Mass Flow Controllers & Meters


PCU–Series: Gas Flow Portable Calibration Unit

When a single flow meter won’t cover all of your calibration needs, consider using an Alicat PCU-Series Gas Flow Portable Calibration Unit. Alicat’s PCU is a secondary calibration standard that combines up to 3 high-accuracy flow meters of varied ranges (max 500 slpm) with totalizers into a rugged industrial carrying case for go-anywhere portability. PCUs can be powered by 4 AA batteries or the included AC/DC power supply adaptor.

  • Versatile. Quickly calibrate multiple instruments across a combined turndown range of up to 100,000:1 (for example 5 sccm – 500 slpm) with easy push-connect fittings or optional compression fittings.
  • Accurate. Measure live flow rates and flow totals with NIST-traceable accuracy (as good as 0.5% reading) for a variety of gases down to 1/1000th of full scale, or define your own gas composition with COMPOSER™.
  • Rugged. The PCU houses the flow meters within a rugged hard case and can withstand drops if they should occur.

PCU’s are also available in our Whisper™ configuration with low pressure drop (PCUW-Series) and 316L configuration for use with corrosive gases (PCUS-Series).

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Example Application shown with 2 Alicat components sold separately.



  • Available ranges:
    • Choose any 3 flow meters with ranges up to 500 slpm (PCU and PCUS) or 250 slpm (PCUW)
    • All flow meters include a flow totalizer
  • Operation range (Turndown ratio): up to 1,000,000:1 (combined turndown from 3 instruments)
  • High-accuracy calibration, NIST-traceable (standard on PCU’s): +/- (0.6% of the reading) for mid flow
  • Repeatability: 0.2% of the full-scale range
  • Typical measurement response time constant: 5-10 ms
  • No warm-up time required

Operating conditions

  • Compatible gases: 98 (PCU and PCUW) or 130 (PCUS) pre-loaded selectable gas calibrations; additional mixtures definable with COMPOSER™
  • Operating temperature: -10°C to +60°C
  • Max internal pressure (static): 145 psig/160 psia (PCU and PCUS) or 45 psig/60 psia (PCUW)
  • Max differential pressure (inlet to outlet): 75 psid (PCU and PCUS) or 15 psid (PCUW)
  • Proof pressure: 175 psig (190 psia)
  • STP/NTP: user-selectable (defaults to 25°C & 1 atm STP/0°C & 1 atm NTP)

In the box

  • Portable calibration unit with up to 3 high-accuracy mass flow meters mounted internally
  • Push-connect fittings mounted below each flow meter’s display
  • USB A-B cable for connection to a computer
  • Double-ended 9-pin D-sub serial cable for connection to a multi-drop breakout box (sold separately)
  • Universal power supply
  • NIST-traceable calibration certificates for each flow meter

Model Variations 

  • Low pressure drop (PCUW)
  • Aggressive gases (PCUS, see below)

Corrosive Gases (PCUS-Series)

Instruments in the standard PCU are also available with an optional “S” configuration (PCUS) for use with corrosive gases. In this configuration, we upgrade the flow body and sensor to 316L stainless steel and the elastomers to FFKM.

Build Options

Part numbers below are just a few examples of PCU range combinations. Any 3 flow meters with ranges up to 500 slpm may be included in a standard PCU. Alicat’s PCU-Series is suitable for use with non-corrosive gases.







Part numbers below are just a few examples of PCU range combinations. Any 3 flow meters with ranges up to 1500 slpm may be included in a PCUS. Alicat’s PCUS series is suitable for use with corrosive gases.






Part numbers below are just a few examples of PCU range combinations. Any 3 flow meters with ranges up to 250 slpm may be included in a PCUW. Alicat’s PCUW-Series is suitable for use with non-corrosive gases.







Calibration of multiple flow instruments

Alicat’s portable calibration units (PCU) combine three battery-powered flow meters of complimentary ranges in a single case, each with totalizer and NIST-traceable high-accuracy calibration to a primary flow standard. With three overlapping measurement ranges, the PCU is capable of a total turndown of a million to one, making this an extremely versatile instrument.

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