Pepperl+Fuchs KCD2-SOT-2 2-Channel Transistor Switch Amplifier

KCD2-SOT-2 two-channel transistor output switch amplifier

The KCD2-SOT-2 is a two-channel switch amplifier with passive transistor outputs. It takes NAMUR sensor or dry contact signals, isolates them and passes them to a control system input as fast electronic switching signals of up to 5 kHz. Compared with the relay version KCD2-SR-2, it has no moving parts and switches faster, which suits pulse and counting duty and PLC digital inputs that are sensitive to contact bounce.

Seven Star LLC supplies the KCD2-SOT-2 in Oman and the GCC as an independent supplier in Muscat.

KCD2-SOT-2 designation

The KCD2-SOT-2 belongs to the narrow 12.5 mm K-System housing family, and the datasheet names it a switch amplifier, a 2-channel signal conditioner with 24 V DC supply through the Power Rail and two passive transistor outputs. Its sibling KCD2-SR-2 has relay outputs. The datasheet gives SIL 2 with systematic capability SC 3 under IEC/EN 61508.

The transistor outputs are passive: they need an external supply from the control side. Rated voltage is 30 V DC and rated current 50 mA, and the 1-signal is the external voltage minus a maximum of 3 V.

Technical specifications of the KCD2-SOT-2

How the KCD2-SOT-2 differs from a relay amplifier

The input stage and the line fault monitoring are the same as in the relay version: NAMUR current thresholds around 1.2 to 2.1 mA, cable break detection at 0.1 mA or below and short-circuit detection at 6.5 mA or more. What changes is the output stage. A solid-state transistor follows the input within 200 µs and can pulse up to 5 kHz, so rapidly changing signals from, for instance, a rotating toothed wheel are reproduced faithfully.

DIP switches reverse the operating mode and switch the fault detection off. A fault is shown by LEDs per NAMUR NE 44 and signalled on the collective error line of the Power Rail.

Because the output is a passive transistor, the load circuit must be powered by an external source of up to 30 V DC, which is normally the digital input module of the PLC.

The off-state leakage current of 10 µA or less is low enough not to hold a typical 24 V digital input in the on state, while the saturation drop of up to 3 V at 50 mA should be subtracted from the input threshold calculation. A PLC input that needs more than 50 mA, or inputs that sink large inrush currents, should be driven through the relay version or an interposing element instead.

Where to use the KCD2-SOT-2

Use it for PLC inputs that count pulses or that must avoid contact wear. For mains-voltage loads or inputs that need potential-free relay contacts, select the KCD2-SR-2 or, for load switching, the KFD2-RSH-1.2E.L3.

The module sits on the same Power Rail as the other KCD2 modules and can be powered through the KFD2-EB2 power feed.

Selection and ordering checklist for the KCD2-SOT-2

• Output type: transistor for high speed or relay for contacts
• PLC input compatibility, including external supply voltage and 50 mA limit
• Maximum pulse rate
• Fault detection settings
• Ambient temperature and extended-range mounting conditions
• Quantity of channels

Installation notes

Wire the NAMUR sensors to terminals 1 to 4 and the PLC inputs to terminals 5 to 8, observing polarity of the passive transistor outputs. Set DIP switches before power up.

To commission, check each channel with the sensor in the active and inactive state and test the cable fault function. Where the extended 70 °C range is needed, follow the mounting conditions in the manual.

Typical applications in Oman and the GCC

Speed and rotation pickups, limit switch signals feeding PLC inputs, and high-cycle counting in packaging, bottling and cement handling are good uses. In the Gulf, solid-state outputs also avoid contact corrosion in dusty or humid cabinets.

Power dissipation of the module is limited to 800 mW including the output stage, so full rows of these narrow modules remain a modest heat load even in cabinets with limited ventilation. Planning a spare module per major panel is advisable because the 12.5 mm family is normally replaced as a unit, without field repair.

Transistor and relay versions

Datasheet values.

Information to send with an RFQ for the KCD2-SOT-2

Please supply the following.

• PLC input type and voltage
• Pulse rate
• Number of channels
• Quantity and delivery date

Documents and quotation

The manufacturer datasheet for the KCD2-SOT-2 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.