I have dt80 and have a thermistor in channel 1. It was initially giving me values at the require sample time but they appeared to be too high. While trouble shooting this , the values returned became invalid with overrange message. Different channels were tried, same result. Tried to do a resistance measurement, same result. I short circuited the input channel block screws with some copper wire. Measurement returned "3.5" ohms. How to proceed?

When the thermistor is checked with a meter it gives a reading of 11k ohms which for a YS 44016 thermistor at room temperature is in the right ballpark so the thermistor is ok.

Hi Ian,

May we know if you are using a series 3 or 4 logger? Series 3 logger cannot read above 11 kohms, while series 4 logger can read up to 1 Mohms using a particular current excitation III (2 uA). If your program is not using current excitation III, it will appear as an OverRange.

In series 4, there is extra care when reading 2 wire resistance as you need to check the internal resistance first by short-circuiting them (as the method that you did). This resistance value would negate the reading output as a correction.

Regardless, we recommend using the R6 wiring configuration to read any resistance above 11 kohms rather than using current excitation III due to the resolution and accuracy benefits.

Best regards,
dataTaker Expert

This logger is a series 4 device. Where can I find more information on the R6 reference? It's not obvious using the dEx-2 interface.

I have replace the ys16 with a ys04 sensor and am using separate excitation. Values returned look much closer to those expected.

Hi Ian,

The R6 configuration and calculation to get the shunt resistor value are in the manual. In dEX 2.0, you can implement a normal 2-wire resistance reading. You can use a calculation to revert it back to the actual resistance and apply thermistor scaling. The scaling must be declared in a manual channel.

Therefore if you plan to use R6 configuration, you need to read the sensor as a resistance channel (not as the thermistor) and run everything via manual channels.

Best regards,
dataTaker Expert