7-10 Inputs, Outputs, Timers, and Other Control Logic Date Code 20001006
SEL-351 Instruction Manual
Figure 7.10: Configured Manual Close Switch Drives Local Bit LB4
Local bit LB4 is set to close the circuit breaker in the following SELOGIC Control Equation setting:
CL = LB4
SELOGIC Control Equation setting CL is for close conditions, other than automatic reclosing or
serial port CLOSE command (see Figure 6.1 in Section 6: Close and Reclose Logic).
Additional Local Control Switch Application Ideas
The preceding factory settings examples are OFF/MOMENTARY switches. Local control
switches configured as ON/OFF switches can be used for such applications as:
• Reclosing relay enable/disable
• Ground relay enable/disable
• Remote control supervision
• Sequence coordination enable/disable
Local control switches can also be configured as ON/OFF/MOMENTARY switches for
applications that require such. Local control switches can be applied to almost any control scheme
that traditionally requires front-panel switches.
Local Control Switch States Retained
Power Loss
The states of the local bits (Relay Word bits LB1 through LB8) are retained if power to the relay is
lost and then restored. If a local control switch is in the ON position (corresponding local bit is
asserted to logical 1) when power is lost, it comes back in the ON position (corresponding local bit
is still asserted to logical 1) when power is restored. If a local control switch is in the OFF position
(corresponding local bit is deasserted to logical 0) when power is lost, it comes back in the OFF
position (corresponding local bit is still deasserted to logical 0) when power is restored. This
feature makes the local bit feature behave the same as a traditional installation with panel-mounted
control switches. If power is lost to the panel, the front-panel control switch positions remain
unchanged.
Courtesy of NationalSwitchgear.com
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