Cascading Analog or Digital Outputs of National Instruments DAQ Devices

Updated May 3, 2018

Reported In

Hardware

  • PCIe-6321
  • NI-9266
  • NI-9265
  • Multifunction I/O Device

Issue Details

I would like to cascade the outputs of my DAQ device in order to increase the total voltage / current output. Can I do this with my device?

Solution

For most NI DAQ devices (devices that uses the DAQmx driver), cascading will not be supported. Whether or not it is possible to cascade across channels or devices is a matter of the isolation that is implemented in the DAQ device. The relevant types of isolation with respect to DAQ devices include channel-to-channel isolation, bank (channel-to-bus) isolation, and channel-to-earth ground isolation. Devices can be cascaded across isolated sections. This is to say that a device with channel-to-channel isolation would allow cascading across channels whereas a system with channel-to-earth isolation would allow cascading across devices (though this may cause measurement accuracy issues beyond specification).

The outputs of DAQ devices will typically share a common ground path, meaning that the channels can not be cascaded. To determine the isolation of your DAQ device, reference the Major Differences Between E Series, M Series, and X Series NI DAQ Devices maintained by National Instruments. Recommended practice for increasing the voltage or current output of a system is to use amplification circuitry external to the DAQ device. 

 

Additional Information

For further information on Isolation in this context, see the related links section.

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