Target Ramp Down - Metasys - LIT-12011288 - Software Application - Metasys Building Automation System - 6

DLLR Technical Bulletin

Product
Building Automation Systems > Building Automation Systems > Metasys Building Automation System
Document type
Technical Bulletin
Document number
LIT-12011288
Version
6
Revision date
2013-10-15

Another attribute of the Sliding Window Alg Advanced section of the DLLR object UI is Target Ramp Down Enabled. This optional attribute ramps down the target incrementally over the course of one interval. The default setting is False. The behavior prevents excessive, immediate shedding by the DLLR object. The following values are used:

Trev = revised target level

Told = target level at the time the target level is decreased

Tnew = new target level

N = number of readings of electrical consumption per demand interval

j = 1, 2, 3, ..., N

Note: This algorithm computes a revised target level (Trev) following a decrease in the target level from Told to Tnew.
Figure 1. Ramp Down Algorithm

The process loops on j after each new reading of energy consumption.

Figure 2 shows the revised target level following a decrease in the target level from Told to Tnew. Notice that the revised target level follows a decreasing staircase pattern. In this example, the number of readings (N) of electrical consumption per demand interval is five. Upon a second target change within the same interval, a new stair step begins, which uses the current ramped target value (Trev) as Told.

Figure 2. Revised Target Level Following a Decrease in Electric Consumption