Encoder Dirty Signal; Early Encoder Failure Detection - Siemens SINAMICS S120 Function Manual

Basic functions
8.20 Encoder diagnostics
8.20.2

Encoder dirty signal

Function description
Some encoders have an additional output, which switches from "high" to "low", if the evaluation
electronics in the encoder can no longer determine a reliable position.
In order to inform you about this, the drive only outputs alarm A3x470
x = encoder number (x = 1, 2 or 3)
1)
Commissioning the function
Connect the corresponding encoder signal with the CTRL input (monitoring signal) of the
device (terminal X521:7). Parameterization is not required.
Note
The input is automatically set to a high level if a wire is broken: As a consequence, for a broken
wire, the encoder is considered to be "good".
8.20.3

Early encoder failure detection

Overview
The early encoder failure detection allows an alarm to be generated at an early stage, before
a detected encoder signal level error results in a hard shutdown. r0458.15 = 1 "Evaluation of the
function reserve" indicates as to whether early encoder failure detection is supported by your
specific hardware.
Function description
For early encoder failure detection, the signals sampled by the encoder disk are locally
monitored. Quality values are calculated from the sampled signals. The signal level (root of
A^2 + B^2) from the incremental signals is used as quality value. The location-related quality
values are analyzed over a longer period of operating time. If the trend indicates a local
deterioration, then the drive issues an appropriate alarm message A3x407
x = encoder number (x = 1, 2 or 3)
1)
366
when an SMC30 is used.
1)
.
1)
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Drive functions