Serviceline Industrial Sensors
Serviceline Explosion Protection

SMART Transmitter Power Supply KFD2-STC4-Ex1.2O

  • 1-channel isolated barrier
  • 24 V DC supply (Power Rail)
  • Input 2-wire and 3-wire SMART transmitters and 2-wire SMART current sources
  • Signal splitter (1 input and 2 outputs)
  • Dual output 0/4 mA ... 20 mA
  • Terminal blocks with test sockets
  • Up to SIL 3 acc. to IEC/EN 61508

Please note: All product-related documents, such as certificates, declarations of conformity, etc., which were issued prior to the conversion under the name Pepperl+Fuchs GmbH or Pepperl+Fuchs AG, also apply to Pepperl+Fuchs SE.

Download the complete datasheet as a PDF:

Datasheet excerpt: Technical data of  KFD2-STC4-Ex1.2O

General specifications
Signal typeAnalog input
Functional safety related parameters
Safety Integrity Level (SIL)SIL 3
ConnectionPower Rail or terminals 14+, 15-
Rated voltage20 ... 35 V DC
Ripplewithin the supply tolerance
Power dissipation1.8 W
Power consumption2.4 W
Connection sidefield side
Connectionterminals 1+, 2-, 3 or 5-, 6+
Input signal0/4 ... 20 mA
Open circuit voltage/short-circuit currentterminals 1+, 3-: 22.7 V / 38 mA
Voltage dropterminals 5, 6 : ≤ 2.4 V at 20 mA
Input resistanceterminals 2-, 3: max. 76 Ω
terminals 1+, 3: max. 500 Ω (250 Ω load)
Available voltageterminals 1+, 3: ≥ 16 V at 20 mA
Connection sidecontrol side
Connectionterminals 7-, 8+,9; 10-, 11+,12
Load0 ... 550 Ω at 20 mA
Output signal0/4 ... 20 mA (overload > 25 mA)
Ripplemax. 50 µA rms
Transfer characteristics
Deviationat 20 °C (68 °F), 0/4 ... 20 mA
≤ 10 µA incl. calibration, linearity, hysteresis, loads and fluctuations of supply voltage
Influence of ambient temperature0.25 µA/K
Frequency rangefield side into the control side: bandwidth with 0.5 Vpp signal 0 ... 7.5 kHz (-3 dB)
control side into the field side: bandwidth with 0.5 Vpp signal 0.3 ... 7.5 kHz (-3 dB)
Settling time200 µs
Rise time/fall time20 µs
Galvanic isolation
Output/power supplyfunctional insulation, rated insulation voltage 50 V AC
Output/Outputfunctional insulation, rated insulation voltage 50 V AC
Display elementsLED
Labelingspace for labeling at the front
Directive conformity
Electromagnetic compatibility
Directive 2014/30/EUEN 61326-1:2013 (industrial locations)
Electromagnetic compatibilityNE 21:2011
Degree of protectionIEC 60529:2001
Protection against electrical shockUL 61010-1:2012
Ambient conditions
Ambient temperature-20 ... 60 °C (-4 ... 140 °F)
Mechanical specifications
Degree of protectionIP20
Connectionscrew terminals
Massapprox. 200 g
Dimensions20 x 124 x 115 mm (0.8 x 4.9 x 4.5 inch) , (W x H x D) housing type B2
Mountingon 35 mm DIN mounting rail acc. to EN 60715:2001
Data for application in connection with hazardous areas
EU-type examination certificateBAS 99 ATEX 7060 X
MarkingEx-Hexagon II (1)G [Ex ia Ga] IIC , Ex-Hexagon II (1)D [Ex ia Da] IIIC , Ex-Hexagon I (M1) [Ex ia Ma] I
Input[Ex ia Ga] IIC, [Ex ia Da] IIIC, [Ex ia Ma] I
Maximum safe voltage250 V (Attention! The rated voltage can be lower.)
Equipmentterminals 1+, 3-
Voltage Uo25.4 V
Current Io86.8 mA
Power Po551 mW
Internal capacitance Ci12 nF
Internal inductance Li 0 mH
Equipmentterminals 2-, 3
Current Io/Current Ii74 mA / 115 mA
Current Ii115 mA
Voltage Uo3.5 V
Current Io74 mA
Power Po64 mW
Equipmentterminals 1+, 2 / 3-
Voltage Ui30 V
Current Ii115 mA
Voltage Uo25.4 V
Current Io115 mA
Power Po584 mW
Equipmentterminals 5-, 6+
Voltage Ui30 V
Current Ii115 mA
Voltage Uo8.7 V
Current Io0 mA
Maximum safe voltage250 V (Attention! The rated voltage can be lower.)
CertificateTÜV 99 ATEX 1499 X
MarkingEx-Hexagon II 3G Ex nA II T4 [device in zone 2]
Galvanic isolation
Input/Outputsafe electrical isolation acc. to IEC/EN 60079-11, voltage peak value 375 V
Input/power supplysafe electrical isolation acc. to IEC/EN 60079-11, voltage peak value 375 V
Directive conformity
Directive 2014/34/EUEN 60079-0:2012+A11:2013 , EN 60079-11:2012 , EN 60079-15:2010
International approvals
UL approval
Control drawing116-0428 (cULus)
IECEx approval
IECEx certificateIECEx BAS 04.0016X
IECEx CML 15.0055X
IECEx marking[Ex ia Ga] IIC , [Ex ia Da] IIIC , [Ex ia Ma] I
Ex nA IIC T4 Gc
General information
NoteBoth output loads must be connected to ensure complete and correct operation within the technical specification.
Open circuit of one of the two outputs will not affect the connected output, but would result in a loss of transmitter supply voltage of up to 0.7 Volt.
Supplementary informationObserve the certificates, declarations of conformity, instruction manuals, and manuals where applicable. For information see


ECLASS 11.027210119
ECLASS 10.0.127210119
ECLASS 9.027210119
ECLASS 8.027210119
ECLASS 5.127210119
ETIM 8.0EC001485
ETIM 7.0EC001485
ETIM 6.0EC001485
ETIM 5.0EC001485
UNSPSC 12.132101514

Details: KFD2-STC4-Ex1.2O


This isolated barrier is used for intrinsic safety applications.

The device supplies 2-wire and 3-wire SMART transmitters in a hazardous area, and can also be used with 2-wire SMART current sources.

It transfers the analog input signal to the safe area as an isolated current value.

Digital signals may be superimposed on the input signal in the hazardous or safe area and are transferred bi-directionally.

If the HART communication resistance in the loop is too low, the internal resistance of 250 Ω between terminals 8 and 9 can be used.

Test sockets for the connection of HART communicators are integrated into the terminals of the device.

Product Documentation: KFD2-STC4-Ex1.2O

Language Selection:
Safety and Security DocumentationLanguageFile TypeFile Size
Instruction manualENGPDF50 KB
Functional Safety ManualENGPDF557 KB
System Manual ENGPDF3673 KB

Design / Simulation: KFD2-STC4-Ex1.2O

Language Selection:
CADLanguageFile TypeFile Size
3-D model / 3-D-ModellALLSTP3048 KB

Approvals: KFD2-STC4-Ex1.2O

Language Selection:
CertificatesCertificate No.LanguageFile TypeFile Size
Australia SIMTARS Group IANZEx 13.2004XALLPDF353 KB
Baseefa IECEx Certificate of ConformityIECEx BAS 04.0016XALLLINK---
CML IECEx Certificate of Conformity Zone 2IECEx CML 15.0055XALLLINK---
Europe Baseefa ATEX Category (1) D ATEX Category (1) GD ATEX Category (1) GBAS 99 ATEX 7060XALLPDF3914 KB
Europe TUV Nord ATEX Category 3 GTÜV 99 ATEX 1499XALLPDF1999 KB
India PESO (India) CCOEA/P/HQ/MH/104/3770 (P345749)ALLPDF551 KB
Japan TIISTC16232ALLPDF3513 KB
Korea KOSHA14-AV4BO-0164ALLPDF287 KB
South Africa MASCMASC MS/17-0862XALLPDF229 KB
USA Canada UL Hazardous Location Certificate of Compliance cULus UL E106378CoC E106378 RepRef E106378-20161215ALLPDF409 KB
Ukraine SERTIS ExSC 21.0646 XALLPDF12351 KB
exida Functional Safety Assessment SummaryP+F 05/09-21 R024ALLPDF349 KB
Control Drawings
Control Drawing UL / Control Drawing UL   ALLPDF28 KB
Declaration of Conformity
EU-Declaration of conformity / EU-KonformitätserklärungDOC-0033GALLPDF86 KB

Associated Products: KFD2-STC4-Ex1.2O

3-pin screw terminal, For KF modules of K-System, Integrated test sockets for connection of HART communicators, Packaging unit: 5 pieces bluepa
3-pin screw terminal, For KF modules of K-System, Integrated test sockets for connection of HART communicators, Packaging unit: 5 pieces greenpa
3-pin screw terminal, For KF modules of K-System, Packaging unit: 5 pieces greenpa
Coding of K-System terminal blocks, Coding of LB/FB-System front sockets, Packaging unit: 20 x 6 coding pinspa
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