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Section 5 – Recorder Setup
Page 61 09/11/2008 REV 0.99
Figure 5-4-2 Alarm Setup
5.4.1.1 Alarm Setup
Pressing the edit button above takes you to the individual Alarm Setup dialog window shown
below right.
The window will show the default Channel and
Alarm setup based upon entry conditions – eg
Channel 2 Alarm 1. The user can change the
Alarm Number and the window will refresh and
show the setup for that alarm.
Channel: The current channel that the alarm
setup refers to. (1 to 18). Defaults to source.
Alm No: The current alarm for the current
channel. (1 to 5)
Alarm Type: This drop down selection box
allows the user to select one of the available
alarm types. The Alarm types are: For Linear,
Square Root, Frequency and Calculated inputs -
None, High, Low, Rate, or Abnormal. For Dry
Contacts and Conditional Inputs the alarm types
are - None, True (or Open), False (or Close) or Abnormal. Any unused alarm must be set to None.
Enable Checkbox: If checked this alarm is enabled, if unchecked this alarm is disabled. Note: to ensure
that any alarms on this channel are active it is necessary to check the Channel Enable AND Master
Enable in the Alarm Master Setup.
Notify Checkbox: If checked the system will attempt to send an email about this alarm condition
provided the email smtp information is correctly setup.
Record Checkbox: If checked this alarm will trigger a recording to start if the record setup has been
configured this way. See Section 5.6 Record Setup.
Setpoint: This is the value in the same engineering units as the channel that the alarm condition is tested
against – also known as the threshold. In the above example, when the input is greater than (high alarm)
350, the alarm will be true. See the definition of other alarm conditions above.
Dead band: This value is the hysteresis for the alarm. Once the alarm is true (active) this value is
subtracted from the setpoint and becomes the new setpoint for the alarm reset. In the above example the
dead band is 10 so once an alarm is active, the input needs to drop below 340 (new threshold) to no
longer be true or active. This prevents chatter about the alarm setpoint. Once the alarm is reset, no longer
true, the setpoint is restored to the original value so the next alarm has to exceed 350 to once again be
active. Note: The dead band cannot exceed the setpoint.
Delay: Enter the time in seconds from the point that the alarm condition becomes true (input exceeds
setpoint) till it is actually reported as an alarm. If the alarm condition is reset (drops below the threshold)
during this delay period, the alarm will not be reported. This feature prevents an alarm condition if the
process is stable apart from a quick aberration that is recoverable.
Rate of Change: Enter the time in seconds (up to a maximum of 600) over which the input cannot
change by more than the setpoint. For example, if the setpoint was 10 and the rate of change is 5
seconds, if the input changes by more than 10 in 5 seconds an alarm will occur. If the setpoint is positive
the rate of change is measured on increasing changes, if the setpoint is negative, the rate of change is
measure on decreasing changes.