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Description
Action Pak models AP1280 and
AP1290 limit alarms offer wide
ranging inputs and flexible
setpoint capability. They accept
six popular thermocouple types
with inputs ranging from -270
C (-454 F) to 1760 C (3200 F).
The AP1280 provides a single-setpoint
alarm while the AP1290 provides
two independent setpoint alarms.
The AP1280 and AP1290 also include
0.25%-50% adjust- able deadbands
and selectable 120/240VAC power.
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Operation
The field configurable AP1280
and AP1290 limit alarm setpoints
can be configured for HI, LO,
latching or fail-safe trip operation.
Non-latching HI and LO setpoints
have respective HI and LO deadbands.
In a tripped condition, the
setpoint is exceeded and the
appropriate red LED is lit.
The trip will reset only when
the process falls below the
HI deadband or rises above the
LO deadband (see figure 1).
To reset a latched setpoint
the signal must be in the safe
region and the line power must
be turned off for at least 5
seconds. For proper deadband
operation, the HI setpoint must
always be set above the LO setpoint.
In
failsafe operation, the relay
is energized when the process
is below a HI setpoint or above
a LO setpoint (opposite for
non- failsafe). In the failsafe
mode, a power failure results
in an alarm condition.
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