Fast Digital to Analog Converter

Other Hardware Science and Measurement
1

I’m a PhD student working in a mechanics laboratory in France (LMT Cachan) and one of the goals of my thesis is to control a hydraulic testing machine using digital image correlation techniques. In order to do this, I need to take a photo of a sample, process it, extract 4 parameters and send them to the testing machine. This process needs to be repeated at a frequency of approximately 80Hz. We need a device to send these values from a Linux computer to the 4 analog entries of the machine (0-10V, 0.5 mA) by coaxial BNC cable. We managed to do this for one channel using an USB connected oscilloscope by sending a continuous current by changing the offset using C++. The problem is that this solution is too slow and has only one channel.

For this we would need a device that has a viable and fast connection (Ethernet, PCI, even USB if recommended) that can send data from a Linux computer (ideally using C++) with a latency of around 1ms, frequency of at least 100Hz, precision of 0.1% and on 4 synchronized analog outputs. Given that I am not particularly specialized in the field of electronics, researching such a device among the large quantity of items produced by your firm proves to be a difficult task.

I would like to know if you have a product that fits our needs and if similar purpose programming has already been done (or could easily be done) to send data from a linux computer to analog outputs (using C++ ideally).

Best regards,
Ionut Prisacari

2

Maybe you could use the arduino yun since it mixes the linux enviroment with the arduino one and then use an external DAC module connected to it... (not sure if it has the speed you want though)

PS: The connectiong between pc <-> arduino could be made through usb.

Links:

https://www.sparkfun.com/products/12918 (there's more than this one and you can even pic an ic yourself and do one, it's just so you have an idea)

jecs

3

Its the latency that will hit you - I don't even have any clue as to the USB serial latency for instance,
this you would have to investigate: (it turns out this is probably tunable)

A directly driven true serial port ought to be of known low latency I'd have thought.

Sounds like a 12 bit DAC like the MCP4922 might be good (you'd need 2 of them for
4 channels), driven from SPI via a small Arduino.