PLC Technology and Control Principles
In modern mill facilities, PLC (Programmable Logic Controller) systems form the fundamental building blocks of efficient and consistent production. These intelligent control systems provide stable product quality even under variable raw material conditions, maximize operational efficiency, and optimize costs, offering significant advantages in today’s competitive market.
As Tanış A.Ş., combining our over 60 years of experience in the milling industry with modern automation technologies, we develop and implement PLC solutions customized for your facilities. With our control systems that optimize all mill processes from raw material acceptance to shipping, we add measurable value to your business.
Mill facilities have unique control requirements:
PLC systems are programmable electronic devices that form the heart of industrial control and automation applications. Their basic components and functions include:
PLC Architecture: The modular structure consisting of CPU (central processing unit), input/output modules, communication modules, and power supply offers scalable solutions according to the different needs of mill facilities.
Input/Output Modules: Processing digital and analog signals, receiving data from sensors and sending commands to actuators. Provides control of parameters such as temperature, pressure, level, and weight in mill processes.
Program Structure: Control logic created using IEC 61131-3 standard programming languages such as ladder diagrams, function block diagrams, and structured text manages process flow.
Communication Protocols: Using industrial protocols such as Ethernet/IP, Profinet, and Modbus TCP, PLC systems communicate with SCADA, HMI, and other devices, creating an integrated control network.
Batch and Continuous Process Control: Requires different control strategies for batch processes like conditioning and continuous processes like grinding.
Sequence Control: Sequence control structures that automate starting, stopping, and operating the system in a specific order and logic minimize operator errors.
Alarm Management: Alarm systems that detect process deviations and equipment failures, alert operators, and provide safe shutdown when necessary are critically important.
Recipe Management: Recipe systems that store parameters determined for different product types and automatically apply them during production transitions ensure product consistency.
Selecting the right PLC hardware for mill facilities depends on the following factors:
CPU Performance: Appropriate processor selection should be made according to facility size, process complexity, and control loop speed.
I/O Capacity: Sufficient input/output capacity should be planned based on the number of sensors, actuators, and control points.
Field Device Integration: Communication requirements of intelligent devices such as motor drives, weighing systems, and speed control units should be considered.
Control Panel Design: Panel layout, cable management, thermal management, and ergonomic access should be meticulously planned for a reliable PLC system.
Redundancy: Uninterrupted operation guarantee can be provided with CPU and power supply backup for critical processes.
An effective operator interface is an important part of system control:
Screen Hierarchy: A logical navigation structure consisting of main screen, process screens, detail screens, and alarm screens enables operators to use the system effectively.
Authorization: Different access rights defined at operator, technician, engineer, and manager levels provide secure system management.
Alarm Management: Effective management of critical situations is possible with prioritized alarm display, acknowledgment, and history functions.
Trend Display: Monitoring critical process variables such as temperature, pressure, and humidity with time-based graphs facilitates process analysis.
Raw Material Acceptance and Pre-processing Automation
PLC applications in the first stage of mill processes:
Grain Reception Systems: Control systems that manage automatic weighing, sampling, and silo assignment based on quality parameters.
Cleaning Equipment: Synchronized control of cleaning equipment such as destoners, trieurs, and sieves and automation that provides optimum performance.
Conditioning Control: PLC control that automatically adjusts water addition amount and resting time according to raw material characteristics.
Silo Management: Systems providing optimum stock rotation and level control by monitoring fill rate, temperature, and humidity.
Advanced control applications in the grinding process, which is the heart of mills:
Roll Control: Applications providing optimum grinding performance with roll gap, feed amount, and speed control.
Sifting Control: Systems that monitor sieve performance, detect blockages, and manage cleaning functions.
Grinding Parameter Monitoring: Control systems that continuously monitor critical parameters such as motor load, temperature, and vibration to provide optimum operating conditions.
Product Flow Management: PLC applications that offer flexible production capability with automatic control of dampers and valves that direct product flow.
Precise control systems for mixing and blending products with different characteristics:
Dosing Control: PLC applications providing precise proportioning with gravimetric or volumetric dosing systems.
Multi-component Mixing: Automatic systems that mix different flour types, additives, and enrichers in specific proportions.
Recipe Management: Recipe systems that store product formulations, perform version control, and manage production transitions.
Product Consistency: PLC applications that monitor mixture homogeneity and continuously control quality parameters.
Packaging and Shipping Automation
PLC control for efficiency and traceability in post-production processes:
Packaging Sequence Control: Automatic control systems that synchronously manage filling, weighing, sealing, and labeling steps.
Weighing Systems: PLC applications providing precise filling control with dynamic or static weighing systems.
Palletizing Systems: Control of robotic systems that stack packages in specific arrangements and stretch wrap them.
Lot Tracking: Data management systems that record production and packaging information and provide traceability.
Advanced PLC Technologies and Integration
SCADA and MES Integration
Integration of PLC systems with higher-level systems:
PLC-SCADA Communication: Infrastructure providing seamless data flow between PLC and SCADA systems with protocols such as OPC UA and MQTT.
Real-time Monitoring: Real-time viewing, recording, and analysis of all process parameters.
Production Reporting: Systems that generate shift, daily, weekly, and monthly production reports and analyze efficiency.
OEE Calculation: Monitoring performance, availability, and quality metrics through Overall Equipment Effectiveness calculations.
PLC-based solutions for future smart factories:
Smart Sensors: Integration of advanced sensor systems that self-monitor, calibrate, and provide diagnostic information.
Edge Computing: Applications providing fast response and bandwidth optimization with local data processing on PLC platforms.
Cloud Integration: Secure transfer of PLC data to cloud platforms, enabling remote monitoring and analysis.
Predictive Maintenance: Integration of smart algorithms that continuously monitor equipment condition and detect potential failures in advance.
Seamless integration between business processes and production systems:
Inventory Integration: Automatic transfer of raw material consumption and product production to the ERP system.
Production Orders: Automatic transmission and execution of production orders from ERP to the PLC system.
Quality Management: Automatic collection of quality data and integration with quality management systems.
Cost Analysis: Integration of production data with cost accounting systems, product-based cost analysis.
Advanced control techniques for efficiency and quality:
PID Control: Automatically tuned PID algorithms for precise control of variables such as temperature, pressure, and flow in mill processes.
Model-based Control: Advanced control strategies that model and predict process behavior.
Statistical Process Control: Control systems that minimize variation in quality parameters using statistical methods.
Energy Optimization: Algorithms that monitor, analyze energy consumption and provide maximum efficiency with minimum energy.
Requirements Analysis and System Design
Comprehensive analysis and design for a successful PLC project:
Functional Requirements: Detailed analysis of equipment to be controlled, processes, and operational needs.
System Architecture: Design of control hierarchy, communication network, and hardware configuration.
I/O List: Comprehensive list of all input/output signals and hardware specification.
Control Algorithms: Design of logical flow and algorithms for process control, sequence control, and safety functions.
Standards for sustainable and reliable PLC programs:
IEC 61131-3 Compliance: Use of standard programming languages such as Ladder Diagram, Function Block Diagram, and Structured Text.
Modular Program Structure: Easy maintenance and development with functional blocks, reusable routines, and modular structure.
Documentation: Comprehensive program documentation with in-code comments, variable definitions, and flowcharts.
Version Control: Recording program changes, reversibility, and change traceability.
Comprehensive testing for reliable and trouble-free systems:
Factory Acceptance Tests: Testing all functions of the system in a controlled environment before delivery.
Simulation: Validation of PLC programs in a simulation environment before field installation.
Loop Testing: Testing each control loop separately, validating inputs and outputs.
Functional Tests: Testing and validating the integrated operation of all equipment and systems.
Critical measures for secure and compliant systems:
Cybersecurity: Protection of PLC systems with access control, encryption, and firewalls.
Emergency Functions: Emergency stop and safety circuits that ensure the system goes to a safe state in situations that would pose safety risks.
Backup Procedures: Regular backup of programs, configurations, and parameters and recovery plans.
Validation: Verification that the system performs its intended functions correctly and reliably.
Operational Efficiency and Performance
Contributions of PLC systems to mill efficiency:
Increased Production Capacity: Reducing interruptions through automatic control and achieving maximum capacity utilization.
Reduced Downtime: 60-80% reduction in unplanned downtime through predictive maintenance and fast fault diagnosis.
Labor Productivity: Automation of manual operations increases production per operator and reduces labor costs.
Raw Material Optimization: 3-7% savings in raw material usage through precise dosing and process control.