Data Sheet

1/6/2018 1046 User Guide - Phidgets Support
https://www.phidgets.com/docs/1046_User_Guide#Measuring_Resistive_Thermal_Devices_.28RTD.29 8/9
This diagram illustrates how to connect the RTD to the PhidgetBridge
with a voltage divider cirtuit.
Where is the Bridge Value given by the
PhidgetBridge (in mV/V) , and and are
the resistances of the known resistors.
Getting Higher Accuracy
In order to get the highest accuracy from the RTD, consider the following:
Use resistors with a high degree of tolerance. There will be less variability in the manufacturing of 0.1%
resistors when compared to 1% resistors.
Measure the known resistors with an ohmmeter. By obtaining the most accurate measurements for the known
resistances, the formula will result in a more accurate measurement of the RTD.
Use a moving average when obtaining the Bridge Value to reduce the amount of noise in the measured
signal.
Estimate or Measure the resistance of the +5V and GND wires between the RTD and the 1046
PhidgetBridge. Add this resistance to the two resistors.
Turn off the power to the RTD (by disabling the channel on the PhidgetBridge) to reduce self-heating of the
RTD.
By using higher resistor values (> 1 Kilo ohm), there will be less self-heating of the RTD, but the resolution
of the measurement will be reduced somewhat. We recommend 1 Kilo Ohm resistors as a reasonable trade
off.
What to do Next
Software Overview - Find your preferred programming language here to learn how to write your own code
with Phidgets!
General Phidget Programming - Read this general guide to the various aspects of programming with
Phidgets. Learn how to log data into a spreadsheet, use Phidgets over the network, and much more.
Phidget22 API - The API is a universal library of all functions and definitions for programming with
Phidgets. Just select your language and device and it'll give you a complete list of all properties, methods,
events, and enumerations that are at your disposal.
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