Siemens SIMATIC ET 200S - What is the ET 200 S distributed I;O system?

1STEP 5V/204kHz
2.6 Functions of the 1STEP 5V/204kHz
ET 200S Positioning
Operating Instructions, 05/2007, A5E00124871-04
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2.6 Functions of the 1STEP 5V/204kHz
2.6.1 Overview
Introduction
The task of the 1STEP 5V/204kHz is to position a drive on certain predefined destinations.
The following functions are available to you to this purpose:
● Search for Reference. The axis is synchronized.
● Incremental Run: The axis is moved by a predefined distance.
● Stopping the Stepping Motor
● Changing Parameters during Operation
See also
Assignment of the Feedback and Control Interfaces (Page 44)
2.6.2 Search for Reference
Functional Description
The reference point marks the point of reference of your drive system (reference cam) for the
following positioning jobs. You can find out the reference point by installing an initiator on the
reference cam and connecting its normally open contact to the REF digital input.
The 1STEP 5V/204kHz ensures the reference point can be reproduced accurately in that it is
always approached from the same direction. You can specify this direction by always starting
the search for reference in the same direction.
Positioning Job for the Search for Reference
The job contains the following information:
● Multiplier G for the velocity/output frequency F
a
● Reduction factor R for the assigned parameters base frequency F
b
● Mode = 1 for search for reference
● Direction selection as start
● STOP at the Reference Cam