Kofloc EX-250S Series Digital Mass Flow Meter


Digital mass flow device which is adopted the own developed both stable high-speed thermal sensors and small proportional solenoid valves and is realized high accuracy and quick response with RS 485 communication in spite of compact.


  • Lower cost but high accuracy measurement
  • High-speed response and zero stability
  • 0-5VDC or 4-20mA Input/output signal and +/-15VDC or 24VDC power supply
  • Mediocrity D-sub 9pin
  • Gases registered in EX-250S are usable by rotary-switch
    *Calculate the flow rate with conversion factor based onN2 gas
  • RoHS compliance, CE marked

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ModelMass Flow ControllerMass Flow Meter
Sensor typeThermal sensor
Valve typeNormally closed proportional solenoid valve-
Applicable gases(*1)N2、Air、H2、He、Ar、O2、CO2 etc.
(Gases not specifically mentioned here are subject to calibration for N2 equivalent.)
Flow range(*2)10SCCM ~ 5SLM
Control(measure)range2 ~ 100%(F.S.)
Response≤ 1sec (within ± 2%F.S.)(*8)
Accuracy(*3)± 1.0%F.S.
Repeatability± 0.2%F.S.
Operating differential pressure(*4)50 ~ 300kPa(Ar、CO2:100kPa ~ 300kPa)-
Inlet maximum pressure500kPa(G)
Proof pressure980kPa(G)
External leak rate(He)≤ 1.0 × 10-8Pa・m3/sec
TemperatureWorking temp.5 ~ 50℃
Accuracy guaranteed temp.15 ~ 35℃
Allowable storage temp.-10 ~ 60℃
Allowable operating humidity10 ~ 90%RH (without dew condensation)
Materials of a gas contact partSUS316, SUS316L, magnetic stainless steel(*5), PTFE, FKM
Electrical connectionDsub 9pin KFC Standard(SEMI standard is compliant)
Flow rate setting signal0~5VDC(input impedance: approx. 1M Ω)-
or 4~20mA(input impedance: approx. 250 Ω)
Flow rate output signal0 ~ 5VDC( load resistance ≧10k Ω)
or 4 ~ 20mA( load resistance ≧500 Ω)
Digital communicationRS485 rotary-switch address setting
Required power supply (DC)+15VDC( ± 5%)100mA , -15VDC(± 5%)150mA
or +24VDC(± 10%) ≤180mA  (MFM would be ≤100mA)
Mounting postureHorizontal installation recommended.