Temperature | Set Point |
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Temperature ramps to Set Point at a set rate
Time
AlarmsAlarms are activated when the output level, process value or temperature leaves a defined range. A user can configure how and when an alarm is triggered, what action it takes and whether it turns off automatically when the alarm condition is over.
Configure alarm outputs in the Setup Page before setting alarm set points.
Alarms do not have to be assigned to an output. Alarms can be monitored and controlled through the front panel or by using software.
Process and Deviation Alarms
A process alarm uses one or two absolute set points to define an alarm condition.
A deviation alarm uses one or two set points that are defined relative to the control set point. High and low alarm set points are calculated by adding or subtracting offset values from the control set point. If the set point changes, the window defined by the alarm set points automatically moves with it.
Select the alarm type with Type [`A;ty] (Setup Page, Alarm Menu).
Alarm Set Points
The alarm high set point defines the process value or temperature that will trigger a high side alarm. It must be higher than the alarm low set point and lower than the high limit of the sensor range.
The alarm low set point defines the temperature that will trigger a low side alarm. It must be lower than the alarm high set point and higher than the low limit of the sensor range.
View or change alarm set points with Low Set Point [`A;Lo] and High Set Point [`A;hi] (Operations Page, Alarm Menu).
Alarm Hysteresis
An alarm state is triggered when the process value reaches the alarm high or alarm low set point. Alarm hysteresis defines how far the process must return into the normal operating range before the alarm can be cleared.
Alarm hysteresis is a zone inside each alarm set point. This zone is defined by adding the hysteresis
value to the alarm low set point or subtracting the hysteresis value from the alarm high set point.
View or change alarm hysteresis with Hysteresis [`A;hy] (Setup Page, Alarm Menu).
High Side Alarm Range | Alarm High Set Point |
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Alarm Low Set Point
Low Side Alarm Range
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Alarm Latching
A latched alarm will remain active after the alarm condition has passed. It can only be deactivated by the user.
An active message, such as an alarm message, will cause the display to toggle between the normal settings and the active message in the upper display and [Attn] in the lower display.
Push the Advance Key to display [ignr] in the upper display and the message source in the lower display.
Use the Up ¿ and Down ¯ keys to scroll through possible responses, such as Clear [`CLr] or Silence [`SiL]. Then push the Advance ‰ or Infinity ˆ key to execute the action.
See the Keys and Displays chapter and the Home Page chapter for more details.
An alarm that is not latched
Turn alarm latching on or off with Latching [`A;LA] (Setup Page, Alarm Menu).
The alarm state begins when the temperature reaches the Alarm High Set Point
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Watlow | • 63 • | Chapter 9 Features |