Siemens Sinamics S120 Function Manual page 358

Function modules
7.8 Basic positioner
Figure 7-14
A modulo axis has an unrestricted traversing range. The value range of the position repeats
itself after a specific value that can be parameterized (the modulo range or axis cycle), e.g.
after one revolution: 360° -> 0°. The modulo range is set in parameter p2576, the offset is
activated with parameter p2577. The modulo offset is undertaken at the setpoint end. This is
provided with the correct sign via connector output r2685 (correction value) to appropriately
correct the position actual value. EPOS initiates the activation of the correction via a rising
edge of binector output r2684.7 (activate correction) (r2685 (correction value) and r2684.7
(activate correction) are already connected as standard with the corresponding
binector/connector input of the position actual value conditioning). Absolute positioning
details (e.g. in a motion command) must always be within the modulo range. Modulo offset
can be activated for linear and rotary length units. The traversing range cannot be limited by
a software limit switch.
With active modulo offset and the application of absolute encoders, as a result of potential
encoder overflows, it must be ensured that there is an integer ratio v between the multiturn
resolution and the modulo range.
The ratio v can be calculated as follows:
● 1. Motor encoder without position tracking:
● 2. Motor encoder with position tracking for the measuring gear:
● 3. Motor encoder with position tracking for the load gear:
● 4. Motor encoder with position tracking for the load and measuring gear:
● 5. Direct encoder without position tracking:
● 6. Direct encoder with position tracking for the measuring gear:
With position tracking it is recommended to change p0412 or p2721.
Function diagrams (see SINAMICS S120/S150 List Manual)
● 3635 Interpolator
● 4010 Position actual value conditioning
356
Modulo offset
v = p0421 × p2506 × p0433 × p2505 / (p0432 × p2504 × p2576)
v = p0412 × p2506 × p2505 / (p2504 × p2576)
v = p2721 × p2506 × p0433 / (p0432 × p2576)
v = p2721 × p2506 / p2576
v = p0421 × p2506 × p0433 / (p0432 × p2576)
v = p0412 × p2506 / p2576
Function Manual, (FH1), 01/2012, 6SL3097-4AB00-0BP2
Drive functions