Indexed Actual Value Acquisition - Siemens SINAMICS S120 Function Manual

9.7.1.1

Indexed actual value acquisition

Function description
The indexed actual position value acquisition permits, e.g. length measurements on parts as
well as the detection of axis positions by a higher-level controller (e.g. SIMATIC S7) in addition
to the position control, e.g. of a belt conveyor.
Two more encoders can be operated in parallel with the encoders for actual value
preprocessing and position control in order to collect actual values and measured data.
The indexed acquisition of actual values can preprocess an actual position value at each of the
three encoder outputs. The parameter p2502[0...3] is used to select the encoder evaluation for
position control.
The parameters of the indexed actual value acquisition are indexed four times. The indices 1
to 3 are assigned to the encoder evaluations 1 to 3. The index 0 is assigned to position control.
The parameter r2521[0...3] can be used to retrieve the current actual values of all connected
encoders. For example, the actual position value for position control in r2521[0] is identical with
the value r2521[1] if the position control uses encoder evaluation 1. The signal source for a
position offset can be set in parameter p2516[0...3].
The absolute encoder adjustment is initiated via p2507[0...3] = 2, and its successful completion
is reported via p2507[0...3] = 3. The signal source "Reference point coordinate for the position
controller" p2598[0] is interconnected with p2599 during basic positioning. The other signal
sources are not interconnected in the standard configuration.
The measuring probe evaluation can be enabled for the encoder evaluation x, which is not
assigned to position control, via p2509[x]. The signal sources are assigned via p2510[0...3], the
edge evaluation is set via p2511[0...3]. The measured value is available in r2523[x] if, in the
status word for encoder x (encoder 0: r2526.0..9, encoder1: 2627.0..2, Encoder2: r2628.0..2,
encoder3: r2529.0..2) the "Measurement value valid" bit is set.
The actual position values of the different encoders can be read out using parameter
r2521[0...3]. These actual position values can be corrected with a signed value from
p2513[0...3] after a 0/1 signal from the signal source in p2512[0...3].
In addition, the actual velocity value (r2522[0...3]) and the position offset for absolute encoders
p2525[0...3] can be processed for each encoder by the higher-level controller.
Features
● Encoder assignment (p2502[D])
● Absolute encoder adjustment (p2507[E])
● Activate measuring probe evaluation (p2509[0...3])
● Measuring probe evaluation selection (p2510[0..3])
● Measuring probe edge (p2511[0..3])
● Activate actual position value processing, correction value (p2512[0...3])
● Actual position value processing, correction value (p2513[0...3])
● Position offset (p2516[0...3])
● Actual position value (r2521[0...3])
Drive functions
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Function modules
9.7 Position control
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