Series-EPW

Supported Applications

The ACI Series EPW converts a pulse or digital PWM signal into a proportional pneumatic output ranging from 0 to 20 psig. The series is designed for applications requiring the translation of electrical control signals—such as relay contact closure, transistor (solid state relay), or Triac inputs—into precise air pressure levels. It supports both direct and reverse acting configurations via firmware versions.

Key functional capabilities include:

• Pneumatic signal generation proportional to input timing ranges
• Manual override potentiometer for varying pneumatic output independent of the input signal
• A 0-5 VDC feedback signal that varies linearly with the selected branch pressure range, indicating resultant line pressure
• Field calibration capability up to a maximum of 20 psig (138 kPa)

Operating Conditions & Performance

The Series EPW operates within an ambient temperature range of 35 to 120°F (1.7 to 48.9°C) and a humidity rating of 10 to 95% non-condensing. Storage is supported from -20 to 150°F (-28.9 to 65.5°C). The unit requires an air supply pressure between a minimum of 20 psig (137.9 kPa) and a maximum of 25 psig (172.38 kPa).

Performance specifications include:

• Output Pressure Accuracy: 2% full scale at room temperature (above 1 psig or 6.895 kPa); 3% full scale across the operating temperature range (above 1 psig or 6.895 kPa)
• Jumper Selectable Output Ranges: 0-10 psig (0-68.95 kPa), 0-15 psig (0-103.43 kPa), and 0-20 psig (137.9 kPa)
• Input Pulse Trigger Level: 9-24 VAC or VDC @ 750Ω nominal
• Minimum Off Time Between Pulses: 10 milliseconds
• Pneumatic Tubing Requirement: Branch line minimum of 2 in³ (33.78 cm³) volume; recommended branch line length is a minimum of 25 ft of 1/4" O.D. poly tubing for standard models, or as specified by the specific model's exhaust characteristics.

Configuration Options

The series offers three primary configurations distinguished by their valve architecture and fail-safe behavior:

• EPW (Constant Bleed): A constant bleed interface where branch exhaust response time is determined by the bleed orifice size (0.007" standard) and pressure differentials. On power failure, it continues to bleed until branch pressure reaches zero psig.
• EPW2 (Two Valve / Non-Bleed): Incorporates two valves with one controlling exhaust; does not bleed air at set point. Branch exhaust flow is not limited by an internal restrictor and response time is similar to the load rate. On power failure, branch line pressure remains constant provided there are no leaks.
• EPW2FS (Fail-Safe): A two-valve fail-safe model featuring a 3-way branch exhaust valve that allows for the exhaust of branch line air upon power failure.

Additional configurable options include:

• Gauge Models: Available with an integrated pressure gauge (0-30 psig range, ±2.5% Midscale accuracy).
• Firmware Versions: Version 1 and Version 4 support standard timing ranges; Version 2 supports Solydne or Staefa duty cycle inputs.
• Filtering: Furnished with an integral-in-barb 80-100 micron filter (Part # PN004). An optional external 5 micron in-line filter (PN021) is available for installation between the air supply and main barb connection.
• Mounting: Designed with electrical terminals on one end and pneumatic connections on the other. A DIN Rail Adapter Kit is offered as an accessory.

Key Product Differences

The Series EPW distinguishes models by exhaust capacity, gauge inclusion, and input timing compatibility:

• Exhaust Capacity: Standard EPW/EPWG models list an exhaust of 41 SCIM (0.6719 Liters). The EPW2 family lists an exhaust of 750 SCIM (12.29 Liters).
• Gauge Integration: Models with the "G" suffix include a pressure gauge; non-suffixed models do not.
• Firmware Versions: Version #4 provides reverse acting operation compared to Version #1. Version #2 supports specific duty cycle inputs (0-10s Duty Cycle or 0.023-6s).