REM 543 Protection,
Monitoring and Control
Page 33
Technical Reference Manual
Part 1, General
ABB Network Partner
4.1.6.4.
Oscillation suppression
Oscillation suppression is used to reduce the load from the system when a binary input,
for some unrecognized reason, starts oscillating. A binary input is regarded as oscillat-
ing if the number of valid status changes (= number of events after filtering) during 1
second is greater than the set value Input osc. level (Oscillation level). During oscilla-
tion, the binary input is blocked (status is invalid) and an event is generated.
The binary input is regarded as non-oscillating if the number of valid status changes
during 1 second is less than the set value of Input osc. level minus the set value of Input
osc. hyst. (Oscillation hysteresis). When the input returns to a non-oscillating state, the
binary input is deblocked (status is valid) and an event is generated.
The parameters Input osc. level and Input osc. hyst. can be found in the menu Configu-
ration/General.
4.1.6.5.
Attributes of a binary input for protection terminal configuration
The status of the input (value), the time tag for the status change (time) and the validity
of the binary input (invalidity) can be issued for each binary input by the attributes
BI#IV, BI#, BI#Time and BI#Count, where # denotes the number of the input. These
attributes are available in the machine terminal configuration and can be used for differ-
ent purposes.
Invalidity (BI#IV)
When a binary input oscillates, the invalidity attribute IV changes to TRUE (1) and the
input is blocked. The binary input is regarded as being blocked and oscillating if the
number of status changes per second exceeds the set Input osc. level value (events/s).
When a binary input does not oscillate, the invalidity attribute IV changes to FALSE (0)
and the input becomes operative. The binary input is regarded as being operative and
non-oscillating if the number of status changes per second is less than the set Input osc.
level value minus the set Input osc. hyst. value (events/s).
Value(BI#)
Depending on the status of the binary input, the binary input value is TRUE (1) or
FALSE (0). The BI# value changes on the rising or falling edge of the input. To prevent
undesired status changes of the binary input due to switch debouncing, etc., the change
of the attribute value is delayed by the time of filtering.
A counter attribute of a binary input is not handled when the input is programmed as a
normal binary input.
Parameter
Values
Default
Input osc. level
2..50 events/s
50 events/s
Input osc. hyst.
2..50 events/s
10 events/s
