PID Nightmare

kalabdel said:

You may have the basic knowledge to understand the topic and those asking the questions do not and while they're willing to learn their lack of those basics require answers that they may understand; and only they know how basic that is. So the answers you found in a web search maybe completely nonsensical to them....

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OT:


Fair point, thanks for the alternative viewpoint. I will attempt to be more patient and understanding.



That said, there is also the question of why is, or maybe what ignorant manager has put, that OP in such a position, i.e. where they are asking a question when they know so little about the topic. Am I wrong to be concerned about someone programming a PLC, that may control dangerous machinery or materials, when they do not understand summat as simple as proportions (scaling).


Hey, I'm not much better myself: when I got the 3V Lithium batter from the ex-Radio Shack, I blithely soldered wires onto the ends of it; I learned here recently that could have ended vary badly.



To my mind, any who programs - PLC, RPi, PC, supercomputer - would be well served by taking a course in machine code programming, so they understand the bits and how CPUs handle them: take care of the bits, and the bytes, words and longwords take care of themselves.




P.S. it could also be the opposite of a

• wrong,
• unjust,
• or improper

hand spring.


Google tells me the actual phrase is right hand wound vs. left hand wound, although the latter is also what I often get when nailing summat wi' a 'ammer And my grammar OCD says it should be hyphenated i.e. right-hand.

We do this all the time with simple two valve (high low) control. The key we have found to getting accuracy is to vent the jacket before switching over to the lower valve (we have a vent valve in parallel with the steam trap). This is usually 4-6 degrees before target. It’s a lot cheaper than the modulation route and we do not see that much difference in time.



And yes heating and cooling in the same jacket does lead to cracking over time.

twocozz said:

And yes heating and cooling in the same jacket does lead to cracking over time.

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Another method is using a recovery tank, you would use this twice, once as a preheat and also as a precool, this will also help save the integrity of the tank as the heat and cooling (shocking) is what causes the metal to be fatigued and crack... sometimes this lengthens the process to I have also seen customer opt for just replacing the tank every few years and keep the speed of the process

I agree with Twocoss, just use trickle valves when close to set point then on/off control off the trickle valves. You could also use PWM using the PID if that suits you with on/off valves.

Electricians and Controls Engineers are in short supply right now. There is a lot of competition between companies right now for these positions, so it is possible that the experienced engineers at the OP's company left for a higher paying job and the OP was then the "Most Experienced" person left.

The main issue is using Google as the search engine; everyone should've used askjeeves.com. Jeeves always knew the answer.

mark.t said:

Thank you to those who offered their help and expertise on this issue. It has been resolved. My respects for those who are willing to help those of us who still don't understand some concepts in the more advance level. Happy Thanksgiving

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mark.t, it's responses regarding how this was rectified which makes people jaded. After the help some people have offered it would polite to tell all how it the problem was rectified, this would help someone else with a similar problem to see other options, to just say problem rectified isn't very respectful.

padees said:

1746-BTM... add whatever comments you like.


It could be interesting...

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Petty sure that thing is the worst card ever made for the SLC500 series. It makes the HSCE2 seems simple. They were rock solid though, once configured.