SSI absolute encoder: Median filter for suppressing position jumps due to incorrectly transmitted position values (from V01.08.00)

Due to the principle the median filter is only used with pure SSI absolute encoders (0x2C40 = 5), where the absolute position is transferred cyclically.
This is not the case for SSI absolute encoders with additional SinCos tracks. With this type of encoder, the absolute position is only transmitted once to set the absolute position. The position is then determined on the basis of the SinCos signals by integrating them.
The one-time setting of the absolute position is monitored in a different way.

Background:
The position delivery of an SSI encoder is generally not subject to monitoring with regard to transmission errors that occur.
If faults falsify the SSI telegram, this can result in jumps in the actual position on the receiver side that do not correspond to the real movement.
A median filter can be used to counteract the effects of these interferences. With the median filter, a number x of the last position values are saved and sorted according to their size (x = depth of the filter  = 1, 3, 5, 9). Only the middle value is ever output as the actual position, which means that incorrect position values are not passed on because they are at the front or back of the list.
The filter is no longer effective if the number of disturbed telegrams occurring directly in succession is greater than half the filter depth and therefore the middle value is also an incorrect value and is passed on.
The output of the middle stored position value results in a dead time that corresponds to half the filter depth * telegram cycle time.

The median filter is switched off when the filter depth x = 1.