Set high resolution on temperature sensors returns wrong (10x) values

[rbresca]

Good morning,

I have temperature sensors (Pt100 and thermocouple) connected to analog imput modules (EP3204) and (EP3314).

As soon as I set the high resolution flag in the modules parameter tab, I've got wrong temperature values. Values are multiplied by a factor of ten (245°C) instead of (24.5°C).

Which is the correct way to handle this situation? Should I use the Adjustment function on the AnalogInput objects?

Should I avoid the high resolution flag at all?

[Bianca]

Good morning,

I can see in the EP3204 documentation that Beckhoff has added this new function for high resolution. If you want to use the higher resolution, you can either compensate the offset with the adjustment function if you are familiar with it, or use the scaling function of the object to shift the measuring range of the terminal. You should be able to see the currently used scaling Min/Max values of the sensors and could use this to narrow the measuring range to the new range for hight resolution.

[rbresca]

Hello,

while I'm waiting for a better solution, I've added a MeanValue variabile which is cyclically updated with the correct scaling (I also compute the mean of ten values, but this is irrilevant here).

I would also apply the scaling solution but I'm not sure how to configure min/max values.

The picture below shows the two different sensors I have in the station.

Which values should I put in the scaling fields? Let's check the first case: we have _rawValue of 2354 (==23.54°C) and _rawMax=8500.

I have found that putting 85°C/-20°C (instead of 850°C/-200°C) gives me the correct temperature.

But what happens if the temperature rises above 85°C?

 

 

[Bianca]

I would assume that the sensor is generating an overrange signal above 85°C, as is always the case when your reading is above the sensor's measuring range.