what shall I put in the "device reference in" in the Read.vi?? for my USB-8451, where I found the name to be USB0::0x3923::0x7166::01349C20::RAW??

chihway · ‎04-04-2008

as title

what shall I put in the "device reference in" in the Read.vi?? for my USB-8451, where I found the name to be USB0::0x3923::0x7166::01349C20::RAW??

i put the whole name in and it keep telling me
Error -301706 occurred at NI-845x I2C Read.vi
NI-845x: The device reference is invalid. Verify that the supplied device reference contains a valid device name.

Thanks!

Chris G in AE · ‎04-07-2008

Howdy chihway,

We have some great documents on how to do USB Raw Communication in LabVIEW. Check out that article and also the one in the related links section. They should give you all the information you need to get started.

Sincerely,

Chris G in AE

Dennis_Knutson · ‎04-07-2008

I haven't use the 8451 but it just doesn't seem right that it should appear as a USB RAW device or that the user has to run the driver wizard to create a VISA interface to it. Shouldn't the installation of the 8451 driver take card of this and make the device appear as something other than RAW?

Chris G in AE · ‎04-09-2008

Chihway,

I apologize for misreading your post the first time around. Dennis is only half correct in this case. The USB-8451 is supposed to show up as a USB-RAW device in MAX, but you do not have to run the driver wizard to create an interface to it. In Measurement and Automation Explorer, select the USB-RAW device under USB Devices and create a VISA alias (I always use 8451) by typing it in the "VISA Alias on My System" box. You should then be able to use that alias for all communication. I hope this post helps a little more than the last one!

Sincerely,

Chris G in AE

chihway · ‎04-10-2008

Thanks a lot, things are working now. But then there's another problem here. We are planning to connect the I2C bus with several (5~6) AD 7747 chips so that we can read measurements from them at the same time...and now all the slaves have the same address....Is there any convinient way we can program the addresses of these chips? The solution we came up was to use I2C multiplexer PCA9544A. Is there any examples I can find on programming PCA9544A through I2C? Thanks!

chris_amadasun · ‎04-11-2008

Hello,
You will have to go through the application notes of the I2C multiplexer chip.
In that diagram it should outline how you can connect devices of the same address.

Let us know if you need any assistance finding these documents.

Christian A
National Instruments
Applications Engineer

LabVIEW

what shall I put in the "device reference in" in the Read.vi?? for my USB-8451, where I found the name to be USB0::0x3923::0x7166::01349C20::RAW??

what shall I put in the "device reference in" in the Read.vi?? for my USB-8451, where I found the name to be USB0::0x3923::0x7166::01349C20::RAW??

Re: what shall I put in the "device reference in" in the Read.vi?? for my USB-8451, where I found the name to be USB0::0x3923::0x7166::01349C20::RAW??

Re: what shall I put in the "device reference in" in the Read.vi?? for my USB-8451, where I found the name to be USB0::0x3923::0x7166::01349C20::RAW??

Re: what shall I put in the "device reference in" in the Read.vi?? for my USB-8451, where I found the name to be USB0::0x3923::0x7166::01349C20::RAW??

Re: what shall I put in the "device reference in" in the Read.vi?? for my USB-8451, where I found the name to be USB0::0x3923::0x7166::01349C20::RAW??

Re: what shall I put in the "device reference in" in the Read.vi?? for my USB-8451, where I found the name to be USB0::0x3923::0x7166::01349C20::RAW??