4 analog outputs 6009

[dsiap]

Hi all,

This may be/is a stupid question, but given that there are only two analog outs on the ni 6008/9, does anyone have experience controlling four signals with one?  The alternative is of course to order another daq/module with that capability, but I have a couple of these on hand.  My initial idea was to use a rail and control switches with the digital outs to set each channel to what I wanted, but unbeknownst to me the system goes back to a default as opposed to keeping the last setpoint when isolated from the source; so I need four continuous sources.  

Thanks

[Henrik_Volkers]

For slow changes in the analog output you can use sample and hold circuits and digital out lines to control them.

Something like LF398

Or some I²C/SPI DACs where you bitbang the output with the DO lines .....

But only if you want to learn about this stuff and have the time... otherwise another 6009 is cheaper.

[SnowMule]

I'll +1 for a second DAQ. For the price, you're still money ahead than a 6343.

[dsiap]

Well, I already have a 9162 carrier on hand so I could go with the 9263.  Which is roughly the same cost as two 6008/9s and doesn't need the op amps and other circuitry.

That being said I'll try playing around with the sample and hold stuff (I'm obviously pretty inexperienced) and seeing if I can get anything to work.

Thanks!