Siemens SINAMICS S120, Function Manual

Page: 375 / 1094

Basic functions
7.20 Tolerant encoder monitoring
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
375
Effect
You can calculate the influence of the filter time on the maximum possible speed as follows:
n_max [rpm] = 60 / (p0408
· 2 · r0452)
Here, p0408 is the pulse number of the rotary encoder.
Example
Specifications:
● p0408 = 2048
● r0452 = 10.24 [μs]
n_max is then calculated as follows:
● n_max = 60 / (2048 · 2 · 10.24 · 10
-6
) = 1430 [rpm]
As a consequence, with this filter time you can operate the motor up to a maximum of 1430
rpm.
7.20.5 Edge evaluation of the zero mark
This functionality is suitable for encoders, where the zero mark ≥ 1 pulse wide. I n this
particular case, errors would otherwise occur as a result of the edge detection of the zero
mark.
For a positive direction of rotation, the positive edge of the zero mark is evaluated and for a
negative direction of rotation, the negative edge. As a consequence, for encoders where the
zero mark is wider than one pulse, it is possible to parameterize them with equidistant zero
marks (p0404.12 = 1), i.e. the zero mark checks (F3x100, F3x101
1)
) are activated.
Commissioning
1. Set parameter p0437.1 = 1 to activate the "edge evaluation of the zero mark" function.
The factory setting p0437.1 = 0 keeps the operation at the known zero mark detection.