Configured for isolated 4-20 mA signal conditioning in hazardous-area instrumentation, the Pepperl+Fuchs KFD2-STC5-Ex1.20 (KFD2-STC5-Ex1.20 SMART Transmitter Power Supply) supplies 2-wire and 3-wire SMART transmitters and transfers one field input to two galvanically isolated control-side outputs. The device supports HART, BRAIN, and Foxboro protocols.

Hardware Specifications

The manufacturer specifies a 20 x 124 x 115 mm housing and approximately 200 g mass. The dimensions correspond to the installed housing rather than an external shipping carton.

Intrinsic Safety and Signal Isolation

The KFD2-STC5-Ex1.20 is a 1-channel isolated barrier with a signal-splitter function. The field-side 4-20 mA input can supply 2-wire or 3-wire SMART transmitters and 2-wire SMART current sources. The control side provides two isolated 4-20 mA outputs.

Both control-side outputs can be configured independently as current sink or current source outputs. The internal 250 ohm resistors at terminals 9 and 12 can provide the HART communication resistance where required by the control circuit. HART digital communication superimposed on the analog signal is transferred bidirectionally.

The device supports HART, BRAIN, and Foxboro SMART protocols. The specified intrinsic-safety parameters include a maximum safe voltage of 250 V and input-side entity parameters including Uo of 26.2 V, Io of 93 mA, and Po of 634 mW for the applicable terminal arrangement.

Ordering Information

• Model: KFD2-STC5-Ex1.20
• Product family: K-System isolated barriers
• Device type: SMART Transmitter Power Supply
• Standard device configuration: 1 field-side input and 2 isolated control-side outputs
• Mounting: 35 mm DIN mounting rail
• Connection: Removable screw terminals
• Power supply: 18 to 30 V DC through Power Rail or terminals 14+, 15-
• Supplied configuration should be checked against the applicable Pepperl+Fuchs ordering documentation and hazardous-area certificates.

Field Installation Guidelines

DIN-rail mounting

• Install the module on a 35 mm DIN mounting rail according to EN 60715.
• Maintain the manufacturer-specified mounting conditions when operating at the extended temperature range up to 70 deg C.
• Provide sufficient access to the removable terminals for wiring and service.

Signal wiring

• Connect the field-side 4-20 mA circuit to terminals 1+, 2-, and 3 according to the applicable wiring diagram.
• Route hazardous-area signal wiring separately from non-intrinsically-safe circuits where required by the installation design.
• Use the appropriate shield termination method defined by the plant grounding and intrinsic-safety installation standard.
• Verify transmitter loop polarity and available voltage before commissioning.

Control-side wiring

• Select sink or source operation according to the receiving input circuit.
• Observe the specified 0 to 600 ohm output load range.
• Use the internal 250 ohm resistor when required for HART communication resistance.
• Unused outputs may be short-circuited to reduce internal power dissipation by up to 100 mW per channel, according to the manufacturer documentation.

Delivery Information

• Delivery time: 3-5 days when payment is finished.
• Shipping: DHL, FedEx, or UPS.
• Packaging: anti-static industrial packaging with impact protection for industrial electronic equipment.

Frequently Asked Questions

Q: What type of input signal does the KFD2-STC5-Ex1.20 accept?
A: The field-side input is a 4-20 mA analog signal and supports 2-wire and 3-wire SMART transmitters as well as 2-wire SMART current sources.

Q: How many control-side outputs are provided?
A: Two isolated 4-20 mA outputs are provided. Each output can operate in current sink or current source mode.

Q: Does the module support HART communication?
A: Yes. HART signals superimposed on the analog signal can be transferred bidirectionally. Test sockets for HART communicators are integrated into the terminals.

Q: What is the specified output load range?
A: The control-side output load range is 0 to 600 ohm. The internal 250 ohm resistor can be used as a load for HART communication.

Q: What are the operating temperature limits?
A: The specified ambient operating temperature is -20 to 60 deg C. An extended range up to 70 deg C is permitted when the mounting conditions specified in the manual are followed.