Bihl+Wiedemann BWU3363 PROFINET ASi Gateway Module

Bihl+Wiedemann BWU3363 PROFINET ASi Gateway Module: Retrofit-Compatible Upgrade for Legacy AS-Interface Systems

The Bihl+Wiedemann BWU3363 is a ruggedized PROFINET AS-Interface (ASi) Gateway Module engineered for demanding industrial environments where legacy fieldbus infrastructure must be preserved while migrating to modern PROFINET-based control architectures. As a direct retrofit-compatible replacement for end-of-life ASi master modules, the BWU3363 bridges the gap between existing AS-Interface sensor/actuator networks and contemporary Siemens S7-1500, S7-1200, or third-party PROFINET controllers — enabling a smooth, low-risk upgrade path without wholesale rewiring of field devices.

Designed for installation in harsh production environments — including those with elevated vibration, wide temperature swings, and high EMI exposure — the BWU3363 delivers the communication reliability and diagnostic depth that maintenance engineers require when modernizing aging control cabinets. Its compact DIN-rail form factor fits directly into existing panel layouts, minimizing installation space concerns during retrofit projects.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

Successful integration of the BWU3363 into a legacy control system begins well before the physical swap. Engineers must first audit the existing AS-Interface network topology: document every slave address (A/B addressing for extended mode), confirm the total current budget against the installed Bihl+Wiedemann BWN-PSU24 or equivalent ASi power supply, and verify that the flat ASi cable routing and yellow cable termination points remain intact. In many retrofit scenarios, the existing ASi flat cable and field-mounted sensors — such as Bihl+Wiedemann BWU2797 or BWU2798 ASi sensor/actuator modules — can be retained without modification, dramatically reducing rewiring cost and downtime.

On the control side, the migration from PROFIBUS to PROFINET requires updating the PLC’s hardware configuration. For Siemens-based systems, this means importing the BWU3363 GSDML file into TIA Portal, assigning a PROFINET device name and IP address, and remapping the I/O process image addresses to match the existing PLC program logic. If the legacy system used a Siemens CP 342-5 PROFIBUS communications processor, it will be replaced by a standard PROFINET interface on the S7-300/400 or a native port on the S7-1500. Engineers should cross-reference the old DB (data block) structures against the new PROFINET I/O byte offsets to avoid address conflicts that could trigger unintended actuator outputs during first power-up.

Control cabinet space is frequently a constraint in retrofit projects. The BWU3363’s compact housing allows it to occupy the same DIN-rail slot as most legacy ASi masters, but engineers should confirm backplane depth and cable bend radius before finalizing the panel layout. Where a Bihl+Wiedemann BW3153 or BW3154 ASi Analyser is available on-site, it can be used to scan the live ASi network and export a slave list, providing a reliable baseline for address verification before the cutover. Similarly, if the control system includes a Siemens KTP700 or KTP900 HMI panel, the PROFINET topology change may require updating the HMI’s communication driver and refreshing tag bindings that previously referenced PROFIBUS slave diagnostics.

For systems that include safety-rated field devices — emergency stops, light curtains, or safety door switches wired through an ASi Safety at Work (SaW) monitor — the BWU3363’s SaW-compatible architecture allows these devices to remain on the same ASi segment. The safety monitor’s F-address and safety parameters must be re-validated after any gateway replacement, and a functional safety test (proof test) should be conducted in accordance with the machine’s safety plan before returning the line to production. Where the existing system used a standalone Bihl+Wiedemann BWU3150 or BWU3152 ASi Safety Monitor, confirm firmware compatibility with the BWU3363 gateway before commissioning.

Signal isolation requirements should also be reviewed during retrofit planning. In environments with long cable runs or mixed AC/DC field wiring, signal isolators or ASi repeaters may be needed to maintain network integrity. The BWU3363 supports ASi repeater segments, allowing the existing network to be extended without re-addressing slaves. Document all repeater positions and segment lengths in the updated network diagram to support future maintenance activities.

Downtime Control During System Migration

Minimizing production downtime is the primary concern for any control system retrofit. The BWU3363 supports a structured migration approach that allows pre-configuration and bench testing before the physical cutover, significantly reducing the time the production line is offline.

Begin by configuring the BWU3363 on a bench test rig using the Bihl+Wiedemann ASi Control Center software. Connect a representative sample of ASi slaves — or use the actual slave list exported from the BW3153 Analyser — to verify address assignments, I/O data mapping, and diagnostic behavior before the module is installed in the live panel. Simultaneously, update the PLC program in TIA Portal offline, importing the GSDML file and adjusting I/O addresses, so the program is ready to download the moment the hardware is in place.

During the physical cutover window, follow a structured sequence: isolate the ASi segment, remove the legacy gateway, install the BWU3363, restore ASi power, and verify slave detection before enabling PROFINET communication. Use the BWU3363’s integrated web server to confirm all slaves are detected and fault-free before initiating PLC communication. This staged approach protects the original program logic — no changes to the field wiring or slave configuration are required if the address mapping has been correctly pre-validated.

For systems where even brief interruptions are critical, consider a parallel-run strategy: install the BWU3363 alongside the legacy gateway on a secondary ASi segment, validate all I/O data in shadow mode, and perform the final switchover during a planned maintenance window. This approach is particularly effective in continuous-process industries where a cold restart of the production line carries significant cost. Throughout the migration, maintain a rollback plan — retain the legacy gateway and its configuration backup until the BWU3363 has completed at least one full production cycle without fault.

All units supplied by NINERMAS are pre-tested prior to shipment and covered by a 12-month warranty against manufacturing defects. In-stock availability supports rapid deployment, reducing the lead-time risk that is common with end-of-life spare parts procurement.

Retrofit Support FAQ

Q1: Is the BWU3363 a direct replacement for older Bihl+Wiedemann PROFIBUS ASi gateways?
The BWU3363 is a functional replacement for legacy Bihl+Wiedemann PROFIBUS-based ASi masters in terms of AS-Interface network management, but the upstream fieldbus changes from PROFIBUS to PROFINET. This requires a PROFINET-capable PLC or communications module on the controller side. The ASi field wiring, slave addresses, and sensor/actuator devices can typically be retained without modification, making the BWU3363 a cost-effective upgrade path rather than a full system replacement.

Q2: What commissioning steps are required after installing the BWU3363?
After physical installation, assign a PROFINET device name and IP address (via TIA Portal or the integrated web server), import the GSDML file into the PLC hardware configuration, download the updated program, and perform an ASi network scan to confirm all slave addresses are detected. Verify I/O data consistency between the PLC process image and the expected field device states before enabling automatic mode. For safety-rated segments, conduct a full functional safety test and document the results.

Q3: Can existing ASi flat cable and field wiring be reused with the BWU3363?
Yes. The BWU3363 uses the standard AS-Interface flat cable interface and is compatible with existing yellow ASi cable installations. Terminal connections at the gateway follow the standard ASi+ and ASi- polarity convention. Confirm cable condition and total network length (maximum 100 m per segment without repeater) before reuse. No re-termination of field devices is required if the existing cable is in good condition.

Q4: What warranty and stock availability does NINERMAS provide for the BWU3363?
NINERMAS supplies the BWU3363 with a 12-month warranty covering manufacturing defects and DOA (dead-on-arrival) replacement. Units are pre-tested prior to shipment. In-stock inventory is maintained to support urgent retrofit and breakdown replacement requirements. Contact our team for lead time confirmation and volume pricing.