DC motor speed control

[AMITNPUJARI]

Hi there,
 
I want to control a DC motor with LabView. Both Switching ON/OFF and its speed control.
 
(I am using PCI-MIO-16E-4 (NI) card with SCB-68 (NI) board. I am using LabView 8.5 full development system.)
 
Attaching the VI, I am using for switching motor on/off; please guide me whether it is correct way or not.
 
Also, I am not getting idea as to how can I control motor speed? Because, if I generate analog output, how I can vary/control that output to match/vary motor speed.
 
Could anybody please guide me in this regard.
 
Thanks.
Amit
 
 
 
 


DC motor on or off.vi:
http://forums.ni.com/attachments/ni/250/38959/1/DC motor on or off.vi

[Ian Colman]

Hi Amit, You were definatly on the right tracks for turning the motor on or off using a digital output. I have made some small modifications to the front panel and the setup of the DAQmx Write VI as you can see. In its current state the program will provide a digital high or low on the line specifed on the front panel, as the button on the front panel is pressed. The problem is, it is very unlikely that you have a motor that is capable of running off the power supplied by your PCI-MIO-16E-4 DAQ card. You will need some sort of buffer / external power source to provide sufficient power to the motor, rather than using this DAQ board as your power source. As for speed control, you can either control the speed via an analogue output waveform that is buffered and used as armature voltage of the motor, or you can use a Pulse Width Modulated signal to control the effective voltage level that the motor sees. Both of these methods can be implimented using National Instruments hardware and software.Could you let me know the nature of the motor that you wish to control and the application that it will be used for so that I can reccomend the best method of motor control for your needs please?Best Regards,Ian CApplications EngineerNational Instruments UK & Ireland


DC motor on or off.vi:
http://forums.ni.com/attachments/ni/250/39020/1/DC motor on or off.vi

[AMITNPUJARI]

Hi Ian,
Many thanks for immediate reply and suggestions with the motor ON/OFF VI.
Thanks for correcting it, as now I got the idea, where I needed correction.
About the motor (which I want to control) and its application:
Currently motor is run by proper drive which powers it, but eventually we want to get rid of that drive so that we can control the motor independent of drive, solely on PC and LabVIEW.
Specifications of motor are:
Voltage: 220/240V
Current: 1.38/0.8 Amp
Frequency: 50Hz
Phases: 3
RPM: 3000
The motor is being used for generating vibrations for medical application,
therefore we need fine control over motor speed and its switching (ON/OFF).
Please guide me through the best possible way for it (controlling the motor).
Thanks and regards.
Amit
 
 
 

[Ian Colman]

Hi Amit,Sorry I just posted a response and realised I needed to change the suggested information. Please bare with me whilst I look into this query further for you.Best Regards,IanMessage Edited by Ian Colman on 04-09-2008 10:07 AM

[AMITNPUJARI]

Hi Ian,
Many thanks, I shall wait.
Thanks.
Amit

[AMITNPUJARI]

Hi Ian,
I am attaching data sheet of motor I am using, also attaching data sheet of controller/drive I am currently using to drive motor.
Thanks and regards.
Amit


Vibtec%20Vibrators.pdf:
http://forums.ni.com/attachments/ni/250/39034/1/Vibtec%20Vibrators.pdf


Vibtec%20Controllers.pdf:
http://forums.ni.com/attachments/ni/250/39034/2/Vibtec%20Controllers.pdf

[Ian Colman]

Hi Amec, It does seem that your motor is a 3-Phase Linear Induction motor. This makes the situation more complex as National Instrumets does not have products to deal with 3-Phase induction motors directly. We have several great products to operate and interface with DC Servo Motors and Stepper Motors but you will need to use a 3-phase AC drive (such as the Vibtec VSC) to operate your 3-phase induction motor. If this Vibtec control unit has any sort of electronic interface to accept commands from external sources, it may be possible use LabVIEW to write a program that interfaces with this drive and therefore your motor. I reccomend that your next course of action is to look into whether your drive can be controlled electronically, as unfortunatly it is not possible to directly interface with your induction motor using NI Products.Please let me know your thoughts on this,Best Regards,Ian

[AMITNPUJARI]

Hi Ian,
Thanks for information about all these interfacing. I suppose electronic interface is possible through controller drive (VSC) and SCB- 68 (NI) Board. And even if electronic interfacing is not possible on this drive, right now, we will try and buy the suitable one since we need to change the hardware according to interfacing requirements of LabVIEW. As using LabVIEW for controlling this and other parameters is our software plan.
Once I speak with my adviser on this issue of hardware interfacing, If I have any query then I shall post it immediately.
But, for the time being assuming that, we can control the motor electronically, could you please guide me through how I can precisely control the speed of the motor via LabVIEW programming.
Many thanks.
Thanks and regards.
Amit
 

[Ian Colman]

Hi Amit,
Well I can't really recommend a definite method that you could use to control the motor speed untill you have settled on a drive to be used. This is because the signals to be passed to a motor drive vary from drive to drive so once you have some sort of definite interface we can discuss this further. Although I am more than willing to give all the advice i can on the issue, I do need to know what 3rd party hardware you have and what signals it expects for control.
What is it exactly that you wish to do with LabVIEW ultimatly? Is it just a matter of controlling motor speed or is it something more involved?
Best Regards,Ian 

[AMITNPUJARI]

Hi Ian,
As you can see from the datasheet which I attached previously, this motor is used specially for generating vibrations.
So increasing speed of motor we will increase the vibrations. That is what we intend to do with motor speed.
At the moment there is no hardware involved apart from motor, its drive and SCB 68 board.
I shall post my query further, once I disuss this interfacing issue with my advisor.
Thanks and regards.
Amit
 
 

[Ian Colman]

Hi Amit,
Okay thanks for letting me know. I look forward to hearing from you once you have discussed this further.
Best Regards,
Ian

[Kaunteya]

Hi Ian,
 
I discussed the interface issue with my adviser and the power supply driving the motor is going to remain.
So this makes things easier as power supply has an arrangement, where I can connect 10Volt analog signal (coming from) PC/DAQ. 
 
So I suppose, no more I need PWM, as I will be using analog voltage to control the motor speed, so varying the voltage I should be able to control motor speed.
 
If this is OK then, how can I go for it.
I suppose I need to generate analog output (0 to 10 volt), which can be controlled by a knob control from the front panel.
 
Please advise me on the same.
 
Thanks and regards.
Amit

[Ian Colman]

Hi Amit,Okay that sounds good. This is very easy to do in LabVIEW so please take a look at the attached VI.
Best of Luck,
Ian


Analogue Output.vi:
http://forums.ni.com/attachments/ni/250/39229/1/Analogue Output.vi

[Kaunteya]

Hi Ian,
Sorry for late reply, thank you very much for the VI, I was on the correct lines only I used the round knob instead of flat control, you have used. Many thanks.
If I have any further query, I shall post again.
Thanks for your advise.
 
Thanks and regards.
Amit
 

[Kaunteya]

Hi Ian,
Last time, the VI you posted for motor speed control (by varying analog ouput).
In that VI, on front panel, how do you decorate the things? Specially that blue line, I am not getting that in function's pallet?
Where can I find it or how can I go about it.
Please let me know.
 
Regards.
Amit
 

[Ian Colman]

Hi Amit,
 
The pallette you need on your front panel is the 'Modern>>Decorations' palette. In here you will find an item called 'Flat Box'. You can then go to 'View>>Tools Palette' and change the colour of the box's border to whatever you want as shown in the attached screenshot.
 
Best Regards,
 
Ian


Change Colour.JPG:
http://forums.ni.com/attachments/ni/250/39414/1/Change Colour.JPG

[Kaunteya]

Hi Ian,
That is great, many thanks.
Thanks and regards.
Amit
 

[Ian Colman]

Hi Amit, Okay there seems to be a bit of confusion here that I'd like you to clear up for me if possible. The all of your posts refer to the motor being DC, however it seems like the specs you gave are for an AC 3-Phase 50Hz Linear Induction Motor. It is fundamental to my hardware reccomendation that you can confirm the motor being used, whether it is AC or DC, maybe include a model number / manafacturer if possible so we can be absolutly sure of what is going on here. If you could let me know this I'll be more than happy to help you Amit.Best Regards,Ian

[AMITNPUJARI]

Hi Ian,
I beg your pardon, I am not quite sure whether the motor is AC or DC,
I apologies for the heading of the posts, if it is wrong. The specifications which I mentioned are correct and manufacturer is VIBTECH, serial number being: 040261596.
The motor should be AC as the drive which I am using for it is AC drive for running 3-phase induction motor.
Does this gives you enhough/correct information to decide whether motor is AC or DC?
Thanks and regards.
Amit
 

[BME genuis]

Ian,
I need help in figuring out how to control my DC motor.  It is 1/4 HP @ 1725 RPM, 90V, 2.8A full scale.  I need around 200 in-lbs of torque for my application.  I have a SCXI-1124 and a motor controller. 
Thanks,
-Scott

[Ian Colman]

Hi Scott,
One of my colegues,the community or I will be more than willing to help you with your motor problem, but it would be a great help if you could copy your post into a new thread. This way one of our team can pick it up (as this thread is viewed as resolved on our system) and it makes it easier for members of the community to see your query and help you out aswell.
Best Regards,
Ian

[AnalogKid2DigitalMan]

Amit:
On the pdf for the motor drive, it shows:

Optional extras,

Additional overloads to run multiple vibs

Door interlocked isolator ( IP 55)

Digital display of motor frequency

Remote control

Line chokes, when total length of cables

to vibrators exceeds 10 meters
Digital inverter
 
Contact the manufacturer and ask about the remote control option- what it does, and what input is needed for control.
-AK2DM

[AMITNPUJARI]

Hi AK2DM,
 
Thanks for advise, I shall find out about remote control.
 
Thanks and regards.
Amt

[dadsf]

can any expert out there help me in my project? im doing 750W AC motor rpm control using labview 8.5 and  im using USB NI 6008 DAQ..how can i interface the DAQ with the motor..and how to generate the PWM to control the motor RPM..how does the PWM signal related with the RPM? thanks