Schweitzer Engineering Laboratories SEL-387E - Local Bits

8-12 Front-Panel Operation Date Code 20080110
SEL-387E Instruction Manual
Local Bits
In more specific terms, local control asserts (sets to logical 1) or deasserts (sets to logical 0) what
are called local bits LB1 through LB16. These local bits are available as Relay Word bits and
are used in SEL
OGIC control equations.
Local control can emulate the following switch types in
Figure 8.2 through Figure 8.4.
Lo
g
ical
1
LBn
(n=1
through 16)
Relay
Word
Bit
ON
position
OFF
position (logical 0)
Figure 8.2: Local Control Switch Configured as an ON/OFF Switch
Lo
g
ical
1
LBn
(n=1
through 16)
Relay
Word
Bit
OFF position
(logical 0)
MOMENTARY
position
Figure 8.3: Local Control Switch Configured as an OFF/MOMENTARY Switch
Lo
g
ical
1
LBn
(n=1
through 16)
Relay
Word
Bit
ON
position
OFF
position (logical 0)
MOMENTARY
position
Figure 8.4: Local Control Switch Configured as an ON/OFF/MOMENTARY Switch
Local control switches are created by making corresponding switch position label settings.
These text label settings are set with the SET command or viewed with the SHO command via
the serial port. Refer to SHO P (Show Port Settings) in Section 7: Communications.
Table 8.1: Correspondence Between Local Control Switch Positions and Label Settings
Switch Position
Label
Setting Setting Definition Logic State
not applicable NLBn Name of Local Control Switch not applicable
ON SLBn “Set” Local bit LBn logical 1
OFF CLBn “Clear” Local bit LBn logical 0
MOMENTARY PLBn “Pulse” Local bit LBn logical 1 for one
processing interval
Note that the first setting in Table 8.1 (NLBn) is the overall switch name setting.