Watlow CPC400 - Manual (Page 81)

CPC400 Series User’s Guide Chapter 3: Operation and Setup
Doc. 0600-2900-2000 Watlow Anafaze 67
Upon power up or when the set point changes, the behavior
of the deviation alarms depends upon the alarm function:
• If the alarm function parameter is set to standard,
then deviation alarms do not activate until the after
the process variable has first come within the devia-
tion alarm band. This prevents nuisance alarms.
• If the alarm function parameter is set to boost, then
the deviation output switches on whenever the set
point and process variable differ by more than the de-
viation setting, regardless of whether the process vari-
able has been within the deviation band. This allows
you to use boost control upon power up and set point
changes.
Global Alarm
The CPC400 comes equipped with a global alarm output.
The global output is activated if one or more of the follow-
ing conditions occurs:
• A system alarm occurs, or
• A failed sensor alarm occurs and is unacknowledged,
or
• A process alarm occurs and is unacknowledged. The
global alarm occurs only if the alarm function is set to
standard in the Alarms menu. (The global alarm does
not occur if the alarm function is set to boost.)
The global alarm output stays active until all alarms have
been acknowledged.
When the global alarm output is active, it conducts current
to the controller’s dc common. When the global alarm out-
put is not active, it does not conduct current.
NOTE! You cannot configure any parameters for the glo-
bal alarm. The active state of the global alarm out-
put is NOT affected by the D/O alarm polarity
parameter in the Global setup menu.
Setting Up Process Variable Retransmit
The process variable retransmit feature retransmits the
process variable of one loop (primary) via the control output
of another loop (secondary). This signal is linear and pro-
portional to the engineering units of the primary loop in-
put.
Typical uses include data logging to analog recording sys-
tems, and long distance transmission of the primary signal
to avoid signal degradation. The retransmitted signal can
also be used as an input to other types of control systems
such as a PLC.