I enjoy funny stories. I could tell a hundred about similar situations. After many years of reflection, I think that 95% of the problems found in this type of owner-programmer-operator interaction story are caused, one way or another, by poor communications.
1. The owner did not write clear specifications that said exactly what he expected the machine to do, so the programmer worked in the dark until near the end when he was able to start the machine and see the problems first hand.
2. The PLC programmer did not develop an outline of his proposed program to give to the owner, with step-by-step descriptions of how he proposed to write the program. No one at the customer company knew what was in the black box until it was delivered.
3. The HMI programmer did not use clear labels on his controls. Some operators could figure out how to run the machine, others did not understand some of the steps. There were buttons labeled "CLOSE". Close What? Stop What? Start What? The process consisted of steps, but no where on the control panel did the operator know what step the machine was performing. This type of mis-communication leads to maintenance problems.
4. There were no overall graphic schematic of the process, so most operators did not have a clear idea of the whole process, but tried to limp by with inadequate knowledge. Training was poor to none, with old guys quitting and new guys coming in with a 5-minute instruction session followed by "you will learn on the job in no time at all".
5. Changes and revisions were made from design start up until the machine was started up. No one had a clear idea of all the changes, as the operators were trained based on the original program that had been changed a hundred times.
6. The machine did not have a good user manual, with clear instructions and directions. There were very few drawings and diagrams.
Lack of commmunication, poor commuication, lack of understanding of the existing instructions, poor training, and such can be summed up as 95% of the owner-programmer-operator problems. The other 5% are really the easy part to solve: the machine malfunctions. Solving the big 95% means that a bunch of people are going to have to learn to talk to each other.
Why did the other operators not know about the reject delay timer? You got it: poor communication. For some reason, the people who knew about that timer did not think it important that all operators be instructed about its function. Ideally, the instructions would be included in the HMI panel program.