Basic positioner (EPos)

Overview

• Absolute and relative positioning
• Linear and rotary axis
• Motor encoder or direct measuring system
• 4 referencing modes
• 16 traversing blocks
• Direct setpoint input (MDI)
• Jog mode
• Backlash on reversal compensation
• Following error monitoring
• Cam signals

The positioning functions are only available in the CU250S‑2 Control Unit and are functionally identical to the positioning functionality of SINAMICS S110. Due to its flexibility and adaptability, the basic positioner can be used for a wide range of positioning tasks.

The functions are easy to handle both during commissioning and during operation. Furthermore, they are characterized by their comprehensive monitoring functions.

Many applications can be carried out without external position controllers.

The EPos basic positioner is available as an additional function module that can be activated, and is used for the absolute/relative positioning of linear and rotary axes (modulo) with both rotary and linear motor encoders (indirect measuring system).

User-friendly configuring and commissioning including control panel (operation using PC) and diagnostics with the STARTER commissioning tool V4.3 or higher.

In addition to extremely flexible positioning functions, EPos offers a high degree of user-friendliness and reliability thanks to integral monitoring and compensation functions.

Different operating modes and their functionality increase flexibility and plant productivity, for example, by means of "on-the-fly" and bumpless correction of the motion control.

Preconfigured PROFIdrive positioning frames are available which, when selected, automatically establish the internal "connection" to the basic positioner.

Functionality of the EPos basic positioner

Lower-level closed-loop position control with the following essential components

• Actual position value processing (including the lower-level measuring input evaluation and reference mark search)
• Position controller (including limits, adaptation and pre-control calculation)
• Position control cycle 8 ms (speed control cycle 2 ms)
• Monitoring functions (standstill, positioning and dynamic following error monitoring, cam signals)

Mechanical system

• Backlash on reversal compensation

Limitations

• Speed/acceleration/delay/jerk limitation
• Software limit switches (traversing range limitation by means of position setpoint evaluation)
• Stop cams (traversing range limitation using hardware limit switch evaluation)

Referencing or adjustment

• Set reference point (for an axis at standstill that has reached its target position)
• Search for reference (separate mode including reversing cam functionality, automatic reversal of direction, referencing to "output cam and encoder zero mark" or only "encoder zero mark" or "external zero mark (BERO)")
• Flying referencing (seamless subordinate referencing is possible during "normal" traversing with the aid of measuring input evaluation, generally evaluation, e.g. of a proximity sensor). Subordinate function for the modes "jog", "direct setpoint input/MDI" and "traversing blocks")
• Absolute encoder alignment

Traversing blocks mode (16 traversing blocks)

• Positioning using traversing blocks that can be stored in the drive unit including block change enable conditions and specific tasks for an axis that was previously referenced
• Traversing block editor using STARTER
• A traversing block contains the following information:
  • Job number and job (e.g. positioning, waiting, GOTO set jump, setting of binary outputs, travel to fixed stop)
  • Motion parameters (target position, override speed for acceleration and deceleration)
  • Mode (e.g.: hide block, continuation conditions such as "Continue_with_stop", "Continue_flying" and "Continue_externally using high-speed probe inputs")
  • Job parameters (e.g. wait time, block step conditions)

Direct setpoint input (MDI) mode

• Positioning (absolute, relative) and setting-up (endless closed-loop position control) using direct setpoint inputs (e.g. via the PLC using process data)
• It is always possible to influence the motion parameters during traversing (on-the-fly setpoint acceptance) as well as for on-the-fly changes between the setup and positioning modes.
• The direct setpoint specification operating mode (MDI) can also be used in the relative positioning or setup mode if the axis is not referenced. This means that on-the-fly synchronization and re-referencing can be carried out using "flying referencing".

Jog mode

• Closed-loop position controlled traversing of the axis with "endless position controlled" or "jog incremental" modes (traverse through a "step width"), which can be toggled between