The Pepperl+Fuchs KFD2-RR-EX1 thermometer resistance repeater transfers RTD signals from hazardous areas to a safe-area control system. This 1-channel isolated barrier accepts standard platinum resistance sensors. For instance, you can connect Pt100, Pt500, or Pt1000 in 2-wire, 3-wire, or 4-wire configurations. The device outputs a linear resistance signal that mirrors the input. Furthermore, its accuracy reaches 0.1% of full scale. The Pepperl+Fuchs KFD2-RR-EX1 draws power from the Power Rail, simplifying installation in crowded cabinets.
Rated voltage: 20 ... 35 V DC (24V DC nominal via Power Rail).
Number of channels: 1.
Input type: RTD (Pt100, Pt500, Pt1000) or variable resistor.
Output type: Resistance output (proportional to input).
Accuracy: 0.1% of span.
Line fault detection (LFD): Yes, for Pt100 inputs.
Safety rating: Up to SIL2 (SC 3) per IEC/EN 61508.
Housing width: 12.5 mm (space-saving design).
Transfer direction: From field circuit (hazardous area) to safe-area control system.
The Pepperl+Fuchs KFD2-RR-EX1 connects to resistance temperature detectors or potentiometers.
Supported RTD types: Pt100, Pt500, Pt1000 (IEC 60751).
Lead wire configurations: 2-wire, 3-wire, or 4-wire connection.
Measuring range: Configurable depending on the sensor.
Line fault detection: Monitors for sensor wire break or short circuit when using Pt100 in 3-wire or 4-wire mode.
The output is a resistance signal that directly follows the input resistance. This output connects to standard analog input cards or resistance-sensing devices.
Output range: Corresponds to the input resistance range (e.g., 0–400 Ω for Pt100).
Output load: Specified in the datasheet for linear operation.
Accuracy reaches 0.1% of the configured measurement span. This high precision makes the KFD2-RR-EX1 suitable for temperature-critical processes. For example, use it in chemical reactors, pharmaceutical dryers, or food sterilization lines. The device also maintains stability over temperature variations within its ambient range of -20°C to 60°C.
Engineers rated the Pepperl+Fuchs KFD2-RR-EX1 for functional safety up to SIL2 according to IEC/EN 61508 (SC 3 capability). You can integrate it into safety instrumented functions (SIF) that monitor temperature for emergency shutdown or interlock logic. Always verify the entire loop’s SIL rating during system design.
Ex input classification: Intrinsically safe circuit for connection to hazardous areas.
Connect the RTD located in Zone 0, Zone 1, or Zone 2 (gas) or Zone 20, Zone 21, Zone 22 (dust). The output side resides in the safe area or Zone 2.
The KFD2-RR-EX1 includes line fault detection specifically for Pt100 sensors in 3-wire or 4-wire connections. LFD identifies two fault conditions:
Sensor wire break: Current drops below a threshold.
Sensor short circuit: Current rises above a threshold.
Upon detecting a fault, the device drives its output to a predefined error level (upscale or downscale). Additionally, many systems use a separate fault relay or status indicator (check your specific configuration).
First, mount the Pepperl+Fuchs KFD2-RR-EX1 on a 35 mm DIN rail. It requires a Power Rail for 24V DC distribution. The narrow 12.5 mm housing saves valuable panel space. Then connect the RTD field wires to the Ex-side terminals. Use shielded cable for long runs to minimize electromagnetic interference.
Next, connect the output resistance signal to your analog input card. Most cards accept resistance directly or via a voltage divider. Finally, configure any DIP switches or jumpers for your specific RTD type and lead wire configuration. Refer to the device label or manual for exact settings.
1 x Pepperl+Fuchs KFD2-RR-EX1 resistance repeater
1 x Terminal label sheet
1 x Quick start guide (English/German)
Carriers: FedEx, UPS, DHL.
All shipments include tracking and insurance. Express delivery typically takes 3–5 business days.
1. Can the KFD2-RR-EX1 work with a 2-wire Pt100 sensor?
Yes. The Pepperl+Fuchs KFD2-RR-EX1 supports 2-wire, 3-wire, and 4-wire connections. However, for 2-wire connections you lose lead wire compensation. Use 3-wire or 4-wire for best accuracy.
2. What output type does this device provide?
It provides a resistance output that replicates the input resistance. This output connects to instruments that measure resistance directly. For a 4–20 mA output, choose a different model like the KFD2-UT2-EX1.
3. How does line fault detection work on the KFD2-RR-EX1?
LFD monitors the Pt100 loop current. A wire break causes current to drop near zero. A short circuit causes excessive current. The device then drives the output to a fault-indicating level (upscale or downscale as configured).
4. Is this device approved for Zone 0 applications?
Yes, the Ex input circuit is intrinsically safe for connection to Zone 0 (gas) and Zone 20 (dust) provided you follow the control drawing parameters.
5. Do I need a separate power supply for the KFD2-RR-EX1?
No. It draws its 24V DC from the Pepperl+Fuchs Power Rail. You just need one power feed module like the KFD2-EB2.R4A.B for the entire rail. This simplifies wiring in multi-channel systems.
| Brand Name | Pepperl+Fuchs |
| Model No. | KFD2-RR-EX1 |
| Product Type | Thermometer Resistance Repeater |
| hasMerchantReturnPolicy | Adjust according to reality |
| Shippingdetails | Adjust according to reality |
