Low Pressure Drop Gas Mass Flow Meters

The FMA-LP1600A Series mass and volumetric flowmeters use the principle of differential pressure within a laminar flow field to determine the mass flow rate. A laminar flow element (LFE) inside the meter forces the gas into laminar (streamlined) flow. Inside this region, the Poiseuille equation dictates that the volumetric flow rate be linearly related to the pressure drop. A differential pressure sensor is used to measure the pressure drop along a fixed distance of the LFE. This, along with the viscosity of the gas, is used to accurately determine the volumetric flow rate. Separate absolute temperature and pressure sensors are incorporated and correct the volumetric flow rate to a set of standard conditions. This standardized flow rate is commonly called the mass flow rate and is reported in units such as standard cubic feet per minute (SCFM) or standard liters per minute (SLM). Standard units include a 0 to 5 V output (4 to 20 mA optional) and RS232 communications. The gas select feature can be adjusted from the front keypad or via RS232 communications. Volumetric flow, mass flow, absolute pressure, and temperature can all be viewed or recorded through the RS232 connection. It is also possible to multi-drop up to 26 units on the same serial connection to a distance of 38 m (125′). These flowmeters can be portable with an optional battery pack (-B models).

Specifications
Mass Reference Conditions: (STP) 25ۥC, 14.7 PSIA
Accuracy: ±(0.8% of rdg ± 0.2% FS)
Repeatability: ±0.2%
Turndown Ratio: 200:1
Response Time: 10 ms typical default response time for 63.2% of a step change. A variable register allows response time to be field adjustable via RS232 communications.
Output: 0 to 5 Vdc standard
Operating Temperature: -10 to 50°C (14 to 122°F)
Zero Shift: 0.02% FS/°C/atm
Span Shift: 0.02% FS/°C/atm
Humidity Range: 0 to 100% non-condensing
Pressure (Maximum): 50 psig
Measurable Flow Rate: 125% FS
Supply Voltage: 7 to 30 Vdc (15 to 30 Vdc for 4 to 20 mA output)
Supply Current: 40 mA typical current draw; 100 mA available supply recommended
Cable Connection: 8-pin mini DIN
Wetted Parts: 302 and 303 SS, FKM, silicone RTV, nylon 616, aluminum
Ingress Protection: IP40
-LSS (Option):316LSS, 303SS, 430FRSS, Perfluoroelastomer standard, FKM, EPDM, Buna, Neoprene
Communications: RS232 standard, RS485 (optional)