Lot of 4 ACT HVAC interface modules, used, in excellent condition and sold with a 30-day unconditional warranty. The PTS4.1G is a Floating-Point to Pressure Interface and includes a pressure gauge. This interface is made by Automation Components Inc (ACI) but also sold under the Schneider Electric, Siemens, and Johnson Controls labels. Manufacturer’s Description: The PTS4.1 converts two digital (increase or decrease) signals from relay contact closures, transistors, or triac inputs into a proportional pneumatic signal of 0-10, 5-15 or 0-15 psig (jumper selectable). The pneumatic output increases when the UP input is on, or decreases when the DOWN input is on. The pneumatic output changes full scale (from minimum to maximum) in 90 seconds with 255 steps of resolution. The PTS4.1’s closed loop electronic design will maintain the last commanded pneumatic pressure. An on-board microprocessor measures the signal input and a solid-state pressure transducer measures branch line pressure. The PTS4.1 uses these two values to automatically increase or decrease branch line air pressure. In the event of a power failure, both PTS4.1 valves close, shutting o main air and branch line bleed. If a power brown-out occurs, the PTS4.1 automatically reboots its on-board processor. During a power brown-out, power to the processor on the PTS4.1 is shut down, while the pressure output remains the same. When proper power level is restored, processor automatically powers up and branch pressure output defaults to 0 psig.