Tape/Vol. 11: Distributed Control of Cells and FMS Systems.

Tape/Vol. 12: Integrated Shopfloor Control (ISC).

 

In this program we discuss the following:

• Distributed control of cells and FMS systems
• Requirements analysis
• Local Area Networks (LANs) linking cell controllers and the factory LAN
• Factory and plant-wide control, area control, cell and sensory level control
• Integrated Shopfloor Control (ISC) discussion, examples and software demonstration by ERT Ltd.
• Shopfloor data collection and analysis
• Interactive team and/or individual exercises. 

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Next, consider that in-order to optimize production and data interchange between different cells and systems, the system designers have to link individual, stand-alone cells into a network. This is indicated below. The factory LAN (Local Area Network), and below that, as the cell control network is linked into a communicating system.

The vido screen print illustrates a modern manufacturing cell/ system under distributed control. (At the top right hand side notice the Automated Storage and Retrieval System, then the railed cart, painted orange, that provides the material handling link between the ASRS and the processing stations/ machine tools. Also notice the overhead transportation system, in the front, used for tools between the tool-store and the individual Automated Tool Storage/ Changer systems). (Courtesy of Yamazaki Mazak, Japan).

An enterprise - wide IT system architecture

The 'big picture' is always exciting because it shows the difference between efficient and wasteful enterprise information systems.

The concept illustrated below, courtesy of DEC, gives a simplified view of the way the sensors and machine processes are integrated with the PLC (Programmable Logic Control) and other devices, running fast fieldbus and profibus networks at cell control level, as well as with the plant and then with the enterprise-wide systems.

As part of a team, discuss, or if you are studying on your own, think about the following:

• What are the most important components of an enterprise-wide network?
• What processes do different components perform?
• How do the different components communicate with each other and with "outside" systems?
• What data do they communicate?.. To whom? .. and Why?

Preferably as part of a team, discuss and consider the following:

• Discuss integrated and distributed shop floor control (ISC) principles and technologies;
• Who is using the ISC information ?
• What information is communicated and why?
• What are the basic ISC system components ?
• Discuss traceability... Why is tracebility of parts, objects and events important?
• CNC program version control...How do operators control different CNC program versions?
• Performance data analysis... How and why is performance data recorded and analysed?
• Information reproduction and report generation... What sub-systems generate such reports and for whom?

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In this video program Mr. Wim Onink discusses the following:

• Integrated Shopfloor Control (ISC) (ERT case study and software demonstration cont.)
• Signal monitoring at shop floor level
• Real-time shop floor data collection; Process analysis
• Ordering and costing information collection and analysis
• ISC with industrial case studies and examples; Integration
• The "linguistics" of interfacing versus shop floor data integration
• Interactive team and/or individual exercises. 

Based on the presentations consider and discuss the following...

• Discuss shop floor signal monitoring...
• What information is collected and why ?
• Who is using this information ?
• What are the CIM application areas ?
• What are the methods for analyzing the obtained data

In this image (taken from the original digital video clip) you can see a small CNC lathe with an integrated robot arm that is employed to load and unload parts from a buffer (this can be seen on the left hand side of the image) to the machine tool under CNC control (Computer Numerical Control). Obviously the loading/ unloading robot's controller must communicate with the machine tool's CNC controller to avoid any conflicts. (Note, taht a "conflict" in this case can mean that the robot crashes the part into the sliding door, or the chuck of the machine, and others).

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In this image (taken from the original digital video clip) you can see a vertical CNC mill with a probing head aligning the co-ordinate axes of the part program with the actual part. The benefit of this technique is that even if the part is loaded onto the machine with some error, however small that error is, the machine will automatically correct this by re-aligning itself. This particular Hitachi-Seiki machine can re-align itself in 3D. (This is an advanced feature. Most machines can do this only along 2 axes).

Based on the presentations consider and discuss the following...

• Discuss shop floor monitoring...
• Interfacing versus integration...what is the difference?
• Shopfloor data collection methods... and
• data analysis methods and their use.

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Based on the presentations consider and discuss the following...

• Discuss Integrated Shopfloor Control (ISC) Management issues...
• Why do we need such systems and what are the tangible benefits?
• What are the objectives of ISC systems?
• Why is modular (object oriented) development important ?
• What are the spin-offs of such systems?

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