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How to connect NR01 to CR1000 without 4WB100


Fasad Sep 2, 2020 07:12 AM

Hi all, 

I have problem with my NR01 sensor. I tried to connect it to CR1000 without 4WB100 and I still have NaN values in temperature. I know that I need 100 Ohm resistor (I have it) but how the conection of cable 2 should looks? 

I will be grateful for your help!

Marcin


aks Sep 2, 2020 04:56 PM

Your message is a little confusing. I will be able to help if I know what 100 Ohm resistor do you have? Is it 4WB100 or is it just a resistor with two leads? You need a precesion resistor ideally 0.1% or better.


Fasad Sep 3, 2020 01:54 AM

Dear aks, 

In fact, my question may be confusing.

I have a 100 Ohm 0.1% resistor with two wires.
My question is: The wires in NR01 of cable 2 are responsible for the temperature, the program made in Short Cut tells that the signal wire (white) from PT100 should be connected to channel 6H, the reference wire (green) to 6L, while the red and blue wires should be connected to 4WPB100.

And now the main question is how to skip the 4WPB100 step and connect the red and blue wires to the 5H, 5L and VX1 ports to use a two wire resistor?


aks Sep 3, 2020 12:35 PM

There are a few ways to do this depending on accuracy desired and # of channels available.

Highest accuracy is obtained using a four-wire configuration. But you need two differential channels.

You connect your sensor in series with a fixed resistor of high precision, one of the excitation ports (e.g. Vx1)

Measure differential voltages across sensor as well as the fixed resistor. Then use Ohm’s law to find the value of the sensor resistance. Then use instruction PRTCALC to find the temperature. A possible configuration is shown in the diagram attached.

You can also make two Single ended measurements and do the same calculation, the accuracy will, be a little less but still good for most applications. But you save one fifferential channel.

Please check your e mail for a wiring diagram I sent. Please let me know if you need any further help

Thanks


Fasad Sep 4, 2020 03:07 AM

Thank you for the answer, your diagram explained to me how to connect the NR01 with the use of a resistor. Actually everything works as it should. 

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