NI9171 Chassis Ground / Earth Reference

[samfau2]

Hello,

I have an NI9237 inserted into an NI9171 USB chassis and have a query regarding grounding of the system. I have a number of pressure transducers connected to the device via 30 awg 4 core screened cable.

I notice there is a screw terminal on the rear of the NI9171 for chassis ground. If, as suggested in the manual I connect this point to an earthing point within my test area, will this provide suitable grounding for the system or would you also expect to ground the pressure transducers themselves?

Will this give me a floating or earth referenced measurement system?

Thanks,

Sam

[lhedlund]

Dear Samfau2,

I would like you to have a look at page 11 in the NI 9237 Operating instruction document:

http://www.ni.com/pdf/manuals/374186e.pdf

What you will see is that "The NI 9237 is isolated from earth ground....". There is instructions on how do connect so that the device doesn't get damage.   

In other words the chassis connection to earth does not imply grounding for connected devices on the NI9237. I recommed you to make sure that the pressure transducers are connected properly to prefered ground.

Best regards

Lars