The Challenge
A major UK automotive manufacturer in the West Midlands needed to introduce a new long wheelbase vehicle variant into its production programme. The existing conveyor network included a skid buffer system — a section of conveyor infrastructure that holds and routes vehicle bodies between production stations — which had been designed and programmed around the dimensions and routing requirements of the standard vehicle range.
Introducing a long wheelbase variant created a controls challenge. The existing PLC routing logic did not account for the additional length of the new variant, and without modification the buffer would not handle the new vehicles correctly. The routing rules, sequencing logic, and HMI all needed to be updated to accommodate the new variant safely and reliably, without introducing risk to the existing production programme running alongside it.
The brief: Reconfigure the Allen Bradley Rockwell PLC routing logic and update the HMI to accommodate long wheelbase vehicle variants within the existing skid buffer conveyor network. Develop offline, commission on site, and achieve full customer buy-off with startup support to ensure clean production handover.
What Duke Did
Offline PLC Development
Duke Control Systems developed the updated routing logic entirely offline before any changes were made to the live system. Working in Allen Bradley Rockwell, the existing PLC program was reviewed in detail to understand how the current routing rules operated across the buffer network, and the modifications required to accommodate long wheelbase vehicles were designed, built, and tested in the offline environment.
This offline-first approach is essential on a live production system. Making changes directly on a running line introduces risk that is simply not justified when the same work can be done and validated in simulation first. By the time the modified software was ready for site, it had already been thoroughly tested against the expected operating scenarios.
HMI Updates
Alongside the PLC changes, the HMI screens used by operators to monitor and interact with the skid buffer system were updated to reflect the new routing logic and provide clear visibility of long wheelbase vehicle positions within the buffer. Operators needed to be able to see at a glance how the buffer was behaving with the new variant in the mix, and the HMI updates ensured this was the case from day one of production running.
On-Site Commissioning
With the offline development complete, Duke's engineers commissioned the updated software on site, working through the buffer system methodically to verify that the new routing logic operated correctly with both standard and long wheelbase variants present. Edge cases and mixed-variant scenarios were tested carefully to confirm the system behaved correctly across all expected operating conditions.
Customer Buy-Off and Startup Support
Once commissioning was complete, Duke supported the formal customer buy-off process, demonstrating the updated system's behaviour against the agreed specification and working through the sign-off requirements with the customer's engineering team. Following buy-off, Duke remained on site to provide startup support during the initial period of production running, ensuring that any issues arising as the new variant entered the live production mix were addressed immediately rather than allowed to become production problems.
Introducing a new vehicle variant into an existing production programme is always a careful piece of work. The routing logic has to be right first time, because a buffer fault in the middle of a shift does not just stop one car — it can stop the whole line. Offline development and thorough commissioning are not optional on a project like this.
Introducing a new variant or product into your line?
Whether it is routing logic, sequencing, or HMI changes, we can handle the PLC development and commissioning to get your line ready without disrupting current production.
Start a Conversation →The Outcome
The updated PLC routing logic and HMI were successfully commissioned and signed off by the customer. Long wheelbase vehicles entered the skid buffer system alongside the existing standard range without issue, with the routing logic correctly handling mixed-variant production from the outset. Duke's startup support ensured that the transition into live production was smooth, and the customer confirmed a successful handover with no production issues arising from the controls changes.
At a Glance
- Sector: Automotive, West Midlands, UK
- Scope: PLC routing reconfiguration, HMI development, commissioning, customer buy-off, startup support
- Platform: Allen Bradley Rockwell
- System: Skid buffer conveyor network
- Change: Accommodation of long wheelbase vehicle variants
- Approach: Full offline development before any live system changes
- Status: Complete. Full customer buy-off achieved, clean production startup.