Primary States (Fan Return or Exhaust Volume Match Control) - Metasys - Johnson Controls - LIT-12011147 - Software Application - Controller Configuration Tool - 13.1

Controller Tool Help
Product
Controls > Control Tools > Controller Configuration Tool
Document number
LIT-12011147
Version
13.1
Revision date
2019-12-04

  • Off: The fan is off when the module is in this mode of operation.

  • Max: The return fan is commanded to its maximum speed. The Return Fan Percent Cmd output is set to 100%.

  • Min: The analog fan output (Return Fan Percent Cmd) is zero, and the fan control output (Return Fan OnOff) is on when the module is in this mode of operation.

  • Hold: Hold the outputs at their current position.

  • Failsoft: When in this mode of operation, the return fan tracks the supply fan. This mode is a fault mode entered if either flow sensor is unreliable.

  • VOL Control: When in this mode of operation, the return fan controls the return flow to maintain a differential flow (Volume Diff Setpoint) between the return and supply ducts. This operation is volume matching.

The following table illustrates the State Output dependencies on Mode and Flow Reliability inputs.

Table 1. Fan Return or Exhaust Volume Match Control Command Hierarchy

Mode

Flow Reliable

State

Off

*

Off

Min

*

Min

Max

*

Max

Hold

*

Hold

VOL Control

TRUE

VOL Control

FALSE

Failsoft

Zero VOL Control

TRUE

Zero VOL Control

FALSE

Failsoft