Siemens siprotec 7SA6 User Manual page 144

Configuration
Filtering / Contact
Chatter
Suppression
Transformer Tap
Changer (TxTap)
5-20
briefly undefined conditions or contact chattering will not lead to an alarm; however,
defined changes in the condition (final positions) are immediately reported.
Figure 5-17 Information properties — example for information type "Double Point Indication"
(DP)
For input indications (single point indications 63, double point indications '3),
transformer tap indication 7[7DS (if available), filter times may be entered (pick-up
and drop-out delays) to suppress momentary changes in potential at the binary input
(e.g. contact chatter), refer also to Figure 5-16 and 5-17. Filtering occurs during an
input change of state, with the same setting values whether coming or going.
Information is only distributed when the new state continues to exist after a preset time
interval (in milliseconds). The setting range is from 0 to 86,400,000 ms or 24 hours.
Whether or not the filter interval is restarted for each change of state during the filtering
(filter re-triggering) is selectable.
It is also possible to set chatter suppression for each indication (Figure 5-16 and 5-17).
The contact chatter settings, themselves, are set the same for all input indications (see
Sub-section 5.2.7).
The transformer tap changer position is communicated, via binary inputs, in a
specified encoding format (maximum of 62 positions). Only binary inputs that are in
direct order with regard to numbering can be used.
For the encoding formats available (binary code, BCD code, "1 of n" code), four
settings (number of positions, number of bits, display offset, and position change) may
be programmed. Their bit pattern corresponds to an individual transformer tap
changer position which is represented in the device display and in the indication
buffers (Figure 5-18).
Having set "with moving" the stage setting is only recognized as valid and accepted
when the moving contact signals that the stage has been achieved.
7SA6 Manual
C53000-G1176-C133-1