Trying to control a 5v DC motor

[Nick_Easter]

Dear all,

I am trying to build an screw elevator (used to lift 1.5 lbs) with controlled by Labview, using Scb 68.  I have to use circuit breaker switches at each floor levels and to control a DC motor (5v-9v).  How can I get an DC output from Scb 68 and which channels can I use?  how should I connect the switches (miniature snap switches)? I just want the elevator to work, the speed, acceleration and velocity of motor is not an issue in my case!

Thanks a lot in advance,

Nick,

Michigan Mechs.

[S_Kanchap]

Hi Nick,

SCB-68 is a connector block, you need to use motion controller or daq card to serve you purpose. Of course you have to use a connector block in either case.

[Jason N]

Nick,

What type of hardware are you connecting the SCB-68 to?  Is it an NI-Motion board or an NI-DAQ board?  This will determine how you connect the signals and program your application.  Please let me know. 

Jason N

[Nick_Easter]

Hi Jason,

                  First of all thanks for a nice reply!! I am connecting it to NI-DAQ board, there was a reply before saying I need a motion controller which will cost upto $ 2000 and I am not allowed to spend that money.  What I am trying to build is a simple DC motor controlled (connected to gear set with a lead screw) by NI-DAQ connected to SCB 68 and I have two roller switches which will sense the elevator when it reaches upper most or lower most level. (Switches : SPDT changeover switch is rated 5 amps at 250VAC and has a body size of 3/4x1/4x3/8" from radioshack.com).  This is a low funded project because "the experiment concentrates on a Brain disease which has to be tested when a person is sleeping or standing, so to simulate two different position of human brain a glass container filled with distilled water has to be lifted 3 feet which is considered ideal human torso height", so as the experminent has a different theme this will be an accessory upgrade of present model and I do not need to be very precise to control velocity and acceleration of the elevator.  I have to write a supporting program which detects the position of elevator (UP or DOWN) and send it to other position once commanded by the computer.

My task for this project will be to control a DC motor which rotates the lead screw thus taking the platform UP or DOWN.  So I am wanting to connect the motor 5V and two switches to different channels in SCB 68, I can buy a relay switch if that helps.  This is my first week that I have recieved my SCB 68 card, so I am at a beginners level with SCB, but I have been writing programs since 4 years, so i am very good at that.

Thanks  Jason,

Have a wonderful day,

Nick
Michigan Mechs

[Jason N]

Nick,

You should be able to use a DAQ board with LabVIEW to meet the requirements of this project.  The trickiest part will probably determining the position of the motor.  Will you be using an encoder with the motor, or will it just be moving between the two limit switches?  If it is just moving between two limit switches then it won't be too bad.  NI DAQ boards by themselves have a low current voltage output, so you may need to use them to trigger relays.  What are the signal requirements (voltage and current) for the motor and the switches? 

The way the program could work would be to monitor the switches with an input line to determine when there is voltage present and the switch is on or when there is no voltage present and the switch is off.  When a command is given to move the motor, depending on which switch it is stopped at, you could send a voltage output to the motor to start it moving.  When it hits the next limit switch, the program would read this even and then stop outputting voltage to the motor.  This is a rough outline, but it is definitely possible.  Does this sound like what you need to do? 

If you have any specific questions about a particular DAQ board it would be best to post these questions in the DAQ discussion thread.  I can help you any questions about the motion components. 

Jason N

[Nick_Easter]

Hi Jason,

                  I was working on SCB and tried to connect the motor today in morning but it didnt work as it gives out 20 mA.  So I was looking for a DPDT relay switch which could solve the purpose.  But it was exactly as You said.  I will post my question on DAQ thread for the channels to be used.  Thanks for the suggestion it works.

Keep it up buddy,

Nick,

Michigan Mechs.