Smarter than a limit switch (a shuttle driven by a common AC motor does not stop exactly in position) Manufacturer: "The shuttle is not stopping right in position" Programmer: "Yes, it is due to the shuttle mass inertia, you must change the limit switch position to compensate the inertia stroke" Manufacturer: "Can you avoid it by software?" Programmer: "Unfortunately not, I am stopping the shuttle as soon as the limit switch trips" Manufacturer: "Why don't you detect the limit switch BEFORE it trips?"

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ROFL. Sounds all too familiar a question from one or two managers I know. The only cure is to educate them (sigh).

Reply to
Paul E. Bennett

--[snip]-- My two like that are...

I was explaining to a client who was testing his shinny new DCS that the valve in question only had a closed limit switch thus the DCS can only detect if the valve is closed or it is not closed and trying to get over the fact that in this case "not closed" is not the same as "open".

"Oh that was the same on our old DCS I thought this new one would be able to work out things like this!" (Note this was not intended to be humour).


Another client was testing some parts of the DCS and asked could he change a certain item. I explained that the particular item was engineer access only so the answer was no. "What happens if I try", he asked "oh you get a message saying you are not an engineer", I informed him. "How does it know that" he enquired!

Cheers, Mark, Merrydown Controlware Limited, Hull

Reply to
Mark Evans

I had one manager who decided he was going to send a communications log file to the vendor to have them figure out what went wrong in communications. The file contained every byte of information transferred between two computers for the last week or two until the link broke. Somewhere in the last 100 lines of the file was an error code which showed what went wrong.

I thought that sending it electronically or via tape would be a good idea, but he figured that a hard copy was best. First he had to print it out. About a half hour later he comes over and asks if I could look at the printer as it had stopped. As I was checking the printer this fellow was positively vibrating and talking about how getting this file to the vendor would stop the problems once and for all. After I got it going again, I started looking at the file. A few calculations showed that this log file would be about 13,000 to 20,000 pages long. In the spirit of cooperation I asked if he was going to fax it.

I would say he declined, but that would hardly do service to the rather amusing minute of dawning enlightenment transforming to frantic actions (on his part) which followed. I just killed the job and let him figure out what to do with 3/4 of a box of paper he just printed.


Reply to
Herman Family

You've had suggestions like that too, eh John? I was once asked to time a pump that filled a tank in a section of a plant that was far from being properly automated. A lot of sequencing was required that depended on operator intervention at specific times. Feed back consisted of operators looking at each other during a fill and one yelling to the other "Stop! It's full now!"

A production supervisor actually asked me if I could turn off the pump starter after 10 minutes and 30 seconds because "that's how long it takes to fill the tank".

After they were properly "edjucated" they installed a level transmitter on the tank :)

Reply to
Ursa Major

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