Not so much a PLC question

I have a project that we have been working on for about a year. It is up and running but I have data sent to me ever night to review how the process is working and make adjustments as I see fit.

One area is manual temperature control of a space. It does not need to be exact and nothing is ruined if things get a bit high although energy is wasted. After looking at this for several months I thought a visual alert of temperature going over 100 degrees might be nice. That appears to be poor thinking on my part. The operators now seem to be waiting for the alert before attempting to control the temperature.

Is this typical thought process of operators, people in general?

Is this typical thought process of operators, people in general?

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Yes, it's the "If it aint broke, don't fix it" approach.
How else are they alerted of the need to make an adjustment? Are they supposed to check periodically without being reminded?

Steve Bailey said:

Yes, it's the "If it aint broke, don't fix it" approach.
How else are they alerted of the need to make an adjustment? Are they supposed to check periodically without being reminded?

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When not making physical adjustments or taking samples, they monitor the process on an HMI in a separate room. It can be a bit boring, hence the thought of an indicator. I can lower the alert setting or remove it entirely.

I found out the hard way & repeatedly that things need to be made Idiot-Proof.

Then I was informed that I was underestimating the quality of idiots the HR department was hiring.

If there's one thing operators are good at, it's making life easy for themselves.

If you want them to do something, set up something to annoy them or make their life difficult if they don't. Easy!

Prime example: I just set up a whole new line in a factory where the operators were used to using e/stops as machine stops. The new e/stops I put in, obviously, shut down the entire line if pressed, and it could take up to an hour to restart everything. The client was worried about all the downtime they would incur on this new line, given the operator's current philosophy toward pressing e/stops. I explained my theory of the selective genius of operators when it comes to giving them more time to sit down in the control room, but he wasn't convinced.

When I trained the operators on the line, I explained to them the concept of the "emergency stop" being for "emergencies", and the "production stop" being for "production", and the concept of "If You Press An Emergency Stop You Are Not Going To Have A Good Day". Within the first month, each shift pressed an e/stop once, and never again

So back to the original question: if you need the operators to be controlling something, find a way to annoy them if they don't

the basic alarm program in the following post contains a "nag" alarm that reminds the operator (over and over and over if necessary) that all is not well ...

http://www.plctalk.net/qanda/showthread.php?p=538924&postcount=5

for your application (at least the way that I understand it) you might consider having an alarm lamp "flicker" when the temperature is a LITTLE too high ... the lamp could stay on for a greater percentage of time as the temperature continues to climb ... it could be made to stay on solid once the "fix it or the system shuts down" value has been reached ...

that logic isn't covered in the program I linked but it wouldn't be hard to set up ...

If your process "knows" what temperature it is could it also control it? Or is it manually adjusted to give the operators something to do?

bernie_carlton said:

If your process "knows" what temperature it is could it also control it? Or is it manually adjusted to give the operators something to do?

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It is manually adjusted because the owners did not want to spend the dollars on full automation. The manager did comment at planning the operators were going to have to be there anyway, they just as well have something to do.

Ron Beaufort said:

the basic alarm program in the following post contains a "nag" alarm that reminds the operator (over and over and over if necessary) that all is not well ...

http://www.plctalk.net/qanda/showthread.php?p=538924&postcount=5

for your application (at least the way that I understand it) you might consider having an alarm lamp "flicker" when the temperature is a LITTLE too high ... the lamp could stay on for a greater percentage of time as the temperature continues to climb ... it could be made to stay on solid once the "fix it or the system shuts down" value has been reached ...

that logic isn't covered in the program I linked but it wouldn't be hard to set up ...

Click to expand...

Good idea, and pretty simple even for my skill level.