FS10A Analyzer Flow Switch/Monitor

Flow Switch Summary

The FS10A is a universal flow switch and monitor specifically designed for gas and liquid process analyzer sampling systems. The FS10A is a fast responding, highly repeatable sensor which installs easily into a standard tube tee fitting or new SP76 (NeSSI) modular manifold. 

The FS10A utilizes proven thermal dispersion flow measurement technology with FCI proprietary equal mass sensing to achieve outstanding sensitivity and repeatability. The instrument’s wetted parts are superior corrosion-resistant 316L stainless steel with Hastelloy-C sensor tips. The sensor element has no moving parts to foul, clog or maintain which ensures continuous reliability and no maintenance costs. There are no cavities, orifices or dead-legs to trap or contaminate samples which preserves sample integrity and faster system sampling times. 

FS10A electronics are packaged in a rugged, fully-sealed, aluminum housing which provides exceptional protection and long-life under all process conditions. The electronics can be integral mounted with the sensor element resulting in unibody, self-contained unit or the electronics can be separated from the sensor for remote mounting. The remote configuration is useful when sensor installation area is subjected to high temperatures or to mount the front panel and display in a more convenient location. 

The instrument provides a top-mounted, flow rate monitoring LED array for at-a-glance visual indication of proper flow rate to the analyzer or sampling system, that an alarm/trip has been reached, and as indication the unit is powered and operating. The flow switch's setpoint is conveniently user settable via two push-buttons accessible at the top of the unit or via the RS232C I/O port.


  • For gases and liquids
  • Superior low flow sensing
  • SP76 Mounting (NeSSI) systems or tube tee
  • Requires only one SP76 block
  • Push button or RS232 set-up
  • Single configuration meets all flow ranges, 100:1 turndown
  • Choice of outputs: Open collector (N-Channel) or relay, and 4-20 mA
  • LED array shows flow rate and switch trip
  • Integral or remote
  • Simple, screw-in installation
  • No moving parts
  • No cavities or dead-legs


  • Media Compatibility: All gases and liquids compatible with 316L stainless steel or Hastelloy-C
  • Process Connection: 1/4″ NPT; compatible with 3/8″, 1/2″ tube tee, 1/4" with 1/8" injection tube adapters and SP76 adapter (FCI part number 019897-01)
  • Flow Sensitivity/Range:
  Air / Gas Liquids
  Min Max Min Max Min Max Min Max
1/8" tube adapter with 0.0625" ID injection tube 10 2,000 0.02 5 0.70 18.00 0.01 0.30
1/8" tube adapter with 0.0940" ID injection tube 25 5,000 0.05 10 1.50 40.00 0.03 0.60
1/4" tube tee 50 20,000 0.10 40 4.00 100.00 0.07 1.70
SP76 adapter 50 20,000 0.10 40 4.00 100.00 0.07 1.70
3/8" tube tee 180 50,000 0.40 100 14.00 350.00 0.20 5.50
1/2" tube tee 375 100,000 0.80 200 30.00 750.00 0.50 12.00
  • Repeatability: ± 0.5% of reading
  • Tempature Compensation:
  • ​Standard: ± 30 ºF [± 16 ºC]
Optional Extended: ± 100 ºF [± 55 ºC]

Temperature Coefficient: For temperatures > ± 30 ºF [± 16 ºC] and with optional extended temperature compensation
Gas: Maximum ±0.025% of reading/ºF up to 500 ºF [± 0.05% of reading/ºC up to 260 ºC]
Liquid: Maximum ± 0.2% of reading/ºF up to 250 ºF [± 0.367% of reading/ºC up to 121 ºC]
  • Turndown Ratio: 5:1 to 100:1

Flow Element

  • Materials of Construction:
    (Wetted parts) 316L stainless steel with Hastelloy C-22 thermowells; Optional, all Hastelloy-C
  • Operating Temperature:
    Standard: -40 °F to 250 °F [-40 °C to 121 °C]
    Optional: -40 °F to 500 °F [-40 °C to 260 °C]; remote configuration only
  • Operating Pressure:
    Tube tee fitting: 500 psi [34 bar(g)]
    SP76 adapter: Per SP76 manifold specifications up to 500 psi [34 bar(g)] maximum

  • Enclosure: NEMA 4X [IP66], anodized aluminum
  • Operating Temperature: -40 °F to 160 °F [-40 °C to 71 °C]
  • Output Signals: 
  Block 6, Order Code D Block 6, Order Code E
Open Collector N-Channel (100mA)  
Relay, SPDT; 1A @ 24 Vdc; 120 Vac (ATEX DC only)  
4-20mA Trending Output *
RS232C Serial I/O
  • Display: 10 LED array, red; sequential lighting proportional to flow trend and flashes at setpoint
  • User Interface: Two top-mounted push buttons to program switch/trip point, zero and span setting, relay hysteresis and time delay; button operation may be user disabled to prevent unwanted changes; all set-up functions also programmable via RS232C port
  • Input Power: 24 Vdc (21.5 to 32 Vdc); maximum 2.5 Watts
  • Remote Configuration: Transmitter/electronics are separated from flow element and interconnected with a cable; flow element has potted cable terminating in an M12 for direct plug-in connection with the electronics; cable lengths available in 6′, 15′ or 30′ [2 m, 5 m or 10 m]; optional extended temperature service to 500 °F [260 °C] requires selection of the interconnecting cable with PTFE jacketing

Certifications and Ratings

  • FM, FMc:
Nonincendive, Class I Division 2 Groups A, B, C, D;
Class II, Division 2 Groups E, F, G; Class III, T4@Ta=71°C Type 4X
  • ATEX:
II 3 G Ex nA IIC T4 Gc
II 3 D Ex tc IIIC T 81ºC Dc
  • IECEx:
Ex nA and Ex t
Ex nA IIC T4 Gc
II 3 D Ex tc IIIC T 81ºC Dc
  • Other:
CE Mark, CRN, Complies with Canadian Electrical code requirements of ANSI / ISA 12.27.01-2011 as a single seal device.
  • SIL:
SIL 2 compliant, safe failure fraction (SFF) 90%


  • ATEX (Remote)
  • ATEX (Standard)
  • CE
  • CRN
  • FMc (Remote)
  • FMc (Standard)
  • FM (Remote)
  • FM (Standard)
  • EAC/TR CU (Russia)
  • IECEx (Remote)
  • IECEx (Standard)
  • SIL