Which platform should I use?

When I was able to choose a controls platform myself, there were 5 factors I would consider when evaluating a new system.
By Frank Lamb November 5, 2014

When I worked for automation distributors I was required to promote and recommend only the products that the distributor sold. This sometimes caused a conflict of interest: is this the most appropriate solution for this application? The first distributor I worked for sold Omron and Eagle-Signal PLCs. If I was in a plant that was full of Allen-Bradley controls this could be a tough sell… the customer usually had a significant investment in both hardware and training particular to A-B. In his case he was tired of paying for the yearly software licenses that Allen-Bradley charges hundreds of dollars for. Of course there was no economical way for either of us to do this, so the plant remained A-B.

The next company I worked for was an Allen-Bradley distributor. As a product specialist I learned that A-B required all of their distributors to staff several technical specialists and of course this costs money. In return Allen-Bradley distributors get protected territories and the customers get support and training on their products.

When I started my own automation company I generally had to use whatever the plant specified. This required having a lot of different software packages and of course paying the dreaded support fees to both Allen-Bradley and Siemens. There were occasions however where I was able to choose a controls platform myself. There were a variety of factors I would consider when evaluating a new system:

  1. Existing hardware, software and training. Is there already a majority of one type of controller in the plant? Do the maintenance and engineering departments like it and are they trained? How much support will they need?
  2. Cost. How much is the customer willing to spend to implement the solution?
  3. Spare parts. Are replacement components readily available in the local area?
  4. Suitability. Will a micro PLC do the job? Will there be a large amount of data that will need to be recorded and analyzed? Will the processor be fast enough/have enough memory? Are special purpose cards such as high resolution analog, servo or math/basic required? 
  5. Ease of programming. Is the software user-friendly? Are there special purpose instructions or functions to make programming easier?

All of these things would have an impact on the platform I would choose.