The Johnson controls Variable Air Volume Modular Assembly (VMA) AP-VMA1420-0 is a configurable digital controllers, and combines a controller, pressure sensor, and/or actuator housed in one preassembled unit.

Features and Benefits

The Johnson Controls AP-VMA1420-0 Integrated Module Includes controller, pressure sensor, and/or actuator, and is preassembled to reduce installation time. The enhanced actuator provides a fast response stepper motor that drives the damper from full open to close in 30 seconds.  Automated Commissioning uses Proportional Adaptive (P-Adaptive) and Pattern Recognition Adaptive Control (PRAC) for continuous loop tuning while advanced diagnostics offer damper stall detection, starved box detection, actuator motor duty cycle, VAV box flow test, and other diagnostics. Network communications enables integration into a Building Automation System (BAS) and easy configuration provides simple question/answer software format for quick selection of project-specific applications. Software addressing allows remote addressing and identification from a configuration tool.

Actuator Enhancements

The AP-VMA1420-0 uses an actuator with a fast response stepper motor, which is quiet (<35 dBA) and precise (23 K resolution). The stepper motor drives the damper from full open to full close in 30 seconds. This significantly reduces the time to commission and balance a VAV terminal box. The stepper motor quickly and accurately adjusts the damper position in response to new conditions, minimizing position hunting and motor runtime. The AP-VMA1420-0 requires an external floating/3-wire (incremental) or proportional actuator.

Advanced Diagnostics

The AP-VMA1420-0 has several unique diagnostic features. Diagnostics include damper stall detection, starved box detection, actuator motor duty cycle, VAV box flow test, and others.

The VMA constantly monitors the space temperature and airflow and generates alarms to alert the operator of setpoint deviations. The operator can react quickly, taking corrective action to get the system back into desired operation. This assures occupants better comfort control.

Simply mount, wire, configure, download, and commission the controller. Because the AP-VMA1420-0 performs loop tuning automatically, there is no need to set proportional bands and integration terms. Also, there is no need to set any jumpers or switches. Even network addressing can be done via software, if desired. The AP-VMA1420-0 is configured to detect the damper end-stops automatically. On power up, the actuator drives to both hard stops on the VAV box and remembers these positions. These automated features get the system operating quickly.

Hardware

The AP-VMA1420-0 modular assembly is in a durable, plenum-rated, plastic housing. The controller and pressure sensor are enclosed in one module attached to the actuator. The unique plastic housing may eliminate the need for a separate enclosure for plenum-rated construction. Check code requirements for appropriate applications. Line voltage relays and transformers still require an enclosure. The N2 communication connector has removable screw terminals. Input/Output (I/O) connections to the VMA are easy-to-use spade lugs. If you prefer screw terminal I/O connections, be sure to order the appropriate optional removable screw terminal kit accessories. The differential pressure sensor in the AP-VMA1420-0 provides consistent flow readings with minimal drift. This means auto-zero calibration is required less often. There are no filters to change, which ensures accuracy. A Light-Emitting Diode (LED), visible through the housing, indicates that power is connected and communication has been established.

Applications

Product Specifications