DAQ Grounding

[superglglgl]

Hello,

i have a question about DAQ grounding.

I use NI 9215 BNC + NI 9181.

Using the ground screw on the side ---> NI 9181 is grounded.

Because NI 9215 is connected to NI 9181 with the 15-pin D-SUB connector ---> NI 9215 is grounded.

My question is:

actually just the chassis of NI 9181 and NI 9215 are grounded.

But the channel and instrumentation implifier in NI 9215 are NOT grounded because of the channel-to-earth isolation.

In other words AIGND is isolated from this chassis grounding.

Am i right?

with best regards

Lei

[superglglgl]

anyone can help?

[Larry_Morgan · Accepted solution]

Hi Lei,

You are correct, the AI+ and AI- connections on the 9215 are isolated. They have no electrical connection to the 15-pin DSUB. 

[superglglgl]

Larry, thank you!