More recently, the bidirectional synchronous serial interface biss open serial protocol has come into the market. Encoders and inclination sensors absolute encoder absolute encoders can be used in any factory and logistics automation setting, where shaft rotational movement requires absolute detection. Absolute encoders hengstler brand ssm servo small motor series ac36 signal cable color 5 730 v u b white 0 v u n brown clock yellow clock green data pink data grey a whitegreen 1 a browngreen 1 b redblue 1 b 1greypink 5v sensor violet 1 0v sensor 1black 1only with sc absolute encoder electrical connections e321846 standard. Practical circuit design and implementation of the communic. However, as clock frequency increases, the maximum cable run decreases, a limitation common to all protocols. The proprietary standards, hiperface and endat are competing solutions.
H25dss12gcs3sm18 for the parity bit option add s at the end of the model number with the description s parity bit msb 1 ssi compatible output with parity. The host computer is the master of the bus, while the encoders are slaves. Sitara am437x or c2000 mcu to run the corresponding encoders master protocol. Receiving electronics must include an appropriate receiver as. Gmbh in 1984 for transmitting the position data of absolute encoders for this reason, some. Ssi is a widely used serial interface with pointtopoint connection between plcmaster and encoder.
To maintain this condition and to ensure safe operation, installation, connection and service, work may be performed only by qualified. After the timeout, the encoder is ready to transmit the next ssidataword. Ssi synchronous serial interface master application note. Though position encoders typically provide the feedbackposition data of motors, this encoder allows closedloop control of. Ssi uses a clock pulse train from a controller to initiate a gated output from the sensor. Slits indicates binary code strings of 2 pulsesrev from the center. This enables a simple and lowcost connection to the encoder, with dynamic speed adjustment, all while benefiting from the high noise resistance of a differential. Ioni pro servo drive supports ssi encoders starting from. Universal digital interface to absolute position encoders rev. Keep in mind that ssi and profibus dp are masterslave systems and require the controller to signal the encoder to transmit position. Absolute value encoder communication interface design.
Dn is most significant bit, d0 is least significant bit. The next text described basic properties of ssi interface and protocol. Ssi encoders use two twisted pair wires plus two wires for power. I am using pic18f4550pic18f4431 for absolute encoder interface through ssispi protocol with the help of differential line driverreceiver ics respectively am26ls31x andam26ls32ax. Ssi theory synchronous serial interface ssi is a widely used serial interface standard for industrial applications especially, rotary encoders. Transfer rates baud are also dependent on cable lengths. Ssi serial interface rotary encoders from fraba posital. Integrating absolute encoders an overview of spi, rs485. The design allows the host processor to activate either the 4wire rs485 physical interface to connect to an endat 2.
You insert the module into a point io terminal base that provides common power, communication, and wiring connections for the ssi sensors. Number of bits transferred is programmable from 1 to 32. Two interface protocol variants are factoryconfigurable. Ssi stands for synchronous serial interface and is commonly used with standalone absolute encoders given that it is a pointtopoint, one slave per master configuration. A hollow ring, true absolute functionality and high speed operation make this encoder suitable for.
Though position encoders typically provide the feedbackposition data of motors, this encoder allows closedloop control of motors. Number of transducer inputs four transducer input isolation optically isolated 1,500 vac programmable parameters ssi setup parameters ssi clock frequency number of ssi bits number of data bits msb number data type data logic data. Ssi linear encoder, linear encoder with ssi interface. Absolute linear encoders with ssi protocol for fagor and others. The data rate of ssi protocol encoders depends on both resolution and cable length. Synchronous serial interface ssi is a widely used serial interface standard for industrial. The recommended receiver is a max 491 transceiver in receive mode. Vw3a3420 digital encoder interface module schneider. Depending on the communication method, signals will vary but the oscilliscope should show the output signals varying.
It is used in industrial applications which require transfer rates, safety, flexibility and a minimized implementation effort. H25dss12gcs3sm18 for the parity bit option add s at the end of the model number with the description s parity bit msb 1 ssi compatible output with parity option. The biss interface has roots in ssi and a simplified interbus. Plc, microcontroller or other control systems to a slave e. Ssi is based on rs422 standards and has a high protocol efficiency in addition to its implementation over various hardware platforms, making it very popular among sensor manufacturers. Our ai25 ssi absolute encoder offers up to 22 bit singleturn and 12 bit multiturn positioning, board temperature range, onboard diagnostics and multiple shaft sizes. As shown in figure 2, rotation slits are lined from the center on concentric circles. The most popular open communications protocol is synchronous serial interface ssi. Use the designation, s3 between the code format designation and the output connector designation.
Sei absolute encoder communications protocol user guide each encoder on the bus is assigned a unique hexadecimal address between 0 and e. If the encoder ssi transmission protocol offers no possibility to check the encoder actual values or the transferred data to the control the user. Depending on the protocol of each interface, additional information, such as speed or diagnostic data, can also be provided. The encoder utilizes a clock signal, provided by the user interface, to time the data transmission. Aksim tm is a noncontact high performance offaxis absolute rotary encoder designed for integration into spaceconstrained applications. Ssi is a serial protocol that provides absolute positional feedback for encoder applications. The k23ssir2iuc is a small and favourably priced, but extremely powerful converter for industrial applications, which will convert sensor and encoder information, which is available in the ssi format into an analog signal or into a serial rs 232rs 485 format. Many companies, including both domestic and overseas, have introduced encoder communication interfaces with the ssi absolute value. The fagor sa linear encoders are manufactured with the following default values. If55 gateway fully complies with the canopen device profile for encoders class 2 protocol. Encoders cannot initiate commu nication, rather the host sends commands and the encoders respond. Encoders magnetic absolute encoder, ssi interface with bissc protocol, 4096 steps per revolution for combination with brushless dcmotors series aes4096 aes4096 steps per revolution 4 096 resolution 12 bit signal output ssi interface with bissc protocol supply voltage u dd 4,5. In this paper, based on the features of ssi protocol.
Figure 2 shows the communication format and a data frame map. Ssi synchronous serial interface master application note posital. Synchronous serial interface ssi is a widely used serial interface standard for industrial applications especially, rotary encoders. Encoders magnetic absolute encoder, ssi interface with bissc protocol, 4096 steps per revolution for combination with brushless dcmotors series aesm4096 aesm4096 steps per revolution 4 096 resolution 12 bit signal output ssi interface with bissc protocol supply voltage u dd 4,5. Amcis me15 ssi rotary shaft encoder is designed for cost sensitive applications that require bulletproof reliability. Synchronous serial interface ssi ssi is typically a synchronous simplex oneway masterslave communication protocol that uses differential signaling and has no chipselect signal. Synchronous serial interface ssi is a widely used serial interface standard for industrial applications between a master e.
The ssi is a synchronous standard, meaning that the clock signals for the data exchange are provided by the controller and are typically limited to 1. Absolute encoders output the absolute value of rotation angles. To function correctly the configuration of the ssi protocol in the linear encoder must match the configuration of the ssi protocol in the unit the linear encoder is connected to see the description of the parameters on page 10 of this manual. Ssi encoder, or the 2wire rs485 interface with power over rs485 to connect to a hiperface dsl encoder. You can toggle between both modes with a dip switch see. Ssi encoders offer alldigital, binary or gray code, pointtopoint communication interface providing unidirectional. Tb529 understanding epcs ssi encoders encoder products. After the timeout, the encoder is ready to transmit the next ssi dataword. The length of the dataword is 14 bits, the coding can be selected binary or gray table 3. Smc20 is configure with user defined encoder absolute ssi protocol sincos. Ssi compatible serial code s3 serial synchronous interface ssi data transmission sequence 1.
Universal digital interface to absolute position encoders. In this chapter only nanoip is considered, although it is identical to apply the ssi protocol to any other socket based network protocol. Dear expert,i have application which i connect linear encoder sick ttk70 ssi encoder see detail in attached file to smc20 module. Page 3 050517tk 6 29 ssi protocol protocol standard ssi the ssi data transmission of an absolute encoder position value is based on a shift register, where. The data frame length of ssi encoders depends on the control device and. Serial synchronous interface ssi serial synchronous interface is a widely used serial interface between a position sensor and a controller. In terms of absolute value encoder applications, ssi communication protocol, as an earlier implementation of communication protocol, has been widely used recently.
Whether your ssi device is a singleturn or multiturn rotary encoder or a linear sensor, then you can easily and reliably connect it to the fieldbus network. Synchronous serial interface, or ssi, is a simple serial communications protocol designed for data transfer between computers or user terminals and. Ssi synchronous serial interface is a digital protocol used by many encoder feedback device manufacturers. This code read a bit absolute rotary encoder, which use ssi syncronize serial interface. Ssi provides a direct reading of the physical position, so it requires the end. The encoders are used for position control of servo motors mounted on machine tools or robots.
How to choose the right protocol for your application mr. Learn more about all absolute encoder interface protocols here. Controller provides a series of pulses or differential pulse pairs on the clock input lines. Shgag and shgab series spherosyn absolute linear encoder with ssi interface revision 11. Dynapar is a leading manufacturer of encoder products like shaft encoders.
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