multi devices to read analog input by using usb-6210 w\c#

[Simon838]

Hello everyone,

I am using two USB-6210 devices to read 13 channels of AI in differential connections by using C#.

My program only can read all AI channels in one device. if I try to read all of the AI channels in two devices, it tells me the devices don't support multi device in one Task. Therefore, I use the example of the multi devices as reference code. However, It also doesn't work. It says the specified property is not supported by the device or is not applicable to the task. Property: NationlInstruments.DAQmx.Timing.ReferenceClockSource. Status Code: -200452. 

Does anyone knows how to read all AI channels in both devices?

Regards,

Simon

[Kevin_Price · Accepted solution]

Well, the error code is right.  Your devices *don't* support multi-device tasks.

To sync your 2 devices for AI sampling, designate one as the master.  It will export its sample clock out to a PFI pin, you'll physically wire that PFI pin to a similar one on the other device.  And then the other device will import its sample clock from that PFI pin.  It might be important to physically wire together DGND pins from each device as well.

In this scheme, the master device should be the last one to start.

At bottom is a partial snippet of what the code would look like in LabVIEW, but the corresponding physical wiring will also be necessary.  I don't know the syntax for C#, but the naming is usually recognizable. 

The main new function here you haven't already used is known in LabVIEW as "DAQmx Export Signal".  It's used to route the master device's internal AI sample clock out to a PFI pin.  The other new thing is that the other device configures its sample timing such that the sample clock is imported from one of its PFI pins.

-Kevin P

[Simon838]

Thank you very much. I just start using the 6210 devices and never touch the LabVIEW before. It may take me a while to digest whole thing.