Economical Power Supply (R)evolution by Bihl+Wiedemann

Why New Power Supplies?

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 now offering a new generation of power supplies, which replaces the previous ASi power supplies. All of our new power supplies are 30 V and feature state-of-the-art technology. They are ideally suited for parallel ASi-5/ASi-3 communication. This marks the first time that a complete range of power supplies specially optimized for ASi-5 communication is available.

Advantages of the New Power Supplies

Seamless ASi-5

All new power supplies have been optimized and extensively tested for use with ASi-5/ASi-3 Gateways. This ensures that the power supplies guarantee 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 previous 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 new 30 V power supplies are clearly more compact compared to special ASi power supplies because they no longer contain any decoupling coils. The new power supplies 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.



Detailed Diagnostics
in the 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.

Bihl+Wiedemann offers the right combination for every application: Both power supplies and ASi-5/ASi-3 Gateways are perfectly matched to each other.



The Right Power Supply for Every Application


The new family of 30 V power supplies delivers 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 new products:

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

FAQs about Power Supplies

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.

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.


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.

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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?

We would be happy to assist you.


Contact us now