Happy’s Essential Skills: Computer-Aided-Manufacturing, Part 1—Automation Protocols

Estimated reading time: 19 minutes

I have addressed automation planning previously in this series, so I hope by now you realize the difference between ‘automation’ and ‘mechanization.’ In printed circuit fabrication and assembly, most of what is advertised is mechanization. But when you get to assembly test, then you begin to see true automated solutions. The difference between the two is the networking and protocols that supply the information and data. An industry for us to look to as an example: our brothers in semiconductor fabrication. This industry has had fully automated factories since the mid-1980s.

INTRODUCTION

This column is dedicated to the automation protocols that currently exist and some new ones just coming on the market. In Part 2, I will present some examples from my own projects.

The ‘messages and recipe data’ needed for production scheduling-to-machine connections has evolved over the years. The selections to be covered here are:

• Serial RS-232C/RS-485
• Parallel IEEE-488/HP-IB
• MAPS™ protocol
• SECS I & SECII/GEM protocols
• OML
• IPC-2541
• LAN (IEEE-802.3 and TCP/IP)
• Wireless and IoT

Recipe-to-Machine and Machine-to-Machine

When I started working with automation control in 1970, we had ASCII characters in parallel cabling. So we started by using these printer and teletype protocols to control machines. Sometimes, we had only BCD to work with! Today you have the ‘lights-out-factory’ and Industry 4.0 initiatives. A lot of progress is the result of the automotive industry’s application of PLCs and robots to manufacturing. Figure 1 shows what the Germans foresee for Industry 4.0^[1]. Figure 2 shows the 4-level hierarchy of CAM, while Figure 3 shows typical networked factory control units.

Figure 1: The scope of Industry 4.0 enables an intelligent plant (planet). (Source: Advantech)

Figure 2: Enterprise and plant control topology showing the 4-level hierarchy. (Source: Renesas Edge—Big Data in Manufacturing)

I was fortunate to be employed by Hewlett-Packard. Their 2116-model computers (and later, the 2110) were real-time-interrupt driven computers and ideal for machine control. HP had even developed a CNC machine control system but decided not to sell it since it did not fit their instrument or computer sales force’s experience. They sold all the CNC systems to Allen Bradley in Milwaukee, Wisconsin. Thus, I ended up working frequently with AB to buy back the software that HP had developed. This was serendipitous as AB introduced me to their programmable logic controller (PLC) technology. PLCs became a major tool in machine control.

Figure 3: Typical industrial automation controllers and PLCs. (Source: Wenatchee Valley College, Nevada)

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