Checklist, computer hardware

Section 1. Provides a checklist for evaluating the computer hardware (equipment) and additional software (programs) required to operate the system. The flexibility and ease of use of the system and the availability of training and other types of vendor support are also addressed. 

After a controller has been designed, built, and tuned in an off-line environment, the next big step is to install it in the plant computing hardware and commission it. Since, at this stage, it becomes possible for the controller to directly modify how the plant is running, one must proceed methodically and with caution. Use checklists. Be observant and, at least initially, monitor all of the variables related to the controller frequently and thoroughly. Below is a good suggested procedure. 

With the case for computer use made, some cautions are in order. Computers are still bulkier than simple pencil-and-paper checklists. Computer reliability is not perfect, so inadvertent data loss is still a real possibility. Finally, software and hardware date much more rapidly than hard copy, so results safely stored on the latest media may be unreadable 10 years later. How many of us can still read punched cards or eight-inch floppy disks In contrast, hard-copy records are still available from before the start of the computer era. 

At the time of the study addressed in the present paper, [Pitblado 88] a total of 17 incidents had been reported in the Netherlands over a 4 year period on computer controlled plants, which related to the computer system or to the human interaction with the computer. These failures led mainly to small and medium scale releases from the flare systems, but in one case led to plant damage and in another to a fireball. Table 1 shows a summary checklist indicating the number of failures in each category (hardware, software, human), from which it can be seen that human errors during operations were associated with 59% of the incidents. Errors were mainly due to inadequate, insufficient or incorrect information supplied to the operators (59%) and a failure to correctly follow procedures (47%). Human errors in design were involved in 29% of incidents. Hardware and software failures were less prominent. 

---