Dear Colleagues,

Most of us being clever (or believing we are clever); try and get components or parts in a design or installation to have more than one function or purpose. This is to minimise materials used and the time or energy consumed by other manufacturer and user.

Be Wary
However, you have to be wary about the people that are then required to install, commission and then use this system of yours. They may not have the requisite level of skill and care. Or indeed, the ability to maintain the system over its life.

Many years ago, I remember being forced to use hard wired relays rather than a PLC (Programmable Controller) for an electrical control system in central Africa. The owners of the mine believed that the maintenance of a PLC would be impossible with limited skills and know-how in the area; whereas a relay was easily understood and could be replaced by walking into the local hardware store to buy a replacement (well, almost). A PLC with software represents the ultimate in multi functionality with software doing a multitude of things which previously were done with a series of individual relays and modules.

The corollary is true of course – the greater the sophistication of the user, the lower the risk of failure and the more predictable her environment is; the more you can afford to be multifunctional with your designs.

Catastrophic Failure Casts a Pall on Your Design
However, you also need to assess the risk of installation and operation. If a failure of a multifunctional part could cause a catastrophic failure of the entire system; you may also need to reconsider your design here.

Thanks to 101 Things I learned in Engineering School by John Kuprenas with Matthew Frederick for some interesting reading on this topic.

If you’re brave you could take a leaf out of Steve Jobs’ book:

Here’s to the crazy ones. The misfits. The rebels. The trouble-makers. The round pegs in the square holes. The ones who see things differently…they change things. They push the human race forward. And while some may see them as the crazy ones, we see genius.

Yours in Engineering Learning,

Steve