KCD2-SCS-Ex2 Pepperl+Fuchs Transmitter Power Supply Isolator 2 Channel Intrinsic Safety Barrier 4-20mA
Product Overview
The KCD2-SCS-Ex2 is a versatile 2-channel isolated barrier from Pepperl+Fuchs' K-System, specifically engineered for intrinsic safety applications requiring either analog input or analog output functionality. Each channel can be independently configured as a transmitter power supply (powering 2-wire SMART transmitters) or a current driver (driving SMART I/P converters and positioners).
With a compact 12.5 mm width and 24 V DC power supply (via Power Rail or terminals), this device provides complete galvanic isolation between field and control circuits while supporting bidirectional SMART communication for intelligent field device configuration and diagnostics.
Certified for SIL 2 (SC 3) acc. to IEC/EN 61508 and approved for hazardous area installation with [Ex ia Ga] IIC certification, the KCD2-SCS-Ex2 is the ideal solution for analog signal transfer in safety-related and explosive atmosphere applications.
Key Features & Benefits
- First-of-its-Kind 2-Channel AI/AO Barrier: The industry's first 2-channel, dual-function analog input/analog output intrinsic safety barrier in a 12.5 mm housing
- Configurable Per Channel: Each channel can be independently configured via DIP switches as either a transmitter power supply or current driver
- Bidirectional SMART Communication: Supports digital communication for SMART devices using current modulation
- Intrinsic Safety Certification: ATEX and IECEx certified with [Ex ia Ga] IIC marking for installation in Zone 0, 1, and 2 hazardous areas
- SIL 2 Certified: Safety Integrity Level 2 (SC 3) acc. to IEC/EN 61508
- High Drive Capability: Provides ≥15 V at 20 mA in transmitter mode; drives loads up to 650 Ω with ≥13 V at 20 mA in current driver mode
- Configurable Control Side Operation: For analog input signals, the control side can be operated either as a current source or current sink
- Line Fault Detection: In current driver operation, an open field circuit presents high impedance (>100 kΩ) to the control side
- Compact 12.5 mm Width: Ultra-slim design maximizes DIN rail density in crowded control cabinets
- Wide Operating Temperature: Functions reliably from -40°C to +70°C
Technical Specifications
General Specifications
| Manufacturer |
Pepperl+Fuchs SE |
| Product Type |
SMART Transmitter Power Supply / SMART Current Driver |
| Model |
KCD2-SCS-Ex2 |
| Signal Type |
Analog input / Analog output (configurable per channel) |
| Channels |
2 |
Functional Safety
| Safety Integrity Level (SIL) |
SIL 2 |
| Systematic Capability (SC) |
SC 3 |
Supply
| Connection |
Power Rail or terminals 9+, 10- |
| Rated Voltage |
19 ... 30 V DC |
| Ripple |
≤ 10 % |
| Rated Current |
≤ 88 mA at 24 V |
| Power Dissipation |
≤ 1.4 W |
| Power Consumption |
≤ 2.1 W |
Analog Input Mode (Transmitter Power Supply)
| Suitable Field Devices |
2-wire SMART transmitters |
| Signal |
0/4 ... 20 mA, limited to approx. 30 mA |
| Field Circuit Terminals |
1+, 2- (Ch1); 3+, 4- (Ch2) |
| Available Voltage |
min. 15 V at 20 mA; min. 18 V at 4 mA |
| Control Circuit Terminals |
5-, 6+ (Ch1); 7-, 8+ (Ch2) |
| Load |
max. 350 Ω (source output) |
| Control Side Operation |
Configurable as current source or current sink |
Analog Output Mode (Current Driver)
| Suitable Field Devices |
SMART I/P converters (positioners), on-site displays |
| Signal |
0/4 ... 20 mA, limited to approx. 30 mA |
| Field Circuit Terminals |
1+, 2- (Ch1); 3+, 4- (Ch2) |
| Load |
max. 650 Ω |
| Voltage |
min. 13 V at 20 mA |
| Voltage Drop |
max. 6 V |
| Line Fault Detection |
>100 kΩ at max. 30 V, with field wiring open |
Transfer Characteristics
| Deviation |
max. 20 µA (incl. calibration, linearity, hysteresis, loads, supply fluctuations) |
| Temperature Influence |
<2 µA/K (-40 ... 70°C) |
| Frequency Range |
0 ... 3 kHz (-3 dB) |
| Settling Time |
max. 200 ms |
| Rise/Fall Time |
max. 100 ms (10 ... 90%) |
Galvanic Isolation
| Field Circuit/Control Circuit |
basic insulation, 300 Veff |
| Field Circuit/Power Supply |
reinforced insulation, 300 Veff |
| Control Circuit/Power Supply |
basic insulation, 300 Veff |
| Control Circuit/Control Circuit |
functional isolation, 50 V |
Hazardous Area Specifications (Ex ia)
| Marking |
II (1)G [Ex ia Ga] IIC |
| Output Voltage (Uo) |
25.2 V |
| Output Current (Io) |
100 mA |
| Output Power (Po) |
630 mW |
| Internal Capacitance (Ci) |
1.05 nF |
| Internal Inductance (Li) |
0 |
Ambient Conditions
| Ambient Temperature |
-40 ... 70 °C (-40 ... 158 °F) |
Mechanical Specifications
| Degree of Protection |
IP20 |
| Connection |
Screw terminals |
| Mass |
approx. 115 g |
| Dimensions (W x H x D) |
12.5 x 124 x 114 mm (0.5 x 4.9 x 4.5 inch) |
| Housing Type |
A2 |
| Mounting |
35 mm DIN mounting rail acc. to EN 60715:2001 |
Function Description
The KCD2-SCS-Ex2 is a configurable isolated barrier for intrinsic safety applications. Each of the two channels can operate independently in either mode:
Mode 1: Transmitter Power Supply (Analog Input)
- Powers 2-wire SMART transmitters located in hazardous areas
- Transfers the 4...20 mA measurement signal from the field to the control system
- Provides bidirectional HART communication for transmitter configuration and diagnostics
- Minimum available voltage: 15 V at 20 mA ensures reliable transmitter operation
- Control side can be configured as current source or current sink via DIP switches
Mode 2: Current Driver (Analog Output)
- Drives SMART I/P converters, valve positioners, and displays in hazardous areas
- Repeats the 4...20 mA control signal from the PLC/DCS to the field device
- Supports bidirectional HART communication for positioner configuration and feedback
- Drives loads up to 650 Ω with ≥13 V at 20 mA
- Line fault detection identifies open field circuits for control system monitoring
Unique Application Capability: Positioners ensure that the actuator is brought into a position specified by the control system. They are often equipped with analog position indicators whose feedback confirms that the position specification has been performed. Previously, a separate isolator module was required for the input and output signal. With the KCD2-SCS-Ex2, these two functions can be used in one device for the first time -- positioner control on one channel (AO) and position monitoring (AI) on the second channel.
Signal Flow
Analog Input Mode (Transmitter Power Supply):
Hazardous Area Safe Area
2-wire SMART Transmitter ──► KCD2-SCS-Ex2 ──► 4...20 mA to PLC/DCS
◄── (Bidirectional HART) ◄── HART Communicator
Analog Output Mode (Current Driver):
Safe Area Hazardous Area
PLC/DCS 4...20 mA ──► KCD2-SCS-Ex2 ──► 4...20 mA to SMART I/P
HART Communicator ◄── (Bidirectional HART) ◄── Positioner/Valve
Applications
The KCD2-SCS-Ex2 is specifically designed for analog signal transfer in hazardous area installations:
| Oil & Gas |
Powering pressure/temperature transmitters on offshore platforms; driving I/P converters for pipeline control valves in Zone 1 areas |
| Chemical Processing |
Isolated analog input for reactor monitoring; analog output for chemical dosing valve positioning in explosive atmospheres |
| Pharmaceutical |
SIL 2 certified signal transfer for safety-related batch control; solvent handling equipment with Ex ia protection |
| Power Generation |
Transmitter power supply for gas turbine monitoring; current driver for boiler feedwater control valves |
| Valve Positioner Applications |
Combined positioner control (AO) and position feedback monitoring (AI) in a single device -- eliminates need for separate isolator modules |
Typical Field Devices Connected
- 2-wire SMART pressure, temperature, level, flow, and pH transmitters (Analog Input mode)
- SMART I/P converters for pneumatic valve positioning (Analog Output mode)
- SMART valve positioners with HART communication and analog position feedback (AI + AO combined)
- Field-mounted displays with 4...20 mA input (Analog Output mode)
Why Choose the KCD2-SCS-Ex2?
Industry-First 2-Channel AI/AO Design -- The KCD2-SCS-Ex2 is the first 2-channel, dual-function AI/AO intrinsic safety barrier in a 12.5 mm housing. This unique capability allows positioner control and position monitoring in a single device -- previously requiring two separate isolator modules.
Complete Intrinsic Safety Package -- Certified with [Ex ia Ga] IIC for Zone 0, 1, and 2 hazardous areas, the device provides the highest level of intrinsic safety protection for gas groups IIC (hydrogen, acetylene), IIB, and IIA.
SIL 2 Certified for Safety Applications -- Certified acc. to IEC/EN 61508 with Systematic Capability SC 3 (TÜV Rheinland), the KCD2-SCS-Ex2 is suitable for use in safety instrumented systems (SIS) up to SIL 2.
Configurable Control Side Operation -- For analog input signals, the control side can be operated as either a current source or current sink via front-panel DIP switches, providing compatibility with any control system architecture.
Bidirectional SMART Communication -- Full HART transparency allows digital configuration, calibration, and diagnostics of SMART field devices directly through the isolation barrier -- no additional hardware required.
Space-Saving Design -- At just 12.5 mm width, the KCD2-SCS-Ex2 provides two complete analog signal channels in a compact footprint, maximizing DIN rail density.
High Drive Capability -- The current driver mode delivers ≥13 V at 20 mA into 650 Ω loads, providing sufficient power for demanding positioners and long cable runs.
Proven Pepperl+Fuchs K-System -- The K-System is the industry standard for signal conditioning and isolation, trusted globally for reliability, quality, and long service life.
KCD2-SCS-Ex2 vs. Related Models
| Model |
Channels |
Modes |
Terminal Type |
Special Features |
| KCD2-SCS-Ex2 |
2 |
Configurable (AI/AO per channel) |
Screw terminals |
Ex ia IIC, SIL 2, bidirectional HART, first 2-channel AI/AO barrier |
| KCD2-SCS-Ex2.SP |
2 |
Configurable (AI/AO per channel) |
Spring (push-in) |
Same function, spring terminals |
| KCD2-SCS-Ex2-IL |
2 |
Configurable (AI/AO) |
Screw |
Intrinsically safe loop version |
| KCD2-SCD-Ex1 |
1 |
Current Driver only |
Screw |
Single-channel, AO only |
| KFD2-SCS-Ex2 |
2 |
Configurable (AI/AO) |
Screw |
K-System equivalent (different housing series) |
Ordering Information
| Part Number |
KCD2-SCS-Ex2 |
| Brand |
Pepperl+Fuchs SE |
| Product Family |
K-System |
| Country of Origin |
Germany |
| Condition |
New, Original, Factory Sealed |
| Minimum Order Quantity |
1 piece |
| Warranty |
Manufacturer's standard warranty |
| Shipping |
Immediate dispatch via DHL, FedEx, UPS, TNT |
Contact our sales team for volume pricing, datasheet downloads, or technical application support.
Compliance & Certifications
| Certification |
Status |
Details |
| ATEX |
✅ Certified |
UL 22 ATEX 2786X -- II (1)G [Ex ia Ga] IIC |
| ATEX Zone 2 |
✅ Certified |
UL 22 ATEX 2787X -- II 3G Ex ec IIC T4 Gc |
| IECEx |
✅ Certified |
IECEx ULD 22.0020X -- [Ex ia Ga] IIC |
| SIL 2 |
✅ Certified |
IEC/EN 61508, SC 3 (TÜV Rheinland) |
| UL/cULus |
✅ Listed |
E106378, Control Drawing 116-0490 |
| DNV Marine |
✅ Approved |
TAA00001WX |
| RoHS |
✅ Compliant |
Lead-free |
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