Solution
Check your hardware's Datasheet under
Safety Voltages and/or the device's
Circuitry diagram.
In general, if a module has its ground connected directly to chassis ground it will not have any
Channel-to-earth ground isolation (this information is found under
Safety Voltages >>
Isolation in the device's datasheet).
Example 1: Digital Module - Isolated from Chassis Ground
For the NI 9375 C Series Module look at the
NI 9375 Datasheet . Under
Safety Voltages >>
Isolation, we can see there is
Channel-to-earth ground isolation. Therefore, the NI 9375 is isolated from chassis ground.
Example 2: Analog Module - Not Isolated from Chassis Ground
For the NI 9234 Sound and Vibration Module look at the
NI 9234 Datasheet . Under
Safety Voltages >>
Isolation, we can see there is no
Channel-to-earth ground isolation. Also, looking under
Circuitry, the diagram references the symbol for
Chassis Ground. Therefore, the NI 9234 is not isolated from chassis ground but is connected directly to chassis ground.