PLC Conversions

Modernizing Process Controls

About Curelom Engineering

I started working in the industrial automation industry in 1988. The newest Allen-Bradley PLC at that time was the PLC5. I began doing PLC2 to PLC5 conversions almost immediately. The conversions went well.

In 1995 I had an opportunity to do two PLC3 to PLC5 conversions. Since my other conversions had gone well I had full confidence that this would go well also. I sent out the PLC3 programs to be converted. The going price was $2500 per program. I thought that would save me a lot of typing and therefore worth the price. The PLC5 program I got back was so full of translation errors that I spent the next several weeks doing a rung by rung cleanup. I went back to the people that had done the conversion and asked for my money back. Nope, sorry, “as is” was the reply.

About this same time I took a class in Visual Basic. Wanting to practice what I had just learned, I thought, “The conversion utility that they used didn’t work that great … I bet I can build a better conversion utility.” In my spare time over the next year I programmed a PLC3 to PLC5 conversion utility.

Now I needed to test it in a real application. It wasn’t long until a colleague of mine was doing a PLC3 conversion. I asked if he would let me convert the program for him. He agreed and emailed me the program. I ran it through my utility and sent it back to him within the hour. He was amazed. During start-up he found only one translation error which he was able to reprogram very quickly. (Incidentally, only three programming errors were ever found in that original conversion utility). 

Word started to spread that I had a conversion utility that would convert PLC3 to PLC5. Soon I started getting requests to do other conversion utilities; PLC3 to ControlLogix, PLC5/250 (Pyramid Integrator) to ControlLogix, PLC5 to ControlLogix (not the Translation Tool), and SoftLogix5 to ControlLogix.

One day in 2002 I got a call and was asked if I could do a Modicon to ControlLogix conversion. Up to this point I had only written Allen-Bradley to Allen-Bradley conversion utilities. I told the guy that I could but it would take two to three months to write the utility. He told me that they were in a hurry and would do the conversion by hand. I thanked him and started working on a conversion utility anyway. Three months later my conversion utility was finished. I assumed that they had long since finished their manual conversion and had done the start-up. I called to see if they would look over the converted program that my utility created to see how well it had converted. I was surprised to find out that they had been converting code manually this whole time and were only about half of the way through (it was a very large program). When they showed the end-customer the program that my utility created, the end-customer requested that they use my converted program and not the one they had spent months typing in by hand.

I had been asked many times if I would create a GE to ControlLogix utility. So in 2005 I started working on a GE to ControlLogix utility. I was about three-fourths of the way done in 2006 when I got an email wanting to know if I could do a GE conversion. I replied that I could. They were expecting just the program to be converted but when I delivered the ControlLogix program to them with program, data table, and documentation they were very pleased. 

In early 2007 I decided to make my own conversion utilities and provide PLC conversion services to the public via the internet.

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