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Showing results 1 to 25 of 500
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Search: Posts Made By: Peter Nachtwey
Forum: LIVE PLC Questions And Answers Today, 09:57 AM
Replies: 81
Views: 4,487
Posted By Peter Nachtwey
Wouldn't these test cause faults for the scan...

Wouldn't these test cause faults for the scan being too long?
Forum: LIVE PLC Questions And Answers June 14th, 2019, 07:40 PM
Replies: 17
Views: 896
Posted By Peter Nachtwey
What are you trying to control? It may...

What are you trying to control?


It may not be possible depending on what you are trying to control.
Forum: LIVE PLC Questions And Answers June 13th, 2019, 05:31 PM
Replies: 28
Views: 1,471
Posted By Peter Nachtwey
+10^100 I hate repeating myself.

+10^100

I hate repeating myself.
Forum: LIVE PLC Questions And Answers June 13th, 2019, 10:00 AM
Replies: 7
Views: 475
Posted By Peter Nachtwey
I have a MicroLogix 1500. It only has a serial...

I have a MicroLogix 1500. It only has a serial port and is barely adequate for a RMC75S (serial ).
We use CompactLogix in a PLC to RMC training labs. There is no problem there.

There are...
Forum: LIVE PLC Questions And Answers June 12th, 2019, 02:45 PM
Replies: 7
Views: 417
Posted By Peter Nachtwey
I don't like Ken's answer because when there is a...

I don't like Ken's answer because when there is a change the steps will keep being made until the PV = SP but this can cause over shoot when too many steps are made before the pump can respond.

We...
Forum: LIVE PLC Questions And Answers June 12th, 2019, 01:18 PM
Replies: 7
Views: 475
Posted By Peter Nachtwey
It depends on what you are trying to do and which...

It depends on what you are trying to do and which Rockwell PLC you are using.
The Control Logix supports the 1756-HYD02 the uses start stop or PWM MDT rods.
There is also the 1756-M02AS that...
Forum: LIVE PLC Questions And Answers June 8th, 2019, 01:54 PM
Replies: 81
Views: 4,487
Posted By Peter Nachtwey
I think that a less memory intensive test is...

I think that a less memory intensive test is required for small computers.
Also, there need to be 3 different tests. One for bit twiddling, one for integers and one for floats. Some smaller...
Forum: LIVE PLC Questions And Answers June 2nd, 2019, 03:47 PM
Replies: 9
Views: 616
Posted By Peter Nachtwey
That can result in discontinuous changes in the...

That can result in discontinuous changes in the output. The total from the flow loop may not be less than the pressure loop and the flow loop is again limiting.
It is best not to change the...
Forum: LIVE PLC Questions And Answers June 2nd, 2019, 10:07 AM
Replies: 9
Views: 616
Posted By Peter Nachtwey
I am surprised that none of the Rockwell fans...

I am surprised that none of the Rockwell fans have jumped in to tell us how to do a low select.

If you are going to roll your own then try this. There are two control loops 0 and 1
Error0 = SP0...
Forum: LIVE PLC Questions And Answers June 1st, 2019, 07:53 PM
Replies: 9
Views: 616
Posted By Peter Nachtwey
The problem lies with the implementation. If...

The problem lies with the implementation.
If only proportional gains are used, this is easy.
The problem lies in how to limit the integrators from winding up.
Limiting the integrator output is...
Forum: LIVE PLC Questions And Answers June 1st, 2019, 04:04 PM
Replies: 9
Views: 616
Posted By Peter Nachtwey
Use two PI blocks and use low select. This...

Use two PI blocks and use low select. This shouldn't be too hard if the low select is implemented correctly
Forum: LIVE PLC Questions And Answers June 1st, 2019, 02:34 PM
Replies: 16
Views: 1,039
Posted By Peter Nachtwey
I would first try to reduce the source of the...

I would first try to reduce the source of the 'noise'.
Maybe it can't be done! If the current transducer is monitoring armature current the signal will be 'noisy' because it will be some sort of...
Forum: LIVE PLC Questions And Answers May 29th, 2019, 11:40 PM
Replies: 11
Views: 592
Posted By Peter Nachtwey
PLC vs PC is the wrong questions. It should be ...

PLC vs PC is the wrong questions.
It should be
PLC vs commercial PC vs Industrial PC.
We still do some industrial computer systems.
Commercial PC are not good enough. They are not able to...
Forum: LIVE PLC Questions And Answers May 26th, 2019, 11:04 PM
Replies: 15
Views: 658
Posted By Peter Nachtwey
Yes, I know that proportional only control is...

Yes, I know that proportional only control is simple and will work for simple applications but there comes a point where the performance is not good enough. It is worth while to put the extra effort...
Forum: LIVE PLC Questions And Answers May 26th, 2019, 08:35 PM
Replies: 15
Views: 658
Posted By Peter Nachtwey
Pandiani pointed to some of my articles. The...

Pandiani pointed to some of my articles.
The first article is old. I was written when we only had our second generation hydraulic controllers. Actually, the issue of how to control a hydraulic...
Forum: LIVE PLC Questions And Answers May 23rd, 2019, 11:16 PM
Replies: 15
Views: 658
Posted By Peter Nachtwey
Why do you say this? A simple proportional...

Why do you say this?

A simple proportional gain will always have lag or following error. The extra time it takes to get into position, without feedforwards, will slow productions. The bandwidth...
Forum: LIVE PLC Questions And Answers May 19th, 2019, 11:22 PM
Replies: 6
Views: 518
Posted By Peter Nachtwey
We are small but pack a powerful punch.

Good! I don't regard Siemens as serious competition.
Bosch-Rexroth and Beckoff are. Our controller are often communicating
with Siemens PLC over ProfiNet now in overseas projects. The US and...
Forum: LIVE PLC Questions And Answers May 19th, 2019, 09:04 AM
Replies: 6
Views: 518
Posted By Peter Nachtwey
The C240 is a simple servo motor controller. it...

The C240 is a simple servo motor controller. it is not a hydraulic servo controller.
A RMC150E H1 would work for analog feedback.
It makes me cringe when I hear about analog feedback. This...
Forum: LIVE PLC Questions And Answers May 14th, 2019, 10:55 AM
Replies: 19
Views: 1,149
Posted By Peter Nachtwey
You should read my articles ...

You should read my articles
https://www.hydraulicspneumatics.com/controls-instrumentation/plc-vs-motion-controllers
and...
Forum: LIVE PLC Questions And Answers May 14th, 2019, 02:41 AM
Replies: 19
Views: 1,149
Posted By Peter Nachtwey
I doubt it too. Most hydraulic amplifiers use...

I doubt it too.
Most hydraulic amplifiers use PWM to move the spool.
I was assuming JRoss's intentions were to use a PWM signal to an SSR that would control the current to the valve.
The output...
Forum: LIVE PLC Questions And Answers May 13th, 2019, 10:01 PM
Replies: 19
Views: 1,149
Posted By Peter Nachtwey
How fast do you think you can PWM and get the SSR...

How fast do you think you can PWM and get the SSR to switch?
It probably will not be fast enough. That is the PWM frequency will not be fast enough. Next, the PLC will probably not be fast...
Forum: LIVE PLC Questions And Answers May 13th, 2019, 05:09 PM
Replies: 19
Views: 1,149
Posted By Peter Nachtwey
NO! I would be wary.

NO!


I would be wary.
Forum: LIVE PLC Questions And Answers May 13th, 2019, 12:28 PM
Replies: 10
Views: 1,019
Posted By Peter Nachtwey
One of our regional sales managers has a...

One of our regional sales managers has a sarcastic wit that is funny like the OP's post. I will miss his trip reports when he retires.
Forum: LIVE PLC Questions And Answers May 9th, 2019, 10:52 AM
Replies: 0
Views: 233
Posted By Peter Nachtwey
PLCs vs Motion controllers part 2

https://www.hydraulicspneumatics.com/controls-instrumentation/hydraulic-servo-control-using-plc-part-2

Pandiani found a flaw in my plots.
Forum: LIVE PLC Questions And Answers May 8th, 2019, 12:22 PM
Replies: 14
Views: 915
Posted By Peter Nachtwey
I thought you were designing a real system. I...

I thought you were designing a real system.
I write magazine articles for
https://www.hydraulicspneumatics.com/
The next article will be about how to calculate and use the valve flow constant, Kv.
Showing results 1 to 25 of 500

 
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