05-07-2020 04:46 AM
Hello NI forum :). It's nice to join such a community 🙂
I hope you will be able to help me...
Is it possible to generate with 6009 card output signals outside 0 - +5V range?
I successfully generated a differential signal to run galvo by connecting my 6009 to a computer. On AOO I generate a 0 - +5V signal and on AO1 constant 0V.
Is it possible to change this configuration/ add something to a program program and to generate differential -10 + 10V signal
(especially since the card accepts such input range?)
Thank you in advance for your help
Joanna
05-07-2020 08:23 AM - edited 05-07-2020 08:24 AM
Hi Liiung,
@Liiung wrote:
Is it possible to generate with 6009 card output signals outside 0 - +5V range?
No.
The USB6009 works exactly as written in the SpecSheet…
05-07-2020 08:29 AM
<nodding her head with sadnes>
I had hoped some clever trick exist...
Thank you!
05-07-2020 08:52 AM
Its successor, the USB-6002, has AO capabilities of ±10 V.
Bob Schor
05-08-2020 11:54 AM
@Liiung wrote:
<nodding her head with sadnes>
I had hoped some clever trick exist...
Thank you!
Assuming you are trying to create a sine wave, here's a trick to try...
Pass the 0-5v output through a capacitor and then an opamp to amplify it to +/-10V.
05-08-2020 08:59 PM
Well, if you're going to get "clever" like that, you can also do the following (you need a little understanding about Op Amps and how to use resistors and feedback to add (or subtract) two voltages and how to "multiply" (or amplify) by 4.
Assume you want a signal that goes from -10v to +10v, and you have a USB 6009 that only goes from 0 to 5v. You want 0 v from the DAC to become -10v, and +5 from the DAC to become +10v. To simplify the thinking, I'm also going to assume your "signal" goes from -10 to 10, so you'd "ideally" send it to a DAC that goes from -10v to 10v.
So what do you have to do to your signal? Well, you can transform [-10, 10] into [0, 5} by dividing by 4 ([-2.5, 2.5]) and adding 2.5 ([0, 5]). Send this to the DAC. Now build a circuit that subtracts 2.5v (you can use AO1 to generate a +2.5v signal, and make your op amp do the subtraction) and amplify the result by 4. Presto, the output goes from -10v to +10v. It needs a few resistors (3?), an inexpensive op-amp (do people use 741's anymore?), and an appropriate power supply (±15v, probably).
Bob Schor