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Mean Well KNX-40E-1280D KNX Power Supply 1280mA - Diagnostic 1280A

EIB/KNX power supply with integrated chokeno load power consumption < 0.5W
SKU KNX-40E-1280D
$221.82 USD
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Overview

KNX-40E-1280D is the model of this series: rated current 1280mA, rated power 38.4W, typical efficiency 86%.

MEAN WELL, the leading standard power supply manufacturer, continues to promote the building automation technology for making a green and sustainable society. After the launch of KNX-20E-640, the new KNX power supply KNX-40E-1280(D) is proudly introduced. The KNX Power Supply KNX-40E-1280(D) is a 1280mA power supply with high efficiency and a small footprint of only 4SU(72mm). The device has a KNX bus choke output and additional output for auxiliary power. The -30~+70°C wide temperature operating range can meet all kinds of applications. For troubleshooting, monitoring purpose, output voltage, output current, bus traffic, device temperature and other actual measurement values can be sent via KNX. LED indicators are used in case of normal operation, overload conditions and RESET operation. It is perfectly suitable to power up any products labeled with the KNX trademark.

Features

  • EIB / KNX power supply with integrated choke
  • Compact size with 4SU width(72mm)
  • Safety extra low voltage(SELV)
  • Suitable for TP1-256
  • 180~264VAC input
  • Protections: Short circuit / Overload(short-circuit-proof)/ Over voltage
  • Cooling by free air convection
  • Isolation classⅠ
  • LED indicator for normal operation, bus reset and bus overload
  • Monitoring of output voltage, output current, bus traffic load and device temperature
  • Provide Wide variety of diagnostic and logic function
  • Over Voltage category Ⅲ
  • 3 years warranty

Specifications

KNX-40E-1280DSpecifications from the official datasheet (2025-04-18 edition)

OUTPUT

BUS OUTPUT VOLTAGE WITH CHOKE
Bus,30V (KNX black/red terminal block)
DC OUTPUT VOLTAGE WITHOUT CHOKE
30V(Additional output for ancillary power)
RATED CURRENT
1280mA
RATED POWER
38.4W
RIPPLE & NOISE (max.)Note.2
100mVp-p
SHORT CIRCUIT CURRENT
2.8A
SETUP, RISE TIME
1000ms, 50ms/230VAC at full load
AC MAINS FAILURE BACK-UP TIME (Typ.)
200ms/230VAC at full load

INPUT

VOLTAGE RANGE
180 ~ 264VAC 176 ~ 280VDC
FREQUENCY RANGE
47 ~ 63Hz
EFFICIENCY (Typ.)Note.3
86%
AC CURRENT (Typ.)
0.5A/230VAC
INRUSH CURRENT (Typ.)
COLD START 60A(twidth=1200μs measured at 50% Ipeak)/230VAC
LEAKAGE CURRENT
<1mA / 240VAC

PROTECTION

OVERLOAD
205 ~ 235% rated output power Protection type : Constant current limiting, recovers automatically after fault condition is removed
OVER VOLTAGE
33 ~ 35V Protection type : Hiccup mode, recovers automatically after fault condition is removed

FUNCTION

RESET
Physical button for the bus reset: Blank type:Press the RESET button for at least 20 seconds to reset the KNX Bus D type:Press the RESET button once,it will reset the KNX Bus last for 20 seconds automatically
LED INDICATORS
Please refer to the “Explanation of LED Status”
CHOKE
One integrated choke

ENVIRONMENT

WORKING TEMP.
-30 ~ +70°C (Refer to "Derating Curve")
WORKING HUMIDITY
20 ~ 95% RH non-condensing
STORAGE TEMP., HUMIDITY
-40 ~ +85°C, 10 ~ 95% RH non-condensing
VIBRATION
10 ~ 500Hz, 2G 10min./1cycle, 60min. each along X, Y, Z axes
TYPE OF PROTECTION
IP20 design
OVER VOLTAGE CATEGORY
Ⅲ ,According to BS EN/EN61558, BS EN/EN50178,altitude up to 2000 meters

SAFETY & EMC (Note 4)

SAFETY STANDARDS
BS EN/EN61558-1,BS EN/EN61558-2-16;BS EN/EN50491-3 approved
WITHSTAND VOLTAGE
I/P-O/P:4.2KVAC I/P-FG:2KVAC
ISOLATION RESISTANCE
I/P-O/P, I/P-FG:100M Ohms / 500VDC / 25°C/ 70% RH
EMC EMISSION
Compliance to BS EN/EN50491-5-2,-5-3;BS EN/EN61000-3-2,-3-3
EMC IMMUNITY
Compliance to BS EN/EN50491-5-2,-5-3;BS EN/EN61000-4-2,3,4,5,6,8,11, heavy industry level

OTHERS

MTBF
1414.2K hrs min. Telcordia SR-332 (Bellcore) 217.1Khrs min. MIL-HDBK-217F (25°C)
DIMENSION
72*90*57mm (W*H*D)
MOUNTING
35mm mounting rail according to DIN BS EN/EN60715
PACKING
0.328Kg ; 48pcs/16.4Kg/1.02CUFT
Test conditions and notes5
  1. 1. All parameters NOT specially mentioned are measured at 230VAC input, rated load and 25°C of ambient temperature.
  2. 2. Ripple & noise are measured at 20MHz of bandwidth by using a 12" twisted pair-wire terminated with a 0.1uf & 47uf parallel capacitor. Measure before Choke.
  3. 3. Efficiency before choke.
  4. 4. The power supply is considered a component which will be installed into a final equipment. The final equipment must be re-confirmed that it still meets EMC directives. For guidance on how to perform these EMC tests, please refer to “EMI testing of component power supplies.” (as available on https://www.meanwell.com//Upload/PDF/EMI_statement_en.pdf)
  5. 5. The ambient temperature derating of 3.5°C/1000m with fanless models and of 5°C/1000m with fan models for operating altitude higher than 2000m(6500ft).

Technical drawings

KNX-40E-1280D Block Diagram
Block Diagram
KNX-40E-1280D Mechanical Specification
Mechanical Specification
KNX-40E-1280D Configuration and Commissioning
Configuration and Commissioning
KNX-40E-1280D Communication Object Table (Only for KNX-40E-1280D)
Communication Object Table (Only for KNX-40E-1280D)
KNX-40E-1280D Typical application
Typical application

Typical applications

  • Intelligent home control
  • Modern building automation
  • Lighting control
  • HVAC system
  • Security system
  • Blinds and shutters
  • Monitoring systems
  • Energy management
  • Alarm monitoring

Downloads

FAQ

Can the KNX-40E-1280D be used for a higher-capacity KNX control cabinet in building management?

Yes. This model is rated at 30V, 38.4W, and 1280mA, so it suits KNX building management cabinets that need a 1280mA bus supply. It is also designed as a DIN rail power supply for panel use.

Is the KNX-40E-1280D suitable for centralized KNX automation panels in commercial control enclosures?

It is well suited to centralized KNX control enclosures that use a 30V KNX supply and need the 38.4W, 1280mA rating. The integrated choke lets it feed the KNX bus directly. Its 72 × 90 × 57 mm (W × H × D) size mounts on a standard 35mm DIN rail in cabinet layouts.

Can I use the KNX-40E-1280D in a PLC cabinet that also includes KNX-based building control functions?

Yes, when the KNX portion of the cabinet needs a dedicated 30V KNX power supply within a 38.4W and 1280mA rating. The DIN rail format makes it practical for mixed-control cabinets where panel organization matters. It should still be selected as a KNX power component, not as a general-purpose cabinet supply.

Should the KNX-40E-1280D be installed only inside an enclosure or cabinet?

It is best used inside a control cabinet or enclosure. The operating temperature range is -30°C to +70°C (refer to the derating curve), and the unit has an IP20 design. That makes protected indoor cabinet use the appropriate environment.

How does the KNX-40E-1280D compare with the other models in the KNX series?

The KNX-40E-1280D is a 38.4W, 30V, 1280mA model. The KNX-40E-1280 in the same series has the same 38.4W, 30V, 1280mA rating. The D version adds a fuller diagnostic LED set and a KNX communication object table, and its RESET button resets the bus with a single press instead of a 20-second hold.

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Other KNX-40E Models

1 other model
ModelPower Voltage Current IP RatingPrice
Mean Well KNX-40E-1280 KNX Power Supply 1280mA 1280A 38.4W 30V 1.28A IP20$128.67 View
Mean Well KNX-40E-1280D KNX Power Supply 1280mA - Diagnostic 1280A
Mean Well

Mean Well KNX-40E-1280D KNX Power Supply 1280mA - Diagnostic 1280A

$221.82 USD

KNX-40E-1280D is the model of this series: rated current 1280mA, rated power 38.4W, typical efficiency 86%.

MEAN WELL, the leading standard power supply manufacturer, continues to promote the building automation technology for making a green and sustainable society. After the launch of KNX-20E-640, the new KNX power supply KNX-40E-1280(D) is proudly introduced. The KNX Power Supply KNX-40E-1280(D) is a 1280mA power supply with high efficiency and a small footprint of only 4SU(72mm). The device has a KNX bus choke output and additional output for auxiliary power. The -30~+70°C wide temperature operating range can meet all kinds of applications. For troubleshooting, monitoring purpose, output voltage, output current, bus traffic, device temperature and other actual measurement values can be sent via KNX. LED indicators are used in case of normal operation, overload conditions and RESET operation. It is perfectly suitable to power up any products labeled with the KNX trademark.

Features

  • EIB / KNX power supply with integrated choke
  • Compact size with 4SU width(72mm)
  • Safety extra low voltage(SELV)
  • Suitable for TP1-256
  • 180~264VAC input
  • Protections: Short circuit / Overload(short-circuit-proof)/ Over voltage
  • Cooling by free air convection
  • Isolation classⅠ
  • LED indicator for normal operation, bus reset and bus overload
  • Monitoring of output voltage, output current, bus traffic load and device temperature
  • Provide Wide variety of diagnostic and logic function
  • Over Voltage category Ⅲ
  • 3 years warranty

Typical applications

  • Intelligent home control
  • Modern building automation
  • Lighting control
  • HVAC system
  • Security system
  • Blinds and shutters
  • Monitoring systems
  • Energy management
  • Alarm monitoring
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