Kofloc DF-350C Digital Mass Flow Meter

 The Model DF-350 Series is a digital mass flow controller with an integral indicator that operates on a 24-V power supply. It offers features equivalent to the DF-250 Series designed for up to 50 SLM.


  • High accuracy (±1% S.P.), fast response (≤ 1 sec in all ranges)
  • Support of multiple ranges and multiple gases
  • Communication functions installed as a standard feature (RS485)
  • RoHS CE standard compliant
  • Driven by a single 24 V DC supply voltage
  • With or without indicator (selectable)
  • Selectable Input/output signal

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Sensor typeThermal sensor
Valve typeNormally closed proportional solenoid valve
Applicable gases*1N2, Air, H2, He, Ar, O2, CO2, etc.
(Gases not specifically mentioned here are subject to calibration for N2 equivalent.)
Flow range*210 SCCM to 10 SLM20 to 50 SLM
(20 to 30 SLM for CO2)
Control range2 to 100% (F.S.)
Response*3Total flow rate control range ≤ 1 sec (within ±2% F.S.)
Accuracy*4±1.0% F.S.
Operating differential pressure*550 to 300 kPa (100 to 300 kPa for Ar and CO2)100 to 300 kPa (150 to 300 kPa for Ar and CO2)
Inlet maximum pressure500kPa(G)
Proof pressure980kPa(G)
External leak rate≤1.0 x 10-8 Pa·m3/sec (He)
TemperatureWorking temp.5 to 50℃
Accuracy guaranteed temp.15 to 35℃
Allowable storage temp.-10 to 60℃
Allowable operating humidity10 to 90% RH (without dew condensation)
Materials of the gas contact partSUS316, SUS316L, magnetic stainless steel, Ni, PTFE, PCTFE, and FKM
Electrical connectionD-sub 15-pin male, high density, HR-10A (two)
Flow rate setting signal0 to 5 V DC (input impedance: approx. 1 MΩ), or 4 to 20 mA (input impedance: approx. 250 Ω)
Flow rate output signal0 to 5 V DC (load resistance 10 kΩ), or 4 to 20 mA (load resistance ≤ 500 Ω)
Digital communicationAddress setting with RS485 rotary switch or indicator: up to 99 devices (9600 bps)
Event inputThree contact inputs (non-insulated)
Event outputThree NPN open collectors (non-insulated, max. rating 35 V, 50 mA)
Required power supply (DC)+24 V DC (±10%), 300 mA max. (DC jack, D-sub)
Joint*61/4 F900 (standard), 1/4 UJR, Rc 1/4
Mounting postureHorizontal installation recommended.
Weight*7Approx. 950 gApprox. 1100 g