Designing a replacement for an obsolete Electro Cam control system
Patrick Griffin is a maintenance technician working in the plastics industry for the last 20+ years with primary focus being the repair, upkeep, & design of electrical, electronic, automation, and both relay & PLC control logic. He submitted his project to Arduino blog about using Teensy Arduino on a Maac vacuum former:
This story revolves around one of the workhorse machines in the company where I work: a Maac vacuum former. It is a solid, well-designed machine with a solid, well-designed control system that Maac contracted out to the Electro Cam systems group. As with any industrial equipment, as time goes by the OEM develops new products that replace their old stuff, technologies advance, and eventually they start the formal process of obsoleting their older inventory.
The situation started out years ago, long before I arrived on the scene, when the company I work for hired a contractor to add some automation to the Maac. When the automation was added almost all of the Electro Cam system was necessarily replaced with an Allen-Bradley SLC500 PLC to provide the changes in logic & the additional I/O points to do all of the new functions. The only Electro Cam components left in the Maac are the parts in the 84 zone oven controller.
We have been aware that more and more of it’s components, especially the Electro Cam controls, were being obsoleted. Recently we were put in the position to ask ourselves what our options are when one of these proprietary controls have a permanent catastrophic failure. What we learned was that we would be given few options through the official channels. We would have to leave the machine down and idle for an undetermined amount of time while the failed component was sent to Electro Cam for assessment and possible repair. This would certainly take longer than a week, but my gut says it would be closer to a month. There are also no guarantees that the part could be repaired at all. We were quoted a price for a replacement as starting at $4500, but with no promises.
Not having a replacement for a proprietary single-sourced part on the shelf is scary. Worse is when that single source says that they really can’t help you. This is one of several (maybe many) triggers for the maintenance department that I am a part of to fly wildly into a re-engineering frenzy.
Read the complete story and take a look at the schematics, on his website.