Pepperl+Fuchs / Current Sink Source Selection
KFD2-STC5-1 is a Pepperl+Fuchs single-channel SMART transmitter power supply classified as a signal conditioner. Its output can operate as a current sink or current source. This guide centers on that interface choice, helping engineers compare the control input and field device before writing a clear specification for a safe-area measurement loop.
Choose the current-loop operating mode
First, identify which part of the control-side circuit supplies loop power. Then compare the receiving analog input with the manufacturer sink and source connection diagrams. The required wiring depends on this choice. Consequently, a purchase description should include the receiving card reference rather than assuming that all 4 to 20 mA inputs connect alike.
KFD2-STC5-1 field device support
Official features include two-wire and three-wire SMART transmitters and two-wire SMART current sources. The product provides one measurement channel and a 4 to 20 mA output. Therefore, identify the actual field device wiring type before completing the selection. Also, retain the distinction between a transmitter supply connection and a separately powered current source.
Keep the non-Ex designation visible
The manufacturer classifies this version as a signal conditioner. Its model does not include an Ex input designation. Do not transfer an intrinsically safe application assessment from a similarly named Ex product. Instead, have engineering match the exact model to the intended circuit and location. This keeps the procurement record aligned with the approved use.
Plan measurement and communication access
The terminal blocks include test points, and the official documentation describes the current-loop connections. First, check the expected analog signal at the receiving input. Then verify the required SMART communication path and loop resistance. In addition, include test access in the panel handover so later diagnostics can follow a documented connection arrangement.
A complete inquiry for an analog interface
- Full model and existing article number, where available.
- Field transmitter type and receiving analog card reference.
- Intended sink or source mode, quantity, and required delivery date.
The product lists safety capability up to SIL 2 with manufacturer conditions. Any safety-related use still requires assessment of the complete function. Ask for the documentation needed to maintain that record alongside the commercial offer.
