Race Technology

Hi,

Just a basic question for a non-tecchy for the moment.

How do I wire up the pull up resistor please? The help file states as below

"The red lead should be attached to the +5v supply from the Data Logging Units, the black lead should be connected to the ground connection on the Data Logging Units and the white lead should be connected to an analogue input."

What I am not sure of is that there are two terminals on the temperature sensor but three wires - what gives? Can someone post a quick diagram maybe please?

Thanks for the help
phil

Do I understand correctly that you have a two wire sensor and want to add a resistor to make it a three wire sensor?

not sure bought your temp sensor for my dl1, just need somone to tell me how to wire it as i dont understand the help file - thanks

One more question on this subject.

I picked up a couple of temp sensors at a swap meet that already have 2k pull-up resistors inline. If I understand the purpose of the pull-up resistor (force the no-signal state of the sensor to a non-floating value) then it shouldn't matter that RT suggests a 1k resistor and my sensors have 2k resistors. Have I got that right?

MattyR

Matty:

The purpose of the extra resistor cited by Race Technology is to make a voltage divider circuit so that a voltage, not a current, is fed back to the analog input of the DL. The necessary connections are +5V, Ground and Analog in.

The 2k resistor may very well be OK, depends on how it is wired in and the resistance of tyhe sensor element.

Have a look at the Help files, might also be handy to consult a EE or ETech friend for some further explanation.

Best Regards,

Thanks Al. So I guess that would lead me to the next question - do the DL1 MkII analog channels have an embedded resistor?

-MR

Matty:

The reference resistor needs to be in the sensor harness, there isn't one in the DL1.

Guys

I have the same question. Using a two terminal sensor and not sure about the pull up resistor. I've asked a few techies but getting different answers!

Wyn

Resistor value depends on the resistance range of the sensing element, what you want is to get a reasonable range of voltages back at the extremes of measurement, ie, say, 1.5 - 4, not 4.5 - 4.51 or .003 - .005.

The exact resistor value is not critical, as long as you can do a calibration with known inputs (typically temperatures).