7-2
Inputs, Outputs, Timers, and Other Control Logic
Date Code 20011205
SEL-311A Instruction Manual
Figure 7.1: Example Operation of Optoisolated Inputs IN101 Through IN106
Input Debounce Timers
Each input has settable pickup/dropout timers (IN101D through IN106D) for input
energization/deenergization debounce. Note that a given time setting (e.g., IN101D = 0.50) is
applied to both the pickup and dropout time for the corresponding input.
Time settings IN101D through IN106D are settable from 0.00 to 2.00 cycles. The relay takes the
entered time setting and internally runs the timer at the nearest 1/8-cycle. For example, if setting
IN105D = 0.80, internally the timer runs at the nearest 1/8-cycle: 6/8-cycles (6/8 = 0.75).
For most applications, the input pickup/dropout debounce timers should be set in 1/4-cycle
increments.
The relay processing interval is 1/4-cycle, so Relay Word bits IN101 through IN106 are updated
every 1/4-cycle. The optoisolated input status may assert input debounce timer settings less than
1/4-cycle, because these timers run each 1/8-cycle. However, Relay Word bits IN101 through
IN106 may not be available until the next 1/4-cycle relay processing interval.
If more than 2 cycles of debounce are needed, run Relay Word bit IN
n
(
n
= 101 through 106)
through a SEL
OGIC
control equation variable timer and use the output of the timer for input
Summary of Contents for SEL-311A
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