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 > PLCS.net - Interactive Q & A > LIVE PLC Questions And Answers

PLC training tools sale

Reply
 
Thread Tools Display Modes
Old May 8th, 2019, 02:28 PM   #1
JGax
Member
Mexico

JGax is offline
 
Join Date: Nov 2013
Location: Mexicali
Posts: 23
Question ACS800, Speed Limits

Hi all.
First thanks in advance.

I'm working with a conveyor application. It has a ACS800 that ran a motor to drive a reducer and finally a chain conveyor.

In general its running fine... we use fieldbus RETA01.

We want to ran at 3000 rpm. drive receive the info from plc and starts... but the speed just reach 2780 rpm.... no more..... I check the Speed limits on 20.02 parameters.... which is set to 3200 rpms....

Now, seems like limits are a calculation from motor data plate on 99.xx parameters.... and change does not effect the speed....

DTC mode is selected.... supervision parameters are now for testing purposes....

Is the any way to make the motor at higher speed that what VFD calculate?

Thanks for your help
  Reply With Quote
Old May 8th, 2019, 02:35 PM   #2
Dirt
Member
Sweden

Dirt is offline
 
Join Date: Apr 2008
Location: Stockholm
Posts: 266
Have you checked actual frequency from the drive?

Sounds like the motor is running at its asychronous speed.

Did you do an ID run from the ACS800?

What are your settings on 20.08, 99.02 and 99.04?

Why run it in torque mode when you want a constant speed? Might be torque limiting the speed.

Last edited by Dirt; May 8th, 2019 at 03:24 PM.
  Reply With Quote
Old May 8th, 2019, 03:22 PM   #3
jraef
Member
United States

jraef is offline
 
jraef's Avatar
 
Join Date: May 2006
Location: Northern California
Posts: 1,711
When you have a VFD in torque control mode, you are telling it that torque is the primary thing you want maintained, speed is secondary. So the drive may or may not respond to a speed command the same way.
  Reply With Quote
Old May 8th, 2019, 03:30 PM   #4
g.mccormick
Member
United States

g.mccormick is offline
 
Join Date: Jul 2012
Location: IN
Posts: 613
What is 20.04 max torque limit?
  Reply With Quote
Old May 8th, 2019, 03:37 PM   #5
JGax
Member
Mexico

JGax is offline
 
Join Date: Nov 2013
Location: Mexicali
Posts: 23
Well, I talked to ABB support....
After review all what some of you asked above... all is ok and performs ok.

Reduced the problem to the communication profile... its using the Generic Profile and it limit the reference speed sent over Ethernet.... to exactly 2872.7
lol

I have to change to ABB profile so that reference speed is not limited.... puff....

Is not fun... have to change PLC logic.

Thanks for your support.... as soon I finish the logic and test will update results.

Regards
Jesus
  Reply With Quote
Old May 9th, 2019, 09:40 AM   #6
kamenges
Member
United States

kamenges is offline
 
kamenges's Avatar
 
Join Date: Nov 2002
Location: Brillion, WI
Posts: 3,739
Just as an aside, DTC, or Direct Torque Control, does NOT infer that the drive command mode is torque control. DTC is the motor flux control method ABB has chosen to use for their high performance drives, as opposed to using the more popular field-oriented control through a PWM driver that most other drive manufacturers use. It is very likely the OP was in speed control mode through this whole exercise.

Keith
  Reply With Quote
Old May 9th, 2019, 03:24 PM   #7
JGax
Member
Mexico

JGax is offline
 
Join Date: Nov 2013
Location: Mexicali
Posts: 23
Hi all

UPDATE!!

Well.... I call a local company to help with this... but curiously they don't believe what ABB support says about change the profile to get the reference speed....

Im not sure what really happened but those guys change the nominal motor data into parameters 99.xx.

Nominal hz of 60 they changed for 80hz
Nominal rpms from 1720 nominal they typed on 2220

Mag Id again and all seems to work now.... the reference speed was increased.....

What do you guys think of?

if Profile where the issue as the reference speed was truncated by... the no mater what the data plate is.... the reference should no go any higher its a bits issue....

guy from ABB says that Generic profile truncate the reference from PLC... now I don't believe that...

Regards
  Reply With Quote
Old May 9th, 2019, 03:35 PM   #8
g.mccormick
Member
United States

g.mccormick is offline
 
Join Date: Jul 2012
Location: IN
Posts: 613
You need to find the manual that describes the profile data. The speed may not be in rpm value, but in a percentage value with some weird scaling. It's been awhile, but I sorta kinda remember that being the case.
  Reply With Quote
Old May 9th, 2019, 03:41 PM   #9
JGax
Member
Mexico

JGax is offline
 
Join Date: Nov 2013
Location: Mexicali
Posts: 23
Thanks I will look at....
I was not there when the guys make some changes and they refuse to explain what solved the issue....
I'm thinking they don't know exactly what happened... lol

I need the truth
  Reply With Quote
Old May 9th, 2019, 05:22 PM   #10
kamenges
Member
United States

kamenges is offline
 
kamenges's Avatar
 
Join Date: Nov 2002
Location: Brillion, WI
Posts: 3,739
I have never tried to use the generic profile before. i have always used the ABB drive profile or the ODVA drive profile.

I know with the ABB drive profile i have used the speed command value will go to +/-20000 bits through the adapter and that equates to the value in 46.01 or 46.02 depending on whether you are using speed or frequency command mode.

If the generic profile works the way I think it does you are mapping values directly into specific drive parameters. What parameter are you mapping speed into?

When you use the word "nominal" I assume you mean motor nameplate data values. changing those seems like a pretty odd thing to do. Please confirm what you mean when you say "nominal".

Keith
  Reply With Quote
Old May 9th, 2019, 06:10 PM   #11
Gene Bond
Member
United States

Gene Bond is offline
 
Join Date: May 2004
Location: Indianapolis, IN
Posts: 315
Without also changing the Motor Rated Voltage, wouldn't you be sending too low of a voltage to the motor at reduced speed/frequency? Maybe an autotune takes care of that...
  Reply With Quote
Old May 10th, 2019, 08:27 AM   #12
kamenges
Member
United States

kamenges is offline
 
kamenges's Avatar
 
Join Date: Nov 2002
Location: Brillion, WI
Posts: 3,739
That is correct, Gene Bond. that is why I was trying to confirm if by "nominal" he meant "nameplate". If the frequency and speed were changed without a corresponding change in nameplate voltage the motor will be undermagnetized. I'm not sure if the autotune function would account for this or not. My guess is it would to some degree but not completely.

Keith
  Reply With Quote
Old May 10th, 2019, 08:49 AM   #13
Gene Bond
Member
United States

Gene Bond is offline
 
Join Date: May 2004
Location: Indianapolis, IN
Posts: 315
I have seen ABB (Baldor/Reliance) RPM-AC motors with some pretty wacky nameplates! The above setting sounds like something they'd do. Normally when I run into a nameplate that I really don't believe, I do a little manual tuning at 30hz or so (fixed v/f mode), playing with the voltage to see where the valley in No-Load Amps is, and figure that the nameplate voltage should be about 20% above this (of course calculating it for nameplate Hz) (or just after the no-load amps start to rise), for a basic sanity check.

I *ASSUME* the DTC mode is like most manufacturer's flux-vector modes, where the nameplate data is just a starting point for auto-tune, and actual voltage levels are the result of current based on load, resistance, primary and secondary inductance (power factor), etc. I have heard good things about DTC, other than issues with low inductance and/or higher modulation frequencies on high performance applications.

So, it may not matter that much.
  Reply With Quote
Old May 15th, 2019, 12:45 PM   #14
JGax
Member
Mexico

JGax is offline
 
Join Date: Nov 2013
Location: Mexicali
Posts: 23
Quote:
Originally Posted by kamenges View Post
That is correct, Gene Bond. that is why I was trying to confirm if by "nominal" he meant "nameplate". If the frequency and speed were changed without a corresponding change in nameplate voltage the motor will be undermagnetized. I'm not sure if the autotune function would account for this or not. My guess is it would to some degree but not completely.

Keith
Quote:
Originally Posted by kamenges View Post
I have never tried to use the generic profile before. i have always used the ABB drive profile or the ODVA drive profile.

I know with the ABB drive profile i have used the speed command value will go to +/-20000 bits through the adapter and that equates to the value in 46.01 or 46.02 depending on whether you are using speed or frequency command mode.

If the generic profile works the way I think it does you are mapping values directly into specific drive parameters. What parameter are you mapping speed into?

When you use the word "nominal" I assume you mean motor nameplate data values. changing those seems like a pretty odd thing to do. Please confirm what you mean when you say "nominal".

Keith
Nominal is the motor data plate.
And I verify again about the Profile.... the Generic is able to handle +-20000 as reference, so that was not the problem in this case...
Still looking for the real issue....
  Reply With Quote
Old May 15th, 2019, 12:49 PM   #15
JGax
Member
Mexico

JGax is offline
 
Join Date: Nov 2013
Location: Mexicali
Posts: 23
Quote:
Originally Posted by kamenges View Post
That is correct, Gene Bond. that is why I was trying to confirm if by "nominal" he meant "nameplate". If the frequency and speed were changed without a corresponding change in nameplate voltage the motor will be undermagnetized. I'm not sure if the autotune function would account for this or not. My guess is it would to some degree but not completely.

Keith
Well the guy came again to check another system with same symptom...
again he type in motor data... Nominal RPM from 1720 he typed 2220, for Nominal Frec of 60 he typed 80... and the ran ID Mag.... then just change the limits on 20XX and 11XX or 16XX he did not allow me to saw again..... lol
but I have a old parameter backup, will upload and compare and share what he exactly changed...

Regards
  Reply With Quote
Reply
Jump to Live PLC Question and Answer Forum

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Topics
Thread Thread Starter Forum Replies Last Post
Logix 5000, RSView 32 work receipe and speed control Densam LIVE PLC Questions And Answers 1 March 20th, 2012 01:48 PM
s7-200 High Speed Pulse Output / Counter hawkeyen2001 LIVE PLC Questions And Answers 0 September 19th, 2007 07:28 AM
OT - Slip Ring Resistor Calcs Kidblue LIVE PLC Questions And Answers 14 April 1st, 2005 08:19 AM
Speed Control Vs Current Control Moses LIVE PLC Questions And Answers 5 March 18th, 2005 09:32 PM


All times are GMT -5. The time now is 08:05 AM.


.