NI USB 6218 on Mac OS - will only read 8 differential channels?

[lmd2]

okay some background, I am a LabVIEW architect, been drawing code almost 16 years on the PC. A client needs a daq system on MAC OS - I am using a new MacBook Pro with an NI USB 6218, NI DAQmx Base 3.4 (btw this download of NI DAQmx Base came with C examples only and not LabVIEW, what's with that?) Anyway, after a bit of a learning curve I have the hardware reading voltage (Dev1/ai0:7) doesn't seem as robust as on a PC (sadly) but it is working. The 6218 is 32 channels SE or 16 differential, but if I try to read 16 channels (Dev1/ai0:15) I get the following error:

Error 200077 Specified value for input terminal configuration is not valid for this channel

I am attaching a small VI that I have been using to get the hardware up and running.

Any feedback would be greatly welcomed

thanx

lmd2

[Dennis_Knutson · Accepted solution]

That's not the correct channel list. When you select differential, ai0 is paired with ai8, ai1 is paired with ai9, etc. You do not list the second channel of the pair, So, to get 16 channels, you have to specify Dev1/ai0:ai7,Dev1/ai16:ai23

[lmd2]

thanx Dennis, works like a charm

enjoy your holidays!!

[JoeFriedchicken]

---

@lmd2 wrote:

I am using a new MacBook Pro with an NI USB 6218, NI DAQmx Base 3.4 (btw this download of NI DAQmx Base came with C examples only and not LabVIEW, what's with that?)

---

DAQmx Base does ship with examples for LabVIEW, but the driver does not plug in to the Example Finder's framework. Do you see a 'daqmxbase' folder if you change the Example Finder's to show you examples by directory (and not by task)?

[lmd2]

Thanks Joe,

yes I see the examples. I had looked in the DAQmx Base directory, not in the LabVIEW directory. I actually installed DAQmx Base on the MacBook pro before installing LabVIEW 2010, So that probably threw my off,

And thanx for the linx, I figured there was an OS X group, but hadn't gotten around to searching it out.