USB-2408 Compatibility With ULx LabVIEW Drivers

[Jon Morris]

I am trying to use the ULx drivers with the USB-2408.  ULx recognized the device and channels but throws an error when trying to read the temperature (TC) measurement.  The error says that "the hardware does not support temperature measurement".  This device has a native TC measurement and linearization function that seems cannot be accessed by ULx.  Is that true?

[Fausto]

Hello @Jon Morris.

With a USB-2408 (and USB-2416 Series), a user must configure the channel types (whether it be voltage and/or temperature) in InstaCal.  Take a look at the LabVIEW example attached to this Reference Document.  The example can be used to measure both voltage and temperature.

https://digilent.com/reference/daq-and-datalogging/documents/usb-2416-usb-2408-with-labview

 

Regards,

Fausto

[Jon Morris]

19 hours ago, Fausto said:

Hello @Jon Morris.

With a USB-2408 (and USB-2416 Series), a user must configure the channel types (whether it be voltage and/or temperature) in InstaCal.  Take a look at the LabVIEW example attached to this Reference Document.  The example can be used to measure both voltage and temperature.

https://digilent.com/reference/daq-and-datalogging/documents/usb-2416-usb-2408-with-labview

 

Regards,

Fausto

Thanks for the reply.  We did figure out to use AI voltage read rather that temperature.  However, we missed controlling the HW clock acquisition rate through LV rather than Instacal.

We are only using one channel and so would like to get the maximum rate of 3750 Hz.  The vi errors out indicating the max rate for this device is 378 Hz.  Any suggestions here?

[Jon Morris]

Here is what I found about controlling the acquisition rate. 

1. Instacal must be used to set the maximum rate. This also sets the onboard filtering.
2. LabVIEW must be completely closed and then relaunched in order to "use" the new acquisition rate
3. The ULx timer vi may be used to run at a lower than max acquisition rate.
4. The calculation 1/(1/(max Hz) + 640us) sets the max rate the timer vi can use for a single channel.  i.e. 1ch@ 3750Hz => 1103Hz is the max rate the ULx timer vi can use.