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.

---------->>>>>Get FREE PLC Programming Tips

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 0.32 seconds.
Search: Posts Made By: Tom Jenkins
Forum: LIVE PLC Questions And Answers February 11th, 2019, 05:26 PM
Replies: 2
Views: 202
Posted By Tom Jenkins
ASME PTC 19.5 is the most authoritative guide to...

ASME PTC 19.5 is the most authoritative guide to flow measurement. The equation relating differential pressure to flow will vary based on the primary element - pitot tube, orifice, flow tube, etc.
Forum: LIVE PLC Questions And Answers February 6th, 2019, 12:27 PM
Replies: 8
Views: 284
Posted By Tom Jenkins
Yes, it is Figure 9.8

Yes, it is Figure 9.8
Forum: LIVE PLC Questions And Answers February 6th, 2019, 10:53 AM
Replies: 8
Views: 284
Posted By Tom Jenkins
Your method for controlling the aerator until it...

Your method for controlling the aerator until it hit max and then controlling air flow should be OK. I'd use floating control on each, with time delays between actions as dictated by process system...
Forum: LIVE PLC Questions And Answers February 6th, 2019, 09:17 AM
Replies: 8
Views: 284
Posted By Tom Jenkins
Skip the PID. Just use the floating control...

Skip the PID. Just use the floating control method. "Adjust wait and see" in other words.

I am curious about your system. You seem to be combining mechanical aeration and diffused aeration. This...
Forum: LIVE PLC Questions And Answers February 6th, 2019, 09:13 AM
Replies: 7
Views: 427
Posted By Tom Jenkins
I made a business out of doing DO control. It is...

I made a business out of doing DO control. It is very complex, non-linear, has long process and transport delays, multiple min/max restrictions, huge load and process variations ....

I did not use...
Forum: LIVE PLC Questions And Answers February 5th, 2019, 11:33 AM
Replies: 7
Views: 555
Posted By Tom Jenkins
UL, and NEC, and FM are not laws and of...

UL, and NEC, and FM are not laws and of themselves have no mechanism to force compliance.

However, many local jurisdictions (i.e. states, counties, municipalities, etc.) cite the above-mentioned...
Forum: LIVE PLC Questions And Answers February 1st, 2019, 09:51 AM
Replies: 6
Views: 295
Posted By Tom Jenkins
Let's clarify some terms. Flow RATE is...

Let's clarify some terms.

Flow RATE is volume of flow per unit time - gallons per minute or liters per hour, for example.

It looks like you really want to control volume discharged - gallons...
Forum: LIVE PLC Questions And Answers January 28th, 2019, 04:58 PM
Replies: 56
Views: 2,931
Posted By Tom Jenkins
Hit a momentary E-Stop on what should have been a...

Hit a momentary E-Stop on what should have been a three-wire control circuit. The starter was wired wrong by the factory (at no extra charge), and when released I got full voltage to a motor spinning...
Forum: LIVE PLC Questions And Answers January 9th, 2019, 12:58 PM
Replies: 6
Views: 437
Posted By Tom Jenkins
It depends on what you are doing. If you are...

It depends on what you are doing. If you are working with actuator forces or other calculations that are based on pressure differences you can ignore atmospheric pressure and work with gauge...
Forum: LIVE PLC Questions And Answers January 9th, 2019, 10:01 AM
Replies: 20
Views: 1,548
Posted By Tom Jenkins
I got tired of breaking taps and related hassles....

I got tired of breaking taps and related hassles. I went to this:

https://www.mcmaster.com/jack-nuts

https://www.mcmaster.com/installation-tools-for-bulbed-rivet-nuts
Forum: LIVE PLC Questions And Answers January 7th, 2019, 05:33 PM
Replies: 58
Views: 4,620
Posted By Tom Jenkins
Well, I had to call it something! :dance:

Well, I had to call it something! :dance:
Forum: LIVE PLC Questions And Answers January 2nd, 2019, 01:16 PM
Replies: 58
Views: 4,620
Posted By Tom Jenkins
Jenkins Law: The technology least understood is...

Jenkins Law: The technology least understood is always the cause of any problem.
Forum: LIVE PLC Questions And Answers December 29th, 2018, 10:12 AM
Replies: 29
Views: 2,729
Posted By Tom Jenkins
Going into a system that the operators have been...

Going into a system that the operators have been struggling with for years and getting them running right after just a few days.
Forum: LIVE PLC Questions And Answers December 28th, 2018, 10:47 AM
Replies: 9
Views: 862
Posted By Tom Jenkins
Congratulations!

Congratulations!
Forum: LIVE PLC Questions And Answers December 14th, 2018, 04:24 PM
Replies: 48
Views: 2,855
Posted By Tom Jenkins
Whiskey go with Red Breast:...

Whiskey go with Red Breast: https://www.redbreastwhiskey.com/en-EN/

Scotch go with McCallans: https://www.themacallan.com/en
Forum: LIVE PLC Questions And Answers December 10th, 2018, 07:08 PM
Replies: 20
Views: 1,412
Posted By Tom Jenkins
Perhaps the attached will help. Torque on any one...

Perhaps the attached will help. Torque on any one shaft, such as the headshaft, is unchanging.

Ignoring friction, power is unchanging throughout the system. (First Law)
Forum: LIVE PLC Questions And Answers December 7th, 2018, 02:09 PM
Replies: 6
Views: 597
Posted By Tom Jenkins
:beer: "The nice thing about standards is...

:beer:

"The nice thing about standards is that there are so many to choose from."
Anonymous
Forum: LIVE PLC Questions And Answers December 2nd, 2018, 10:36 AM
Replies: 7
Views: 379
Posted By Tom Jenkins
You could use PLC outputs directly, but it isn't...

You could use PLC outputs directly, but it isn't good practice even if they are rated for that current or more. Switching that much current will cause some arcing, which erodes contacts, so...
Forum: LIVE PLC Questions And Answers November 28th, 2018, 10:50 AM
Replies: 2
Views: 255
Posted By Tom Jenkins
I suggest you get a copy of ASME PTC 19.5, which...

I suggest you get a copy of ASME PTC 19.5, which covers everything you want to know about orifice flow meters.

Regardless of the gas, the math is the same. You may run into a problem with low...
Forum: LIVE PLC Questions And Answers November 20th, 2018, 03:41 PM
Replies: 24
Views: 1,779
Posted By Tom Jenkins
I have had good luck over the years with Omron....

I have had good luck over the years with Omron. They are available with a variety of coils and in on-delay, off-delay, and repeat cycle models.
Forum: LIVE PLC Questions And Answers November 19th, 2018, 11:55 AM
Replies: 20
Views: 1,412
Posted By Tom Jenkins
Mutual misinterpretation, I guess - no problem. ...

Mutual misinterpretation, I guess - no problem.

I always start with the load by figuring torque and horsepower. Then I work backward to the motor demand. Then, whether there is a mechanical speed...
Forum: LIVE PLC Questions And Answers November 16th, 2018, 05:29 PM
Replies: 20
Views: 1,412
Posted By Tom Jenkins
No, it is not. The only place that violates...

No, it is not.

The only place that violates the First Law is a nuclear reaction, and that is governed by e=mc˛.

The equation for torque vs. hp and speed still applies. The power into the VFD...
Forum: LIVE PLC Questions And Answers November 16th, 2018, 02:02 PM
Replies: 20
Views: 1,412
Posted By Tom Jenkins
First LAW of Thermodynamics: Energy is not...

First LAW of Thermodynamics: Energy is not created or destroyed.

Power is energy per unit time.

Therefore the horsepower throughout your system is always the same, minus losses to friction, of...
Forum: LIVE PLC Questions And Answers November 15th, 2018, 03:23 PM
Replies: 19
Views: 944
Posted By Tom Jenkins
True enough. This happened to be a plot I found...

True enough. This happened to be a plot I found while looking for something else.

I guess you'll just have to take my word for the fact that the amps/flow were controlled to the set tolerance,...
Forum: LIVE PLC Questions And Answers November 15th, 2018, 12:47 PM
Replies: 19
Views: 944
Posted By Tom Jenkins
Here is an example of floating control on an...

Here is an example of floating control on an inlet throttled blower. Amps are proportional to air flow.The application was dissolved oxygen (DO) control of a variable level sequencing batch reactor...
Showing results 1 to 25 of 500

 
Forum Jump

All times are GMT -5. The time now is 04:44 PM.


.