You are not registered yet. Please click here to register!


 
 
plc storereviewsdownloads
This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.
 
Try our online PLC Simulator- FREE.  Click here now to try it.

New Here? Please read this important info!!!


Go Back   PLCS.net - Interactive Q & A > Search Forums

Showing results 1 to 25 of 500
Search took 0.13 seconds.
Search: Posts Made By: Peter Nachtwey
Forum: LIVE PLC Questions And Answers Yesterday, 11:43 PM
Replies: 2
Views: 252
Posted By Peter Nachtwey
ch,ch,ch, Changes.....

I was wondering about what to use as the title of this thread. David Bowie’s Changes won out over Yes’ Perpetual Change. Like both and am a fan of both but they are both gone. :(


Anyway,...
Forum: LIVE PLC Questions And Answers Yesterday, 10:53 PM
Replies: 2
Views: 397
Posted By Peter Nachtwey
The best thing to do is to replace the valve with...

The best thing to do is to replace the valve with a valve that has 0 or extremely small dead band. The dead band makes the system A 10% dead band is a killer if you want precise positioning at the...
Forum: LIVE PLC Questions And Answers September 20th, 2022, 03:33 PM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
OK, here is a more detailed model. The example...

OK, here is a more detailed model. The example was originally a Matlab example at the University of Michigan. I didn't like their example so I used their data and showed how to do it right....
Forum: LIVE PLC Questions And Answers September 20th, 2022, 12:44 PM
Replies: 10
Views: 854
Posted By Peter Nachtwey
He has made contact with Delta's technical...

He has made contact with Delta's technical support. I too am interested. I haven't been told of any resolution yet.
Forum: LIVE PLC Questions And Answers September 20th, 2022, 12:45 AM
Replies: 10
Views: 854
Posted By Peter Nachtwey
I will let the software and tech support...

I will let the software and tech support department know about this. Be ready to provide a copy of what didn't download to our tech support so we can duplicate this problem.


This is strange....
Forum: LIVE PLC Questions And Answers September 19th, 2022, 12:26 PM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
Yes, it is probably more complicated, I don't...

Yes, it is probably more complicated, I don't think my model is exactly right. Accelerations should be integrated twice to get position, not once. However, the delay is so small it can be assumed to...
Forum: LIVE PLC Questions And Answers September 13th, 2022, 10:28 AM
Replies: 14
Views: 1,677
Posted By Peter Nachtwey
Can you solve the problems posted on this forum? ...

Can you solve the problems posted on this forum? If not you can learn from them. The problem I see that most have is they are in a plant and only see one set of problems that apply to their plant. ...
Forum: LIVE PLC Questions And Answers September 10th, 2022, 11:24 AM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
Yes, for the open loop velocity model as a...

Yes, for the open loop velocity model as a function of control output.

However, in the video I am controlling position so the velocity must be integrated to yield position. So the open loop...
Forum: LIVE PLC Questions And Answers September 9th, 2022, 11:54 AM
Replies: 22
Views: 3,161
Posted By Peter Nachtwey
Trump warned about becoming dependent on Russia's...

Trump warned about becoming dependent on Russia's gas. No one listened.

JesperMP is right about having comfort that wasn't accessible to our fore fathers. Most of us are descendants of pretty...
Forum: LIVE PLC Questions And Answers September 9th, 2022, 12:53 AM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
The PV or target position should be red. ...

The PV or target position should be red.
Otherwise you are correct, the mass of the wheel makes the time constant due to the inertia of the wheel and motor very long by design.



No! I don't...
Forum: LIVE PLC Questions And Answers September 8th, 2022, 12:48 PM
Replies: 6
Views: 779
Posted By Peter Nachtwey
Use fractional math although the easy thing to do...

Use fractional math although the easy thing to do is to use LREALs.
Not enough info was given to provide an optimal solution.
Forum: LIVE PLC Questions And Answers September 7th, 2022, 09:59 PM
Replies: 22
Views: 3,161
Posted By Peter Nachtwey
There was $1.5B solar farm failure in California....

There was $1.5B solar farm failure in California.
Getting $1B back is not a good return on investment at this current time but CA needs the power. The alternative could be worse.
I don't see the...
Forum: LIVE PLC Questions And Answers September 6th, 2022, 10:08 AM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
The models don't need to be linear. That is the...

The models don't need to be linear. That is the whole point of using differential equations. Also, the non-linear valve identification isn't perfect but the means squared error is a mere 0.000031....
Forum: LIVE PLC Questions And Answers September 5th, 2022, 08:52 PM
Replies: 22
Views: 3,161
Posted By Peter Nachtwey
This guy knows what he is doing. He started out...

This guy knows what he is doing. He started out with solar panels for his RV and then made so much money off of YouTube he bought a house which is now one big solar panel lab....
Forum: LIVE PLC Questions And Answers September 5th, 2022, 03:23 PM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
This was a problem presented by a student in the...

This was a problem presented by a student in the Netherlands. The problem was presented back in 2010 back when LinkedIn had engineering forums.
The student wasn't able to give much information. He...
Forum: LIVE PLC Questions And Answers September 3rd, 2022, 05:09 PM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
You can make a I-P controller where the P term...

You can make a I-P controller where the P term acts only on the change in the PV


Yes, the gains for a PID and I-PD or PI-D are the same. The gains place the closed loop poles, not the zeros. ...
Forum: LIVE PLC Questions And Answers September 2nd, 2022, 11:55 AM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
The reason your calculations are not the same as...

The reason your calculations are not the same as mine is that you are apply the proportional and derivative gains to the error. I am not. I am applying the proportional and derivative gains only...
Forum: LIVE PLC Questions And Answers September 1st, 2022, 11:56 AM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
We use Levenberg-Marquardt for our auto tuner for...

We use Levenberg-Marquardt for our auto tuner for motion control. It works very well but the code is written in C and is very fast. The python implementation is slow. I have an example where I am...
Forum: LIVE PLC Questions And Answers August 31st, 2022, 11:29 PM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
Look at #73 That is NOT the way to do it....

Look at #73


That is NOT the way to do it. Dead time should be simulated like one simulates the transmission delay in a coax cable. It is an infinite number of poles with short time constants....
Forum: LIVE PLC Questions And Answers August 30th, 2022, 12:24 PM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
No! MPC has no gains! It does require an...

No! MPC has no gains! It does require an accurate model. MPC estimates the MV or control outputs for each iteration N times in the future. The control outputs are determine by minimizing the SSE...
Forum: LIVE PLC Questions And Answers August 30th, 2022, 01:25 AM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
Assuming you want the SSE for the hotrod.txt...

Assuming you want the SSE for the hotrod.txt data.



RMS error = 0.436
final_simplex: (array([[ 3.75741204, 0.68461421, 2.84927027, 77.84024028, 0.35401924],
[...
Forum: LIVE PLC Questions And Answers August 29th, 2022, 01:06 PM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
Using an external trigger isn't exactly...

Using an external trigger isn't exactly automatic. Why not monitor for abrupt changes in the SSE?


If you are only considering SOPDT or FOPDT the SOPDT will always win.
There really isn't a...
Forum: LIVE PLC Questions And Answers August 26th, 2022, 03:44 PM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
I think it is an good idea. You should try to...

I think it is an good idea. You should try to get some real examples.


If you get some traction with your program, I would add more features or abilities.

BTW, does the program "know" it...
Forum: LIVE PLC Questions And Answers August 25th, 2022, 02:14 PM
Replies: 39
Views: 3,685
Posted By Peter Nachtwey
That will be interesting. I was a reactor...

That will be interesting. I was a reactor controls officer on nuclear submarine back in the late 70's. To make the reactor small the uranium must be highly enriched. There is also a trick to how...
Forum: LIVE PLC Questions And Answers August 25th, 2022, 12:40 PM
Replies: 101
Views: 21,481
Posted By Peter Nachtwey
You shouldn't use step jumps if you limit the...

You shouldn't use step jumps if you limit the ramp speed. The ramps will limit the response, not the physics of the motor, load and drive. The motor ramping should be disabled. If not then the...
Showing results 1 to 25 of 500

 
Forum Jump

All times are GMT -4. The time now is 04:47 PM.


.