Watlow PPC-2000 - Manual (Page 119)

PPC-2000 User’s Guide Chapter 3: Operating with AnaWin 3
Doc.# 30002-00 Rev 2.3 Watlow Anafaze 95
Alarms
The controller has three different kinds of alarms: failed sensor
alarms, the global alarm, and process alarms. For information
on each of these alarms, refer to the following sections.
Failed Sensor Alarms
Failed sensor alarms indicate T/C breaks and failed RTDs due
to open leads.
When a channel is in Auto or Tune mode and a failed sensor
alarm occurs, the controller sets the channel to Manual control
at the Sensor Fail Heat% or Sensor Fail Cool% set in the Channels
spreadsheet.
A failed sensor alarm is only detected for an input that is
selected as the PV Source for a channel.
Global Alarm
The global alarm occurs when a channel alarm set to Alarm (not
Control) occurs or when there are any failed sensor alarms. If an
alarm occurs, the !Alarm screen displays the corresponding
alarm message. The global alarm output stays on until the
original alarm is acknowledged.
Process Alarms
Process alarms include high and low deviation and high and
low process alarms. Each of these alarms may be enabled or
disabled. If enabled, each may be set to function as an alarm or
a control. Refer to Alarms on page 123 for descriptions of the
parameters used to set up these alarms. Table 3.2 describes the
difference between Alarm type and Control type alarms.
Table 3.2 Alarm Types
Alarm Type Description
Alarm
Standard alarm function. Digital output, or Soft
Bool, if selected, activates on alarm, deactivates
when channel is not in alarm. Global alarm output
activates and requires alarm acknowledgment to
clear.
Control
Digital output, or Soft Bool, if set, activates on
alarm, deactivates when channel is not in alarm.
Global alarm output does not activate. No alarm
acknowledgment required to clear.