DALL Damper: Control Min Limit - 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

In this mode, two PIDs are enabled simultaneously.

  1. UV Zone Damper Limit Control: Control Min Limit state’s PID (controls damper from 0%-MinPos based on DA-T and DA-Tllsp)

  2. UV Zone Damper Control:Control Min state’s PID (controls damper from 0%-MinPos based on ZN-T and ZN-Thsp)

These rules apply to the Control Min Limit:

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

  • The Saturation Status from the Limit Min PID is published as the DPRcs.

  • If ZONE is HOT, UV Zone Damper Control: Control Min state’s PID requests the damper to open (eventually saturates high). This is ignored as the maximum cooling allowed is already 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 Min state’s PID eventually has a smaller value than the UV Zone Damper Limit Control: Control Min Limit state's PID. The DA-T rises (less OA brought in) and the UV Zone Damper Limit Control: Control Min Limit state’s PID requests the damper to open, and eventually saturates high. This setting triggers the transition to the Zone Damper state. The UV Zone Damper Control: Control Min state’s PID then continues in control and the UV Zone Damper Limit Control: Control Min Limit state’s PID is disabled.

  • If DA-T is COLD, then the UV Zone Damper Limit Control: Control Min Limit state’s PID eventually requests the damper to fully close and saturates low.