Pepperl+Fuchs1163081-Channel Intrinsic-Safety Isolated Barrier / SMART Transmitter Power Supply, 4-20 mA, HART, Ex ia IIC, DIN Rail

Product Description

What this part is:
A Pepperl+Fuchs KFD2-STC3-Ex1 SMART transmitter power supply from the K-System — a single-channel intrinsically safe isolated barrier. It supplies a 2-wire transmitter sitting in a hazardous area and passes the resulting 4 to 20 mA measurement to safe-area output terminals, with galvanic isolation between the two. Digital protocol signals ride on top of the analog value and are transferred in both directions, so a handheld communicator works through the barrier.

Decoding the designation:
KFD2 – K-System isolated barrier, 24 V DC powered, 20 mm DIN-rail housingSTC – SMART transmitter power supply, current output3 – generation within the STC lineEx1 – one intrinsically safe channel116308 – Pepperl+Fuchs order number for this device

What these specs mean in practice:
Two numbers decide the loop design. The barrier makes roughly 16.5 V available to the field transmitter at 20 mA, so check that against your transmitter’s minimum operating voltage before committing. On the output side the maximum load is 1000 Ω, but HART needs at least 230 Ω in the loop — put a low-impedance input on it with no series resistor and digital communication stops working even though the analog reading looks fine. The unit ships with KF-STP-BU and KF-STP-GN terminals that have communicator jacks built in, which is how a handheld gets onto the loop without breaking wiring. Power comes either from terminals 7+/8− or by engaging the module onto a PR-03 or UPR-03 Power Rail fed by a KFD2-EB2 power feed module — and the Power Rail must never be back-fed through an individual device’s terminals.

Published specifications:
Channels: 1, intrinsically safe inputSupply: 20 to 35 V DC via Power Rail or terminals 7+, 8−; power loss 1.3 W; consumption ≤1.7 WInput: 4 to 20 mA on terminals 1+, 3−; approx. 16.5 V available at 20 mAOutput: 4 to 20 mA on terminals 9+, 10−, 11+; max. load 1000 Ω, minimum 230 Ω for HART; ripple ≤0.05% of rangeAccuracy: ≤0.03% of range (voltage output), ≤0.05% of range (current output); temperature influence ≤20 ppm/KBandwidth: 0 to 40 kHz at −1 dB, 0 to 100 kHz at −6 dB, both directionsRise time and de-energised delay: 10 µsSMART systems supported: ABB, Bailey, Chessel, Eckhardt-Foxboro, Endress+Hauser, Fuji, Emerson, Smar, Siemens, VEGA, YokogawaHazardous area marking: II (1) G D [EEx ia] IIC, Tamb −20 to +60 °C, circuits in zone 0/1/2Intrinsic safety parameters: Uo 25.2 V DC, Io 93 mA, Po 587 mW; Um 250 VPermitted external reactances: 2.9 µF / 35.2 mH (IIA), 0.82 µF / 17.3 mH (IIB), 0.107 µF / 4.2 mH (IIC)North American entity parameters: Voc 28 V, Isc/It 93 mA, 28 V / 300 Ω; Ca/La 0.14 µF / 3.1 to 4.18 mH (groups A&B), 0.42 to 0.43 µF / 16.7 to 16.83 mH (C&E), 1.14 µF / 34 to 34.21 mH (D, F&G)Certificates and drawings: EC-type examination BAS 01 ATEX 7369; FM certification 4Z6A5.AX, control drawing 116-0129; UL control drawing E 106378; CSA control drawing LR 65756-13; drawing 116-0132Suitable for installation in Division 2Isolation: input/output and input/supply safe electrical isolation per EN 50020, 375 V peak; output/supply basic insulation per EN 50178, 50 V AC rated insulationEMC: EN 61326, EN 50081-2, NAMUR NE 21Ambient temperature: −20 to +60 °CDegree of protection: IP20Dimensions: 20 x 107 x 115 mm; mass approx. 150 g

Quantity and configuration:
Sold as 1 piece. Power Rail PR-03 or UPR-03, the KFD2-EB2 power feed module and any additional terminal blocks are separate accessories and are not included. Confirm whether the removable KF-STP-BU and KF-STP-GN communicator-jack terminals are present before relying on handheld access without rewiring.

Installation and setup notes:
Terminal 12 sits behind an internally applied capacitance and exists so active input cards such as the Foxboro FMB 18 can be driven. For commissioning or test the transmitter-power-supply input may be short-circuited, but Pepperl+Fuchs limits that to six hours maximum. Handheld terminals connect as shown in the device’s circuit block diagram; a series arrangement, as used for the Bailey STT01, is also supported. One power feed module fuses and monitors a group of up to 100 devices on a Power Rail.

Interchange guidance:
The successor to this device is the KFD2-STC4-Ex1 — a functional replacement in the same K-System format, not an identical part; its safety parameters and terminal functions differ, so re-check Uo, Io and the loop resistance figures rather than assuming the loop calculation carries over. KFD2-STV3-Ex1-1 is the voltage-output sibling in the same generation. KCD2-STC-Ex1 is the loop-powered K-System equivalent with no separate 24 V supply. HiD-system modules such as the HiD2030 do the same signal job but mount on a termination board instead of DIN rail and are not interchangeable with this one.