Operational outdoor air humidity - Johnson Controls - LIT-12011950 - Building automation software - Smart Equipment Controller - 5.0

Smart Equipment Controls Sequence of Operation Technical Bulletin

Product name
Smart Equipment Controller
Document type
Technical Bulletin
Document number
LIT-12011950
Version
5.0
Revision date
2024-06-06
Product status
Active

Setpoints and related data

The setpoints and related data include the following items:

  • Operational outdoor air humidity (OprOAH)
  • Outdoor air humidity source (OAHSrc)

Inputs

The inputs include the following items:

  • Network override outdoor air humidity (NetOAH) communicated value on FC Bus
  • Outdoor air humidity input (OAH) to OAH terminals

Operation

Operational outdoor air humidity (OprOAH) is effective only if an economizer board has been connected to the UCB and an input has been present following the last RELEARN SYSTEM (Relearn) operation. The operational outdoor air humidity (OprOAH) parameter then appears in the UCB display. The network override outdoor air humidity (NetOAH) and outdoor air humidity input (OAH) parameters are only shown in the UCB display menu if an economizer board is connected to the UCB.

The highest priority valid input is used for the operational outdoor air humidity (OprOAH). The operational outdoor air humidity (OprOAH) has assigned priority for inputs in the following order from highest to lowest:

BAS Override
Indicates network override outdoor air humidity (NetOAH)
Local Input
Indicates outdoor air humidity input (OAH)
Unreliable
Indicates no valid input is available and single enthalpy and dual enthalpy economizer free cooling changeover methods that use operational outdoor air humidity (OprOAH) are not permitted

Network override outdoor air humidity (NetOAH) is used if a value is set or communicated within the past 15 minutes. If 15 minutes pass without a communicated value, the UI displays Value Timed Out and the next highest priority input is used.

Outdoor air humidity input (OAH) is used if the humidity sensor is connected to the OAH terminals.