PR49-24G Sensor accuracy and variation

Hardware
1

I have 4 PR49-24G sensors all set up on my test bench and have been logging data.

Sensor%20Setup
Sensor Setup.jpg4032×3024 796 KB

When I built a dashboard to show the data stream from all of them I noticed they showed some wildly different values.

Dashboard%20Display
Dashboard Display.png2987×1763 498 KB

The first one I bought appears to be a revision M (This is the purple line) it is also plugged into wall power.
The three I bought at a later date are revision Ls which seem a little weird to me but whatever. (They are the orange, light blue and dark blue and powered by battery)
As you can see while the revision L seem to have good precision, they seem to have poor accuracy.
The revision m seems to not be getting a similar reading to the other devices.

Is there some sort of sensor calibration step I missed maybe?
Anything else I can test?

On a separate note, the devices have the same settings given to them from the gateway with delay times and what not but the revision M sends data 24 times faster than the revision L

2

Hi Mark,
The board REV change was made to production easier. No diff in design. Sometime we have the old REV board already built so use them.

We did made a change in firmware. The 3 new one you have keeps the sensor on for a longer time before taking samples. The longer time lets sensor heating plate settle to appropriate temp.

The new one will have a higher version firmware.

The strange this is the temp humidity data. It should be same in all sensors.

The ethanol and H2 data does depend on the calibration. When sensor powers up it it self calibrates.

Can you do this –
take all 3 sensors in a cleanest ( most clean air area you can find) and power reset all of them at same time and than log the data.

3

Bhaskar,

Thanks for the quick reply.
I will try resetting all the devices in the same clean environment and logging new data.

The two most important pieces of data to me are temp and humidity.
Is there a way for me to update all of the devices to the same firmware?
Having such a substantial difference like that based on software will not be acceptable for my use case.

-Marc

4

Hi Marc,
Yes, we can update same firmware in all. the temp humidity sensor used int this product is SHT25 so the temp humidity values should be extremely accurate and same in all sensors.

I will run few units here and see if i observe same behavior.

Thanks

5

Hi Bhaskar,

Is that something I will be able to do or will I have to send them back to you?

Thanks,
Marc

6

Hi Marc,
We will need the sensors back.
please use this link to fill out an RMA
https://ncd.io/contact-us/product-returns/

Thanks