circuit, including DSP chip, 422 protocol conversion chip and BiSS-C protocol servo motor encoder;422 protocol conversion chip is connected between DSP chip and BiSS-C protocol servo motor encoder, for converting the SPI clock signal output by DSP chip into the clock differential signal that BiSS-C protocol servo motor encoder can identify, and the position differential signal from BiSS-C protocol servo motor encoder is converted into the SPI signal that DSP chip can receive.The application has the advantages of simple structure, low cost, small CPU resource occupation and wide application range.

Description

Technical Field

[0001] This invention belongs to the field of electric motor technology, specifically relating to a real-time absolute position reading circuit for a servo motor encoder. Background Technology

[0002] Currently, domestically produced permanent magnet synchronous motor servo drives are developing towards miniaturization, compactness, and low cost. The BiSS-C protocol, due to its high-speed serial protocol, simple structure, and suitability for conditions requiring high acceleration and smooth speed control, has been widely used in absolute position encoders for high-precision position control. Its fully digital connection design ensures the security and reliability of communication transmission. Furthermore, its simple and compact structure, flexible layout, and low hardware requirements significantly reduce installation and maintenance costs. Currently, the control board CPU of permanent magnet synchronous motor AC servo drives is mainly a DSP; therefore, constructing a simple and reliable circuit that utilizes DSP peripherals for real-time absolute position reading of the servo motor encoder is of great significance. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention provides a real-time absolute position reading circuit for a servo motor encoder, comprising a DSP chip, a 422 protocol conversion chip, and a BiSS-C protocol servo motor encoder. The 422 protocol conversion chip is connected between the DSP chip and the BiSS-C protocol servo motor encoder, used to convert the SPI clock signal output by the DSP chip into a clock differential signal recognizable by the BiSS-C protocol servo motor encoder, and to convert the position differential signal from the BiSS-C protocol servo motor encoder into an SPI signal receivable by the DSP chip. This invention has the advantages of simple structure, low cost, low CPU resource consumption, and wide applicability.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows:

[0005] A servo motor encoder absolute position real-time reading circuit includes a DSP chip, a 422 protocol conversion chip, and a BiSS-C protocol servo motor encoder;

[0006] The 422 protocol conversion chip is connected between the DSP chip and the BiSS-C protocol servo motor encoder. It is used to convert the SPI clock signal output by the DSP chip into a clock differential signal that the BiSS-C protocol servo motor encoder can recognize, and to convert the position differential signal from the BiSS-C protocol servo motor encoder into an SPI signal that the DSP chip can receive.

[0007] The BiSS-C protocol servo motor encoder is used to transmit the real-time position of the motor rotor.

[0008] Preferably, the SPI peripheral clock of the DSP chip is configured to be a falling edge reading with no phase delay.

[0009] Preferably, the DSP chip is a JDSPF28335.

[0010] Preferably, the 422 protocol conversion chip is a 2682E.

[0011] Preferably, the BiSS-C protocol servo motor encoder is 1617-U01C-2RW, with 17 bits per single turn and 16 bits per multi-turn.

[0012] Preferably, the RXDH, RXDL, TXDH, and TXDL pins of the 422 protocol conversion chip are connected to the DATE+, DATE-, CLOCK+, and CLOCK- pins of the BiSS-C protocol servo motor encoder, respectively.

[0013] Preferably, the SPIMISO and SPICLK pins of the DSP chip are connected to the RXD and TXD pins of the 422 protocol conversion chip, respectively.

[0014] The beneficial effects of this invention are as follows:

[0015] (1) Compared with traditional feedback methods such as rotary transformers and tachometer motors, its structure is simpler.

[0016] (2) It is compatible with all microcontrollers with SPI peripheral modules and has strong applicability.

[0017] (3) No hardware or software required for axis-angle conversion, making it easier to implement and cheaper.

[0018] (4) It consumes little CPU resources and only requires 2 pins to complete the encoder position reading. Attached Figure Description

[0019] Figure 1 This is a circuit diagram of the present invention;

[0020] Figure 2 This is a schematic diagram of the wiring signal pins of the DSP chip of this invention;

[0021] Figure 3 This is a schematic diagram of the wiring signal pins of the 422 protocol conversion chip of the present invention;

[0022] Figure 4 This is a schematic diagram of the wiring signal pins for the BiSS-C protocol servo motor encoder of the present invention;

[0023] Figure 5 This is a diagram of the peripheral circuit of the 422 protocol conversion chip of the present invention;

[0024] Figure 6 The waveforms of the two pins of the DSP chip of this invention are shown. The blue waveform is the SPIMISO pin signal, and the yellow waveform is the SPICLK pin signal. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Figure 1 A schematic diagram of a real-time absolute position reading circuit for a servo motor encoder provided by the present invention is shown below. Figure 1 As shown, the real-time absolute position reading circuit of the encoder includes: a DSP chip, a 422 protocol conversion chip, and a BiSS-C protocol servo motor encoder. The servo motor encoder, conforming to the BiSS-C communication protocol, is used to transmit the real-time position of the motor rotor. The 422 protocol conversion chip is connected between the DSP chip and the BiSS-C protocol servo motor encoder. It converts the SPI signal output by the DSP chip into a clock differential signal that the BiSS-C protocol servo motor encoder can recognize, and converts the position differential signal from the BiSS-C protocol servo motor encoder into an SPI signal that the DSP chip can receive. The SPI peripheral clock of the DSP chip needs to be configured for a falling edge reading without phase delay.

[0027] In this invention, the DSP chip used is JDSPF28335; the 422 protocol conversion chip used is 2682E; and the absolute encoder used is 1617-U01C-2RW, with 17 bits for single-turn and 16 bits for multi-turn. The JDSPF28335 chip is a high-end domestically produced DSP chip; the 2682E chip is a domestically produced 422 protocol conversion chip; the pin definitions of the JDSPF28335 chip are shown in Table 1, the pin definitions of the 2682E chip are shown in Table 2, and the pin definitions of the 1617-U01C-2RW are shown in Table 3.

[0028] Table 1 Pin Definitions of JDSPF28335 Chip

[0029] Serial Number pin number name meaning 1 97 SPIMISO Master input, slave output 2 98 SPICLK SPI clock signal

[0030] Table 2 Pin Definitions of the 2682E Chip

[0031]

[0032] Table 3 1617-U01C-2RW Pin Definitions

[0033]

[0034]

[0035] The peripheral circuit of the 422 protocol conversion chip (model 2682E) of this invention is as follows: Figure 6 As shown in the diagram. The RXDH, RXDL, TXDH, and TXDL pins of the 2682E are connected to the DATE+, DATE-, CLOCK+, and CLOCK- pins of the 1617-U01C-2RW encoder, respectively. The SPIMISO and SPICLK pins of the JDSPF28335 chip are connected to the RXD and TXD pins of the 2682E, respectively. Figure 5 The capacitor in the figure is represented by C, and the capacitance value is shown in Table 4.

[0036] Table 4 Capacitor Values

[0037]

[0038] Depend on Figure 6 As can be seen, the SPIMISO pin signal (blue waveform) begins to return to the absolute encoder position after the second rising edge of the SPICLK pin signal (yellow waveform). The waveform is clear and effective, proving that this position reading method can effectively read the encoder position in real time.

Claims

1. A real-time reading circuit for absolute position of a servo motor encoder, characterized in that, Includes a DSP chip, a 422 protocol conversion chip, and a BiSS-C protocol servo motor encoder; The 422 protocol conversion chip is connected between the DSP chip and the BiSS-C protocol servo motor encoder. It is used to convert the SPI clock signal output by the DSP chip into a clock differential signal that the BiSS-C protocol servo motor encoder can recognize, and to convert the position differential signal from the BiSS-C protocol servo motor encoder into an SPI signal that the DSP chip can receive. The BiSS-C protocol servo motor encoder is used to transmit the real-time position of the motor rotor.

2. The servo motor encoder absolute position real-time reading circuit according to claim 1, characterized in that, The SPI peripheral clock of the DSP chip is configured to be a falling edge readout with no phase delay.

3. The servo motor encoder absolute position real-time reading circuit according to claim 1, characterized in that, The DSP chip used is JDSPF28335.

4. The servo motor encoder absolute position real-time reading circuit according to claim 1, characterized in that, The 422 protocol conversion chip is a 2682E.

5. The servo motor encoder absolute position real-time reading circuit according to claim 1, characterized in that, The BiSS-C protocol servo motor encoder is 1617-U01C-2RW, with 17 bits for single-turn and 16 bits for multi-turn.

6. The servo motor encoder absolute position real-time reading circuit according to claim 1, characterized in that, The RXDH, RXDL, TXDH, and TXDL pins of the 422 protocol conversion chip are respectively connected to the DATE+, DATE-, CLOCK+, and CLOCK- pins of the BiSS-C protocol servo motor encoder.

7. The servo motor encoder absolute position real-time reading circuit according to claim 1, characterized in that, The DSP chip's SPIMISO and SPICLK pins are connected to the RXD and TXD pins of the 422 protocol conversion chip, respectively.

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