Attributes (Fan Return or Exhaust Volume Match Control) - Johnson Controls - Metasys - LIT-12011147 - Software Application - Controller Configuration Tool - 15.0

Controller Tool Help

Brand
Johnson Controls
Metasys
Product name
Controller Configuration Tool
Document type
User Guide
Document number
LIT-12011147
Version
15.0
Revision date
2022-11-18
Language
English

The following table describes the attributes used by the Fan Return or Exhaust Volume Match Control modules.

Table 1. Fan Return or Exhaust Volume Match Control Attributes

Name

Type 1

Description

Default Value

Fan Return or Exhaust Volume Match Common Attributes

EF-OUTSTATE or RF-OUTSTATE (State)

V, G

Indicates the current operational mode of the output controller. This output is the current state of the activity.

Off

Set Name: AHU RF VOL State

Mode

 

Contains the desired mode of operation.

Off

Set Name: AHU RF VOL Mode

Process Units

 

Allows the user to define the units for the process.

l/s, cfm

Set Name: Unit

Return Fan Control Status

V

Displays the PID Status. The possible values are normal, overridden, disabled, low, timing low, high, and timing high.

Normal

Set Name: Control Status

Return Fan OnOff

V

On/off signal for the return fan.

Off

Set Name: Off/On

Return Fan Percent Cmd

V

Contains the analog signal for the return fan used to command a fan speed. This output can range from 0% to 100%.

0.0%

Return Flow

 

Use to connect the return airflow or the exhaust airflow to this input.

10000 l/s, 22000 cfm

Supply Fan Percent Cmd

 

Contains the analog signal from the supply fan used in the Failsoft mode.

0.0%

Supply Flow

 

Discharge airflow.

10000 l/s, 22000 cfm

Vol Process Range

 

Specifies that the magnitude of the range that the PID Process Variable traverses as the PID Present Value varies between its minimum and maximum values. For example, the process range should be configured to be the design flow of the return fan.

10000 l/s, 22000 cfm

Volume Diff Setpoint

 

Contains the volume differential (Supply Flow - Return Flow or Supply Flow - Exhaust Flow) setpoint.

0 l/s, 0 cfm

Variable Capacity Return Fan Volume Match Control Specific Attributes

Low Limit Process Variable

 

Low limit temperature process variable. This temperature is usually the mixed air temperature or the preheat air temperature.

7 °C, 45 °F

Low Limit Proportional Band

 

Defines the temperature range where the flow differential setpoint is reset to control the low limit process variable to the low limit temperature setpoint.

5 °C, 9 °F

Low Limit Setpoint

 

Contains the upper threshold for the low limit process function. When the low limit process variable is above this temperature, the return fan may be modulated to maintain the desired flow differential between the supply duct and the return duct. Below this setpoint, outdoor air levels may be limited by resetting the differential flow setpoint.

7 °C, 45 °F

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