usb-6008 voltage for SSR control

[seancampbells]

Hi all,

I'm following the National instruments procedure to operate a fan using an SSR with a USB DAQ-6008. http://www.ni.com/example/31411/en/#toc5

I need a minimum of 3 volts from my daq to control. This should be no problem as I can get up to 5V. However when I measure using a voltmeter I get 5v but when I connect the wiring for some reason it will only give me 1.49V. Disconnect the cable again it measure as 5v.

Has anyone any idea what Im doing wrong ?

cheers

S.

[A.E.M]

Hi

The output current drive for Analog Output is 5 mA. My guess is, that your device is using to much power.

Manual for 6008, p. 21

[seancampbells]

H Alex,

thanks for your reply. I suppose whats really thowing me is that if I go into MyDAq I can manually request 5 V and teh fan works. However run it in a VI and no joy, back to 1.49 it goes...so weird.

many thanks

S.

[Michael_78]

I have not found an ssr which the 6008 will drive. But I have joined 2 channels together and that worked fine. You have to drive the outputs at the same time. That involves writing to the whole port at once. This involves fun with logical bit masking. So go ahead and have fun.
Michael. Speaking from experience

[seancampbells]

Hi,

thanks for your reply, I have a Fentek SSR-25 switching a 230VAC circuit with now problems. The issue is with the SSR mentioned in the NI procedure http://www.ni.com/example/31411/en/#toc5

[Dennis_Knutson]

You've been told what the problem is with the 6008. What are you asking now?

[seancampbells]

Denis,

the 6008 can switch the SSR when I manually input 5VDC in the MyDaq interface. But when I run it in a VI it only outputs 1.49V.

[Michael_78]

Ok. Now it's time to see the vi. And what is mydaq interface? Max? And are you using an analoge output? Why?

[Dennis_Knutson]

The myDAQ and 6008 are two different pieces of hardware so your comment makes no sense. Which one are you actually using?