Free Available Chlorine Analyzer (Non-reagent Type) FC400G

The FC400G non-reagent free available chlorine analyzer adopts the polarographic method, using a rotating electrode to continuously measure online the concentration of free available chlorine.

The FC400G is a microprocessor-based, intelligent free chlorine analyzer whose development was based on Yokogawa's long experience with residual chlorine analysis.

The FC400G is intended for measurements in the water distribution network, at pumping stations, water delivery points, schools, and public facilities.


  • One-touch simple calibration.
  • Output range can be arbitrarily set in the range of from 0-1 mg/l to 0-3 mg/l in the field.
  • Line segment output is available for output signals.
  • Easy confirmation of inter-electrode applied voltage/current characteristic (plateau characteristic). This allows understanding of the detailed sensor characteristics in the application.
  • Rotating electrode/ceramic bead cleaning has been improved to realize further effective and continuous automatic cleaning.
  • Easy-to-maintain (-clean) cell construction.


Measured Object Free chlorine in tap water
Measuring System Polarographic method using rotating electrode
Measuring Range 0 to 3 mg/l
Output Range Can switch between arbitrary ranges (each between 0 to 1 mg/l and 0 to 3 mg/l)
Output Signal 4 to 20mA DC (load resistance: 550 Ω or less) or 1 to 5V DC (output resistance : 300 Ω or less)
Sample Conditions Temperature: 0 to 50℃
pH: 6.5 to 7.5
Flow Rate: 0.1 to 2.5 l/min
Pressure: 1 to 150 kPa
          100 to 740 kPa (when a dedicated sampling unit is provided)
Conductivity: 100 to 300 μS/cm
SS (Suspended Solid): 10 mg/l or less
Electrode Indicating electrode: Rotating gold electrode
Reference electrode: Silver electrode (with Pt1000 RTD installed)
Electrode Cleaning Ceramic bead cleaning
Ambient Temperature -30 to 70℃
Installation Indoor (Outdoor use requires protection against rain.) (Direct sunlight must be avoided.)
Power Supply 100/110/200/220 V AC ±10 %, 50/60 Hz
Weight Approx. 6 kg


% display shows value relative to the upper limit of a range.

Linearity ±5 % of full scale
Repeatability 2 % of full scale
Stability Zero drift; ±1 % of full scale/month or less
Span drift; -10 % of full scale/month or less
Response time Approx. 2 min (90 % response time)

Looking for more information on our people, technology and solutions?

Contact Us