# RTD Simulator vs Resistors

I want to use an RTD simulator for my project to simulate the PT100 0r PT1000. But I ant to learn that is it really necessary to use a simulator? Of course I can use some different kind of resistors for that purpose. Is there difference between than use RTD simulator or use resistors?

• The difference is your tolerance for errors Commented May 1, 2022 at 18:18

You can use resistors (usually a decade box is used, made with precision wirewound resistors) but it's less convenient perhaps to dial in a precise resistance that corresponds to a specific temperature.

A simulator might be a bit cheaper than a good decade box, but it is convenient. Simulators make assumptions about RTD current and excitation that work in most cases. If you're trying to do something very special, such as sub-mK measurements and control, check that the specifications of the simulator (or resistors) are adequate.

It might seem absurd that a simulator might cost more than the RTD sensor or meter.

Traceability on calibration can be expensive or complicated if you are not experienced in metrology. Also, if the cost of not meeting expected accuracy is more than the cost of calibration, you need to choose from your options to make, buy, rent or subcontract your metrology calibration needs.

If you have the design skills and the cost of time is included, you can certainly use a 0.01% accurate 100 Ohm resistor for 0'C offset and another for gain if you can validate your results hopefully with NIST traceable sources.

Probe temperature coefficient 0.00385 Ω/Ω/°C nominal
Nominal probe resistance at 0 °C 100 Ω
Probe hysteresis ±0.01°C (default) 0.001°C or 0.1°C (optional)

Assuming this is for demonstration a simulator in not needed. You can build your own by place a pot in series with a resistor where the resistor is the value of the lowest resistance you expect and the pot value should be as close as possible to the max resistance minus the resistor. Approximation should be close for simulation but no guarantee of accuracy. If you have a four wire setup connect two wires to each end of the resistors. Three wires connect the source and sense to one end and the common to the other end of the resistors. This works nicely and more then likely you can read the pseudo temperature on the instrument.