In the field of automation, particularly within the framework of ISA-95, significant opportunities and challenges have emerged for effective data management. Consequently, this discussion delves into the fundamental concepts of the ISA-95 standard and its criticality in optimizing manufacturing processes.
In the transition of industrial manufacturing from manual operation to unmanned operation, the Industrial Automation and Control System (IACS) servers as the core enabler. It replaces human intervention in executing a series of operations, such as equipment startup/shutdown, parameter regulation, and fault pre-warning, ensuring efficient, stable, and secure production. Whether it is the coordination of multiple arms in car assembly lines or the automation and control of chemical processing lines required to conduct precise temperature and pressure experiments, the processes of industrial automation are becoming significantly more complex. These complex processes require more than simple automation; they require a comprehensive industrial automation system, often referred to as an “intelligent brain and neural network” for manufacturing. In industrial automation, the systems are hierarchically organized and divided in five levels. These five levels are described by the called Purdue Model or Automation Pyramid.
1.Field Level
Industrial automation systems typically employ a five-layer 'Automation Pyramid' architecture, with the Field Level situated at the very base. In essence, the Field Level functions as the 'sensory organs and limbs' of industrial automation, responsible for direct interaction with the physical world. In industrial automation, the Field Level constitutes the lowest tier of the system architecture, interacting directly with physical production processes and taking responsibility for data acquisition and the execution of control actions.
Functional of the Field Level:
| Category | Technical Function | Industry Examples |
|---|---|---|
| Data Acquisition | Conversion of physical phenomena into measurable electrical signals (Analog/Digital). | Sensors & Transmitters: Thermocouples (temp), RTDs, Pressure Transmitters, Flow Meters, Encoders (position). |
| Execution & Control | Translation of control signals into physical action or mechanical energy. | Actuators: Control Valves, Variable Frequency Drives (VFDs), Servo Motors, Pneumatic/Hydraulic Cylinders. |
| Ancillary & Integration | Hardware that bridges the gap between field devices and high-level controllers (PLC/DCS). | Distributed I/O: Remote I/O Modules, Intelligent MCCs, Specialized Motion Controllers, Industrial Robots. |
2.Control Level
In industrial automation, the Control Level represents a pivotal tier within the hierarchical architecture. It is primarily responsible for the real-time execution of control logic, processing sensor data, and driving actuators to achieve precise regulation of physical processes
Primary Control Level Equipment:
PLC - (Programmable Logic Controller) - A type of computer which is used for sequential and logic control in discrete (non-continuously produced) manufacturing facilities such as an assembly line, robot cell or kiosk. The PLC is widely used for automation in manufacturing and processing industries.
DCS (Distributed Control System) - what is it? DCS is an analog closed-loop control system used in the continuous process industries such as petro-chemical, power generation, water treatment and other similar applications.
Dedicated Controllers and PID Controllers: Including robot controllers and motion controllers, these are frequently integrated into PLCs or DCSs for the precise regulation of parameters such as temperature, pressure, and flow.
3.Supervisory Level
The third tier of the automation hierarchy is defined as the 'Supervisory Level.' While the preceding level utilizes PLCs, this level employs SCADA—an acronym for Supervisory Control and Data Acquisition. SCADA essentially integrates the functions of the lower levels to enable data access and system control from a centralized location. It typically includes as well a Graphical User Interface (GUI) or HMI (Human Machine Interface) and remote control.
Function of Real Time Production Monitoring System: acquire production information in real time from the field devices like PLC/DCS/sensors, and provide clear Visual Interface (HMI) for the operators to monitor the real time production information, and send setpoint / command to the lower-level controllers. It is also responsible for historical data logging, as well as alarm and report generation.
Typical Systems: The SCADA (Supervisory Control and Data Acquisition) system is the quintessential representative of this tier; it is also commonly referred to as the Supervisory Control System (Host PC System), serving as the 'Industrial Brain' of the operation.
4.Planning Level
Create Systems design and manage production scheduling, work order and quality processes for a variety of manufacturing clients. At a high level, we can coordinate a manufacturing operation to ensure that the correct resources are allocated to a task to meet a set of production objectives. This high level layer of manufacturing automation automates production planning and scheduling at a macro level and coordinates the resources assigned to a production task. It defines the production objectives, determines the resources needed to meet those objectives, schedules the production, coordinates the tasks involved in the production and manages the information flow between the business systems (ERP, PLM). The highest level of the automation pyramid performs long-term scheduling, order processing and financial/accounting functions. Strategic management decisions are performed at this highest level of the automation pyramid. Create Systems then distributes the production orders and production instructions to the lower levels of automation (MES) and captures the status of executed production tasks from automated manufacturing execution systems.
5.Management Level
As the apex of the automation pyramid, this layer comprises Enterprise Resource Planning (ERP) systems designed to manage business operations, including finance, sales, procurement, and strategic planning. Data from lower levels is integrated into these systems to facilitate high-level decision-making. This category encompasses information regarding Production Planning and Scheduling. It includes data pertaining to production orders, work orders, production sequences, task start and completion times, as well as any modifications to the production schedule. MPL also encompasses information relevant to manufacturing process performance analysis, such as plant and line performance data, for example cycle time, throughput, downtime, manufacturing KPIs, quality etc. This type of information may include details on Quality Control / Compliance such as quality standards, inspection results / test data, non-conformities (NCs), corrective / preventative actions (CPA/CPA) etc. The module contains also information about Equipment Maintenance, reliability and Asset Management. Information includes maintenance calendars and schedules, performed activities (repairs, PMAs, etc.) as well as MRO (Maintenance, Repair and Operations) inventories. Data about Condition Monitoring (CM) and Predictive Maintenance (PDM) tests performed are also included.
Summary:
The EA (Equipment and Asset) Object Model of the Equipment Object within the ISA-95 standard defines physical production equipment or resources and their associated logical resources. The Model structures the hierarchy of manufacturing equipment and establishes a standard naming convention for describing, monitoring, controlling and maintaining production equipment. Addressing the business needs of industrial management, the ISA-95 standard promotes interoperability and integration of equipment and processes across the manufacturing enterprise.
