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Search: Posts Made By: Peter Nachtwey
Forum: LIVE PLC Questions And Answers Yesterday, 07:16 PM
Replies: 24
Views: 972
Posted By Peter Nachtwey
I doubt there are many that can. Originally we...

I doubt there are many that can. Originally we used Numerical Recipes in C. Later I bought two books on splines and graphics. Yes, graphics use splines to cover their wire frame images. Once one...
Forum: LIVE PLC Questions And Answers Yesterday, 04:47 PM
Replies: 24
Views: 972
Posted By Peter Nachtwey
The best PLCs should have a cubic spline cam...

The best PLCs should have a cubic spline cam table or similar. We have found these to be very handy for linearizing functions. The advantage of using a cubic spline is that it is similar to the...
Forum: LIVE PLC Questions And Answers July 4th, 2020, 07:50 PM
Replies: 24
Views: 972
Posted By Peter Nachtwey
Nooooooo! Why not divide the level into two...

Nooooooo!
Why not divide the level into two ranges? There is a linear section that is easy to approximate. Then it will be easy to fit a second order equation to the non-linear section. A cone...
Forum: LIVE PLC Questions And Answers July 4th, 2020, 05:04 PM
Replies: 24
Views: 972
Posted By Peter Nachtwey
L D[AR2,P#0.0] is the best/easiest solution so...

L D[AR2,P#0.0] is the best/easiest solution so far.
The OP's PLC probably isn't very sophisticated so simple algorithms are are probably best.



Third order polynomials can have two inflection...
Forum: LIVE PLC Questions And Answers July 4th, 2020, 10:35 AM
Replies: 24
Views: 972
Posted By Peter Nachtwey
I don't see the point you are trying to make. ...

I don't see the point you are trying to make.



Not very useful. You can't hear the cats growling, howling and screeching as the train goes by.



However, it would be good to know the...
Forum: LIVE PLC Questions And Answers June 28th, 2020, 09:15 AM
Replies: 23
Views: 1,231
Posted By Peter Nachtwey
I think there are many opinions for ultimate. I...

I think there are many opinions for ultimate.
I have a 2015 Mac Book Pro I5 with a 13 inch screen. It works fine for what I bought it for which is for sales mostly. It had to run all day one a...
Forum: LIVE PLC Questions And Answers June 26th, 2020, 04:32 AM
Replies: 13
Views: 575
Posted By Peter Nachtwey
dmroeder, something you should try is...

dmroeder, something you should try is pyinstaller. It can make 1 .exe file out of your python files. The resulting .exe is very big with python38. The python38 version is less than half as big. ...
Forum: LIVE PLC Questions And Answers June 25th, 2020, 10:34 PM
Replies: 13
Views: 575
Posted By Peter Nachtwey
Nice work dmroeder. I didn't know pylogix...

Nice work dmroeder. I didn't know pylogix existed. I will tell the guys at work.


I have written a python program used to calculate hydraulic cylinder bore, rod diameter, HPU and accumulator...
Forum: LIVE PLC Questions And Answers June 18th, 2020, 01:22 PM
Replies: 13
Views: 1,215
Posted By Peter Nachtwey
NO! that would be too expensive! Incremental...

NO! that would be too expensive!

Incremental encoders are cheap. Slide resistors are cheap and absolute.
It depends on which feedback is easiest to interface to your motor's drive or PLC.

All...
Forum: LIVE PLC Questions And Answers June 17th, 2020, 07:20 PM
Replies: 25
Views: 1,359
Posted By Peter Nachtwey
35 years ago the potatoes would go down a...

35 years ago the potatoes would go down a conveyor with about 10 women on each side. They would look at the potatoes going by and if they looked bad they would cut out the bad part with a knife. In...
Forum: LIVE PLC Questions And Answers June 17th, 2020, 11:09 AM
Replies: 25
Views: 1,359
Posted By Peter Nachtwey
There should be only potatoes. Other material...

There should be only potatoes. Other material shouldn't make it that far. The potatoes are steamed, then rolled in an abrasive chamber the rubs the skins off. The potatoes are shot by a water...
Forum: LIVE PLC Questions And Answers June 17th, 2020, 09:28 AM
Replies: 25
Views: 1,359
Posted By Peter Nachtwey
Simco Ramic was a competitor. I think they have...

Simco Ramic was a competitor. I think they have been out of business for a long time now. At least I haven't heard about them for a long time.


I can't believe 100ft/sec. Maybe per minute. If...
Forum: LIVE PLC Questions And Answers June 17th, 2020, 03:00 AM
Replies: 25
Views: 1,359
Posted By Peter Nachtwey
I don't know anything about Kiremko or Tomra, ...

I don't know anything about Kiremko or Tomra, Key is a competitor.

We are actually the outside R&D for the major potato processing company. This potato processing company actually owns the...
Forum: LIVE PLC Questions And Answers June 16th, 2020, 07:12 PM
Replies: 25
Views: 1,359
Posted By Peter Nachtwey
Here is a link to 3 solutions. Each requires a...

Here is a link to 3 solutions. Each requires a different configuration of the two timer/counters.
https://deltamotion.com/peter/Mathcad/Mathcad%20-%20length_grader.pdf

L D[AR2,P#0.0] worked out...
Forum: LIVE PLC Questions And Answers June 16th, 2020, 04:04 PM
Replies: 25
Views: 1,359
Posted By Peter Nachtwey
You got it! At least the general idea. You...

You got it! At least the general idea.
You found the simplest solution. There are 3 that I can think of depending on you you use the photo eyes.
I was hoping to post an evil emoji but you ruined...
Forum: LIVE PLC Questions And Answers June 16th, 2020, 02:48 PM
Replies: 25
Views: 1,359
Posted By Peter Nachtwey
Bad assumption. The fry accelerates due to...

Bad assumption. The fry accelerates due to gravity and that isn't dependent or weight or mass. PLC scan times are too slow and irregular. However, PLCs do have counter cards. We used an off the...
Forum: LIVE PLC Questions And Answers June 16th, 2020, 02:32 PM
Replies: 25
Views: 1,359
Posted By Peter Nachtwey
Yes, this technique can be used for other things...

Yes, this technique can be used for other things besides potato strips. The lengths were used to build a histogram. The data was used to allocate potatoes by size to different plants. The end...
Forum: LIVE PLC Questions And Answers June 16th, 2020, 12:05 PM
Replies: 25
Views: 1,359
Posted By Peter Nachtwey
A challenge. Finding the length of a potato strip

No trivial trains and tunnels this time!

This is an actual problem that was solved about 20 years ago by one of our engineers. The goal is to measure the length of a potato strip rapidly. The...
Forum: LIVE PLC Questions And Answers June 15th, 2020, 01:20 PM
Replies: 37
Views: 11,348
Posted By Peter Nachtwey
First, are you doing position or force sine...

First, are you doing position or force sine waves?
Assuming you are doing position sine waves.
Usually people under estimate the acceleration rates required. The velocity goes up proportional to...
Forum: LIVE PLC Questions And Answers June 15th, 2020, 09:53 AM
Replies: 37
Views: 11,348
Posted By Peter Nachtwey
That is what motion controllers are for. Good...

That is what motion controllers are for. Good ones can produce sine waves at very high frequencies because the loop time is 0.25 milliseconds. On top of that the amplitude, frequency, phase and...
Forum: LIVE PLC Questions And Answers June 14th, 2020, 12:42 PM
Replies: 58
Views: 2,642
Posted By Peter Nachtwey
Your first solution worked but it is not a...

Your first solution worked but it is not a general case. It is very application specific. The next person may want to do a similar thing with 6 bits or some other number of bits. Are we to have a...
Forum: LIVE PLC Questions And Answers June 14th, 2020, 03:15 AM
Replies: 58
Views: 2,642
Posted By Peter Nachtwey
Teasing

I think Parky's first solution is good enough to solve his problem but what if there were 32 bits and only one can be set? Then Parky's solution is not very good.

What bothers me about the forum...
Forum: LIVE PLC Questions And Answers June 12th, 2020, 02:24 PM
Replies: 18
Views: 1,099
Posted By Peter Nachtwey
Way back when Terry Wood would go on and on about...

Way back when Terry Wood would go on and on about Karaugh maps. The trick is to get from one state to another without race conditions or unpredictable glitches. Since ladder doesn't scan...
Forum: LIVE PLC Questions And Answers June 9th, 2020, 06:03 PM
Replies: 65
Views: 3,618
Posted By Peter Nachtwey
Both drbitboy and OldChemEng seemed to favor a...

Both drbitboy and OldChemEng seemed to favor a rate of change mode but that isn't close to optimal. Basically your gain is an integrator gain because the output is integrated.
The problem is...
Forum: LIVE PLC Questions And Answers June 8th, 2020, 10:29 PM
Replies: 65
Views: 3,618
Posted By Peter Nachtwey
I was trying to make this a right way vs wrong...

I was trying to make this a right way vs wrong way to control a simple first order system. I have an update that I will share tomorrow but for right now I want to know if AdvancedHMI could be...
Showing results 1 to 25 of 500

 
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