analog input - diff or single ended

[hapetter]

Hi.
Can anyone explain the tifferent between single ended analog input and a analog differential input?

How can I choose right?

Lets say I have a 4-20mA 2 wire sensor. What should I select?

Thanks!

Best Regards
Hans Pettersson

 

[kdcui]

I'm not 100 percent certain, but I believe differential cuts down on noise on your analog signal?

But if you choose differential, it uses more registers and you lose the status / config capabilities of the module.

Can anyone confirm / correct?

 

[OkiePC]

My understanding of single ended versus differential only applies to voltage signals.

A single ended signal means that each analog voltage input is one wire, and multiple single ended signals are referenced to one common reference voltage. So, your input card may accept 16 single ended signals, and would also have one "signal common" wire connection.

Differential signals each have two wires wo that they may each have their own common reference point. The analog input measures the voltage difference between the two points. Differential signals are less likely to have problems with noise because any noise present on one conductor in the pair is likely to be present on the other conductor as well. So the analog card will still measure the correct difference. Think of the noise as a temporary voltage offset.

Hopefully, someone with more detailed information can improve this explanation.

Paul

 

[shooter]

okie is not complete correct.

differential means it is measuring the difference between two inputs so the signal can float (not complete free as it is bounded by max voltage input. the disadvantage is it takes two input channels and more calculation.
single input is bounded to ground so not floating and.
When there is a ground loop you will run into problems.