Unitary

Pre-APOGEE

APOGEE

BACnet

PXC.A

 

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Syntax

DC(pt1,pat1,...,pt8,pat8)

pt1 through pt8

Name of the output points to be duty cycled.

- This parameter can be an LDO, LOOAL, LOOAP, L2SL, or L2SP point type.

- Local, virtual, and physical points are valid for pt1, pt2, pt3, and pt4.

pat1 through pat8

Hourly pattern that describes how the point is duty cycled.

-  This parameter can be a local, physical, or virtual point, as well as an integer.

-  This pattern is a four-digit code using the numbers 0 through 7.

-  Each digit represents the on/off pattern for one 15-minute segment of an hour. Table 3-1 lists the numeric codes and their ON/OFF patterns.

Table 3-1.  Duty Cycle Patterns and Numerical Codes.

Point Status During this Time

Code Number for this 15-minute On/Off Pattern

First 5 minutes

Second 5 minutes

Third 5 minutes

OFF

OFF

OFF

0

ON

OFF

OFF

1

OFF

ON

OFF

2

ON

ON

OFF

3

OFF

OFF

ON

4

ON

OFF

ON

5

OFF

ON

ON

6

ON

ON

ON

7

Use

Coordinates the operation of all available equipment to compensate for additional equipment capacity that is not normally needed. During normal system operation, some equipment is cycled off for short periods of time to distribute equipment wear and reduce operating costs.

A maximum of 8 points can be controlled with one DC command.

Do the following to create a duty cycle pattern:

  1. Divide one-hour into four 15-minute segments.
  2. Determine the ON/OFF state for each 5-minute increment of the segment.
  3. Using Table 3-1, assign a number to represent the ON/OFF pattern for each 15-minute segment.
  4. After the patterns are defined, enter the code numbers in reverse order. The right-most digit defines the first 15-minute segment of the hour. The left-most digit defines the last 15-minute segment of the hour.

Example

1000

C  THIS DC COMMAND DUTY CYCLES HFAN

1010

C  ACCORDING TO THE FOLLOWING SCHEDULE:

1020

C

1030

C  FIRST 15 MINUTES – ON, OFF, OFF (1)

1040

C  SECOND 15 MINUTES – OFF, OFF, OFF (0)

1050

C  THIRD 15 MINUTES – OFF, OFF, OFF (0)

1060

C  FOURTH 15 MINUTES – ON, ON, ON (7)

1070

C

1100

DC(HFAN,7001)

Notes

The DC command has a priority of NONE. Therefore, the PPCL program must be structured with IF/THEN/ELSE commands to prevent conflicts between DC and other commands with the same priority.

See also the DCR topic.