XLplc
XLplc is an eXtension Library for PLCs used for Batching and Blending system automation. Any process that combines a number of measured ingredients based on a predefined recipe into a single product or batch will benefit from using XLplc. The cycle is repeated to produce multiple batches. Normally the measured (weighed) ingredients are combined in a mixer where additional ingredients may be added, and the mixture processed further to complete the final product.
The Recipes
The recipes are entered by the plant operator and when run by the Scheduler cause the process to combine specific ingredients in a sequential order. Each recipe is given a name and the operator is free to develop as many recipes as required to meet production requirements.
For continuous flow type systems the use of the Fork & Join recipe commands allows multiple processes to run concurrently.
The Scheduler
The Scheduler is part of the XLplc library and its function is to process the production schedule entered by the plant operator. Each line in the production schedule will process a quantity of batches to a specific recipe. When “Batches Done” is equal to “Batches”, the Scheduler will move to the next “waiting” recipe in the list.
XLplc
XLplc is a configurable PLC library software module developed to meet the requirements of Industry 4.0, and also reduce the cost and simplify the implementation of batch based automation systems. XLplc was written using the OOP extensions to IEC61131 and provides a suite of Function Blocks (FBs) that are utilized to quickly automate ingredient based batching and blending processes.
Data Base API
The PLC provides access to the XLplc database via the SQL API. The database can reside on the PLC or on a remote network connected server. All XLplc data is stored in the database, including logged production history information.
HMI interface API
The function of this API is to only allow valid data entries by the Operator, this protects XLplc from incorrect data, and simplifies the HMI.
XLplc can be used with any HMI or Scada system that supports tag data communication using OPCuA. Included with the XLplc library is our Indusoft HMI/Scada reference design.
The Codex Commands API
A running XLplc system is operator controlled via recipes run by the Scheduler. Each line in a recipe must have a command statement that is executed by this API, which in turn controls the behavior of the XLplc library.
The principle benefit of separating out the Cdx Cmmands into their own API enables the command vocabulary to be extended independent of the XLplc PLC library.
Features & Benefits
- Written using the IEC61131 PLC programming standard ensures XLplc is both configurable and extendible.
- Meets fundamental requirements of ISA88 Master and Control Recipes.
- Process specific automation requirements are controlled using traditional PLC programming techniques using IEC61131.
- Considerably reduces PLC software development time as XLplc provides all the core functionality for batch & blending based processes.
- Large user base ensures a high level of reliability and versatility.
- Recipe validity checks block invalid material path selections.
- Extensive list of predefined alarms gives instantaneous feedback of process faults.
- Reduced commissioning time.
- Extensive logging of production data to the database.
- Exportation of Big Data from the database tables to XML format files.
- Filtering and processing of Big Data files for corporate reporting.
- Interface API for HMI and Scada systems allows implementations using low cost touch screens.
- Built in Alarms only need to be displayed by the HMI/Scada system.
- Configuration only limited by PLC memory size. i.e. ( number of ingredients, recipes, etc…..)
- Recipe command vocabulary (CdxCommands API) can be extended independently of the XLplc library.
The PLC Application
The application programmer uses the XLplc Function Blocks (FB’s) and configuration settings to build up the core module to suit the typology of the batch/blending process equipment.
The following diagram depicts how several FB’s are interconnected to control a typical batch process that has two ingredient storage bins, one scale and one accumulator all connected with material transfer paths.
