回复： connection of 2 wire transmitters in NI PCI 6221 DAQ card in differential mode.

[aamir055]

Hello Everyone

Need to connect 2 wire transmitter in PCI 6221 in differential mode. 

Please suggest the wiring details.

[菜虾]

AI0 and AI8

68PIN: 68  and  34

37DSub:1  and  20

……

[aamir055]

Thanks for your reply 

In a 2 wire transmitter wiring there is close loop power of 24VDC is required for sensor. How we will connect it??

[菜虾]

6221 only have power of DC5V

Use another power

If necessary， common-ground：power GND connect to AI GND

[James_McN]

Hi,

The 6221 can only measure voltage natively and not current.

To measure a current transmitter you will need to provide a separate power supply and a load resistor so the 6221 can measure across the load resistor - being careful to ensure the voltages stay within the limits of the 6221.

There are separate modules for reading current directly. This page links to some at the bottom http://www.ni.com/en-gb/innovations/white-papers/08/fundamentals--system-design--and-setup-for-the-4...