Goodmorning,
I was wondering if someone knows what are the temperature reached by the MOx over the heater profile.
Thanks.
Hello,
Thanks for reaching out Renesas Engineering Community.
I assume that you are referring to the heater temperature during an active measurement is that right?
If you check the datasheet you will see that the operation temperature of the sensing element can reach up to 550 Celsius degrees:
Now during an active measurement this temperature is greater than zero. If you will check also the programming manual for the different library versions and algorithms we give for ZMOD4410:
During the active phase, where a measurement is taken the maximum heater temperature on the peak reaches 400 Celsius degrees.
In case you are referring to something else. Please let us know.
Best Regards,
IK
Hi,
yes I was referring to what are the temperature at which every rmox value are taken.
Thank you.
Would you like to know for a specific algorithm and library version?
I'm using the latest library available of ZMOD4510 - Selective Nitrogen Dioxide and Ozone Firmware - recommended for new designs published on May 31, 2024.
Best,
Matteo
Sorry my mistake, in my previous response didn't notice the part number well.
Again for ZMOD4510 the maximum temperature of the sensing element is:
And as mentioned in the programming manual for NO2+O3 library version a new measurement is taken every 6 seconds. And each measurement include 3 stages a shown here until the next measurement:
And for first stage rmox[0]-> heater temperatures can reach up to 125 Celsius degrees.
For second stage rmox[1] -> heater temperature can reach up to 175 Celsius degrees.
For third stage rmox[2],rmox[3] ->heater temperature can reach up to 225 Celsius degrees.
So on each measurement the maximum heater temperature can be up to 225 Celsius degrees.
thank you very much for the information!
Best regards,
Matteo Verzeroli
is there any documentation about why these temperatures were selected? Maybe some reference about the sensor response to oxidizing gas related to heater temperature? Is there the possibility to change this temperature via the firmware or they are fixed?
Hello Matteo,
I don't think that there is any document published officially about the reason that the measurements are done in stages with different heater temperatures.
The reason that probably this is done is because the heating control makes it possible to generate a temperature profile and get by this way some more information about the sensor.
The behavior of the sensor for different gases is different on each temperature.
Different gas compositions can be identified using different temperatures.
The sensor element sensitivity for each gas is different on each temperature that the internal heater element has.
So as you can understand the value of these temperatures is not random, but has been selected after observation of the sensitivity that the sensor element has to the target gases.
So you can understand that for ZMOD4410 measuring for example TVOCs is different then ZMOD4510 measuring O3.
Also the stages and the temperatures are different for each operation mode for the same sensor.
For example for ZMOD4510 for NO2 O3 operation mode the heating profile is different than for ULP O3 mode:
Since in the first mode also the concentration of NO2 is provided by the algorithm.
Also various measurements are taken in different temperatures or same temperatures in order to generate training data that will be used as input for the algorithms used to output the final measurement results.
By exposing the sensor element to different heater temperatures, is a method also to get information depending the sensor behavior about the sensor age, the MOx-typical sensor drift or production-related scattering of the sensor material info.
Please let me inform you that for each operation mode the values of these heater temperature are fixed and cannot be changed.
Hope this helps!
thanks a lot for the information!
Just one last question. The ZMOD4510 and the ZMOD4410 are made by the same MOx element but used with different temperature profiles or they are different types of MOx? Just to understan better the principle of working of MOx.
Hi Matteo,
Sorry for coming late here to this follow-up question. ZMOD4410 and ZMOD4510 use different materials for their MOX layers and different type of semiconductors.