FMA4000-Series

Supported Applications

The Omega FMA4000 Series comprises programmable gas mass flow meters and totalizers designed for the precise measurement of clean gases. The series supports internal conversion factors for up to 32 specific gases, including Air (AIR), Nitrogen (N2), Oxygen (O2), Argon (AR), Helium (HE), Hydrogen (H2), Carbon Dioxide (CO2), and Natural Gas (NG). These instruments are intended for applications requiring digital flow monitoring with configurable engineering units. The product overview explicitly states that the FMA 4000 Mass Flow Meter will not operate with liquids; only clean gases are allowed to be introduced into the instrument.

Operating Conditions & Performance

The series operates within a gas and ambient temperature range of 5 to 50°C (41 to 122°F). Flow accuracy is specified as ±1% of full scale at calibration temperature and pressure, with repeatability of ±0.15% of full scale. The flow response time features a 600 ms time constant, reaching approximately 2 seconds to within ±2% of the set flow rate for flows between 25 to 100% of full scale.

Maximum gas pressure is rated at 3447 kPa gauge (500 psi). Maximum allowable pressure drop varies by range: for maximum flow ≤10 SLM, the limit is 1.28 kPa (0.18 psi); for maximum flow >10 SLM, the limit is 27.58 kPa (4 psi). The instruments are rated for relative gas humidity up to 70% and maintain leak integrity of 1 x 10⁻⁸ SCCS He max to the outside environment.

Measurement Ranges

The series covers a broad envelope from low flow rates to high volume, with specific ranges including:

• Low Flow: 0 to 5 SCCM through 0 to 1 SLM (Standard Liters per Minute)
• Mid Range: 0 to 2 SLM through 0 to 60 SLM
• High Volume: 0 to 80 SLM and 0 to 100 SLM

A turndown ratio of 50:1 is supported across the series.

Configuration Options

The FMA4000 Series offers extensive configuration options for output signals, communication protocols, and physical construction to meet specific integration needs.

Outputs and Communication

• Analog Outputs: Linear 0 to 5 Vdc (minimum load impedance 3000 Ω) or linear 4 to 20 mA (maximum loop resistance 500 Ω). Max noise is specified as 20 mV peak to peak for the 0 to 5 Vdc output.
• Relay Outputs: Two sets of programmable SPDT relays with latching, rated at 30 Vdc and 1A. These support high and low gas flow alarms.
• Digital Interface: Standard RS232 digital interface is available; units can be configured for RS485 by adding the "-RS485" suffix to the model number at no additional cost.

Housing and Wetted Materials

• Standard Body: Anodized aluminum with brass, 316 stainless steel components, and FKM O-rings. Optional stainless steel bodies are available by adding the "-ST" suffix.
• O-ring Options: Standard FKM; optional Buna, EPR (Ethylene Propylene), or perfluoroelastomer materials.

Process Connections and Dimensions

Inlet and outlet connections utilize compression fittings. The standard configuration for most models is 6.35 mm (¼"). For units with ranges of 60 SLM and larger, the connection size increases to 9.53 mm (⅜"). Optional configurations include 3.18 mm (⅛") or 9.53 mm (⅜") compression fittings.

Physical dimensions vary by flow range:

• 5 mL-10 LPM Range: Overall length A: 3.09 in (78.6 mm); Width B: 5.11 in (129.7 mm).
• 20-50 LPM Range: Overall length A: 4.13 in (104.8 mm); Width B: 6.14 in (156.0 mm).
• 60-100 LPM Range: Overall length A: 4.13 in (104.8 mm); Width B: 6.25 in (158.8 mm).

Key Product Differences

The series is divided into two primary model families distinguished by the presence of a local display:

• FMA-4100 Series: Models without an integral display (e.g., FMA-4102 through FMA-4119). These units provide analog and digital outputs but rely on external monitoring or the RS232 interface for data readout.
• FMA-4300 Series: Models with an integral display (e.g., FMA-4302 through FMA-4319). These feature a local 2-line x 16-character LCD with adjustable backlighting, allowing for direct viewing of flow readings and totalizer values.

All models support automatic sensor zero offset adjustment, which can be activated locally via the maintenance push button (on display models) or remotely via the digital interface. Calibration is performed at standard conditions [101.4 kPa (14.7 psia) and 21.1°C (70°F)] unless otherwise requested.