8.3
Date Code 20090730 Instruction Manual SEL-734 Meter
Logic
Optoisolated Inputs
Input
Debounce Timers
Each input has settable pickup/dropout timers (IN101D and IN102D) for input
energization/de-energization debounce. Notice in Figure 8.1 that a given time
setting (e.g., IN101D = 25 ms) is applied to both the pickup and dropout time
for the corresponding input (see SET G Command on page SET.5 of the
SEL-734 Settings Sheets for valid debounce timer settings).
Time settings IN101D and IN102D are settable from 0 to 25 ms or ac setting.
The meter takes the entered time setting and internally runs the timer at 1 ms.
For example, if setting IN102D = 14, internally the timer runs at 1 ms; the
delay is 14 ms.
The ac setting allows the input to sense ac control signals. The input has a
maximum pickup time of 25 ms and a maximum dropout time of 25 ms. The
ac setting qualifies the input by not asserting until two successive 1 ms
samples are higher than the optoisolated input voltage threshold and not
deasserting until 12 successive 1-ms samples are lower than the optoisolated
input voltage threshold.
For dc applications, the input pickup/dropout debounce timers are set in 1 ms
increments. For example, in the factory default settings, all the optoisolated
input pickup/dropout debounce timers are set at 5 ms (e.g., IN101D = 5). See
SHO Command (Show/View Settings) on page 10.24 for a list of the factory
default settings.
The meter processing interval is 25 ms, so Meter Word bits IN101 through
IN102 are updated every 25 ms. The optoisolated input status may have made
it through the pickup/dropout debounce timer (for settings less than 25 ms)
because these timers run each 25 ms, but Meter Word bits IN101 through
IN102 are updated every 25 ms.
If more than 25 ms of debounce is needed, run Meter Word bit INn (n = 1
through 2) through a SEL
OGIC control equation variable timer and use the
output of the timer for input functions (see Figure 8.10).
Input Functions
There are no optoisolated input settings such as:
IN101 = OUT101
IN102 = ER1
Optoisolated inputs IN101 and IN102 control Meter Word bits IN101 and IN102
that are used in SEL
OGIC control equations.
Courtesy of NationalSwitchgear.com
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