7-30 Inputs, Outputs, Timers, and Other Control Logic Date Code 20001006
SEL-351 Instruction Manual
If the individual settings change causes a change in one or more SELOGIC Control Equation
settings SS1 through SS6, the active setting group can be changed, subject to the newly enabled
SS1 through SS6 settings.
Note: Make Active Setting Group Switching Settings with Care
The active setting group is stored in nonvolatile memory so it can be retained during power loss or
settings change. The nonvolatile memory is rated for a finite number of “writes” for all setting
group changes. Exceeding the limit can result in an EEPROM self-test failure. An average of 10
setting groups changes per day can be made for a 25 year relay service life.
This requires that SELOGIC Control Equation settings SS1 through SS6 (see Table 7.4) be set with
care. Settings SS1 through SS6 cannot result in continuous cyclical changing of the active setting
group. Time setting TGR qualifies settings SS1 through SS6 before changing the active setting
group. If optoisolated inputs IN1 through IN8 are used in settings SS1 through SS6, the inputs
have their own built-in debounce timer that can help in providing the necessary time qualification
(see Figure 7.1).
SELOGIC CONTROL EQUATION VARIABLES/TIMERS
Sixteen (16) SELOGIC Control Equation variables/timers are available. Each SELOGIC Control
Equation variable/timer has a SELOGIC Control Equation setting input and variable/timer outputs
as shown in Figure 7.25 and Figure 7.26.
Timers SV1T through SV6T in Figure 7.25 have a setting range of a little over 4.5 hours:
0.00 - 999999.00 cycles in 0.25-cycle increments
Timers SV7T through SV16T in Figure 7.26 have a setting range of almost 4.5 minutes:
0.00 - 16000.00 cycles in 0.25-cycle increments
These timer setting ranges apply to both pickup and dropout times (SVnPU and SVnDO,
n = 1 through 16).
Courtesy of NationalSwitchgear.com
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