Watlow Series 922 - Manual (Page 64)

64 WATLOW Series 922 User's Manual
Alarms
How To Use The Alarms , Chapter 7
Alarm Types
There are two Alarm Types for each alarm. ALTYP1 and ALTYP2 are the
prompts for Alarm 1 and Alarm 2, respectively. The choices are: Process
alarm (P), or Deviation alarm (D).
For review, a "process" type alarm is one that is set at a fixed degree dis-
tance, either positive or negative, from the mean 0
°
C or 0
°
F. A "deviation"
type alarm is always a fixed degree distance, positive or negative, from Set
Point (SP).
If we change SP, a process type alarm remains where it was originally set,
while a deviation type alarm will shift with SP the same number of degrees as
its value. The examples illustrate a plot of each alarm type.
Here we've added a process alarm function to the basic graph.
Temp
SP1
Actual
0
°
C
Time
Process Alarm
Fixed Distance
from 0
°
Temp
Deviation Alarm - Fixed Degree distance from SP1
SP1
Actual
0
°
C
Time
New SP1
This graph shows a deviation alarm setting, and how it shifts with a change in SP.
Figure 35 -
Alarm Type for
Alarm 1 is a "Devia-
tion" Alarm (ALTYP
1=D)
Figure 34 -
Alarm Type for
Alarm 1 is "Process"
Alarm (ALTYP1=P)