Pv Start - Honeywell DCP551 Mark ΙΙ User Manual

Chapter 5. FUNCTIONS

PV start

NOTE
5-20
When a PV start is set in the program setting, a PV start is performed in a normal RUN
operation.
The program looks for the first point where PV and the program pattern SP are equal
(both PV and SP include bias) and starts operation from there. PV starts are of three
kinds: rising PV start that looks for a point where PV and SP are equal on a rising
RAMP, falling PV start that looks for a point where PV and SP are equal on a falling
RAMP and bi-directional PV start that looks for such a point both on rising and falling
RAMPs.
Note, however, that if there is no point where PV and SP are equal, operation starts from
the beginning of segment 1.
When a PV start has been implemented, the event operating point and the time event
time are automatically corrected. This is described in the figure shown below. When PV
is at (1) in the figure, a rising PV start or a bi-directional PV start starts from B and a
falling PV start starts from C. When PV is at (2) in the figure, a falling PV start or a bi-
directional PV start starts from D and a rising PV start starts from A. When PV is at (3)
in the figure, any PV start starts from A.
Current PV value
B
(1)
A
(2)
(3)
PV start is valid for segments in the selected program but not for segments beyond a pat-
tern link destination.
SP pattern
C
D