Kofloc DF-300C SERIES Digital Mass Flow Controller with Indicator

The Model DF-300C Series is a mass flow controller with an integral indicator that operates on a 24-V power supply, as developed in response to the requests from users of the DF Series.

It inherits the features of the DF-200C Series with enhanced convenience, including accuracy of ±1% S.P., response ≤1 sec (in all ranges), and the multiple-gas, multiple-range versatility, i.e.,
support of seven gases (including reference gas) and the ease of changing the flow rate range of each gas.


  • 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)*2
Flow range*310/30/50/100/300/500 SCCM, 1/3/5/10 SLM*2
Control range2 to 100% (F.S.)
Response*4Total flow rate control range ±1 sec (within ±2% F.S.)
Accuracy*5±1.0% S.P. (> 35% F.S.)
±0.35% F.S. (≤ 35% F.S.)
Repeatability±0.25% F.S.
Operating differential pressure*650 to 300 kPa (100 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℃
Permissible ambient humidity
Allowable operating humidity
10 to 90% RH (without dew condensation)
Materials of a 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*71/4 F900 (standard), 1/4 UJR, Rc 1/4
Mounting postureHorizontal installation recommended.
Weight*8Approx. 950 g