476
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
AUTOMATION LOGIC
CHAPTER 8: AUTOMATION
Automation operators
The following operators are available for the creation of automation logic.
•
One-shots.
•
Boolean operators and latches.
•
Math operators.
•
Virtual outputs.
•
Comparators.
•
Timers.
Unlike earlier versions of the D90
Plus
, automation timers are implemented like gates or
latches and not through the specific setting menus.
The following sub-sections provide additional detail on these operators.
About Boolean operators and latches
The Boolean logic and latch syntax is shown in the following table.
Table 34: Automation logic Boolean operators and latches
Boolean
operators perform Boolean logic operations on any digital input or the output of
any preceding logical operator. The output of a logic operator may be used in further logic
processing. The final output of a sequence of logic operations is stored as a virtual digital
output (
VDO
). The logic operators available in the automation controller are tabulated
below.
A
latch
is asserted on a positive transition of its set input and retains this state until the
positive transition of its reset input. A latch accepts any digital input or the output of any
logical operator to either of its inputs. A total of 256 latches are available in the
D90
Plus
automation controller.
Virtual
output
On
VIRT OP 1 ON
The virtual output is presently in the on state.
Type
State
Example
Characteristics (input is logic 1 or “on” if...)
Syntax
Description
Output is ON if...
NOT
Logical NOT gate. Operates on the previous
operand.
the input is logic 0
OR(2)
to
OR(16)
Logical OR gates. Operate on the previous 2 to 16
operands.
any input is logic 1
AND(2)
to
AND(16)
Logical AND gates. Operates on the previous 2 to
16 operands.
all inputs are logic 1
NOR(2)
to
NOR(16)
Logical NOR gates. Operates on the previous 2 to
16 operands.
all inputs are logic 0
NAND(2)
to
NAND(16)
Logical NAND gates. Operates on the previous 2
to 16 operands.
any input is logic 0
XOR(2)
Logical exclusive OR gate. Operates on the
previous two operands.
only one input is logic 1
LATCH (S,R)
Reset-dominant latch. The operand preceding
LATCH(S,R)
is the reset input. The operand
preceding the reset input is the set input.
there is a positive
transition on the set
input
