Can the PCI-6704 board sink 4 to 20 ma current?

[jcisco]

I want to use the current output channels on the PCI-6704 board to control a 4 to 20 ma signal. I need to know if the PCI-6704 can sink the 4 to 20 ma current?

[John N]

Hello,

The PCI-6704 is cabable of sourcing 4 to 20mA, but not sinking.

An additional and related issue to be aware of when designing a system with a current source is the "Output Compliance". In the manual for the PCI-6704 on page A-2, the Output Compliance is listed as 0 to 10V. This means that the board is designed to operate with the current causing a voltage drop within that range. Thus if you want to output 20mA, then the load should be no more than 500ohms (500ohms * 200mA = 10V).

You can find the manual by searching for "6704" at http:www.ni.com/support . The search box is in Option 3.

Alternatively, here is the direct link: http:www.ni.com/pdf/manuals/322110b.pdf

Hope this helps,

John N
Applications Engineer
National Instruments