DALL Economizer: Control Econ Limit - Johnson Controls - Metasys - LIT-12011147 - Software Application - Controller Configuration Tool - 13.1

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

In this mode, two PIDs are enabled simultaneously.

  1. UV Zone Damper Limit Control: Control Econ Limit state’s PID (controls damper from MinPos-100% based on DA-T and DA-Tllsp) is active.

  2. UV Zone Damper Control: Control Econ state's PID (controls damper from MinPos-100% based on ZN-T and ZN-Tcsp) is active.

These rules apply to the Control Econ Limit:

  • The MINIMUM of the PID outputs is sent to the Percent Cmd.

  • The Saturation Status from the UV Zone Damper Limit Control: Control Econ Limit state’s PID is published as the Control Status.

  • If ZONE is HOT, UV Zone Damper Control: Control Econ state's PID requests the damper to open (will eventually saturate high). This request is ignored since the maximum cooling allowed is being performed (DA-T = DA-Tllsp).

  • If ZONE is COLD (OA that maintains DA-Tllsp overcools the zone) or DA-T is HOT (OA is no longer cold enough to cause DA-T Low Limit issues), the UV Zone Damper Control: Control Econ state’s PID eventually has a smaller value than the UV Zone Damper Limit Control: Control Econ Limit state’s PID. The DA-T rises (less OA brought in) and the UV Zone Damper Limit Control: Control Econ Limit state's PID requests the damper to open, and eventually saturates high. This triggers the transition back to the Economizer state. The UV Zone Damper Control: Control Econ state’s PID then continues in control and the UV Zone Damper Limit Control: Control Econ Limit state’s PID is disabled.

  • If DA-T is COLD, then the UV Zone Damper Control: Control Econ state’s PID requests the damper to go to Minimum Position and saturates low. This setting triggers the transition down to the DALL Heating state.