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Brand: Pepperl+Fuchs
Pepperl+Fuchs KFD2-DWB-Ex1.D Rotation Speed Monitor
Description
KFD2-DWB-Ex1.D rotation speed monitor with relay outputs
The KFD2-DWB-Ex1.D is an isolated barrier from Pepperl+Fuchs that does more than repeat a contact: it measures the pulse frequency of a NAMUR sensor or mechanical contact from a hazardous area and compares it with limits that the user programs. Overspeed and underspeed conditions switch two relays, which makes it a compact speed switch for fans, pumps and conveyors.
The name reads: KFD2 for the 24 V DC isolated barrier range, DWB for the rotation speed (Drehzahl) monitor, Ex1 for a single measuring channel, and .D for the version with a display and keypad programming.
Seven Star LLC supplies this module in Oman and the GCC as an independent supplier in Muscat.
Technical specifications of the KFD2-DWB-Ex1.D
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Pepperl+Fuchs KFD2-DWB-Ex1.D |
| Input I (intrinsically safe) | NAMUR or dry contact, terminals 1+, 3-; pulse duration > 50 µs; 0.001 to 5000 Hz |
| Line fault detection | Breakage I ≤ 0.15 mA, short-circuit I > 6.5 mA |
| Input II (non-intrinsically safe) | Start-up override, terminals 13+, 14-; active at I > 4 mA for min. 100 ms, passive at I < 1.5 mA |
| Start-up override | 1 to 1000 s, adjustable in 1 s steps |
| Measurement | Range 0.001 to 5000 Hz; resolution 0.1 % of value, ≥ 0.001 Hz; measuring time < 100 ms; accuracy 0.1 % |
| Outputs | 2 relays, 253 V AC / 2 A (cos φ ≥ 0.7), 40 V DC / 2 A; response delay ≤ 200 ms |
| Mechanical life | 5 x 107 switching cycles |
| Supply | 20 to 30 V DC, terminals 23+/24- or Power Rail; ≤ 1.8 W |
| Functional safety | SIL 2 acc. to IEC/EN 61508 / IEC/EN 61511 |
| Hazardous area data | TUV 99 ATEX 1408, [Ex ia Ga] IIC; Input I Uo 10.1 V, Io 13.5 mA, Po 34 mW |
| Ambient temperature | -20 to 60 °C |
| Housing | Type C2, 40 x 119 x 115 mm, IP20, 300 g |
How the KFD2-DWB-Ex1.D evaluates speed
The KFD2-DWB-Ex1.D counts sensor pulses within a short window (under 100 ms) and converts them to a frequency with 0.1 % accuracy. The set point you program is a reference frequency; the relay trips if the measured value rises above (overspeed) or falls below (underspeed) it, depending on configuration. For slow shafts the resolution down to 1 mHz allows measurement of very low speeds.
A start-up override stops the machine from tripping the relays during run-up: an external contact on input II holds the outputs in the programmed default state for up to 1000 seconds. Line fault detection watches the sensor cable and reports through a red LED, the relay and, on a Power Rail, the collective error message.
System fit and related parts
The KFD2-DWB-Ex1.D sits between a proximity sensor on a shaft or gear (for example a NAMUR inductive sensor) and a trip or alarm circuit. Where only a plain on/off signal is required, switch amplifiers such as KFD2-SR2-Ex1.W are simpler. If the speed must be a 4 to 20 mA analog signal, a frequency converter from the same K-System range is the right family; confirm the exact model against its datasheet.
Selection and ordering checklist
- Number of pulses per revolution of the target and the speed range to be monitored.
- Overspeed or underspeed setting and relay action.
- Whether start-up override is needed and how long.
- Relay load against 2 A ratings and voltage.
- Sensor Ex data against Uo 10.1 V, Io 13.5 mA, Po 34 mW.
- Supply 20 to 30 V DC or Power Rail.
Installation, commissioning and maintenance of the KFD2-DWB-Ex1.D
Mount the 40 mm wide module on a DIN rail and wire the sensor to terminals 1+ and 3-. Use the front keypad to enter the reference frequency, then spin the machine or simulate pulses with a frequency generator and confirm the relay thresholds. Record the settings in the loop sheet because they are held in the device only.
Test the start-up override with the machine at standstill, and check that the relay returns to the safe state when the sensor cable is disconnected.
Settings worth documenting for the KFD2-DWB-Ex1.D
Record these items for every KFD2-DWB-Ex1.D in the loop folder: reference frequency, overspeed or underspeed mode, relay energized state, start-up override time, and the number of pulses per revolution of the target. With these notes a replacement unit can be programmed in minutes, and a trip investigation can show whether the set point or the machine caused the event.
Choose relay action so that the safe state corresponds to a de-energized relay, since the relay also drops on a line fault or loss of supply. Remember that response delay of up to 200 ms plus the contact delay of about 20 ms adds to the measuring time, so very fast trips need that budget calculated.
Typical applications in Oman and the GCC
Speed monitoring with the KFD2-DWB-Ex1.D is used on cooling-tower and ventilation fans, pump sets, screw conveyors, gas compressors and turbines in Omani oil, gas, cement and power plants, wherever a NAMUR sensor must be isolated from a Zone 1 or 2 shaft area.
Family comparison
| Part | Key difference |
|---|---|
| KFD2-DWB-Ex1.D (this part) | Speed monitor, programmable limits, 2 relays, 40 mm |
| KFD2-SR2-Ex1.W | Switch amplifier, 1 relay output |
| KFD2-VR4-Ex1.26 | Vibration voltage repeater |
| KFD2-GUT-Ex1.D | Temperature converter with trip values, 40 mm |
Information to send with an RFQ
- Part number KFD2-DWB-Ex1.D and quantity
- Sensor type and pulses per revolution
- Speed range and limits
- Relay load
- Supply method
- Delivery location
Documents and quotation
The manufacturer datasheet for KFD2-DWB-Ex1.D is attached on this page, so you can check wiring, approvals and dimensions before ordering. Send the exact part number, quantity and delivery location in Oman or the GCC and Seven Star LLC will reply with a quotation.
Seven Star LLC is an independent supplier in Muscat and is not the manufacturer; confirm availability, lead time and any project approval requirements in your RFQ.
Datasheets & Documents
- Datasheet Pepperl+Fuchs KFD2-DWB-Ex1.D Datasheet Download
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About brand
Pepperl+Fuchs is a German manufacturer of industrial sensors and explosion protection equipment, founded in 1945 in Mannheim by Walter Pepperl and Ludwig Fuchs as a radio repair shop. Defective transformers led them into manufacturing, and the company developed its first proximity switch in the late 1950s. Pepperl+Fuchs is headquartered in Mannheim and is a pioneer of intrinsically safe electrical equipment for hazardous areas.
Seven Star LLC lists Pepperl+Fuchs sensors, isolated barriers, power supplies and hazardous-area mobile devices, and supplies them to instrument and automation teams in Oman by exact model designation.
Pepperl+Fuchs company profile
| Founded | 1945, Mannheim-Sandhofen, Germany, by Walter Pepperl and Ludwig Fuchs |
|---|---|
| Headquarters | Mannheim, Germany |
| Ownership | Privately owned (Pepperl+Fuchs SE) |
| Origins | Radio repair workshop that began making replacement transformers |
| Product families | Inductive, capacitive, ultrasonic and photoelectric sensors, rotary encoders, R2000 LiDAR scanners, KFD and HiC isolated barriers, Zener barriers, remote I/O, purge and pressurization systems, Ex-rated enclosures |
Milestones
- 1945: Walter Pepperl and Ludwig Fuchs open their radio repair shop in Mannheim.
- 1958: The first proximity switch is developed (some company sources say 1959).
Pepperl+Fuchs product families on this page
On the interface side there are two systems. The K-System mounts on DIN rail and is represented here by the KFD2-UT2-Ex2 universal temperature converter. The H-System plugs into termination boards and is represented by the HiD2030 SMART transmitter power supply with HART. The PS1000-A6-24.20 is a 24 VDC, 20 A power supply for cabinets. Sensors listed include the NJ2-12GK-SN NAMUR inductive sensor, the R101 retro-reflective photoelectric sensor and the R2000 2-D LiDAR scanner. For field staff there are the Tab-Ex 05 DZ1 tablet for Zone 1/21 areas and the Smart-Ex 03 DZ2 smartphone for Zone 2/22 and Division 2 areas.
Where Pepperl+Fuchs equipment is used
Isolated barriers sit between field instruments in Zone 0 or Zone 1 and the DCS or safety system in refineries, gas plants and chemical works. NAMUR sensors report valve position and machine states in classified areas. Photoelectric sensors and LiDAR scanners work in conveying, packaging, warehousing and vehicle guidance. Ex-rated tablets and phones are carried on operator rounds and maintenance jobs.
Pepperl+Fuchs products we list
Ordering Pepperl+Fuchs parts: what we need
Send the complete model designation as printed on the device, including every suffix; a single letter can change the supply voltage or the output type. Add the part number if the label shows one. For barriers, tell us the field device and signal type, the number of channels and whether the safety loop needs a SIL-assessed module. For mobile devices, state the zone or division and the regional radio version.
Facts checked against Pepperl+Fuchs's own chronicle pages, October 2026.
Browse Pepperl+Fuchs products by category: Sensors & Transmitters, Industrial Computer, Isolator & Barrier, Power Modules.
FAQ
Questions about the Pepperl+Fuchs KFD2-DWB-Ex1.D Rotation Speed Monitor
Answers from our engineering team on installation, compatibility and integration.
01What does the KFD2-DWB-Ex1.D monitor?
Pulse frequency from a NAMUR sensor or contact, between 0.001 and 5000 Hz, compared with user-programmed overspeed or underspeed limits.
02How are the limits set?
By the keypad on the front of the 40 mm wide module, with a display showing values.
03What is the start-up override?
An input that holds the relay outputs in their programmed default state for 1 to 1000 seconds while a machine runs up.
04What relay ratings apply?
253 V AC at 2 A (cos phi 0.7 or higher) and 40 V DC at 2 A, with a response delay of up to 200 ms.
05What supply is required?
20 to 30 V DC at terminals 23+ and 24- or a Power Rail, up to 1.8 W.
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