NI-9205 - Mixed Measurement Modes

[RobbieD]

Hi,

Have a requirement to measure both a ground-referenced voltage and floating differential voltages using the same card. 

The ground referenced voltage will used to measure a voltage from a thermistor/voltage divider circuit and the floating differential voltages from a battery module.

Looking at the wiring diagrams on the NI website, i.e.... 

Connecting Grounded Differential Signals

Connecting Floating Differential Signals

Connecting RSE Voltage Signals

Connecting NRSE Voltage Signals

All of these configurations require that the signal uses COM as a ground reference.

Does this mean that only a single configuration can be utilised for a single card?

For example, if I connect a battery module's -V to the COM pin, it looks at face value that all measurements irrespective of the channel configuration will be taken with respect to this voltage.

Is this correct, or am I missing something obvious?

Many thanks

Rob

 

 

[ZYOng · Accepted solution]

I believe you can use both DIFF and RSE on different channels in the same module.

Both thermistor and battery signals are floating. The simplest wiring would be RSE for both cases. See Table 1 in Field Wiring and Noise Considerations for Analog Signals

[RobbieD]

Hi ZYOng,

Many thanks for the information, much appreciated.

Cheers Rob