4.3
Date Code 20170601 Instruction Manual SEL-387-0, -5, -6 Relay
Control Logic
Remote Control Switches
Remote Control Switches
Remote control switches are operated via the serial communications port only
(see Section 7: Serial Port Communications and Commands).
Figure 4.1 Remote Control Switches Drive Remote Bits RB1 Through RB16
The outputs of the remote control switches in Figure 4.1 are Relay Word bits
RBn (n = 1 to 16), called remote bits. Use these remote bits in SEL
OGIC
control equations.
Any given remote control switch can be put in one of the following three
positions via the serial port commands shown. Begin with the CON n
(Control Remote Bit n) command, then specify
➤ SRB n (Set Remote Bit n) ON (logical 1)
➤ CRB n (Clear Remote Bit n) OFF (logical 0)
➤ PRB n (Pulse Remote Bit n) MOMENTARY (logical 1 for
one-eighth cycle)
Remote Bit
Application
With SELOGIC control equations, the remote bits can be used in applications
when you want to remotely enable or disable certain logic, depending on
operating conditions of the system. Also, remote bits can be used in operating
Latch Bit control switches in the additional SEL
OGIC Control Equation Sets 1
through 3. Pulse (momentarily operate) the remote bits for this application.
Latch Bits are discussed later in this section.
Remote Bit States
Not Retained When
Power Is Lost
The states of the remote bits (Relay Word bits RB1 through RB16) are not
retained if power to the relay is lost and then restored. The remote control
switches always come back in the OFF position (corresponding remote bit is
deasserted to logical 0) when power is restored to the relay.
Remote Bit States
Retained When
Settings Changed or
Active Setting Group
Changed
The state of each remote bit (Relay Word bits RB1 through RB16) is retained
if relay settings are changed (for the active setting group or one of the other
setting groups) or the active setting group is changed. If a remote control
switch is in the ON position (corresponding remote bit is asserted to logical 1)
before a setting change or an active setting group change, it comes back in the
ON position (corresponding remote bit is still asserted to logical 1) after the
change.
ON position
(maintained
logical 1
position)
OFF position
(maintained
logical 0
position)
MOMENTARY position
(logical 1 for one
processing interval)
Logical 1
RBn
(n = 1 through 16)
Relay
Word
Bit
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