AQ: Friendly system without technicians diagnose
How to make our systems so friendly that they do not need technicians to help diagnose problems? Most of the more obvious answers have been well documented here but to emphasize these points it is normally the case that diagnostics and alarms can dominate the amount of code constructed for an application. That is the amount of code required to fully diagnose an application may be as much if not more than the code required to make the application work in the first place!
I have seen HMIs with diagnostic screens showing an animated version of the Cause & Effects code that allows users to see where the trip condition is. I have also seen screens depicting prestart checks, Operator guides, etc all animated to help the user. Allen-Bradley even have a program viewer that can be embedded on an HMI screen but you would probably need a technician to understand the code.
From a control system problem perspective it is inevitable that you would need to use the vendor based diagnostics to troubleshoot your system. Alarms may indicate that there is a system related problem but it is unlikely that you could build a true diagnostics application in your code to indicate the full spectrum of problems you may encounter. For example if the CPU dies or the memory fails there is nothing left to tell you what the problem is 🙂
From an application/process problem perspective if you have to resort to a technician to go into the code to determine your problem then your alarm and diagnostics code is not comprehensive enough! Remember your alarming guidelines an Operator must be able to deal with an abnormal situation within a given time frame, if the Operator has to rely on a Technician to wade through code then you really do need to perform an alarm review and build a better diagnostics system.
