Driving a 24V Relay with a USB-6009

[ssk]

Hi,

Has anyone got a circuit diagram of how to drive a 24VDC Relay using a USB-6009 and a ULN2803? I have done it before but cannot find my old notes and for some reason I cannot get it going now.

I have set the channel up correctly using the DAQmxBase utility but I still cannot get the relay to switch.

Any help greatly appreciated.

Thanks

[Henrik_Volkers]

http://www.google.de/search?q=ULN2803

Using a voltmeter , check the supply and output voltages. Without meter a 1k+LED can help 😉

[ssk · Accepted solution]

Got it sorted! It was my software not the hardware.

Thanks for the advice anyway.

[sahani]

Hi 

I am using a USB 6009 to drive a 24V relay but as soon i connect the relay to the USB 6009 module the output voltage drops from 5v to 2 v and it is not swtiching the relay. 

Can any one please help me how to switch the relay.

my software is working properly and it the hardware connection where I think I am getting wrong, if any one has got a circuit diagram, it will he great help.

Thanks

Veer

[ssk]

You would want to switch the relay via some kind of buffer (look at the data sheet three posts up for an idea of the device to use).

[sahani]

Hi 

I am using a switch in the digital input line and then the USB 6009 gives a digital output line with 5V , but it is not driving the relay, i want to know do o need to connect any thing in between the realy and the digtial output line. 

Thanks

Veer

[ssk]

Yes, you will need some interface circuitry inbetween the digital output pin and the relay coil (a simple transistor switch would suffice).