Edge Evaluation Of The Zero Mark - Siemens SINAMICS S120 Function Manual

Basic functions
8.21 Tolerant encoder monitoring
Commissioning the function
You commission the function as follows:
1. Set parameter p0438 ≠ 0 to activate the function.
2. In parameter p0438 (square-wave encoder filter time) enter the filter time in the range from
0 to 100 μs. The hardware filter only supports values 0 (no filtering), 0.04 μs, 0.64 μs,
2.56 μs, 10.24 μs and 20.48 μs
If a value is set that does not match one of the discrete values specified above, the firmware
automatically sets the next closest discrete value. The drive does not output an alarm or
fault message.
3. You can see the active, effective filter time in parameter r0452.
Note
The zero mark alarms F3x100, F3x101 and F3x131
with a width of ¼ encoder pulse at half n_max speed, are suppressed when the hardware
filter is activated.
x = encoder number (x = 1, 2 or 3)
1)
Calculating the influence of the filter time on the speed
You can calculate the influence of the filter time on the maximum possible speed using the
following formula:
● n_max [rpm] = 60 / (p0408 · 2 · r0452)
p0408 represents the pulses per revolution of the rotary encoder.
Example
The following values are specified in this example:
● p0408 = 2048
● r0452 = 10.24 [μs]
On the basis of the specified values, calculate the filter time (n_max) using the following formula:
● n_max = 60 / (2048 · 2 · 10.24 · 10
Result: With the calculated filter time, you can operate the motor up to a maximum of 1430 rpm.
8.21.5

Edge evaluation of the zero mark

Overview
The function extension "Edge evaluation of the zero mark" is suitable for encoders, where the
zero mark ≥ 1 pulse(s) wide. In this particular case, errors would otherwise occur as a result of
the edge detection of the zero mark.
372
, that are already output for a zero mark
1)
) = 1430 [rpm]
-6
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Drive functions