Wiedermann BWU1568 AS-I 3.0 Retrofit-Compatible Gateway

Wiedermann BWU1568 AS-I 3.0 Retrofit-Compatible Gateway for Legacy Systems

The Wiedermann BWU1568 AS-I 3.0 is a high-performance AS-Interface (AS-i) gateway designed to bridge legacy fieldbus architectures with modern control platforms. As industrial facilities face increasing pressure to extend the operational life of existing automation infrastructure, the BWU1568 provides a reliable, drop-in compatible solution for engineers managing AS-i network upgrades, control cabinet retrofits, and distributed I/O expansions without full system replacement.

Engineered to AS-Interface Specification 3.0, the BWU1568 supports up to 62 AS-i slaves per segment, enabling high-density sensor and actuator connectivity across legacy production lines. Its dual-master capability and integrated power management make it a preferred choice for system integrators working on phased migration projects where minimizing downtime and protecting existing program logic are critical priorities.

Each unit supplied by NINERMAS undergoes pre-shipment functional testing to verify AS-i bus communication, power output stability, and slave address recognition before dispatch. A 12-month warranty is included with every order, supported by documented test records and long-term spare parts availability commitments.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

Successful integration of the BWU1568 into an existing AS-i network begins with a thorough audit of the current fieldbus topology. Engineers should document all active slave addresses, verify the AS-i power supply output capacity, and confirm that the upper-level controller — whether a Siemens S7-300, S7-400, or a modern S7-1500 series PLC — supports the gateway’s communication protocol variant. Where PROFIBUS DP is the existing upper-level bus, the BWU1568’s GSD file must be imported into the engineering tool (STEP 7 or TIA Portal) and the DP address configured to match the legacy master’s slot assignment.

In control cabinets where space is constrained, the BWU1568’s compact DIN rail footprint simplifies side-by-side installation alongside existing components such as Wiedermann AS-i power supplies, terminal blocks, and signal conditioners. When the retrofit involves expanding I/O capacity, additional AS-i digital input/output modules — including compact 4-channel and 8-channel slave modules — can be added to the AS-i segment without modifying the upper-level PLC program, provided slave addresses are pre-assigned and the total slave count remains within the 62-slave limit.

For facilities running mixed sensor types, the BWU1568 supports both standard AS-i slaves and A/B slaves, allowing engineers to integrate proximity sensors, solenoid valve islands, safety modules, and analog input slaves on a single AS-i segment. This flexibility is particularly valuable during phased retrofits where legacy pneumatic valve terminals are being replaced with AS-i-compatible valve manifolds, or where older discrete wiring is being consolidated onto AS-i flat cable to reduce cabinet wiring complexity.

When the upper-level network is being migrated from PROFIBUS DP to PROFINET, the BWU1568 PROFINET variant provides a direct upgrade path. The AS-i slave configuration and address table can be retained, while the upper-level communication is re-established through the PROFINET interface. HMI screens referencing AS-i diagnostic data blocks should be reviewed and updated to reflect the new GSD/GSDML device structure, particularly for alarm and status visualization linked to AS-i slave fault bits.

In applications involving safety-rated AS-i networks, the BWU1568 works alongside AS-i Safety Monitor modules to maintain SIL-rated emergency stop and safety gate circuits during the retrofit. Engineers should verify that the safety monitor’s slave address assignments and F-address parameters are preserved during gateway replacement to avoid unintended safety function interruptions. Programming cables and AS-i address programming tools are required during commissioning to set or verify slave addresses on newly installed or replacement slaves.

Downtime Control During System Migration

Minimizing production downtime during an AS-i gateway replacement requires careful pre-migration preparation. Before removing the existing gateway, engineers should export the complete AS-i slave configuration — including slave addresses, I/O mapping, and diagnostic parameters — from the current master or engineering software. This configuration backup serves as the reference for re-commissioning the BWU1568 and verifying that all slave addresses are correctly recognized after installation.

Where the control system allows, a hot-standby or parallel commissioning approach can be used: the BWU1568 is pre-configured on a bench test setup using an AS-i power supply and representative slave modules, with the slave address table verified before the unit is installed in the live cabinet. This approach reduces the in-cabinet commissioning window to a wiring changeover and a final bus scan, typically achievable within a planned maintenance window of two to four hours depending on cabinet complexity.

PLC program logic referencing AS-i I/O data blocks should be reviewed before cutover to confirm that input and output byte assignments match the BWU1568’s data mapping. Where the legacy gateway used a different data block structure, a program patch or data block remapping may be required in STEP 7 or TIA Portal before the new gateway is brought online. SCADA and HMI systems connected to the PLC should be tested in simulation mode where possible to confirm that AS-i diagnostic alarms and process values are correctly displayed after the gateway changeover.

NINERMAS maintains in-stock inventory of the BWU1568 and related AS-i components to support urgent replacement requirements, with same-day dispatch available for confirmed orders. Long-term supply commitments are available for maintenance contracts and multi-site retrofit programs, ensuring consistent spare parts availability throughout the system’s operational lifecycle.

Retrofit Support FAQ

Q1: Is the BWU1568 AS-I 3.0 a direct replacement for older Wiedermann AS-i gateways?
The BWU1568 is designed as a functional replacement within the Wiedermann AS-i gateway family. Physical dimensions, DIN rail mounting, and AS-i flat cable connections are compatible with predecessor models. However, engineers should verify the upper-level communication protocol variant (PROFIBUS DP or PROFINET) and re-commission the slave address table after installation, as address configurations are stored in the gateway and not automatically transferred from the replaced unit.

Q2: What pre-shipment testing is performed on the BWU1568?
Every BWU1568 unit supplied by NINERMAS undergoes functional testing prior to dispatch. Testing covers AS-i bus power output, slave address scanning, communication interface initialization, and LED diagnostic verification. Test records are available upon request and accompany units supplied under maintenance contract or long-term supply agreements. A 12-month warranty is provided from the date of shipment.

Q3: Can the BWU1568 be used in a mixed AS-i 2.1 and AS-i 3.0 slave environment?
Yes. The BWU1568 AS-I 3.0 master is backward compatible with AS-i 2.1 standard and A/B slaves. Mixed networks combining legacy AS-i 2.1 discrete I/O slaves with newer AS-i 3.0 analog or safety slaves are supported within the 62-slave address limit. Engineers should confirm slave address assignments and verify that the total I/O data volume does not exceed the gateway’s data mapping capacity for the connected PLC.

Q4: What is the lead time and inventory availability for the BWU1568?
NINERMAS maintains stock of the BWU1568 to support both urgent replacement and planned retrofit projects. Standard orders are dispatched within 1–3 business days. For projects requiring multiple units or long-term supply commitments, NINERMAS offers inventory reservation programs with fixed lead times to support multi-phase retrofit schedules. Contact our technical sales team to confirm current stock levels and arrange supply terms.