Question about electronic accuracy on model 218

Thanks for the question. In this case, accuracy is specified in ohms, so the ±0.02% or reading is referring to the resistance reading of the platinum RTD. At 30 K, a platinum RTD is typically 3.66 ohms, so the total accuracy value should be:

Accuracy(Ω)  = ±0.06 ±0.02% of reading

                    = ±0.06 ±0.02% of 3.66

                    = ±0.06 ±0.0007

                    = ±0.0607 Ω

Once you have the total accuracy in ohms, you can convert to an equivalent temperature using the sensitivity value of that sensor. in the case of the Platinum RTD at 30 K, this is 0.191 Ω/K

Accuracy(K)  = Accuracy(Ω)/Sensitivity(Ω/K)

                    = ± 0.0607/0.191

                    = ± 0.318 K

So you can generate your own temperature-based accuracy and resolution numbers from any sensor, provided you know its resistance (or voltage in the case of diodes) and sensitivity values. If you're just looking for indicative values, our sensor response tables will be useful to you.

Hope this helps.