Siemens Sinamics S120 Function Manual page 387

● Connector inputs
● Accept (p2649, p2650)
Description
The direct setpoint input function allows for positioning (absolute, relative) and setup
(endless position-controlled) by means of direct setpoint input (e.g. via the PLC using
process data).
During traversing, the motion parameters can also be influenced (on-the-fly setpoint
acceptance) and an on-the-fly change can be undertaken between the Setup and Positioning
modes. The "direct setpoint input" mode (MDI) can also be used if the axis is not referenced
in the "setup" or "relative positioning" modes, which means that "flying referencing" (see the
separate section), flying synchronization, and post-referencing are possible.
The direct setpoint input function is activated by p2647 = 1. A distinction is made between
two modes: positioning mode (p2653 = 0) and setup mode (p2653 = 1).
In "positioning" mode, the parameters (position, velocity, acceleration and deceleration) can
be used to carry out absolute (p2648 = 1) or relative (p2648 = 0) positioning with the
parameter p2690 (fixed setpoint position).
In the setting-up mode, using parameters (velocity, acceleration and deceleration) "endless"
closed-loop position control behavior can be carried out.
It is possible to make a flying changeover between the two modes.
If continuous acceptance (p2649 = 1) is activated, changes to the MDI parameters are
accepted immediately. Otherwise the values are only accepted when there is a positive edge
at binector input p2650 (setpoint acceptance edge).
Note
Continuous acceptance p2649 = 1 can only be set with free telegram configuration
p0922 = 999. No relative positioning is allowed with continuous acceptance.
The direction of positioning can be specified using p2651 (positive direction specification)
and p2652 (negative direction specification). If both inputs have the same status, the
shortest distance is traveled during absolute positioning (p2648 = "1") of modulo axes
(p2577 = "1").
To use the positioning function, the drive must be in operating mode (r0002 = 0). The
following options are available for starting positioning:
Drive functions
Function Manual, (FH1), 01/2012, 6SL3097-4AB00-0BP2
– CI: MDI position setpoint (p2642)
– CI: MDI velocity setpoint (p2643)
– CI: MDI acceleration override (p2644)
– CI: MDI deceleration override (p2645)
– CI: Velocity override (p2646)
Function modules
7.8 Basic positioner
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