I felt I wanted to input my two cents here. This is kind of long so be warned.
I am a Journeyman electrician with over 20 years in the petrochemical and automotive industries and currently carry a high voltage certification for substation work which requires it's own special safety procedures. My emphasis currently is robotics, plc, and automation. I was once a dumb rookie plc programmer also. Still am depending on who you ask and when
Anyway, the company I work for has provided many hours of training for me on plc, automation, robotics, hydraulics, system integration, safety systems, etc. It was several years after I started working for this company before I was the least bit comfortable in making an online change to operating equipment during production. Yes I do make changes to logic all the time to keep production running, but I also log them so they get fixed properly during regular maintenance. Yes, I have caused downtime, sequence issues and equipment damage over the years, but rarely.
I asked a lot of questions to the controls engineers I've gotten to know and still ask for their input and assistance on a regular basis. I have earned the controls engineers trust in that they know that I know what I am doing. The controls engineers now routinely give me major changes or additions to the plc logic that they need to do which lightens their load. These changes are to be input even during production. Testing is done of logic changes during break time for anything that could stop production and I am fully aware of what the machine is currently doing and what the new logic is supposed to do. There is still things I do not know much about, but it is mostly system design
The company also does extensive testing including safety systems on new production equipment. This is to ensure the safety system works the way it was designed to. All safety interlocks and devices are hardwired and redundant (runchain 0, runchain 1). Plc gets inputs from hardwire for indication but can not control the hardwire.
The company I work for also hires summer engineering interns. This summer I had the pleasure of working on a new project that was assigned to a couple of these interns. One was having trouble with getting changes made to a program and sometimes complained that her edits were not "showing up" for some reason. I wondered why she was having so much difficulty so I watched over her shoulder for a few minutes and discovered the problem. She did not know how to make online edits or do online programming, so she was going off line making edits then downloading them to the processor, doing this for even the simplest edits. Sometimes she forgot to download the edits. I took a few minutes to show her how to make online edits etc. and test them. She said she learned more in a few minutes about plc programming than in an entire semester at college. Point I am getting at is everyone needs assistance sometimes and that assistance does not always come from a book or the engineer who is supposed to mentor. So if you are new or are having problems, put the ego away and ask questions.
As far as the guy who was working on a conveyor when it started throwing him and his tools off, then it was at least partly his own fault. The other part of fault lies in the company he works for or is contracted to for failing to ensure the employee was following proper safety lockout/tag out and hazardous energy control. The same goes for the employee who was cut by the shear knife when residual air fired the knife. He should have properly tested the locked out equipment and controlled (blocked and tested) the potential energy hazard.
The company I work for (and previous one) provides lockout/tag out and hazardous energy control training every six months. Hazardous energy control is not simply "locking out" the equipment, but making sure that all stored energy has been removed from the equipment and all machine blocks and safety devices are properly installed. This company also has a gate lockout procedure for dealing with common equipment problems during production hours. Every single "gate lockout" box is hardwired into the cells safety circuit and has been very carefully checked and certified by an independent certification. No work may be performed with the gate lockout if the procedure is not listed on the gate placard. No work may be done during non-production hours using the gate lockout procedure.
There are also procedures in place that cover working on live equipment if it is absolutely necessary. These procedures must be reviewed, agreed upon, and signed by safety and everyone else involved before any live equipment is worked on. This procedure also includes a statement as to why the equipment could not be properly locked out and a list of hazards. Yea, this is somewhat CYA, but at least everyone is on the same page and are aware of the hazards.
Lockout locks accidentally left on are not to be removed except by following a certain procedure. Failure to follow the procedure will result in a minimum balance of shift, and 3 days off with lockout and hazardous energy retraining for all involved including supervisors. General procedure is to contact supervisor who will contact his supervisor, Maint coordinator, security and the union. A search will then be made of the locked out equipment for the employee. If the employee is likely not in plant (shift ended, weekend) or otherwise can not be found then security will call the employees home for an ok. If no contact can be made, then a search of the locked out equipment will again be made before the lock is removed by security.
I am ultimately responsible for my own safety.
It is something that has served me well over the years. Especially now when society looks to be a bunch of "don't blame me, it's somebody else's fault" idiots.
