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Brand: Pepperl+Fuchs
Pepperl+Fuchs KFD2-SOT3-Ex1.LB Switch Amplifier
Description
KFD2-SOT3-Ex1.LB single-channel switch amplifier with two outputs
The KFD2-SOT3-Ex1.LB is a one-channel K-System isolated barrier from Pepperl+Fuchs for NAMUR sensors and dry contacts in a hazardous area. Unlike a plain repeater, a single input drives two passive, non-polarized transistor outputs, and a DIP switch decides whether the second output follows the signal or reports a fault. That makes it a convenient way to bring the process signal and a line-fault alarm into the control system from one narrow module.
Decoding the part number: KFD2 is the 24 V DC isolated barrier range, SOT3 the transistor-output switch amplifier, Ex1 means one channel, and the suffix .LB marks the version with a configurable fault or second signal output. The two-channel sibling is the KFD2-SOT3-Ex2, and the active-output pair is the KFD2-ST3-Ex2.
Seven Star LLC supplies the module to projects and maintenance teams in Oman and the GCC as an independent supplier in Muscat.
Technical specifications of the KFD2-SOT3-Ex1.LB
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Pepperl+Fuchs KFD2-SOT3-Ex1.LB |
| Channels | 1 input |
| Input | Dry contact or NAMUR sensor, acc. to EN 60947-5-6; terminals 1+, 2+, 3- |
| Switching point / hysteresis | 1.2 to 2.1 mA / approx. 0.2 mA |
| Line fault detection | Breakage I ≤ 0.1 mA, short-circuit I ≥ 6.5 mA |
| Outputs | Output I and output II, passive transistor, non-polarized, 30 V DC, 100 mA, short-circuit protected; terminals 7, 8 and 8, 9 |
| Output II function | Signal output or fault indication, selected by switch |
| Response time / switching frequency | ≤ 200 µs / ≤ 5 kHz |
| Supply | 19 to 30 V DC via Power Rail or terminals 14+/15-; ≤ 1 W including output dissipation |
| Functional safety | SIL 2, SC 3 acc. to IEC/EN 61508 |
| Hazardous area data | Input Ex ia, Uo 10.5 V, Io 17.1 mA, Po 45 mW; II 3(1)G Ex nA [ia Ga] IIC T4 Gc; EXA 16 ATEX 0016 X |
| Isolation | Reinforced insulation input/output and input/supply, 300 Veff |
| Ambient temperature | -20 to 60 °C |
| Housing | Type B2, 20 x 119 x 115 mm, IP20, approx. 150 g |
How the KFD2-SOT3-Ex1.LB processes the signal
The input circuit of the KFD2-SOT3-Ex1.LB feeds the NAMUR loop and measures its current against the 1.2 to 2.1 mA switching window. Because the transistor outputs are non-polarized, the load can be wired with either polarity, and both outputs share terminal 8 as a common point. The collective error message also goes to the Power Rail, so a rack of modules can raise a single alarm.
The mode switches reverse the action (output conducting or blocking at the active sensor state), switch line fault detection on or off, and select what output II does. In signal mode both outputs mirror the input, useful when two separate PLC cards or a PLC and a hard-wired annunciator need the same contact. In fault mode output II becomes a dedicated alarm channel for cable breakage or short-circuit, so the control system can tell a real open contact from a broken wire.
System fit and related parts
Choose the KFD2-SOT3-Ex1.LB when one valve limit switch or proximity sensor must be monitored with a separate diagnostic channel, as in valve position monitoring where the safety logic needs a healthy-loop signal. When more points are needed per rack slot, the two-channel KFD2-SOT3-Ex2 saves panel space, and the KFD2-ST3-Ex2 is the choice if the PLC card wants an active supply-fed output. Relay-output models such as KFD2-SR2-Ex1.W suit loads above transistor current.
Selection and ordering checklist
- Confirm NAMUR or contact input and note the sensor Ex ia entity data.
- Decide the use of output II: duplicate signal or fault output.
- Verify the PLC input is compatible with a passive transistor (up to 30 V DC, 100 mA).
- Check supply: Power Rail or discrete 19 to 30 V DC.
- Confirm Zone and gas group for the field device and the module location.
- Check ambient conditions inside the panel against -20 to 60 °C.
Installation, commissioning and maintenance of the KFD2-SOT3-Ex1.LB
Mount the module on a 35 mm DIN rail with the field-side terminals (blue) on the hazardous-area side and respect the separation distances stated in the datasheet. Set the DIP switches before energising, then test each state: cover and uncover the sensor, open the loop, and bridge the loop, and compare LED state and PLC input in each case.
If the fault output is used, document the polarity and mode in the loop sheet so that a future technician does not reverse it. Keep a spare module in stock for critical valve monitoring points, and replace by like-for-like with the same switch settings.
Typical applications in Oman and the GCC
Single-channel NAMUR barriers with a fault output such as the KFD2-SOT3-Ex1.LB are typical for emergency shutdown valve position feedback at oil and gas facilities in Oman, for power station fuel gas skids, and for water treatment chemical stores where loop integrity must be visible in the control room. In coastal desalination plants, humid air and salt call for sealed cabinets even though the barrier itself sits in the safe area.
Family comparison
| Part | Key difference |
|---|---|
| KFD2-SOT3-Ex1.LB (this part) | 1 channel, two passive outputs, selectable fault output |
| KFD2-SOT3-Ex2 | 2 channels, one passive output each |
| KFD2-ST3-Ex2 | 2 channels, active outputs from supply |
| KFD2-SR2-Ex1.W | 1 channel, relay output |
Information to send with an RFQ
- Part number KFD2-SOT3-Ex1.LB and quantity
- Field device type and entity parameters
- PLC input voltage and polarity
- Need for fault output
- Power Rail or discrete supply
- Delivery location
Documents and quotation
The manufacturer datasheet for KFD2-SOT3-Ex1.LB 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.
Other Models in the Pf Kfd2 Sot3 Range
Seven Star LLC supplies models from the Pf Kfd2 Sot3 range in Oman and the GCC. Compare the related models below and request a quote for the one that matches your application.
| Model | Category | |
|---|---|---|
| Pepperl+Fuchs KFD2-SOT3-Ex2 2-Channel Switch Amplifier | Isolator & Barrier | View details |
| Pepperl+Fuchs KFD2-SOT3-Ex1.LB Switch Amplifier | Isolator & Barrier | You are viewing this model |
| Pepperl+Fuchs KFD2-ST3-Ex2 2-Channel Switch Amplifier | Isolator & Barrier | View details |
Datasheets & Documents
- Datasheet Pepperl+Fuchs KFD2-SOT3-Ex1.LB 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-SOT3-Ex1.LB Switch Amplifier
Answers from our engineering team on installation, compatibility and integration.
01What does the .LB version add?
It gives two non-polarized transistor outputs from one input, where output II can be set by a switch as a second signal or as a fault indication for line breakage and short-circuit.
02Which inputs are supported?
NAMUR sensors per EN 60947-5-6 and dry contacts fitted with the standard resistor network. Switching point is 1.2 to 2.1 mA with 0.2 mA hysteresis.
03What load can the transistor outputs carry?
Each output is rated 30 V DC and 100 mA with short-circuit protection. The 1-signal is the external voltage minus about 3 V at 100 mA, and off-state leakage is up to 10 µA.
04What is the supply requirement?
19 to 30 V DC from a Power Rail or terminals 14+ and 15-, with power dissipation up to 1 W including the outputs.
05What is the ambient temperature range?
The datasheet gives -20 to 60 °C. The housing is a 20 mm wide type B2 module with IP20 protection.
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