Sensor Main Unit 100A/125A Type FD-R125

FD-R125 - Sensor Main Unit 100A/125A Type

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

Data Sheet (PDF)


CAD Data

360°view (3D PDF)


  • CE Marking
  • CSA




Supported pipe diameter

4" (100 A), ø100 to ø127 3.94" to 5.00"
5" (125 A), ø127 to ø152 5.00" to 5.98"

Supported pipe materials

Metal / resin*1

Supported fluids

Various liquids (i.e. water, oils, chemicals)*1

Supported fluid temperature

- 20 to + 120°C - 4.0 to + 248 °F (no freezing on the pipe surface)*2

Maximum rated flow

Rated flow velocity range: 5.0 m/s
Flow rate range (Typical):
4"(100 A): 2500 L/min 660 gal/min 150 m3 /h
5" (125 A): 3700 L/min 990 gal/min 220 m3/h)

Zero cut flow rate

Zero cut: 0.3 m/s (default)*3
Flow rate (Typical): 220 L / min 60 gal / min 12 m3/h

Display method

Dual row, 5-digit display with white, 14-segment LED; Large status indicator; Output indicators; Stability indicator; Unit indicator

Display update cycle

Approx. 3 Hz

Display resolution

1 (L / min)

Response time

0.5 s / 1.0 s / 2.5 s / 5.0 s / 10.0 s / 30.0 s / 60.0 s / 120.0 s / 200.0 s (variable)

Measurement accuracy

Between 20 and 100% of F.S. : ±2.0% of RD*4*5
Between 6 and 20% of F.S. : ±0.4% of F.S. *4*5

Protection circuit

Power supply reverse connection protection, Power supply surge protection, Short-circuit protection for each output, Surge protection for each output

Zero point error

±0.5% of F.S.*4*6



Flow units

L / min, m3 / h, gal / min

Integrated flow unit display

1 / 10 / 100 / 1000 / 10000 (L)

Pipe temperature measurement accuracy

±3°C ±5.4°F (liquid temperature of - 20 to + 50°C, - 4 to + 122°F)
±5°C ±9°F (liquid temperature of 50 to + 120°C, 122 to 248°F)
(ambient operating temperature of 25°C 77°F)*4

Wiring specifications

Power supply

DC power supply: M12 4-pin connector / AC power supply: M4 screw terminal block (selectable)


When using a DC power supply: M12 4-pin connector / when using an AC power supply: M3 screw terminal block

Input/Output (Selectable)

Output (ch.1/ch.2)

Control output / Integrated pulse output / Error output / Temperature alarm, NPN / PNP setting switchable,open collector output 30 VDC or less, max. 100 mA / ch., residual voltage: 2.5 V or less*7

Analog output (ch.1/ch.2)

Flow rate analog output / Temperature analog output and 4 - 20 mA / 0 - 20 mA (selectable), load resistance: 500 Ω or less*7

External input (ch.2)

Integrated flow reset input / Flow rate zero input / Origin adjustment input (selectable), short-circuit current: 1.5 mA or less, input time: 20 ms or more*7


Power voltage

20 to 30 VDC including 10% ripple (P-P), Class 2 / 100 to 240 VAC - 15% or + 10% (50 / 60 Hz)

Current consumption

When using a DC power supply: 200 mA or less (load current excluded), 400 mA or less (load current included) When using an AC power supply: 15 VA or less

Environmental resistance

Enclosure rating

IP65 / 67 (IEC60259), IP69K (ISO20653), Enclosure Type 4X (NEMA250)

Ambient temperature

- 20 to + 60°C - 4.0 to 140 °F (no freezing)*2

Relative humidity

5 to 90%RH (no condensation)

Vibration resistance

10 to 55 Hz, compound amplitude 1.5 mm 0.06", XYZ axes 2 hours for each axis

Shock resistance

100 m/s2 , 16 ms pulse, XYZ axes, 1000 times for each axis


Main unit size: 218.5 mm × 66.9 mm × 70.7 mm 8.60" × 2.63" × 2.78"


Main unit

Body: aluminum die-casting + coating / PPS, display: reinforced glass, connectors: SUS304-equivalent

Unit rear


Upper/lower bracket



Main unit: Approx. 1.0 kg
Upper/lower bracket: Approx.2.3 kg (including sub unit)

*1 Liquid must allow for the passage of an ultrasonic pulse, as well as not contain large air pockets or excessive bubbles. Detection may be unstable due to the type and status of the pipes.
*2 Perform derating depending on the ambient temperature and liquid temperature when using an AC power supply.
*3 The zero cut flow rate can be changed in the settings.
*4 This value is guaranteed by KEYENCE inspection facilities. Errors will be introduced by the type and status of the pipes, the type and temperature of the fluid, and the zero cut flow rate.
*5 This is the value when considering linearity + span error + repeatability in a stable environment of 25°C 77°F.
*6 It is possible to enhance the precision of zero point error by performing an origin adjustment.
*7 IO-Link: Compatible with Specification v1.1 / COM2 (38.4 kbps) The setting file can be downloaded from the KEYENCE website. If using the unit in an environment where downloading the file is not accessible via Internet, contact your nearest KEYENCE office. IO-Link is either registered trademarks or trademarks of PROFIBUS Nutzerorganisation e.V. (PNO)

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