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MCT-CM

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Latch:

When latching is enabled, the alarm will remain active even after the alarm condition has passed
until acknowledged by the user.  Latched alarms are acknowledged by the user when pressing
the  ‘Reset’  button  on  the  Alarm  screen  or  by  activating  a  digital  input  configured  for  ‘Remote
Alarm  Reset’.    An  alarm  that  does  not  having  latching  enabled  (self-clearing)  will  deactivate
automatically when the alarm condition has passed.

NOTE:

Latching alarms are acknowledged even when the alarm condition is still present when
the user activates the alarm reset. The latched alarm will then automatically clear once
the alarm condition is no longer present. If the alarm reset was not activated during the
alarm period, the alarm will remain latched until the user activates the alarm reset.

Reverse:

When turned on, the digital output assigned to the alarm will be energized in a non-alarm
condition, i.e., fail-safe. When turned off, the digital output assigned to the alarm is normally
open and will close in an alarm condition.

Silent:

This is  used  to control the  method  by which  an  alarm is reported.   When turned off, an alarm
condition  will  trigger  the  audible  alarm  and  the  alarm  notification  icon  will  flash  to  indicate  the
alarm condition.  The buzzer must then be manually silenced by pressing the reset button on the
alarm screen.

If  silent  mode  is  on, the  audible  alarm  will  not  sound  when  the  alarm  condition  occurs.    If  the
alarm latch is turned off, the alarm will not be reported on the alarm screen.  If the alarm latch is
turned on, which requires manual reset by the operator, the alarm will be reported on the alarm
screen in order to notify the user to reset the alarm; however, the alarm notification icon will not
flash.   The  user  must  navigate to  the  alarm  screen  in  order  to determine  if  a  latched  alarm  is
present.

Start Delay:

When the start delay is off, the alarm will activate immediately when the input exceeds the alarm

set points as programmed. When the start delay is on, the input must first enter the normal
operating range (be above the low alarm set point and/or below the high alarm set point) before
the alarm can be activated. Upon the next excursion beyond the alarm set points, the alarm will
then activate.

The start delay feature is typically used on processes that, when in the off state, are in an alarm
condition. This allows the process to be started prior to the alarm(s) being activated and shutting
down the process.

NOTE: The alarm start delay, when activated, inhibits alarm action from power-up of the MCT,

or when entering

‘online’ mode.

The

Digital Output

assignment can be used to assign one of the MCT digital outputs to the alarm. When the

alarm activates, the output will work in conjunction with the alarm and turn on when the alarm is active and off
when the alarm is cleared.

NOTE:

The selected digital output must be configured as a process alarm output. If the digital output selected
is not configured to be a process alarm output, it will not function according to the alarm settings. See
section 10.8 Digital Outputs for information on how to configure the digital outputs.

9.3.1

Set Points and Alarm Message

The alarm set points and alarm message are accessed by pressing the ‘Setpoints’ button at the lower left of
the Alarm screen.