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Search: Posts Made By: Peter Nachtwey
Forum: LIVE PLC Questions And Answers September 22nd, 2018, 11:49 AM
Replies: 19
Views: 577
Posted By Peter Nachtwey
No!!!!!! Sometime you must educate. Other times...

No!!!!!! Sometime you must educate. Other times you must walk away when you don't feel comfortable with their plans.


It is probably the cost difference. Trio is relatively inexpensive compared...
Forum: LIVE PLC Questions And Answers September 18th, 2018, 12:42 PM
Replies: 6
Views: 177
Posted By Peter Nachtwey
I wrote assembly code for the M files.

The M files are stored in a memory chip that interfaces to the SPIOGA ( special purpose input output gate array ) chip. The on board process and the PLC processor had to arbitrate to get access to...
Forum: LIVE PLC Questions And Answers September 18th, 2018, 10:21 AM
Replies: 2
Views: 217
Posted By Peter Nachtwey
I used the Internal Model Control, IMC, method...

I used the Internal Model Control, IMC, method that the controlguru uses. Actually IMC attempts to place one real pole at -1/tc and cancel out the other two poles with zeros so the response looks...
Forum: LIVE PLC Questions And Answers September 15th, 2018, 12:47 PM
Replies: 2
Views: 217
Posted By Peter Nachtwey
Advanced Control: SOPDT Auto Tuning

Attached is a zip file that contains a python script that calculates the PID gains for SOPDT systems. You must install python3, numpy, scipy and matplotlib or Anaconda to run the script. The input...
Forum: LIVE PLC Questions And Answers September 13th, 2018, 10:33 PM
Replies: 19
Views: 813
Posted By Peter Nachtwey
Holy interdependencies Batman!!!!

Since since application is moving air I suppose nothing is linear too.
Are there are formulas for the flow through the fan as a function of RPM and pressure difference?
Are the pressure sensors so...
Forum: LIVE PLC Questions And Answers August 29th, 2018, 10:35 PM
Replies: 30
Views: 1,169
Posted By Peter Nachtwey
The recruiters are idiots and you are doing it wrong.

I never had experience at doing anything the first time except for programming. I learned programming on my own.
I was helping people programming PLCs before I ever touched a PLC. I would draw the...
Forum: LIVE PLC Questions And Answers August 27th, 2018, 08:53 AM
Replies: 7
Views: 483
Posted By Peter Nachtwey
How about automating the switching of a toy train...

How about automating the switching of a toy train set. Then try to run two trains without crashing.
The course should be called automation not control. Control is what I do with poles, zeros and...
Forum: LIVE PLC Questions And Answers August 26th, 2018, 06:22 PM
Replies: 79
Views: 7,370
Posted By Peter Nachtwey
I agree with those that say it is BS. Our motion...

I agree with those that say it is BS. Our motion controllers have more memory than the PLCs that control them. Memory is cheap. The problem is retaining it during power off situations. In our...
Forum: LIVE PLC Questions And Answers August 25th, 2018, 03:27 PM
Replies: 6
Views: 454
Posted By Peter Nachtwey
Move the valve closer to the transmitter. That...

Move the valve closer to the transmitter. That will reduce the dead time.
Use a Smith Predictor. This requires a model of the system and a delay queue.
Delaying the time between loop executions...
Forum: LIVE PLC Questions And Answers August 24th, 2018, 03:20 PM
Replies: 3
Views: 267
Posted By Peter Nachtwey
It appears that PI control is being used and the...

It appears that PI control is being used and the integrator winds up too much. There should be a problem with the PV going below the SP with proportional only control unless the gain is set very...
Forum: LIVE PLC Questions And Answers August 19th, 2018, 01:06 PM
Replies: 16
Views: 1,001
Posted By Peter Nachtwey
Yes, but what do you want for the denominator? ...

Yes, but what do you want for the denominator?
I have a cool program that will calculate gear ratios given any number and desired precision. The denominator could be anything.
Forum: LIVE PLC Questions And Answers August 15th, 2018, 08:22 PM
Replies: 15
Views: 983
Posted By Peter Nachtwey
C, C++, or python. C and C++ are totally...

C, C++, or python. C and C++ are totally different from python. C is good for embedded programming, writing firmware. C++ is good for high end HMIs but C# is probably just as good but a lot...
Forum: LIVE PLC Questions And Answers August 13th, 2018, 09:52 PM
Replies: 15
Views: 1,012
Posted By Peter Nachtwey
We did titanium extrusion in Albany Oregon. I...

We did titanium extrusion in Albany Oregon. I don't know the names of the companies now because they keep changing names.

The aluminum extrusion was done for Vari-wall. They mostly made baseball...
Forum: LIVE PLC Questions And Answers August 13th, 2018, 01:43 PM
Replies: 9
Views: 484
Posted By Peter Nachtwey
There is a difference between acceleration and...

There is a difference between acceleration and force. Force can be measured with a load cell.
Forum: LIVE PLC Questions And Answers August 12th, 2018, 06:28 PM
Replies: 15
Views: 1,012
Posted By Peter Nachtwey
This is getting off topic. The HPU power limit...

This is getting off topic.
The HPU power limit can be handy. I have seen the paint started to melt on pumps that were running beyond their rated power. Perhaps your system never reaches the...
Forum: LIVE PLC Questions And Answers August 12th, 2018, 12:04 PM
Replies: 15
Views: 1,012
Posted By Peter Nachtwey
@Seth350, "In other words, the time...

@Seth350,

"In other words, the time constant will change based on how great or little a change is occurring. Or, how great or little energy is used."
Not quite, my wording is above clear.
You...
Forum: LIVE PLC Questions And Answers August 11th, 2018, 10:59 PM
Replies: 15
Views: 1,012
Posted By Peter Nachtwey
@set350, You should have an idea of whether the...

@set350, You should have an idea of whether the system is integrating or non-integrating, how many poles there are, and whether they are complex ( cause oscillations ) or not.
For instance, I deal...
Forum: LIVE PLC Questions And Answers August 10th, 2018, 10:40 PM
Replies: 15
Views: 1,012
Posted By Peter Nachtwey
@seth350. In layman's terms a pole is something...

@seth350. In layman's terms a pole is something at absorbs or delays energy. A low pass filter you see on this forum is a single pole filter. Yes, it smooths the data but it also delays the data. ...
Forum: LIVE PLC Questions And Answers August 10th, 2018, 04:28 PM
Replies: 15
Views: 1,012
Posted By Peter Nachtwey
This doesn't make sense at all. Z-N is awful for...

This doesn't make sense at all. Z-N is awful for integrating systems such as position control. The overshoot and oscillation would required too much settling time let alone being able to track...
Forum: LIVE PLC Questions And Answers August 10th, 2018, 01:57 PM
Replies: 15
Views: 1,012
Posted By Peter Nachtwey
Advanced Control : Ziegler - Nichols is awful.

Z-N was developed back in 1942. It may have been the only option back then but now there are so many better options. The whole idea of increasing the gain to the point of being marginally stable is...
Forum: LIVE PLC Questions And Answers August 9th, 2018, 11:16 AM
Replies: 6
Views: 390
Posted By Peter Nachtwey
Ditto the suggestion about getting a trend. ...

Ditto the suggestion about getting a trend.


NO, NO, NO, NO!!!! NEVER!!! Z-N keeps control techniques in the dark ages and isn't applicable to many system like tank level control

You should...
Forum: LIVE PLC Questions And Answers August 2nd, 2018, 10:08 PM
Replies: 15
Views: 558
Posted By Peter Nachtwey
When you plug in a USB device, Fusion ( VMWare )...

When you plug in a USB device, Fusion ( VMWare ) asks which operating the USB device should be connected to. You simply make a selection. There is an option chose the default operating system a USB...
Forum: LIVE PLC Questions And Answers August 2nd, 2018, 12:17 PM
Replies: 15
Views: 558
Posted By Peter Nachtwey
There are only three options. VMWare's Fusion,...

There are only three options. VMWare's Fusion, Parallels and Boot Camp. I have been a long time VWWare user going way back so I have stuck with VMWare's Fusion. What I like about it is that I can...
Forum: LIVE PLC Questions And Answers July 31st, 2018, 09:51 AM
Replies: 15
Views: 596
Posted By Peter Nachtwey
Limiting the torque should be easy but if the...

Limiting the torque should be easy but if the actual position falls behind the target position because of the torque limit, the integrator will wind up. There must be a means of prohibiting the...
Forum: LIVE PLC Questions And Answers July 27th, 2018, 09:26 PM
Replies: 9
Views: 710
Posted By Peter Nachtwey
What kind of accuracy to you get? Think of the...

What kind of accuracy to you get?
Think of the frequency of the counter required to get 1mm resolution.
The rise time of the detected signal will cause a lot of variation.
Showing results 1 to 25 of 500

 
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