Schweitzer Engineering Laboratories SEL-311C - Make Active Setting Group Switching Settings with Care

7.27
Date Code 20060320 Instruction Manual SEL-311C Relay
Inputs, Outputs, Timers, and Other Control Logic
Multiple Setting Groups
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 SEL
OGIC control equation settings SS1–SS6 (see
Table 7. 5) be set with care. Settings SS1–SS6 cannot result in continuous
cyclical changing of the active setting group. Time setting TGR qualifies
settings SS1–SS6 before changing the active setting group. If optoisolated
inputs IN101–IN106 are used in settings SS1–SS6, the inputs have their own
built-in debounce timer that can help in providing the necessary time
qualification (see Figure 7.1).