Siemens Projects

The Siemens PLC experience was gained while employed as a senior lecturer at the Port Elizabeth Technikon between 2003 and 2006 (later merged with Port Elizabeth University to become the NMMU). The PLC subject was part of the Control Systems II course. When I was given the course, there were some older Siemens S5 and Telemechanique PLCs without updated software. They were part of previous donations. Joe Maczek of Mechanical Engineering gave us R30,000 from his budget towards the PLCs. Rockwell Automation were asked for quotes for PLCs given our budget, but their pricing would result in two PLCs with software, whereas I was able to buy ten with software from Siemens. In a class of thirty students, this was obviously very important to give as many “hands-on lessons” as possible. A-B would have been easier for me, as I knew the Allen-Bradley PLCs. After we had placed the order with Siemens, Rockwell Automation decided to adjust their price, but when it comes to pricing, “your first price is your only price” as far as the department was concerned. No time for games, offers, bribes or whatever. From there, we received close to R500,000 from Siemens and the German government as part of the Defence offset agreement. (The US companies were not involved in any defence contracts after sanctions, so there would be no offset agreements with US companies anyway).

The companies around Port Elizabeth used mainly Siemens, followed by Telemechanique and Allen-Bradley. Allen-Bradley’s market share gain was at Telemechanique’s expense. Any one of them would have been a good choice for the students.


Siemens Laboratory at NMMU

Siemens Lab

PLC Laboratory

Before the ten S7-315 PLCs were delivered, courses were given on the S7-200 family. The S7-315 racks included ET-2000 I/O on Profibus, a motor on a Profibus connected variable speed drive, and a servo controller. The HMI was a Siemens graphics display. Several switches and lamps were connected to I/O cards and the ET-2000.

Besides the Control Systems II, Process Control IV and Automatic Control IV courses, external companies could send staff to complete the Siemens accredited SERV1, SERV2, PRO1 and PRO2 courses. Two to three five-day courses were offered each month during academic holidays (almost half the year).

Non-certified courses were given for the S7-200 Siemens PLCs to introduce students to PLCs. NMMU attendance certificates were issued for courses without any tests, otherwise students had to complete an automation task at the end of the course.


Courses Attended

The following Siemens courses were completed:

 


Industrial Assistance

The MTRC consulted to industry on several projects. The name was changed to the ACTS. One of the projects was to introduce a Panasonic welding robot into a factory that inherited portions of the old Delta Motor Corp tool room and some presses as part of “transformation” for “Black Economic Empowerment”. The welding robot would not displace existing staff, but allow them to complete a month of production in a few hours, plus enter new markets. The robotic station had four doors where operators could clamp parts in fixtures for welding. I programmed the S7/200 in the panel.

The installation was financed by the Tsumisano Trust as part of ACTS support to local industry. The installation was opened on 7th April, 2006, by the Minister of Science and Technology, Mr Mosibudi Mangena, second from the left. The financial director is on the left, and Mr Potgieter, the factory owner is next to Mr Mangena. Anthony and I are in the background keeping out of trouble.

Minister of Science and Technology South Africa

We presented a paper about the robotic station, which can be downloaded here (PDF) 57 kBytes, or the PowerPoint presentation which is rather large and includes the AVI files listed under the Fixture Access section downloaded here (PPT) 20,4 MBytes:


PLC Panel

S7 PLC panel

The S7-200 was installed for interlocking the doors to access the clamping fixtures. The installation of the PLC and wiring was done by staff — “Electric Anthony” Buhagiar, and a student (on vacation training). The design was done together with the Panasonic welding robot agent, who installed and programmed the robot. The fixture was designed in SolidWorks or Catia by Andrew Young of ACTS. The end-user was delighted as they would be able to complete more orders with repeatable quality.

Fixture Access

Welding station showing clamps

The “two hand control” is part of the orange panel on the left. The open door shows a fixture with six clamps. There are several mechanical CAD files that were converted to short movies by Andrew Young for the talk.

For detailed and animated views of three mechanical structures, download the following files:


Acknowledgements

Many people contributed to the PLC laboratory’s success—Joe Maczek, Karl du Preez in particular. A special thanks to Professor Danie Hattingh for providing office space and a research position before a permanent position became available, as well as creating a productive environment for projects that actually made a difference to ordinary people’s lives. Professor Theo van Niekerk—also a big thank you when juggling the Dean position, the merger, my position and the students who were linked to many of these projects as co-promoter or supervisor. Andrew and William for keeping us focused, entertained and productive. “Electric Anthony” and the students who wired up the PLC lab and the Yenza project. A couple of pictures from the gallery might assist others trying to emulate similar setups.

Photo Gallery