SSI absolute encoder

Synchronous Serial Interface (SSI) is a widely used serial interface standard for industrial applications between a controller and a sensor. SSI is based on RS-422 standards and has a high protocol efficiency in addition to its implementation over various hardware platforms, making it very popular among sensor manufacturers

Ingenia drivers supports a wide range of protocols over the SSI interface to communicate with absolute position encoders.

Parameter

Description

Frame type

Indicates the frame type to be processed. Options are:

  • Generic

  • 3 status bits at the end of the frame

  • 1 error bit at the end of the frame

Frame size

Indicates the total frame size, including position bits and special bits (like error flags).

Codification

Indicates the codification of the position value bits. Options are:

  • Gray

  • Binary

Max clock rate

Indicates the maximum clock rate of the SSI encoder.

Single-turn bits

Indicates the number of bits used to represent the single-turn value.

Single-turn start bit

Indicates the position in the SSI frame of the first single-turn bit.

Multi-turn bits

Indicates the number of bits used to represent the multi-turn value.

Multi.turn start-bit

Indicates the position in the SSI frame of the first multi-turn bit.

Endianness

Indicates the order of the read bits. Options are:

  • MSB

  • LSB

Quick Test

The quick test monitors in real time the SSI position read, according to actual configuration and user units selected.

Example

The next SSI frame is generated by a encoder in binary codification:


 The configuration needed to decode the total position value is:

  • Frame size. 27

  • Codification. 0 (binary)

  • Single-turn bits. 14

  • Single-turn start bit. 3

  • Multi-turn bits. 9

  • Multi-turn start bit . 18