Hi,
I'm using the DAC output from the U3 to control big servo motor, hence the signal coming out from the U3 is amplified by the motor driver. However I'm coming with the problem that when I ask for a zero output on the DAC it still have some residual voltage ,say ~0.02 that still causes a very slow motion on the motor. Is it possible to shut down any current coming from the DAC output? Or some other possible solution?
Regards
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The internal DACs are powered by VS and GND, so they will never quite be able to go all the way up to VS or all the way down to GND. I suggest adding an LJTick-DAC which has a +/-10V output range and thus can go to 0 and below.
https://labjack.com/support/datasheets/u3/hardware-description/dac
https://labjack.com/support/datasheets/u3/hardware-description/dac/typic...
https://labjack.com/catalog/ljtick-dac
Great, I have a LJTick-DAC in Hands, will try using it. Can you just clarify two points for me:
1- My intention is to create a sine wave, with an update rate of at least 10Hz , the LJTick-DAC is able to handle it?
2- I'm using MATLAB, could you please tell me what command should I use to set the voltage I want? Currently I'm using addRequest for DAC followed by GoOne, what would be the case using the LjTick-DAC?
Thank you
1. It typically takes about 1 ms to update the LJTick-DAC. Assume you are able to update the LJTDAC every 1 ms and are doing so to produce a 10 Hz waveform ... that means you will get 100 updates per cycle of your waveform which should make a very sinusoidal looking shape. Now lets say Matlab timing limits you to 10 ms updates so now you are only getting 10 updates per cycle ... that would lead to a piece-wise looking sine shape.
2. See the pseucode on the LJTDAC datasheet:
https://labjack.com/support/datasheets/accessories/ljtick-dac
It uses ePut functions, but you can also to the add/go/get method if you prefer. Realize that 1 ePut is the equivalent of 1 add and 1 go and 1 get:
https://labjack.com/support/datasheets/u3/high-level-driver/overview