HeatingCooling Valves w Shared AO v50 - Johnson Controls - Metasys - LIT-12011147 - Software Application - Controller Configuration Tool - 15.0

Controller Tool Help

Johnson Controls
Product name
Controller Configuration Tool
Document type
User Guide
Document number
Revision date
Important: As of Release 5.0, the HeatingCooling Valves w Shared AO v50 module replaces the HeatingCooling Valves w Shared AO module.

This module controls a four-pipe system (commonly referred to as sequenced heating and cooling control). Such a system consists of two proportional valves both connected to a single analog output. Half the range of the analog output controls the heating valve and the other half controls the cooling valve. For example, moving from 5 volts to 0 volts drives the heating value from fully closed to fully open, while the cooling valve remains closed. Likewise, moving from 5 volts to 10 volts drives the cooling valve from fully closed to fully open while the heating valve remains closed. Typical hardware configurations allow for either the heating or the cooling to be controlled over the low range of the analog output. This is handled in the configuration of the output controller by setting the LowHigh Range Select.

The module accepts as inputs, two modes, a flush mode, a process variable, a cooling setpoint, a heating setpoint, a limited max value and a flush position. Based upon the input modes and parameter settings, the module outputs a common percent command (the proportional signal) along with the calculated cooling and heating percentages and status' for feedback purposes. The heating mode takes precedence over the cooling mode. This module is implemented as a standard Control Activity. This module also incorporates tracking the overridden value of the actual output objects (AO, PAO). The module resets the PIDs to default tuning parameters if the Reset PID Tuning input is not Normal.