ABB REB650, Техническое руководство

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Section 4 Binary input and output modules
4.1 Binary input
4.1.1 Binary input debounce filter
The debounce filter eliminates bounces and short disturbances on a binary input.
A time counter is used for filtering. The time counter is increased once in a millisecond
when a binary input is high, or decreased when a binary input is low. A new debounced
binary input signal is forwarded when the time counter reaches the set
DebounceTime
value and the debounced input value is high or when the time counter reaches 0 and the
debounced input value is low. The default setting of
DebounceTime is 5 ms.
The binary input ON-event gets the time stamp of the first rising edge, after which the
counter does not reach 0 again. The same happens when the signal goes down to 0 again.
Each binary input has a filter time parameter DebounceTimex , where x is the number
of the binary input of the module in question (for example DebounceTime1 ).
4.1.2 Oscillation filter
Binary input lines can be very long in substations and there are electromagnetic fields
from, for example, nearby breakers. Floating input lines can result in binary input
activity. These events are unwanted in the system. An oscillation filter is used to
reduce the load from the system when a binary input starts oscillating.
Each debounced input signal change increments an oscillation counter. Every time the
oscillation time counter reaches the set
OscillationTime , the oscillation counter is
checked and both the time counter and the oscillation counter are reset. If the counter
value is above the set
OscillationCount value the signal is declared as oscillating. If the
value is below the set OscillationCount value, the signal is declared as valid again.
During counting of the oscillation time the status of the signal remains unchanged,
leading to a fixed delay in the status update, even if the signal has attained normal
status again.
Each binary input has an oscillation count parameter OscillationCountx and an
oscillation time parameter OscillationTimex , where x is the number of the binary input
of the module in question.
1MRK 505 277-UUS C
Section 4
Binary input and output modules
41
Technical Manual