There is usually a natural order to things. But there are times when the natural order gets disrupted, and this could be for any number of reasons: we get busy, overloaded with tasks or information, tired, complacent, etc. But when you think about it, most of the excuses we make do not serve to improve the situation, and often can make things worse.
When something pops to the top of your to-do list, perhaps painting the walls, it’s possible to go grab the paint can and brush from the garage and just start painting. It might get the job done quickly enough, but the quality of the job could easily suffer if the walls were not clean, or if the paint were too old, or switch plates and electric outlet covers were not first removed. So you may end up having to repeat at least some part of the process to achieve the desired results.
If development of a safety product is at the top of your to-do list, it’s probably a bit more complex. Sure, a few engineers can put some ideas together, figure out what’s allocated to hardware and software, throw some components onto a PC board, write some code, and voila!... here’s your new safety sensor! But is it really ready for your customers? What happens if field returns start to pile up?
I’m sure this harsh scenario would never happen in your organization. I’m sure you’re making use of all the good practices that are required by IEC 61508 (or whatever safety standards you need to follow). Why? Because it makes sense! I’ll bet you’re planning and reviewing all the requirements before ordering parts and setting up a production line. I’m confident you’re working out the details of the architecture and design before trying to build your prototypes or write software subroutines. I’m positive that your test department has plenty of input to these early development phases. And I think that your marketing team has not sold the product before it’s been tested and certified. Wait a minute, I’m not so sure about that. I just saw a big customer order come in and you need this product done right away… looks like you need to take some shortcuts, doesn’t it?
There are many good reasons that IEC 61508 puts an emphasis on planning before doing, and reviewing before approving; it helps reduce and prevent errors that can cause dangerous failures. It helps to find small problems before they become harder and more expensive to correct.
When the next task pops up on your to-do list, remember: Ready, Aim, Fire! Don’t be courting disaster.