7.19
Date Code 20080213 Instruction Manual SEL-351A Relay
Inputs, Outputs, Timers, and Other Control Logic
Multiple Setting Groups
The operation of these settings is explained with the following example:
Assume the active setting group starts out as setting Group 3. Corresponding
Relay Word bit SG3 is asserted to logical 1 as an indication that setting
Group 3 is the active setting group (see Table 7.3).
With setting Group 3 as the active setting group, setting SS3 has priority. If
setting SS3 is asserted to logical 1, setting Group 3 remains the active setting
group, regardless of the activity of settings SS1, SS2, SS4, SS5, and SS6. With
settings SS1–SS6 all deasserted to logical 0, setting Group 3 still remains the
active setting group.
With setting Group 3 as the active setting group, if setting SS3 is deasserted to
logical 0 and one of the other settings (e.g., setting SS5) asserts to logical 1,
the relay switches from setting Group 3 as the active setting group to another
setting group (e.g., setting Group 5) as the active setting group, after
qualifying time setting TGR:
TGR Group Change Delay Setting (settable from 0.00 to 16000.00
cycles)
In this example, TGR qualifies the assertion of setting SS5 before it can
change the active setting group.
Operation of Serial
Port GROUP
Command and Front-
Panel {GROUP}
Pushbutton
SELOGIC control equation settings SS1–SS6 have priority over the serial port
GROUP command and the front-panel {GROUP} pushbutton in selecting the
active setting group. If any one of SS1–SS6 asserts to logical 1, neither the
serial port GROUP command nor the front-panel {GROUP} pushbutton can be
used to switch the active setting group. But if SS1–SS6 all deassert to
logical 0, the serial port GROUP command or the front-panel {GROUP}
pushbutton can be used to switch the active setting group.
See Section 10: Serial Port Communications and Commands for more
information on the serial port GROUP command. See Section 11: Front-
Panel Interface (Only on Models With LCD) for more information on the
front-panel {GROUP} pushbutton.
Relay Disabled
Momentarily During
Active Setting Group
Change
The relay is disabled for a few seconds while the relay is in the process of
changing active setting groups. Relay elements, timers, and logic are reset,
unless indicated otherwise in specific logic description [e.g., local bit (LB1–
LB16), remote bit (RB1–RB16), and latch bit (LT1–LT16) states are retained
during an active setting group change]. The output contacts do not change
state until the relay enables in the new settings group and the SEL
OGIC control
equations are processed to determine the output contact status for the new
group. For instance, if setting OUT105 = logical 1 in Group 2, and setting
OUT105 = logical 1 in Group 3, and the relay is switched from Group 2 to
Group 3, OUT105 stays energized before, during, and after the group change.
However, if the Group 3 setting was OUT105 = logical 0 instead, then OUT105
remains energized until the relay enables in Group 3, solves the SEL
OGIC
control equations, and causes OUT105 to de-energize. See Figure 7.26 for an
example of output contacts in the de-energized state (i.e., corresponding
output contact coils de-energized).
Active Setting Group
Switching Example 1
Use a single optoisolated input to switch between two setting groups in the
SEL-351A. In this example, optoisolated input IN105 on the relay is connected
to a SCADA contact in Figure 7.18. Each pulse of the SCADA contact
changes the active setting group from one setting group (e.g., setting Group 1)
to another (e.g., setting Group 4). The SCADA contact is not maintained, just
pulsed to switch from one active setting group to another.
Courtesy of NationalSwitchgear.com
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