Power supply with Bihl+Wiedemann – space-saving and economical

30 V power supplies and ASi-5/ASi-3 gateways - together ready for Industrie 4.0 and IIoT

With our ASi-5 devices, you are perfectly equipped for digitization and the requirements of Industry 4.0 – especially thanks to high data bandwidth and shorter cycle times. To complement it, we are offering a modern 30 V power supply generation for our ASi-5/ASi-3 gateways. This generation is ideally suited for parallel ASi-5/ASi-3 communication and is specially optimized for ASi-5 communication. The 30 V power supplies, in combination with our gateways, are directly "Industry 4.0-ready" without additional IO-Link interfaces or other hardware. In addition, they can supply several ASi circuits simultaneously and are space-saving, since they no longer contain decoupling coils.

Advantages of our modern 30 V power supplies

Seamless ASi-5

All 30 V power supplies have been optimized and extensively tested for use with ASi-5/ASi-3 Gateways. The power supplies guarantee in this way a seamless ASi-5 communication. Interference, which is common in power supplies, is reduced to a minimum in areas relevant to ASi-5.


The 30 V power supplies are less expensive than conventional ASi power supplies – mainly because data decoupling is now integrated as standard in our ASi-5/ASi-3 Gateways. This means that a separate decoupling is automatically available for each ASi circuit and one power supply can simultaneously supply several ASi circuits. This also saves you from having to use separate circuit breakers for each ASi circuit.


The 30 V power supplies are clearly more compact compared to special ASi power supplies because they no longer contain any decoupling coils. They are also stackable, which means that they do not require any free space on the left and right. This frees up additional space in the switching cabinet.



Diagnostics in the
ASi-5/ASi-3 Gateway

The 30 V power supplies – in combination with the ASi-5/ASi-3 Gateways – enable continuous monitoring of the power supply currents and voltages of your ASi installation. The OPC UA server of the gateway enables seamless connection to cloud services, such as predictive maintenance.

Detailed diagnostics in the gateway: ready for Industry 4.0 or IIoT

Our 30 V power supplies in combination with our ASi-5/ASi-3 gateways are directly "Industry 4.0-ready" - without the need to invest in additional IO-Link interfaces or other hardware. The power supply and the gateway form a unit that represents the central data point between field and control level. This means that here a lot of information can be gathered, processed and forwarded directly to the IT or OT - without the detour via the PLC.


The diagnostic options in the gateway enable convenient readout of energy-relevant data via OPC UA, among other things. These include:


  • Current

  • Voltage

  • Overvoltage

  • max. current since switch on

  • Earth fault

  • Power fail


You can implement future features directly in your existing system - via a simple and safe firmware update. The combination of 30 V power supplies and ASi-5/ASi-3 gateways is thus a future-proof, intelligent and adaptable component for your Industry 4.0 projects.

Decoupling in the gateway – space-saving, economical and resource-saving

Decoupling in the gateway:

Supply several ASi circuits with one power supply

Decoupling in the power supply:

1 power supply required per ASi circuit

The suitable power supply for every application

The family of 30 V power supplies offers the right size for every application with 4, 8 and 16 A. For example, an 8 A power supply can supply a complete double master gateway with 2 × 4 A decoupling and a single master gateway with 8 A decoupling. A 16 A power supply can supply a complete double master gateway with 2 × 8 A decoupling and two separate double master gateways with 2 × 4 A decoupling each.


The previous generation of ASi power supplies is still available for ASi repeaters and ASi-3 gateways without integrated data decoupling (in the technical data, the criterion "Integrated decoupling, ASi current measurement in the gateway" reads "no").


Overview of our 30 V power supplies:

30 V power supply, 4 A

  • 1 phase, 100 ... 240 V AC (BW4218)

30 V power supply, 8 A

  • 1 phase, 100 ... 240 VAC (BW4219)
  • 3 phases, 400 ... 500 VAC (BW4220)

30 V power supply 16 A

  • 1 phase, 100 ... 240 VAC (BW4221)
  • 3 phases, 400 ... 500 VAC (BW4222)

30 V power supply, 3 A

  • 1 phase, 100 W (BW4223)
  • Suitable for UL Class 2

FAQ about power supplies

Since ASi transmits power and data simultaneously via the yellow cable, the DC power supply must be decoupled from the AC communication. In the past, this was implemented in a special ASi power supply. Bihl+Wiedemann has integrated this data decoupling in all current gateways, so that all devices can now be operated with ordinary 24 V power supplies. However, there are limitations related to maximum cable length and performance. To ensure efficient supply to the participants, as well as use of the full cable length, we recommend our new range of power supplies. This is also optimized for ASi-3 and ASi-5 communication.

Because we have optimized all new power supplies in endurance tests for use with our ASi-5/ASi-3 Gateways. Interference, which is common in power supplies, is reduced to a minimum in areas relevant to ASi-5.

Yes, the previous power supplies – whether 30 V* or ASi – are still available. If a faulty device needs to be replaced, it is recommended to use a replacement device that has the same item number. When designing a new system or refurbishing an existing machine, it is recommended to use the new 30 V power supplies in combination with ASi-5/ASi-3 Gateways.


* With the exception of BW1927, we are happy to offer model BW4220 as an alternative.

Yes, the new power supplies also work very well with classic ASi-3 Gateways. However, only under one condition: in the technical data of the gateway, there must be a "Yes" for the criterion "1 Power Supply, 1 GW for 2 ASi circuits" (see, e.g. BWU2546). For all other ASi-3 Gateways and ASi-3 repeaters the ASi power supplies are of course still available.

If FE is connected to the ASi-5/ASi-3 Gateway (functional earth) of the system earthing, there is +15 V between ASi+ and the system earthing and -15 V between ASi- and system earthing. The new power supplies output a differential voltage of 30 VDC. The balancing with respect to FE – together with the decoupling of the communication from the power supply – is realized in the ASi-5/ASi-3 Gateway.

Yes, the new 30-V power supplies each provide a maximum output current that can be distributed between multiple gateways with decoupling. For example, a possible combination is the operation of two ASi Gateways with two circuits, each with 4 A decoupling in parallel and a 16 A power supply.

This could also be of interest to you

ASi Cable

The yellow ASi cable represents the simplest connection technology and efficient power distribution. Discover how you can save around 68 % on wiring costs compared to round cable solutions.


Discover the options of the latest ASi generation: ASi-5 can now handle larger data volumes at much higher transmission speeds and it enables intelligent sensors such as IO-Link to be integrated with ease.

ASi Power Supplies Are Also Available in the Web Shop

Here you will find our latest 30 V power supplies, which are all ideally suited for parallel ASi-5/ASi-3 communication. Previous ASi power supplies are still available as replacement devices.


The standardized fieldbus system AS-Interface (ASi) helps you drastically reduce your wiring complexity. You also benefit from free choice of topology and cost-effective integration of safety features on the same infrastructure.

Do you have questions about our new 30 V power supplies?

ASi – A resource-saving technology

Thanks to the greatly reduced wiring effort with AS-Interface, you save assembly and material costs. This saves valuable resources.


More information!