13.22
SEL-400 Series Relays Instruction Manual Date Code 20171006
SELOGIC Control Equation Programming
SEL
OGIC Control Equation Elements
Counters
NOTE: Preset values for counters
must not exceed 8,000,000 for
proper operation.
Use counters to count changes or edges in Boolean values. Each time the value
changes from logical 0 to logical 1 (a rising edge), the counter Current Value
increments. Counters are available in the protection freeform area and automa-
tion freeform area, as shown in Table 13.13. Counters have three input parame-
ters, Input, Preset Value, and Reset; and two outputs, Current Value and Output,
as listed in Table 13.14.
In freeform programming, the relay evaluates the counter at execution of the
counter Input SEL
OGIC control equation (PCNnnIN or ACNnnIN). If you enter
an expression for the counter Reset (PCNnnR) or the counter Preset (PCNnnPV),
the values for Reset and Preset that the relay uses are the last values the relay cal-
culates before the input SEL
OGIC control equation calculation. Because the relay
uses the last values for Reset and Preset in this manner, we recommend for most
applications that you enter the Preset, Reset, and Input statements together in the
order shown in Example 13.9. You can view the current value of the counter by
assigning the protection counter current value, PCVnnCV, to a protection math
variable or by assigning the automation counter current value, ACVnnCV, to an
automation math variable. View the math variable values by issuing the appropri-
ate MET PMV or MET AMV commands.
The current value count is stored in volatile memory. Elapsed time resets to zero
for both protection and automation sequential timers when relay power cycles,
you change settings or settings groups, or you perform any function that reboots
the relay.
Table 13.13 Counter Quantities
Type Ty pi cal Q ua ntity Name Range
Protection counters 32 PCN01–PCN32
Automation counters 32 ACN01–ACN32
Table 13.14 Counter Parameters
Type Item Description Setting
Name
Examples
Input Input Value that the relay
counts
Boolean SELOGIC control
equation setting
PCN01IN
CN09IN
Input Preset Value Number of counts
before the output turns
on
Constant or expression for
the number of counts
PCN01PV
ACN09PV
Input Reset Counter reset Boolean SEL
OGIC control
equation setting
PCN01R
ACN09R
Output Current
Value
Current accumulated
count
Value for math SEL
OGIC
control equations
PCN01CV
ACN09CV
Output Output Counter output Value for Boolean
SEL
OGIC control equations
PCN01Q
ACN09Q
Example 13.9 Counter Programming
The freeform programming equations that follow demonstrate how to enter
settings to control a protection counter in protection freeform SEL
OGIC con-
trol equation programming. Programming for an automation counter is similar.
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