Is there any difference between +-20 mA and 4-20 mA?

[loghmani]

I mean some DAQs support both +-20 mA and 4-20 mA. If my DAQ supports only +-20 mA, could I use this DAQ for 4-20mA analog inputs?

[Dennis_Knutson]

Don't you think that 4-20mA input is within a +/- 20mA range?

[loghmani]

Sure, It is. But in some DAQ's specification both of them are mentioned and in some, only one of them is mentioned.

[Dennis_Knutson]

And your question is?

[loghmani]

I have 4-20 mA sensors.Is a DAQ which supports +-20 mA suitable for it? Or I should use a DAQ which supports 4-20 mA?

[Dennis_Knutson · Accepted solution]

You yourself answered the question. You can obviously use a card with a +/- 20mA range to measure a 4-20mA signal. Equally obvious is that the resolution with a +/- 20mA card is not going to be as good. Number of channels, scan rate, price, etc. are all factors in the decision you have to make. Aquick call to your local Sales Engineer should be in order.