Wall-mounted, NEMA 4X standalone ventilation controller for one, two, or three high-performance AT- or AT6-Series gas sensor modules or other 4-20 mA sensors.

Intuitive, menu-driven setup allows on/off, multi-speed, and variable speed control of ventilation equipment in response to user-specified gas concentration levels.

Multi-color LCD and standard horn/light module for local annunciation of escalating alarm levels.

Conforming to Safety Integrity Level 2 (SIL 2) and rigorous international standard EN 50545-1 for parking garages and tunnels, PolyGard®2 monitoring and control systems utilize advanced self-diagnostics and flexible ventilation control functions to ensure maximum human safety without compromising energy efficiency.


• Accepts 4-20 mA signals from up to three AT-, AT6- or other 4-20 mA sensors
• 2-Line, 16-character LCD display with dual color background
• Two (2) SPDT alarm relays, 30 VAC/VDC, 0.5 A
• One (1) 4-20 mA or 2-10 VDC analog output, jumper selectable
• Audible / visual alarm annunciation
• 24 VDC powered
• Menu-driven controller setup
• X-Change sensor technology for low-cost life cycle maintenance
• Digital measurement processing with temperature compensation
• Internal diagnostics including integrated hardware watchdog
• High-impact polycarbonate enclosure, NEMA 4X (IP65)
• Software conforms to SIL 2 standard