Series-EFP

Supported Applications

The ACI Series EFP Floating Point to Pneumatic Output Transducer converts a floating point signal into a proportional pneumatic signal ranging from 0-20 psig. The series is designed for applications including 3 Way Mixing Valve Control, Chiller Loading, Pilot Positioner Control, Pneumatic Valve and Damper Actuator Control, Fan Vane Control, and Compressor Staging.

Operating Conditions & Performance

The transducer operates with an air supply pressure of a maximum 28 psig (193.06 kPa) and minimum 22 psig (151.69 kPa). Output pressure ranges are jumper selectable for 0-10 psig, 0-15 psig, or 0-20 psig. Accuracy is specified as 2% full scale at room temperature (above 1 psig or 6.895 kPa) and 3% full scale across the operating temperature range (above 1 psig). The device operates within an ambient temperature of 35 to 120°F (1.7 to 48.9°C) and a humidity range of 10 to 95% non-condensing.

Power requirements are 24 VAC (+/-10%), 50 or 60Hz, or 24 VDC (+10%/-5%). The digital input signal level is 9-24 VAC/VDC @ 750Ω. A feedback output of 0-5 VDC = Output Span indicates the resultant branch line pressure.

Performance by Model Variant

• EFP: Constant bleed interface; exhaust response time determined by bleed orifice size and pressure differentials. If power fails, it continues to bleed until branch pressure is 0 psig.
• EFP2: Two-valve design that does not bleed air at set point and maintains branch pressure on power failure.
• EFP2FS: Fail-safe model with a three-way exhaust valve for safe branch line air exhaust on power failure.

Digital Input Rates of Change

Rates are selectable via jumpers and vary by firmware version:

• EFP / EFP2 (Version 1): 45s, 90s, 1 min, 2 min.
• EFP2 Version 2: 30s, 3 min, 6 min, 8 min.

Configuration Options

The series offers configurable options for mounting, filtration, and monitoring. Electrical connections utilize 90° Pluggable Screw Terminal Blocks compatible with wire sizes from 16 (1.31 mm²) to 26 AWG (0.129 mm²). Pneumatic tubing size is 1/4" O.D. nominal (1/8" I.D.) polyethylene.

Mounting and Housing

• Gauge Models: Available with a miniature pressure gauge (0-30 psig range, ± 2.5% Midscale accuracy).
• DIN Rail Adapter Kit: Optional accessory for DIN rail mounting.

Filtration and Accessories

• Furnished with integral in-barb 80-100 micron filter (Part # PN004).
• Standard barb (PN002) available for use with an external 5 micron or 10 micron in-line filter (PN021), depending on the source document.
• Transient Voltage Suppressor, Bi-directional, 56 VAC/DC, 1500W (Part # A/D0008) available for shared power circuits with inductors.

Status Indication

The unit features LEDs to indicate status:

• UP LED On / DOWN LED Off: Ramping Up.
• UP LED Off / DOWN LED On: Ramping Down.
• Fast Blink (UP) / Fast Blink (DOWN): Maximum or Minimum Output respectively.
• Slow Blink Both: Output Holding.

Key Product Differences

The Series EFP includes distinct model families based on valve configuration and fail-safe requirements:

• EFP / EFPG: Single-valve constant bleed models. The "G" suffix denotes the inclusion of a pressure gauge.
• EFP2 / EFP2G: Two-valve models that maintain branch pressure and do not bleed at set point. Includes optional Version 2 firmware with extended rates of change (30s to 8 min).
• EFP2FS / EFP2GFS: Fail-safe versions incorporating a three-way exhaust valve for safe air exhaust upon power loss.

All models feature a Manual/Auto Override switch. In MAN function, output can be varied; in AUTO function, output is controlled from the input signal. The ZERO potentiometer is factory calibrated and should not be adjusted.