4.5
Date Code 20130214 Instruction Manual SEL-2414 Transformer Monitor
Logic Functions
General Logic Functions
If setting SETn asserts to logical 1, latch bit LTn asserts to logical 1. If setting
RSTn asserts to logical 1, latch bit LTn deasserts to logical 0. If both settings
SETn and RSTn assert to logical 1, setting RSTn has priority and latch bit LTn
deasserts to logical 0. The SET and RESET default settings are NA.
Power Loss
The states of the latches (LT01–LT32) are retained if power to the device is lost
and then restored. If a latch is asserted when power is lost, it is asserted when
power is restored. If a latch is deasserted when power is lost, it is deasserted
when power is restored.
Settings Change
If individual settings are changed, the states of the latches are retained, as in the
preceding Power Loss explanation. If an individual setting change causes a
change in SEL
OGIC control equation setting SETn or RSTn, the retained states of
the latch bits can be changed, subject to the newly enabled settings SETn or
RSTn.
Latch Settings
Latch states are stored in battery-backed RTC SRAM. An operational battery in
the Real Time Clock is necessary to ensure that Latch settings are not compro-
mised.
Settings SETn and RSTn cannot result in continuous cyclical operation of latch
bit LTn. Use timers to qualify conditions set in settings SETn and RSTn. If you
use any optoisolated inputs in settings SETn and RSTn, the inputs each have a
separate debounce timer that can help in providing the necessary time qualifica-
tion.
Variables/Timers
Operation
Each SELOGIC control equation variable/timer has a SELOGIC control equation
setting input and variable/timer outputs as shown in Figure 4.6. Timers SV01T
through SV64T in Figure 4.6 have a setting range of 0.000–16000.00 seconds.
This timer setting range applies to both pickup and dropout times (SvnPU and
SVnDO, n = 1 through 64).
Figure 4.5 Logic Diagram of a Latch Switch
LT01
R
Q
S
SET01
RST01
IEC 61131-3 Latch
(b)(a)
LTn
SETn
RSTn
(Set)
(Reset)
(n = 01 through 32)
Device
Word
Bits
SELOGIC
Setting
To Next Page
Loading...
