WIEDERMANN BWU1568 AS-I 3.0 BIH1 Replacement Solution

Product Overview

WIEDERMANN BWU1568 AS-I 3.0 BIH1 Replacement Solution: Seamless Transition from Legacy AS-Interface Systems

The WIEDERMANN BWU1568 AS-I 3.0 is a high-performance BIH1 Series AS-Interface 3.0 gateway designed to bridge AS-i field devices with higher-level fieldbus or industrial Ethernet networks. As legacy AS-Interface 2.1 masters and first-generation BIH Series gateways reach end-of-life or become increasingly difficult to source, the BWU1568 AS-I 3.0 provides a direct, specification-matched upgrade path that minimizes engineering rework, preserves existing field wiring, and restores full network functionality with minimal downtime.

Industrial facilities running older WIEDERMANN BIH0 or BIH1 Series AS-i masters — or third-party AS-Interface gateways from discontinued product lines — frequently encounter challenges: obsolete firmware, unsupported diagnostic tools, incompatible PROFIBUS DP or EtherNet/IP integration, and unavailable spare parts. The BWU1568 AS-I 3.0 resolves all of these issues in a single, drop-in replacement module that supports the full AS-Interface 3.0 specification, including extended addressing for up to 62 slaves, combined transaction profiles, and analog data transmission.

From a wiring perspective, the BWU1568 maintains the standard two-wire AS-i cable topology, meaning existing field wiring to sensors, actuators, valve terminals, and I/O modules does not need to be replaced. The module’s power supply input is compatible with standard 24 VDC AS-i power supplies, and the integrated AS-i power feed eliminates the need for additional power conditioning hardware in most retrofit scenarios. Engineers replacing an older BIH1 Series unit will find that terminal assignments and DIN rail mounting dimensions are consistent, reducing panel modification time significantly.

On the communication side, the BWU1568 AS-I 3.0 supports PROFIBUS DP-V1 as its upstream interface, making it directly compatible with existing SIMATIC S7-300, S7-400, and S7-1500 PLC racks where a CP 342-5 or CP 443-5 PROFIBUS master module is already installed. No changes to the PLC hardware configuration are required beyond updating the GSD file and re-importing the slave address table. For sites migrating from older PROFIBUS DP-V0 masters, the BWU1568 remains backward compatible, ensuring that existing ladder logic and function block programs continue to operate without modification.

During a typical retrofit, the migration workflow involves: removing the legacy AS-i master, mounting the BWU1568 on the existing DIN rail, reconnecting the AS-i bus cable and 24 VDC supply, updating the PROFIBUS GSD file in the engineering station, and performing an automatic address detection cycle to re-map all field slaves. The entire process can typically be completed within a planned maintenance window of two to four hours, depending on the number of AS-i slaves and the complexity of the existing program structure.

For sites that also need to upgrade their field-level I/O, the BWU1568 is fully compatible with WIEDERMANN BWU Series AS-i I/O modules, including digital input/output slaves, analog input modules, and safety-rated AS-i slaves for SIL 2 / PLd applications. When combined with a WIEDERMANN BWU2573 AS-i Safety Monitor, the gateway supports integrated safety bus operation without requiring a separate safety PLC or additional wiring infrastructure. Similarly, WIEDERMANN BWU1569 and BWU1570 Series gateways can be used in parallel on the same control cabinet backplane for multi-network or redundant AS-i segment architectures.

For facilities upgrading from older PROFIBUS-based control architectures to Industrial Ethernet, the BWU1568 can serve as an interim solution while the broader migration to EtherNet/IP or PROFINET is planned. Pairing the BWU1568 with a PROFIBUS-to-PROFINET gateway such as the WIEDERMANN BWU3000 Series allows the existing AS-i field layer to remain intact while the PLC backbone is modernized — a cost-effective phased migration strategy that avoids a full field rewire.

From a procurement and project planning standpoint, the BWU1568 AS-I 3.0 is stocked and available for immediate dispatch from our Xiamen warehouse. Each unit undergoes pre-shipment functional testing, including AS-i bus scan verification, PROFIBUS DP communication check, and power supply integrity test. All units are shipped with original manufacturer documentation and are covered by a 12-month replacement warranty from the date of invoice. Express international shipping is available to minimize lead time for urgent maintenance and unplanned downtime scenarios.

Compatibility Comparison Table

Seamless Upgrade Solutions

A complete AS-Interface system migration typically involves more than just the gateway. When replacing a legacy BIH1 Series master with the BWU1568 AS-I 3.0, engineers should also evaluate the condition of associated components. WIEDERMANN BWU Series digital I/O slaves handle field-level signal acquisition and are directly compatible with the BWU1568’s extended addressing mode. For analog process signals, WIEDERMANN BWU analog input modules support 4–20 mA and 0–10 V inputs over the AS-i bus without additional signal converters.

Safety-critical applications benefit from pairing the BWU1568 with a WIEDERMANN BWU2573 AS-i Safety Monitor, which enables integrated emergency stop, light curtain, and safety gate monitoring directly on the AS-i bus. For cabinet-level power distribution, a WIEDERMANN AS-i Power Supply (30 V DC, 4 A or 8 A rated) ensures stable bus voltage across all 62 slave addresses. Where signal isolation is required between the AS-i segment and the PLC I/O rack, a WIEDERMANN signal isolator or repeater module can extend bus length beyond the standard 100-meter segment limit.

For sites also upgrading their HMI layer, a SIMATIC HMI TP700 Comfort or similar panel connected via PROFIBUS DP to the same S7-300 rack will continue to display AS-i diagnostic data without any screen reconfiguration, as the BWU1568 maps all slave status information to standard PROFIBUS DP data words. Programming cable connectivity for the S7 PLC (e.g., SIMATIC PC Adapter USB) remains unchanged throughout the migration.

Retrofit Guidance FAQ

Q: Can I reuse my existing AS-i field wiring?
Yes. The BWU1568 uses the standard two-wire AS-i cable topology. No field rewiring is required when replacing a BIH1 Series or AS-i 2.1 master.

Q: Do I need to modify my PLC program?
In most cases, no. The PROFIBUS DP data structure of the BWU1568 is compatible with existing S7-300/400 function blocks. You will need to update the GSD file and re-import the slave address table in STEP 7 or TIA Portal.

Q: Is the BWU1568 compatible with third-party AS-i slaves?
Yes. The BWU1568 supports all AS-i 2.1 and 3.0 compliant slaves from any manufacturer, including Pepperl+Fuchs, Turck, and IFM Electronic field devices.

Q: What is the maximum AS-i segment length?
100 meters per segment without a repeater. With a WIEDERMANN AS-i repeater module, segments can be extended to 300 meters total.

Q: How long does a typical replacement take?
Most field replacements are completed within 2–4 hours during a planned maintenance window, including address detection and communication verification.

Q: What communication protocols are supported upstream?
PROFIBUS DP-V1 (backward compatible with DP-V0). For EtherNet/IP or PROFINET integration, a protocol gateway module is required upstream of the BWU1568.

Warranty Assurance

Every WIEDERMANN BWU1568 AS-I 3.0 unit supplied by TOPNLMS is covered by a 12-month replacement warranty from the date of invoice. Prior to dispatch, each unit undergoes a structured pre-shipment test protocol: AS-i bus scan (all 62 slave addresses), PROFIBUS DP communication handshake verification, power supply voltage and ripple check, and visual inspection for physical integrity. Units that do not pass all test criteria are quarantined and not shipped.

In the event of a warranty claim, TOPNLMS provides a direct replacement unit dispatched within 3 business days of claim confirmation, with no requirement to return the defective unit before the replacement is shipped for urgent production environments. Our after-sales response team is reachable via email and phone for technical support, configuration assistance, and compatibility verification throughout the warranty period and beyond.

For bulk procurement, project-based orders, and MRO (Maintenance, Repair & Operations) stocking programs, volume pricing and extended warranty options are available upon request.