Honeywell DCP552 Mark II user manual PV start

Chapter 5. FUNCTIONS

■PV start

NOTE

Separate PV start settings can be made in CH1 and CH2 programs.

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.

SP pattern

SP
Current PV value	C
B
(1)
A	D
(2)
(3)	Time

PV start is valid for segments in the selected program but not for segments beyond a pattern link destination.

When a PV start is performed in one or both channels of a program whose both channels have the same segment time settings, the segment number and operating progress time of the two channels do not match.

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