4.7
Date Code 20130214 Instruction Manual SEL-2414 Transformer Monitor
Logic Functions
General Logic Functions
Digital output SC01QD asserts when the counter is at position zero, and digital
output SC01QU asserts when the counter reaches the programmable count value.
Use the reset input (SC01R) to force the count to zero, and the analog output
(SCnn) with analog comparison operators. Table 4.7 describes the counter inputs
and outputs. Control input precedence is first followed by SCnnR, SCnnLD,
SCnnCU, and SCnnCD.
Figure 4.9 shows an example of the effects of the input precedence, with
SC01PV set to 7. The vertical dashed line indicates the relationship between
SC01CU first being seen as a rising edge and the resultant outputs. This indicates
that there is no intentional lag between the control input asserting and the count
Figure 4.8 Counter 01
Table 4.7 Counter Input/Output Description
Name Ty pe Description
SCnnLD Active High Input Load counter with the preset value to assert the output
(SCnQU) (SEL
OGIC setting).
When SCnnLD is asserted, the following are ignored:
➤ SCnnCU
➤ SCnnCD
SCnnPV Input Value This Preset Value is loaded when SCnLD pulsed. This
Preset Value is the number of counts before the output
(SCnQU) asserts (SEL
OGIC setting). The counter will not
increment higher than this value.
SCnnCU Rising Edge Input Count Up increments the counter (SEL
OGIC setting).
Setting this to NA disables the counter.
When SCnnCU has a rising edge, a rising edge on
SCnnCD is ignored (unless SCnn is already at the
maximum value SCnnPV), in which case SCnnCU is
ignored and SCnnCD is processed.
SCnnCD Rising Edge Input Count Down decrements the counter (SEL
OGIC setting).
Setting this to NA disables the counter.
SCnnR Active High Input Reset counter to zero (SEL
OGIC setting).
When SCnnR is asserted, the following are ignored:
➤ SCnnLD
➤ SCnnCU
➤ SCnnCD
SCnnQU Active High Output This Q Up output asserts when the Preset Value
(maximum count) is reached (SCn = SCnPV, n = 01 to
32).
SCnnQD Active High Output This Q Down output asserts when the counter is equal to
zero (SCn = 0, n = 01 to 32).
SCnn Output Value This counter output is an analog value that may be used
with analog comparison operators in a SEL
OGIC control
equation and viewed using the COU command.
SC01PV
SC01R
SC01LD
SC01CU
SC01CD
Counter 01
SC01QU
SC01QD
SC01
SEL
OGIC
Output
NOTE: These counter elements
conform to the standard counter
function block #3 in IEC 61131
-3 First
Edition 1993
-03 International
Standard for Programmable
Controllers—Part 3: Programming
languages.
NOTE: For device configurations that
include either current or voltage
cards, the SEL-2414 tracks the
frequency. When tracking the
frequency, the processing interval
varies with the frequency.
NOTE: If either setting SCnnCD or
SCnnCU is set to NA, the entire
counter nn is disabled.
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