Watlow CPC400 - Manual (Page 80)

Chapter 3: Operation and Setup CPC400 Series User’s Guide
66 Watlow Anafaze Doc. 0600-2900-2000
Alarm Function: Standard Alarm or Boost Output
You can configure each process alarm as either a standard
alarm or a boost alarm:
• A standard alarm provides traditional alarm function-
ality: The operator must acknowledge the alarm mes-
sage on the controller display, a latching global alarm
is activated, and the alarm can activate a user-speci-
fied non-latching alarm output.
• A boost alarm provides on/off control output using the
alarm set points. For example, you could configure a
high deviation alarm to turn on a fan. The alarm acti-
vates a user-specified non-latching output. Alarm
messages do not have to be acknowledged, and the glo-
bal alarm is not activated.
Alarm High and Alarm Low
An alarm high occurs if the process variable rises above a
user-specified value. An alarm low occurs if the process
variable drops below a separate user-specified value. See
Figure 3.7
Enter the alarm high and low set points at the Alarm high
SP and Alarm low SP parameters in the Alarms menu.
Figure 3.7 Activation and Deactivation of Pro-
cess Alarms
Deviation Alarms
A deviation alarm occurs if the process deviates from set
point by more than a user-specified amount; see Figure 3.7.
You can set separate high and low deviation values at the
HiDeviation value and LoDeviation value parameters in
the Alarms menu.
Setpoint
High process alarm set point
Low process alarm setpoint
} Deadband
High process alarm on High process alarm off
Low process alarm on Low process alarm off
High deviation
alarm off
High deviation
alarm on
Low deviation
alarm off
Low deviation
alarm on
Setpoint + Deviation alarm value
Setpoint - Deviation alarm value
} Deadband
} Deadband
} Deadband