Attributes (PCHWP dP Setpoint Reset By Coil Position) - Johnson Controls - Metasys - LIT-12011147 - Software Application - Controller Configuration Tool - 13.1

Controller Tool Help

Brand
Johnson Controls
Metasys
Product name
Controller Configuration Tool
Document type
User Guide
Document number
LIT-12011147
Version
13.1
Revision date
2019-12-04
Language
English

The following table describes the attributes used by the PCHWP dP Setpoint Reset By Coil Position modules:

Table 1. PCHWP dP Setpoint Reset By Coil Position Attributes

Name

Type 1

Description

Default Value

CHW Coil nn Position

 

Indicates the valve positions of the chilled water (CHW) coils.

95%

Effective dP Setpoint

G

Provides the building's CHW differential pressure setpoint as determined by this module based on the valve position of the coils.

34.0 kPa, 5.0 psi

Enable

 

Provides the enable input, which allows the process to run.

False

Maximum dP Setpoint

 

Resets the Effective dP setpoint up to the Maximum dP Setpoint.

276.0 kPa, 40.0 psi

Minimum dP Setpoint

 

Resets the Effective dP setpoint down to the Minimum dP Setpoint. Set this attribute to a value such that when the value is reached and the bypass valve is fully open, the system still meets the largest minimum flow requirement required by the chillers.

34.0 kPa, 5.0 psi

Period

 

Indicates the time, in minutes, that the calculation executes.

5 minutes

Stage Down Threshold

 

Indicates the amount that is subtracted from the current CHW Pressure setpoint when the maximum valve position is less than 90% or is determined to be an outlier. To avoid changing the valve positions too much or too little during a stage down event, set the Stage Down Threshold to approximately 10% of the expected operating point of the building differential pressure. The default value of 2.0 psi works well for building dPs around 20.0 psi.

14.0 kPa, 2.0 psi

Stage Up Threshold

 

Indicates the amount that is added to the current CHW Pressure setpoint when a valve is fully open and not determined to be an outlier. To avoid changing the valve positions too much or too little during a stage up event, set the Stage Up Threshold to approximately 10% of the expected operating point of the building differential pressure. The default value of 3.0 psi works well for building dPs around 20.0 psi.

21.0 kPa, 3.0 psi

Startup Value

 

Indicates the initial plant CHW differential pressure setpoint.

103.0 kPa, 15.0 psi

1 C - Configuration Mode Only, G - Default Element (Generated State, if applicable), SC - Simulation and Commissioning Modes Only, V - Calculated Value (Outputs)