Fast Mode With Ssi Absolute Encoder - Siemens SIMATIC ET 200SP Manual

Product overview
2.2 Functions
2.2.5.1

Fast Mode with SSI absolute encoder

You can use the technology module with an SSI absolute encoder for position input. The
technology module reads the position value via a synchronous serial interface from the SSI
absolute encoder and makes it available to the controller.
You can switch the digital outputs of the technology module exactly at defined position
values, independently of the user program. The comparison values can only be changed
with data record 128 in RUN. Position input with an SSI absolute encoder does not involve
gate control.
Gray-dual conversion
Gray-code and dual-code SSI absolute encoders are supported.
Range for position value
You can specify a frame length of 10 bits to 40 bits for the SSI absolute encoder. The
configurable bit numbers of the LSB and the MSB of the position value in the frame define
the value range. The technology module can read a position value with a maximum length of
25 bits and communicate it to the controller. The position value is treated as unsigned
positive value and can assume values between 0 and 2
Hysteresis
You can specify hysteresis for the comparison values, within which a digital output will be
prevented from switching again. An encoder can come to a standstill at a specific position,
and slight movements may make the position value fluctuate around this position. If a
comparison value or a position value limit lies within this fluctuation range, the corresponding
digital output is switched on and off with corresponding frequency if hysteresis is not used.
The hysteresis prevents these unwanted switching operations.
20
-1.
(MSB-LSB+1)
Technology module TM PosInput 1 (6ES7138-6BA00-0BA0)
Manual, 04/2016, A5E33015755-AC