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Siemens D 31 · 2015
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Function
SINAMICS G120D distributed inverters
0.75 kW to 7.5 kW (1 hp to 10 hp)
CU240D-2 and CU250D-2 Control Units
Functionality of the EPos basic positioner
Lower-level closed-loop position control with the following
essential components
•
Position actual value sensing (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 compensation
Limitations
•
Speed/acceleration/delay/jerk limitation
•
Software limit switches (traversing range limitation by means
of position setpoint evaluation)
•
Stop cams (traversing range limitation by means of hardware
limit switch evaluation)
Referencing or adjustment
•
Setting reference point (with stationary axis)
•
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 pos-
sible during "normal" traversing with the aid of measuring input
evaluation; generally evaluation, e.g. of a BERO). Subordinate
function for the modes "jog", "direct setpoint input/MDI" and
"traversing blocks")
•
Absolute encoder alignment
Traversing blocks mode (16 traversing blocks)
•
Positioning by means of traversing blocks stored in the de-
vice, including continuation conditions and specific jobs for
previously homed axis
•
Traversing block editor using STARTER
•
A traversing block contains the following information:
- Job number and job (e.g. positioning, waiting, GOTO block
jump, setting of binary outputs, travel to fixed endstop)
- 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 measuring inputs")
- Job parameters (e.g. wait time, block step conditions)
Direct setpoint specification mode (MDI)
•
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 input 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 (tra-
verse through a "step width"), which can be toggled between
© Siemens AG 2014