Wonderware's In Touch, a world leading human machine interface (HMI), has been implemented at three out of four plant areas at South African Breweries'(SAB)Rosslyn operation. As a result, SAB Rosslyn has developed a comprehensive site supervisory standard based on In Touch."The implementation of wonderware InTouch-based supervisory standards in three out of four plant areas provides firm platform for future projects in the broader context of manufacturing systems,"says Tim Doyle,Hatch Africa Project manager
The detail of the supervisory standard extends to:
*ontrol system tag naming, description and units of measure.
*Supervisory display layout, hierarchy and control. p Access control.
*Alarms and events.
*PLC interface data structure.
*A standard technology specification.
This means that in the three plant areas there is a similar 'look & feel' and operation on all supervisory applications, which has benefits for training and maintenance. These standards have also been used by SAB in specification form for a new South African brewery in the Eastern Cape.
The standards were initially created by system integrator, Hatch Africa, in close co-operation with SAB Rosslyn as part of a brewhouse upgrade project in 1995. They have since been implemented and advanced in the utilities plant area and have now been extended and installed in the cellars and filtration plant area.
The cellars supervisory system replacement project was undertaken to replace an existing DOS-based supervisory system with a new system based on Microsoft Windows NT and Wonderware InTouch.
The primary motivation for the replacement was that the old system was not Year 2000 compliant. This presented the opportunity to improve current oper-ating philosophies by implementing improved standards and rationalising the supervisory system.
The project included a rewrite of the CIP (cleaning in process) PLC, based on the ANI/SA-S88.01:Batch Control - Models and Terminology standard. SAB Rosslyn now has a Modicon PLC software standard based on S88 batch control standards to provide future integration to a batch control system. The project ran in parallel with a PLC upgrade in the cellars plant area. This ongoing project involves the upgrading and standardisation of Modicon I/O and PLC hardware.
The scope of the project included the design, development, installation and commissioning of a Wonderware InTouch supervisory system in the cellars plant area based on the existing site standards.
The new system, comprising four operator workstations and one technical workstation, replaced seven existing supervisory workstations and a portion of existing mimic panel functionality.
*The design, development, installation and commissioning of a PLC marshalling layer to interface between existing PLC software and the new site supervisory standard configuration.
*The design, development, installation and commissioning of CIP PLC software. The scope included the development of an SAB Rosslyn Modicon PLC Software Standard document in compliance with the ANSI/ISA-S88.01 Standard for Batch Control. This standard forms the foundation for any future Modicon PLC software upgrades.
*The CIP PLC software has been designed to interface seamlessly to a batch execution system. All control modules, equipment modules and phase logic are located in the PLC.
*Commissioning of the complete system included a Y2K system compliance test.
*The project was performed according to Hatch Africa's project management system in terms of ISO certification.
Control module standards
The supervisory and Modicon PLC software stan-dards include identical configuration of each control module type. For example, every open/close valve will be configured in exactly the same way - the same set of tags and tag configuration and the same set of tags for the PLC interface structure. This allowed for the tag database to be auto-generated based on a set of rules and an equipment list with corresponding equipment types.
Great benefits were had in terms of data quality and reduced time to commission. The tag auto-generation was not only used to populate the InTouch database, but also a large proportion of the Modicon Concept PLC software.
Supervisory display standards
The screen is divided into functionally separate areas - four quadrants, alarm banner and display control area.
Mimics are placed within the display area that consists of four quadrants. The contents of the four quadrants are completely flexible, while the contents of the alarm banner and the display control area are fixed. Pop-up displays of any size may be overlaid over any part of the screen, and their location can be changed by dragging them, without any restrictions.
The user has full control over which displays are placed in which quadrants, including the capability to place a large horizontal display across both top or both bottom quadrants. In order to minimise the number of operations required to obtain any information, a set of default display locations exists, which supports a generally applicable display arrangement.
The displays are conceptually structured as a two-level hierarchy. Overview and general displays occupy the top level of the hierarchy whilst summary, detail and specialised displays occupy the bottom level.
The two levels of displays are respectively located in the top and the bottom half of the display area by default. The displays are designed to be used together in a flexible and efficient manner. This is achieved by making the workstation operate within a 'context' chosen by the user - either a complete process cell or a unit in accordance with the S88 standard. To simplify requests for displays and to automatically filter the information being viewed, all displays are based upon the current context. This context is determined by the display that occupies both of the top quadrants.
From within the current context the user can choose to view the alarms, historical trends or Internet Explorer help files associated with that context. This enables the user to always be only 'one click away' from the information required.
For the cellars plant area, the concept of 'pooled' displays was designed and implemented to cater for a specific plant arrangement. In this case, material may be moved through one of several lines to any one of a number of vessels, and plant operation requires visualisation of both units together.
If there were two lines and 50 vessels, this would result in 100 possible combinations and possible displays. These would be time consuming to engineer, maintain and operate.
Two pooled displays cover all of these possibilities. If a line is selected, the pooled display will show the line details and the vessel details (if any), which the line is feeding. If a vessel is selected, the pooled display will show the vessel details and the line (if any) to which the vessel is connected. In effect this means a great reduction in displays and subsequent display maintenance.
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