Introduction - 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

The VMA 1832 is a programmable digital controller tailored for VAV box applications that communicate via the N2 Open Communications protocol, featuring an integrated differential pressure sensor, a damper actuator, and a 32-bit microprocessor. The VMA 1832 controllers are designed to serve as a replacement model for certain VMA14xx Series Controller applications. The VMA 1832 controllers offer many of the features and benefits of the BACnet® based VMA 16xx Series Controllers in an N2 environment, although some differences exist between the network interface. The differences between the VMA14xx Series Controllers and the VMA 1832 controllers are described in Differences between VMA14xx Series and VMA 1832 Series Controller network interface.

The VMA 1832 controller is programmed and commissioned using CCT, whereas the VMA14xx Series controllers are commissioned using HVAC Pro. Figure 1 shows how a CCT user connects to the VMA 1832 for commissioning.
Note: At CCT Release 10.1, VMA 1832 controllers can be set either as N2 devices or as standard BACnet MS/TP devices. This ability provides a potential cost-effective protocol upgrade path for existing customers and should be considered when you install the controller.
Figure 1. Commissioning the VMA1832 Controller Using CCT

Note: This document focuses on creating and using applications for the VMA 1832 controller that match VMA14xx Series Controller applications. It is intended to support scenarios in which the VMA 1832 controller is replacing VMA14xx Series Controllers on existing N2 networks. Refer to the VMA1832 Variable Air Volume Controllers Installation Instructions (LIT-24-10143-373) for detailed installation instructions and sensor replacement and reuse scenarios. Refer to the Controller Tool Help (LIT-12011147) for information on commissioning the VMA 1832 controller.
This document describes:
  • choosing between a pre-built N2 VMA application or a custom N2 VMA application

  • creating an application using the System Selection Wizard

  • uploading a VMA14xx Series Controller and configuring the N2 VMA application

  • loading the application into the VMA 1832 controller
  • defining the custom control modules when a VMA14xx interface is required
  • replacing a VMA14xx with a VMA1832 controller on a NAE
  • replacing a VMA14xx with a VMA1832 controller on a NCM
Important: This document assumes that you have knowledge of HVAC systems, HVAC PRO™, programming methods of CCT, and mapping devices and points into supervisory controllers.