Pepperl+Fuchs KCD2-STC-1 SMART Transmitter Power Supply 12.5 mm

KCD2-STC-1 slim SMART transmitter power supply

The KCD2-STC-1 is the narrow member of the K-System transmitter-supply group. In a 12.5 mm housing it powers a 2-wire SMART transmitter, isolates the loop and delivers a 4-20 mA or 1-5 V signal to the controller. Output mode is selected with DIP switches rather than by rewiring, and HART communication remains available.

Seven Star LLC supplies the KCD2-STC-1 in Oman and the GCC as an independent supplier in Muscat. The module suits cabinets where the number of analog inputs is high and rail length is limited.

KCD2-STC-1 designation

The KCD2-STC-1 belongs to the narrow 12.5 mm K-System housing family and the datasheet names it a SMART transmitter power supply, a 1-channel signal conditioner with 24 V DC supply through the Power Rail. The datasheet lists the input as 2-wire SMART transmitters and current sources, and states that the unit gives isolation for non-intrinsically safe applications.

This narrow design comes with a wider ambient temperature range than the 20 mm KFD2 modules: the datasheet quotes -40 to 70 °C, with extra temperature drift figures for the range -40 to -20 °C.

Technical specifications of the KCD2-STC-1

How the KCD2-STC-1 gives a choice of output modes

Four small DIP switches (S1 to S4) at the front select the output behaviour. In source mode the module itself drives either a 4-20 mA current into a load up to 525 Ω or, using its internal 250 Ω precision resistor, a 1-5 V voltage. In sink mode it regulates the current in a loop that is powered externally with 5 to 30 V.

The transmitter is powered through terminals 1+ and 2-. A second input pair, 3+ and 4-, accepts a current source such as another instrument with its own supply and drops about 5 V. HART signals pass both ways, and the 250 Ω resistor between terminals 6 and 8 supplies the required impedance in loops with low control-side resistance.

The specified bandwidth of 3 kHz and the 50 ms settling time are adequate for HART and for ordinary process signals.

Comparison with the 20 mm STC5 modules

The KCD2-STC-1 trades a few features for width. It lists HART and BRAIN, while the KFD2-STC5-1 also lists Foxboro, and its load range of 525 Ω is lower than the 800 Ω of the KFD2-STC5-1. In return it is about 37 % narrower per channel and has a wider temperature range.

Rail accessories are the same Power Rail and power feed modules used for the K-System.

Selection and ordering checklist for the KCD2-STC-1

• Output mode: current source, current sink or 1-5 V
• Check the controller input resistance against the 525 Ω source-mode load
• Confirm HART requirement and loop resistance
• Confirm the SIL requirement
• Check the -40 to 70 °C range against cabinet conditions
• Plan rail length for 12.5 mm modules

Installing the KCD2-STC-1

Set DIP switches S1 to S4 before commissioning according to the output mode table in the datasheet, then wire the field and control-side terminals. Check that the voltage drop of any extra load, for example 250 Ω x 20 mA = 5 V, is considered in the loop.

A loop test at 4 and 20 mA confirms the scaling. Because the module is narrow, label each module clearly on the front, since adjacent loops are close together.

Typical applications in Oman and the GCC

The slim format is useful in marshalling cabinets and compact junction boxes at wellhead sites, packaged skids and water treatment panels, where many analog inputs have to be isolated in a small space. The wide temperature range supports unheated and shaded outdoor shelters in Oman.

Narrow K-System modules

From the datasheets.

Information to send with an RFQ for the KCD2-STC-1

Please supply the following.

• Output mode required (source, sink or voltage)
• Transmitter model and HART requirement
• Quantity and delivery date
• Supply arrangement

Site conditions in Oman for the KCD2-STC-1

Control cabinets in Gulf plants often run hot, because many sit in outdoor kiosks or in rooms where air conditioning is not always reliable. Before you finalise the KCD2-STC-1, check the permitted ambient range and any derating stated by the manufacturer against the real temperature inside your panel, and leave the recommended spacing around the device so that heat can escape. Long cable runs between the field and the marshalling cabinet are common on large sites, so confirm the signal types, wiring limits and earthing arrangement early in the design.

It also helps to standardise on a small number of part numbers across a project. Keeping a few spare KCD2-STC-1 units on site in Oman shortens recovery time after a fault, and documenting configuration settings makes replacement faster for the maintenance team.

Documents and quotation

The manufacturer datasheet for the KCD2-STC-1 is attached on this page, so the electrical data, terminal assignment and ambient limits quoted above can be checked against the original document before an order is placed.

Seven Star LLC supplies Pepperl+Fuchs products in Oman and the GCC as an independent supplier in Muscat. Send the quantity, the signal types and the project delivery date, and we will confirm availability and lead time in a written quotation.