Controlling a small motor

[Marcello Barboni]

Hello everyone,
I have a small and probably dumb problem I cannot seem to find a solution
for: I need a PCI board to control a small 24V, 3.5W max motor used to
rotate a piezo transducer.
The kind of control I need over the motor is very basic (on/off and little
else), the only requisite is that it can be controlled via software
(preferably labview).

In the future the system will be upgraded to a stepper motor (for which I
found many PCI-based options), but for now we're stuck with this one.

Any suggestions would be greatly appreciated.

Thank you

Marcello Barboni

[Oleg]

Hi,
Most of motors need some "high analog" power voltage (in your case 24V) and a number of logical signals (0-1) to control the direction of the motion, power of motor, performing of steps and some other things.
You can take some external supply for feeding of the motor. And then you can take logical lines from RS232 in yor PC. The control of this lines can be easily done with LV VISA functions.
We have such thing in our lab and it works for years.

Good luck.

Oleg Chutko.

[Doug_Norman]

Hello Marcello,

I've done this quite a few times with NI boards that have analog or digital lines. I've mostly used MIO boards, but a simple digital board will also work. The key is that analog and digital lines typically can't sink much current, so you have to use them to turn on a transistor or relay which in turn controls your 24V motor (via a separate source). The key is finding a transistor or relay that fits "both ends" of your circuit. You need one that will turn on with 5V TTL from the digital line, and yet can handle 24V at 3.5W on the other side. Sometimes I have had to use a combination of a digital line turning on a transistor which turns on a relay. Since you only need 3.5W, I believe you could use a TIP120 transistor. Let me know if you ne
ed a schematic of how to wire this solution. Also, do you need to run the motor in forward and reverse or just on and off?

Regards,

Doug

[Mache]

Hi Marcello,

You need a Metrabyte Compatible I/O Card. The PCL725
was the most famous version of it.

I have used the following card from CyberResearch with phenomenal success

CYPDISO8 8 Mechanical Relays, 8 Isolated Inputs Board

This is a PCI Card with 8 Relay Outputs, which can be individually controlled. They will Handle your Motor Ratings. Unfortunatley the Data Sheet can be Obtained by Fax-On-Demand Only.

If you are not bent on PCI interface, there is another ISA card that will do the job and it is even cheaper.. $150.00 max.

CYDO 24HV/48HV High-Voltage, Direct Drive Digital Output Boards. These will Handle directly 50V/0.5A load. With Motor make sure you include a Freewheel diode to curb the transients.
http://www.cyberresearch.com/fod/fod5315
.pdf


Check www.cyberresearch.com

The Only drawback is that you have to purcahse the drivers seperately for about $50.00. They do have ready LabView Drivers.
http://www.cyberresearch.com/fod/fod6021.pdf

Good Luck!!

Mache