After working extensively with the largest steel producing organization in the world, Automation Software & Engineering (AS&E) developed a Level 2 Control System that provides supervisory control for a Continuous Caster.
Continuous Casting is the process by which molten steel is solidified into a semi-finished billet, bloom, or slab that will later be rolled in the finishing mills. The Caster Level 2 system, which incorporates a whole range of process control and instrumentation components, includes communication modules for data exchange with a wide variety of other systems, including:
- Business/ERP/Level 3/MES Systems — Business system integration is configured to use internally supported data interchange methods. These include but are not limited to TCP/IP sockets, file transfer, MSMQ, Database staging tables, etc.
- External Supervisory Control Systems that provide supervisory control for all units involved in the steel making process such as the:
- Blast Furnace which produces molten iron
- Basic Oxygen Furnaces that convert iron into steel
- Ladle Management Facility which allows fine control of steel properties such as alloy chemistry, vacuum processing and temperature
- Message exchange with External Level 2 Supervisory Control Systems is done using customer developed TCP/IP Sockets and UDP. Incoming information includes heat and unit status information, while outgoing messages contain heat pacing information and production reporting
- Caster Level 1 Control System that provides detailed mechanical and electrical control of the caster machinery such as strand speed, tundish level, spray cooling, mold level, torch cut and run out stations. Level 1 communications use an I/O point based service that modularly provides support for the multiple PLC protocols used in the facility. All of the Level 2 logic is then written using logical I/O points that are PLC and protocol independent.
- Process and Business Data warehouses – This information is generally exchanged directly at the database or PI system interface level. Incoming information includes production standards and practices as well as sales, product and customer information from the Business Data Warehouse database. Outgoing information includes production and process information from cooperating L1 systems, as well as internal tracking and quality information.
- Grade and Practice System containing definitions of operational standard The Caster Level 2 System is designed using modern, reliable technologies such as Microsoft .NET, MSMQ, SQL Server, and WCF. Source code for the entire system is provided and exists in a single .NET solution in order to facilitate building and debugging. The HMI is built using the Windows .NET platform with Visual Studio. Active Directory permissions are based on AD groups and/or users. Permissions are managed in SQL Server which permits dynamic modifications. No re-compiling or system restarts are required. The system features a distributed design for a very scalable solution. For example, an existing implementation supports over 60 instances of the HMI running simultaneously, allowing a large number of authorized users to access and utilize the system at the same time.
The Caster Level 2 System is designed using modern, reliable technologies such as Microsoft .NET, MSMQ, SQL Server, and WCF. Source code for the entire system is provided and exists in a single .NET solution in order to facilitate building and debugging. The HMI is built using the Windows .NET platform with Visual Studio. Active Directory permissions are based on AD groups and/or users. Permissions are managed in SQL Server which permits dynamic modifications. No re-compiling or system restarts are required. The system features a distributed design for a very scalable solution. For example, an existing implementation supports over 60 instances of the HMI running simultaneously, allowing a large number of authorized users to access and utilize the system at the same time.
The System Tracking feature monitors the state of the caster and matches production orders to actual steel production. The responsibility of the tracking process is to follow the steel as it progresses through the casting machine while performing the following major functions:
- Receive information about each heat that is produced by the BOF including location, temperature and status
- Match each heat of steel to a heat that was ordered. These details are obtained from the schedule received from the business/ERP/MES system.
- Continuously:
- Calculate current heat on load arm, cast arm, tundish and mold
- Associate each inch of strand production to its source heat
- Model and track the cuts required to produce the slabs that were ordered and scheduled for production
- Send messages to cooperating subsystems informing them of significant events such as new heat casting, slab cuts and schedule changes
- Detect conditions that must be reported or corrected
These processes allow the system to:
- Track every inch of steel that is cast
- Accurately track and score under degraded conditions. Stock objects such as heats, slabs and schedules can be created to continue production, allowing the caster to create sellable product, even when data are not available from the Level-3 business system or other steel/iron producing units. Production data are queued during periods of lost connectivity and then sent once the communications link is restored
- Handle Aborted ladles that are re-processed at the LMF, then returned to the Caster
- Handle interrupted schedules — where a schedule is started on one cast sequence and finished on another
- Load schedules so that slabs are cast in reverse order and/or on swapped strands or a single strand. This flexibility provides the opportunity to continue casting when there is equipment failure and the operating conditions are less than optimal
The Quality Service is responsible for monitoring the process from the standpoint of detecting flaws in the product, or in the process that created the product. Quality scoring is driven by hierarchal tables enabling qualified personnel to change the behavior of scoring without having to restart the system or recompile any software. Quality scoring parameters are set for all grades, grade groupings, or for specific grades. If desired, qualified personnel can create quality rules “on the fly” (for example “If Customer = “X” and Grade=“Y” and defect “Z” exists, then apply hold code “A”).
This service consists of threads that monitor three views of the final product:
- Inch Scoring — Every inch of every slab is evaluated for possible defects. As each new inch of steel is cast, the quality process collects over 200 different measurements and caster status points. This information is then used to detect approximately fifty different defects.
- Heat Scoring — Heat scoring involves scoring related to the metallurgical properties of each heat of steel. Measurements of the chemical makeup of each heat are calculated at various points in the process and are received and processed by this service. The heat’s chemistry is compared to the standard for the grade of steel that was ordered and defects related to this mismatch are calculated and saved. The chemistry defect code of each slab depends on this scoring.
- Slab Scoring — The slab scoring service aggregates the inch defects and chemistry scoring information for each slab and calculates the final quality codes that are used in determining the slab’s suitability for its order purpose. It also calculates a conditioning code that shows how a slab’s quality can be restored by applying a conditioning “fix up” operation.
Additional features of the Caster Level 2 System include:
- Playback:
- The entire Caster Level 2 system can be run in a playback mode on an offline computer using historical data recorded by the online system during normal production. With the exception of outputs being sent to the Level 1 controllers the system is fully functional, including all HMI functionality. The playback mode is an extremely efficient debugging and analysis tool.
- Real-Time Shadow System:
- The Shadow System provides all functions of the production system in real-time except Level 1 control outputs which are isolated from the plant systems. The shadow system simultaneously tracks the caster along with the production system, including responses to operator interventions made on the production system. Typically, software changes are tested on the shadow system and validated for expected results before being deployed to production.
- Configuration:
- System is designed to be extremely flexible. Constants and mill parameters are stored in a master configuration file or in SQL tables.
- Common Logging:
- All processes use the same mechanism to log events, warnings, errors, and exceptions. Data can be sent to a flat file, SQL, or emailed. SQL event logging is queued to avoid process blocking
- Voice Alarm System:
- System can be fully integrated with the mill radio system
- System is configurable via the Caster HMI. For example, qualified personnel can silence specific voice alarms via the HMI
- Voice alarms utilize Microsoft Text to Speech technology
See how AS&E’s expertise in process control and instrumentation can make a difference in your operation — contact us now.