Watlow Series D8 - Manual (Page 113)

Series D8 User’s Guide Chapter 4: Operation and Setup
Doc. 0600-3120-2000 Watlow Anafaze 95
The RTD alarms are enabled on any channel with Input Type
set to RTD.
Restore Automatic Control After a Sensor Failure
This feature returns a loop to automatic control after a failed
sensor is repaired. To enable this feature:
•
Choose a digital input for the RestoreAuto parameter in
the Control menu.
• Connect the digital input to the dc common terminal on
the controller.
Process Alarms
The D8 has four process alarms, each of which you can con-
figure separately for each loop:
•
Alarm low
• Alarm high
• Low deviation alarm
• High deviation alarm
What Happens if a Process Alarm Occurs?
If a process alarm occurs, the controller does the following:
•
Shows an alarm code on the display. See Alarm Displays
on page 81.
• Activates the global alarm output. See Global Alarm on
page 97.
• Activates the digital output that is assigned to the process
alarm (if applicable). The digital output remains active
until the process variable returns within the correspond-
ing limit and hysteresis. The alarm output deactivates
when the process returns to normal.
Process Alarm Outputs
Any digital output that is not used as a control output can be
assigned to one or more process alarms.
The controller activates the output if any alarm assigned to the
output is active. Process alarm outputs are non-latching—that
is, the output is deactivated when the process returns to nor-
mal, whether or not the alarm has been acknowledged.
Specify the active state of process alarm outputs at the D/O
alarm polarity
setting in the Global setup menu.