blockChange
Information
This subsequence is not directly specified in Guideline36 as it provides a side calculation pertaining to the generalization of the staging sequences for any number of chillers and stages provided by the user.
This subsequence is used to generate the chiller stage setpoint
ySta and a boolean vector of
chiller status setpoint indices y
for the ySta stage.
The inputs to the subsequece are:
-
Plant enable status
uPlathat is generated by Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Generic.PlantEnable.Enable subsequence -
Integer index of initial chiller stage
uInithat is generated by Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Initial subsequence -
Stage up
uUpand downuDowboolean signals that are generated by Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Up and Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Down subsequences, respectively -
Integer index of next available higher
uAvaUpand loweruAvaDowchiller stage, as calculated by Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Status subsequence
If stage down and stage up happen at the same time for any faulty reason the staging down is performed.
If stage down or stage up signal is held for a time longer than delStaCha
multiple consecutive stage change signals are issued.
At plant enable the intial stage uIni is held for at least delStaCha
and until any stage up or down signal is generated.
Per Guideline 36-2021, section 5.20.4.15.a. Each stage shall have a minimum runtime
of delStaCha.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nSta | 3 | Number of chiller stages, does not include zero stage |
| Real | delStaCha | 900 | Hold period for each stage change |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput | uPla | Plant enable signal | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput | uUp | Stage up status | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput | uDow | Stage down signal | |
| Buildings.Controls.OBC.CDL.Interfaces.IntegerInput | uIni | Initial chiller stage (at plant enable) | |
| Buildings.Controls.OBC.CDL.Interfaces.IntegerInput | uAvaUp | Next available stage up | |
| Buildings.Controls.OBC.CDL.Interfaces.IntegerInput | uAvaDow | Next available stage down | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput | yChaEdg | Chiller stage change edge signal | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput | yChaUpEdg | Chiller stage up change edge signal | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput | yChaDowEdg | Chiller stage down change edge signal | |
| Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput | ySta | Chiller stage integer setpoint |
Revisions
-
April 14, 2020, by Milica Grahovac:
First implementation.