15
Model TA502A
panel LED, the associated mimic open collector, and the un-accept outputs will re-
flash or re-activate. This gives the operator an indication of a new alarm condition
that must be re-accepted.
The fault alarm can be accepted similarly with the
A1
&
A2
alarms. The front panel
fault LED will flash and the fault un-accept (FUA) open collector will energize when a
fault is detected. If the operator presses the accept button, the FUA output will de-
energize and the
Fault
LED will stop flashing but stay illuminated until the fault
condition is corrected.
3.5 Resetting Latched Alarms
The user may select a “
latching
” or “
non-latching
” alarm output for
A1
and/or
A2
. If
an alarm output activates and the condition that caused that activation is no longer
present, a non-latching alarm output will reset automatically, whereas a latched alarm
output will need to be reset manually. Resetting latched alarm outputs is
accomplished with the Master Reset Button located on the Facilities Module
(FM002A). Pressing the Master Reset Button will reset any latched conditions that
are no longer valid. Latched alarm conditions cannot be reset until they have been
accepted.
The Master Reset Button performs another function. If the operator presses and
holds the Master Reset Button for two or more seconds, all of the LED’s and LED
segments in the digital display will illuminate for as long as the operator presses the
button. This is called the LED Test. The LED test cannot be performed while the unit
is in alarm, or fault, or during a Card Test.
3.6 CAL Open Collector
There is an open collector that will energize anytime the Field Device is placed in the
Calibration Mode. This open collector output is referenced to the system’s
ground/common. Energizing this output merely provides a path to ground, as is the
case with all energized open collector outputs. De-energized, this output will be in a
high impedance state.
3.7 Card Test Feature
The Card Test Input is provided so that the user can access the Card Test feature
remotely. One end of a normally open SPST switch is connected to this terminal and
the other end is connected to system common (see Figure 19).
To activate the Card Test feature, simply press and hold the switch for at least three
seconds. The front panel LED’s and digital display will begin ramping-up at the start
of the card test. They will continue to ramp-up for the software-selectable ramp-time
specified by the operator (1, 3 or 10 seconds) during the Setup Mode (see Section
4.4). Each alarm level (
A1
&
A2
) will trip when the alarm set point is exceeded. At the
conclusion of the Card Test, the
A1
&
A2
outputs will automatically reset (overriding
any latching option). A Card Test cannot be initiated if the unit is in alarm, or fault, or
during an LED Test.
