Modernizing Paper Machine Wet End Controls for Faster Startup and More Reliable Mixed Runs
CASE STUDY
Hargrove Controls & Automation helps a recycled paper mill convert manual wet end procedures into automated Rockwell PlantPAx sequences that improve consistency, reduce operator workload, and support smoother mixed runs.
OBJECTIVE: The primary objective of the larger project was to modernize the paper machine’s wet end controls in a Rockwell PlantPAx environment while creating intuitive graphics and control routines for operators.
An additional objective was to automate startup, shutdown, flushing, and stock transition sequences that were previously performed manually. A successful solution would help operators run the same sequence consistently, reduce the risk of missed or out-of-order steps, and make it easier to transition between stock types during production. The solution also needed to give operators flexibility to select which vats would run, which stock each vat would use, and when the system should start, stop, flush, or transition.
CHALLENGE: Before the upgrade, operators had to walk the wet end, verify equipment status, check vat levels, and manually open or close flush valves. If steps were missed, delayed, or completed out of order, the process could experience plugging, messes, or downtime. The mill wanted a repeatable sequence that operators could execute the same way every time, reducing the risk of missed or out-of-order steps.
The mill also needed the new sequences and graphics to be practical for operators adjusting to a new control interface and quality control system. One vat added complexity because it required the ability to switch between multiple valve combinations on the fly without shutting the process down. Once the mill approved the change order, Hargrove had approximately two weeks before factory acceptance testing to develop the sequence logic and associated graphics.
Solution
Converting Manual Procedures into Automated Sequences
Hargrove worked collaboratively with the mill’s process engineer and production leadership, asking detailed questions about how the wet end operated and recommending automation for manual startup, shutdown, flushing, and stock transition procedures. Together, the team defined how the system should start, stop, flush, transition, and respond once it reached steady state.
Using that information, Hargrove developed PlantPAx-based sequences that allowed operators to select the desired vats and stock types, then initiate automated functions from the control system. The routines automated steps that previously required manual action, including flushing lines, opening valves to defined positions, confirming flow conditions, and preparing the process for automatic control.
The team also accounted for upset conditions, including device failures, high levels, low flows, and interlocks. Because the mill was moving to a new control environment, Hargrove also worked with the client to make the graphics intuitive for operators in normal and abnormal conditions.
During software FAT, the sequences performed as expected. During commissioning, the most complex vat sequence initially stalled. Hargrove identified the issue, revised the logic on-site, and retested the sequence with the client.
Results
Flawless First Mixed Run and Reduced Operator Workload
After implementation, the mill completed its first true mixed run using the new automated wet end controls. The controls performed as intended, and the improvement was noticeable to the operators running the machine. As the mill’s process engineer shared after the run, “Our first true mixed run went flawlessly. The machine tenders commented that the transition to mixed operation with the new wet end controls was a significant improvement over the previous process.”
The automated sequences gave the mill a more consistent way to manage wet end startup, shutdown, flushing, and stock transitions. Instead of manually opening each flush valve or shutting down each vat individually, operators could use automated flush, shutdown-all, and startup-all functions from the control system. Operators could now perform those functions with a few actions from the operator interface. The new controls also reduced operator workload. Previously, startup checks could require operators to walk the wet end, inspect vat levels, confirm equipment status, and prepare the process for automatic operation. Based on a rough project estimate, automating portions of the sequence reduced startup-related effort by approximately 30 minutes, saving an estimated 8 hours per month.
The mill also gained improved automatic level control. Although the client did not expect to use automatic vat level control regularly with the existing equipment, the upgraded system allowed the mill to run those controls in automatic mode, reducing the number of variables operators had to manage manually.
By taking the time to understand how the mill actually operated, Hargrove helped transform years of operating experience into repeatable control logic that improved consistency, reduced manual effort, and supported smoother mixed operation.
Stay Informed
Read from our blog featuring Hargrove Teammates
From Predictive Maintenance to Process Optimization: AI’s Growing Impact on Industrial Automation
By Ryan Grove, Hargrove Controls & Automation Engineer In industrial automation, new technologies are often adopted gradually due to safety and [...]
Functional Safety Assessments: Verifying Your Safety Systems Will Perform as Intended
by Cheryl Garcia | Process Safety Technical Consultant A functional safety assessment (FSA) is a structured, independent review required by IEC [...]
How Control Narratives Can Ensure Automation Success
By Chase Beard. P.E., Technical Manager, Pulp & Paper Industrial automation project success often hinges on clear communication between technical teams [...]
Subscribe to Our Newsletter
Stay up to date on the latest Hargrove News & Insights.
