How can I connect 1-wire sensor using DAQ?

[depablo]

Hi,

How can I connect 1-wire sensor using DIO in DAQ? I didn't find anything about it on this site.

Thanks.

[Brooks_C]

Hello Depablo,

When making any voltage measurement you need to provide two wires and signal and a reference voltage.  If you have a digital sensor or device with a number of outputs there should also be a reference or ground voltage output so that you're measurement device can read the correct value.  If you don't connect the ground/reference voltage to the DAQ device then you'll be measuring a floating voltage and it won't be accurate.  Voltage is a relative measurement--your sensor may be outputting 5 volts relative to its internal ground, but that ground may be 10 volts above your DAQ cards ground.  If you measure the 5 volt line with your DAQ card you'll read 15 volts and not 5 volts unless you also connect the sensors ground to the DAQ card.  If you're unsure which wire to use as a reference you can either contact your sensor manufacturer, or if you like you can post back with a link to your sensor's data sheet and I can see if I can identify the correct wire.

I hope this helps, and have a great day!

[depablo]

Hi,

I don't want to make any voltage measurement. I want to read information from digital sensor which is using 1-wire technology. You can see some example 1-wire sensor on this document: http://datasheets.maxim-ic.com/en/ds/DS18S20.pdf
I want to know how can I connect this sensor to DAQ.

Thanks.

[Brooks_C]

Hello Depablo,

From the looks of your sensor you need to connect DQ to the digital port and line of your DAQ card, and you also need to connect the GND pin of your thermometer to the DGND pin on your DAQ device.  Even digital measurements need to be referenced to a ground to be read accurately.

Let me know if this helps.

Cheers,