Project Snapshot | Steel Producer

Client: Steel producer – Wire Rod Mill (greenfield project) - India
Industry: Steel rolling / long products
Location: Toranagallu, India
Services provided: I/O allocation from mechanical plan, PLC and RIO panel design, DC drive panel design, main pulpit and local desk design, junction box engineering, documentation
Software used: Eplan Electric P8, MS Office
Hardware used: Siemens S7-400 PLC, ET200M remote I/O, Siemens TP700 Comfort HMI stations, DC drive panels
Key result: Fully engineered control and drive panel package aligned with mill mechanical layout, ready for commissioning and long-term maintenance
Duration: 9 months covering detailed engineering to approved drawings

Client & Project Background

The client was setting up a new greenfield Wire Rod Mill and required a complete control and drive panel engineering package to support high-speed rolling operations. The project covered the entire line, from entry to finishing, and demanded a robust and scalable PLC-RIO architecture matched to the mechanical layout of the mill. APC Engineering Services was engaged to design the main PLC panels, ET200M-based remote I/O panels, DC drive panels, main pulpit and local control desks, and junction boxes using Eplan Electric P8.

Challenge / Requirements

The Wire Rod Mill consisted of multiple process zones (roughing, intermediate, finishing blocks, shears, cooling line, coilers), each with a large number of drives, field devices, and interlocks that had to be reflected precisely in the I/O allocation.
Mechanical and layout plans needed to be translated into a logical and maintainable I/O structure for S7-400 and ET200M stations, considering cable routing, panel locations, and environmental conditions.
Main PLC panels, RIO panels, DC drive panels, main pulpit, local control desks, and various junction boxes all had to be coordinated so that wiring, naming, and interlocking were consistent across the entire mill.
The design needed to support reliable operation at high rolling speeds, provide clear diagnostics, and allow future additions or modifications.

Solution (APC approach)

1. I/O Allocation and Architecture

Studied the mechanical GA drawings and equipment layout of the Wire Rod Mill to map all motors, actuators, sensors, and interlocks to specific I/O points.
Designed a distributed I/O architecture with Siemens S7-400 as the central PLC and ET200M remote I/O panels strategically located near process sections to optimize field wiring and reduce cable lengths.
Grouped I/O by functional areas (e.g., roughing stands, intermediate stands, finishing blocks, shears, cooling conveyors, coilers) to simplify commissioning and troubleshooting.

2. Panel, Pulpit, and Desk Design

Engineered main PLC panels housing the S7-400 CPUs, communication modules, and central power distribution, with clear separation of control and auxiliary circuits.
Designed ET200M-based RIO panels, DC drive panels, junction boxes, and marshalling arrangements in Eplan Electric P8, including detailed terminal assignments and cable numbering.
Developed layouts and schematics for the main pulpit and local control desks, providing operators with controls and indicators for key mill sections and integrating emergency stop and interlock functions.

3. HMI and Control Philosophy

Allocated HMI functions to multiple Siemens TP700 Comfort panels placed at suitable locations, giving local control and status views for specific areas of the mill.
Defined standard signals and naming for speed references, status feedbacks, alarms, and interlocks so that PLC, HMI, and DC drive panels shared a common control philosophy.
Ensured that panel and I/O design supported wire rod mill automation needs such as material tracking, interlocking sequences, and drive coordination.

Results & Benefits

Delivered a complete, consistent design package covering main PLC panels, ET200M RIO panels, DC drive panels, MIMIC Panels, PA Systems, main pulpit, local control desks, and junction boxes, all aligned with the mechanical layout of the Wire Rod Mill.
Simplified installation and commissioning by providing clear I/O allocation, terminal plans, cable schedules, and device tagging, reducing ambiguity for panel builders and install teams.
Established a scalable control architecture with S7-400 and ET200M, allowing the client to expand or modify sections of the mill in the future without redesigning the entire system.
Improved long-term maintainability thanks to standardized naming conventions, structured documentation, and operator stations (TP700 Comfort) tailored to process zones.

Tools & Technologies Used

Design: Eplan Electric P8 for schematic drawings, panel layouts, terminal diagrams, cable lists, and BOMs for PLC, RIO, drive panels, pulpits, local desks, and junction boxes.
PLC & RIO: Siemens S7-400 as the main PLC platform, ET200M remote I/O stations for distributed signal acquisition and control in the mill.
HMI: Siemens TP700 Comfort panels for localized operator control and visualization of key sections of the Wire Rod Mill.
Application domain: Automation and control design aligned with typical wire rod mill requirements (material tracking, interlocking, drive coordination, and process monitoring).

“APC Engineering Services provided a comprehensive control panel and I/O design for our greenfield Wire Rod Mill. Their detailed Eplan documentation for S7-400, ET200M RIO panels, DC drive panels, pulpits, and local desks has greatly simplified installation and commissioning. The structured I/O allocation and clear layouts give us confidence for future expansion and long-term maintenance of the mill’s automation system.”

Case Study