Concentration Sensors Probe type FI-C20D

FI-C20D - Concentration Sensors Probe type

*Please note that accessories depicted in the image are for illustrative purposes only and may not be included with the product.


  • CE Marking
  • CSA





Probe type


Detection principle

Refractive index (surface light source)

Rated concentration range

Brix: 0–20% (nD: 1.32500–1.37000)

Display method

Status indicator light

Display range

Brix: 0–25%

Supported fluids

Non-corrosive aqueous solutions (such as water-soluble coolants, mold release agents, etc.)*1

Supported fluid temperature

0–70°C 32–158°F (no freezing)

Connection diameter

Rated pressure range

Pressure resistance

Display resolution

Brix: 0.01/0.1% (default value: 0.1)
(nD: 0.00001)

Response time

1.0 s / 2.5 s / 5.0 s / 10.0 s / 30.0 s / 60.0 s / 120.0 s / 200.0 s

Measurement accuracy

Brix: ±0.2%*2*3 (nD: ±0.0003)

Concentration unit

Brix nD*4

Temperature measurement accuracy

±1.0°C 1.8°F*2

Power supply

Current consumption

25 mA or less

Environmental resistance

Enclosure rating

IP65/IP67 (IEC60529)

Ambient temperature

–10 to +60°C 14 to +140°F (no freezing)

Relative humidity

35–85% RH (no condensation)

Vibration resistance

10–500 Hz; Power spectral density: 0.816 G2/Hz; X, Y and Z directions

Shock resistance

100 m/s2 (approx. 10 G), 16 ms pulses, 1000 times each for X, Y and Z directions


Liquid end materials

Sensor element: synthetic quartz
Body: aluminum die-cast (nickel chrome plating) / SUS304
Pipe: aluminum alloy (anodized); Gasket: FKM

Other materials

Indicator light: PPSU / TPU / PBT
Cable: PUR


Approx. 480 g 16.93 oz

*1 Use water as the solvent, and use materials that are soluble in water. If the particles are not water soluble, such as with slurry, the refractive index may not change.
*2 This is the guaranteed value from verification performed at KEYENCE inspection facilities. Measurement error may occur depending on the type, condition and temperature of the fluid used by the customer, as well as other factors.
*3 This is the value obtained when sucrose solution is used in a constant 20°C 68°F environment, and absolute error and repeatability is taken into account.
*4 When using solutions other than sucrose solutions, concentration can be adjusted via span adjustment.

Data Sheet (PDF) Other Models