N2 - VAV Box Mode Input - Metasys - LIT-12011829 - Field Device - VMA18 VAV Modular Assembly

N2 VMA Application Note

Product name
VMA18 VAV Modular Assembly
Document type
Application Note
Document number
Revision date

This module is responsible for translating the VAV Box Mode Input and Water Flush Input into the outputs required for a third-generation VAV application. The VAV Box Mode Input uses the Box Mode Enum Set, which contains the Shutdown Closed, Shutdown Open, Warmup, Water System Flush, Low Limit, Satisfied, and Cooling and Heating inputs. The outputs provided are System Mode, Unit Enable, and WarmupCooldown.

The Occupied Sequencer switches between Satisfied Cooling and Heating in the current VAV single duct application. As a result, when the VAV Box Mode is commanded to Satisfied, Cooling, or Heating, the System Mode is set to Auto.

This module is typically placed in the Setpoint Determination column.

You can view and modify the modules in this group's logic.

Figure 1. N2 - VAV Box Mode Input

Table 1 describes the attributes used by the N2 - VAV Box Mode Input module:
Table 1. N2 - VAV Box Mode Input Attributes
Name Type Description Default Value
System Mode G, V The system mode necessary to achieve the state desired based on the inputs Set Name: System Mode
Unit Enable V The output used to turn the box off to close the box when Shutdown Closed is required Set Name: Shutdown/Enable
WarmupCooldown V The output used to indicate a warmup mode is requested when VAV Box Mode Input is Warmup Set Name: OST Warmup Cooldown
Water Flush

The input that forces the VAV Box Controller into a Water Flush mode of operation when set to true False
VAV Box Mode Input

The VAV Box mode command used by N2-based VMA14xx Series Controllers Shutdown Closed Set Name: Box Mode

Note: C - Configuration Mode Only, G - Default Element (Generated State, if applicable), SC - Simulation and Commissioning Modes Only, V - Calculated Value (Outputs)