Short Stories and Scenarios for Innovation

Wired

Murphy?

If there is a right way and a wrong way then as the number of iterations increases so might the number of failures. Similarly, if something is complex there might be a greater risk of failure. Here is a few stories from the world of process control (or factory automation).

Cough-ee

Scene: A very large factory, owned by the world's largest food company, made instant coffee powder.

The day came during the installation of a new computer controlled system when the computer would take control. Prior to this day lots of work had been completed by electricians: connecting all the sensors, scales and actuators up to the computer. A batch of coffee powder had been produced and was sitting in an hopper, which filled large containers that were taken to the bottling part of the factory. The big moment came and the factory was turned from the old system to the new computer system. The computer, in this state, was programmed to keep the hopper door closed, so there should not be any unexpected surprises. So it was a surprise when the switch over instantly opened the hopper door and dropped a very large quantity of coffee powder onto the floor!

At this point we might of expected an embarrassed cough from the computer programmer but none was warranted because the computer and its software were working correctly. So what went wrong? The electrician had wired the actuator for the hopper door the wrong way so that a signal to close the door opened it.

Grrrinder

Scene: Another large factory making animal feed.

In this factory was a large grinder driven by a powerful three phase motor. To run this motor up to full speed a specific sequence of electrical currents were required on the motor wiring. The day came during the installation of a new computer controlled system when the computer would take control. The motor was turned on and picked up speed then during the electrical sequence there was a noise, the motor came to a violent stop, and was ripped off its mounting bolts. Can you guess what happened here? The motor had been wired up incorrectly.

Lessons to learn

What can we learn from this experience?

» Things can be wired up incorrectly.

» Errors should be logged so that we can learn from our mistakes and not repeat them.

» Suggestions could be requested [via a suggestion box perhaps] to prevent such mistakes.

» A (non-destructive) method of testing on-site could be useful.