Precision Digital PD554 - Manual (Page 26)

This is parameter establishes the wait zone range for the wait function. This sets the
deviation value used for the wait function. When set, a running program will not move to the
next segment until the PV is within the wait zone, or the wait time has passed. When OFF,
the wait function will not be enabled. See Fig 5 for more information about this process.
This is the wait time parameter for the wait function, which sets the time the program will
wait for the PV to enter the wait zone before starting the next program segment. The
setting range is OFF (0) to 99.59 (time units set by TMU). When OFF, the wait function
will not be enabled. See Fig 6 for more information.
PV
PV
STC set to PV, with only ascending ramp segments
5
4
3
2
1
Program
Wil l Not Start
B
C
D
E(SSP)
1 2
D
E
C
B
A
5
4
3
2
1
Wait Function
The wait function delays the start of the next program segment, if the next segment is a soak segment (the new
target set point is the same as the previous target set point), until the PV is within a specified deviation range
from the SP, or until the wait time has expired. The wait zone defines the deviation range from the SP the PV
must reach to activate the next segment and the wait time establishes a limit on how long the program will wait for
this to occur befo re activating the next segment. Note that this function will only activate when progressing into a
set point soak segment.
Actual Delay
Time
WZ (Wait Zone)
WZ
WTM (Wait Time)
Segment N Segment N+1 Segment N+2
Point of Wait Function release.
Shift to Segment N+1
SP
PV
Fig 5 : Wait Function Wait Zone Release
In
p
u
t V
al
ue at P
rogr
am S
tar
t
Starting PV At
Program Activation
Immediate
Program
Start Point
Program Set Point
Program Segment
?
NOTE
Time
PD550 Series Nova Programmable Process and Temperature Controller Instruction Manual
26