Lambda GUI not reading

Support forum for the Lambda Shield designed to connect Bosch LSU 4.9 wideband oxygen sensors to Arduino projects.
dgleason
Posts: 14
Joined: 18 Apr 2019 21:45

Lambda GUI not reading

Post by dgleason » 18 Apr 2019 22:08

I've installed the Arduino GUI example and the Lambda Shield GUI program on my computer. When I run the standalone GUI program, it recognizes my board and accurately heats it up normally. However, it reads 0% oxygen and 0 amps.
When I run the Arduino GUI example and open up the serial monitor, I can see that the board is in fact reading, and when exposed to varying levels of oxygen, the readings on the serial monitor change.

I'm fairly confident that the board is functioning - could this be a problem with the GUI program?

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Christian_Bylund
Posts: 52
Joined: 07 Mar 2015 18:09

Re: Lambda GUI not reading

Post by Christian_Bylund » 18 Apr 2019 23:07

Hello,

Thank you for bringing this bug to my attention. I was able to replicate the problem that occurs when the AD value is outside of the lookup table. It returns 0. Please download the updated version 1.1.1 or newer from the website and let me know if you still experience the same problem.
Best Regards,
Christian Bylund
Bylund Automotive AB

dgleason
Posts: 14
Joined: 18 Apr 2019 21:45

Re: Lambda GUI not reading

Post by dgleason » 25 Apr 2019 21:39

I'm now experiencing a very similar problem - it is stuck reading at 2.54 mA and 20.95% oxygen. These values do not change regardless of the actual O2 values.

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Christian_Bylund
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Joined: 07 Mar 2015 18:09

Re: Lambda GUI not reading

Post by Christian_Bylund » 25 Apr 2019 23:19

dgleason wrote:
25 Apr 2019 21:39
I'm now experiencing a very similar problem - it is stuck reading at 2.54 mA and 20.95% oxygen. These values do not change regardless of the actual O2 values.
Hello again,

Do you see no difference in output at all, for example if you breath on the sensor does it still show 20.95%?

Right now 20.95% is the maximum value to be displayed, this could be the reason why it does not change since you are out of range. Could you share the serial output from the Arduino?

If you would be willing to share some more information regarding the application and required measurement range I am sure we can solve it. Also feel free to contact me directly if needed, christian@bylund-automotive.com.

Thank you.
Best Regards,
Christian Bylund
Bylund Automotive AB

dgleason
Posts: 14
Joined: 18 Apr 2019 21:45

Re: Lambda GUI not reading

Post by dgleason » 25 Apr 2019 23:39

Yes, the output does not change at all when breathed on.
The Arduino file works just fine - but the values it reads while in open air are around 26%. This would make sense as to why the GUI isn’t outputting correctly.
Do you think the sensor is reading accurately? 26% seems very high for ambient air.

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Christian_Bylund
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Re: Lambda GUI not reading

Post by Christian_Bylund » 26 Apr 2019 00:14

dgleason wrote:
25 Apr 2019 23:39
Yes, the output does not change at all when breathed on.
The Arduino file works just fine - but the values it reads while in open air are around 26%. This would make sense as to why the GUI isn’t outputting correctly.
Do you think the sensor is reading accurately? 26% seems very high for ambient air.
So for the Windows App you must use the code included in the zip file.

The output should look something like this if you do:
STATUS,0,10325,308,467,301

Regarding accuracy, are you using the X7 jumper to power the Arduino from the 12V? If not do you have a stable 5V USB power source? See section 3.2 and 4.0 in the technical manual for details.

If you get 26% oxygen content it means you are using an older version of the serial output example code not compatible with the Windows APP. Always use the latest versions from GitHub (http://github.com/Bylund).

Just note that it is different codes for serial output and Windows App output. And I assume you have seen our getting started video?
https://www.youtube.com/watch?v=sR3YrV0KHXw

Hope it helps.
Best Regards,
Christian Bylund
Bylund Automotive AB

dgleason
Posts: 14
Joined: 18 Apr 2019 21:45

Re: Lambda GUI not reading

Post by dgleason » 02 May 2019 22:49

My sensor is powered by a 1Amp, 12v wall power source, and the Arduino is powered with a USB connected to the computer.

I believe I'm using the Windows App correctly - I upload the Arduino code to the Arduino, then open up the Windows App.

When viewed in the Arduino Serial Monitor, the output looks like this:
STATUS,1,10495,1010,168,791
which seems correct.

However, this Arduino code doesn't output actual oxygen percentages, and the Windows App seems to think it's maxing out.

I got the higher oxygen level readings (around 26-27%) from the version 1.1 Lambda-Shield-Example Arduino code on Github.
The version 1.2 Lambda-Shield-Example has the same problem as the GUI - it only outputs 20.95%, and does not change unless exposed to extreme oxygen-low environments.

Here's an output from the 1.2:
Measuring, CJ125: 0x28FF, UA_ADC: 1010, UR_ADC: 177, UBat_ADC: 751, Lambda: -, Oxygen: 20.95%

When I hold a lighter to the sensors, the oxygen reading drops as low as 0.5%.

I am concerned that the sensor is legitimately reading 26%, but the code is refusing to output anything above 20.95%.

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Christian_Bylund
Posts: 52
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Re: Lambda GUI not reading

Post by Christian_Bylund » 04 May 2019 23:52

dgleason wrote:
02 May 2019 22:49
My sensor is powered by a 1Amp, 12v wall power source, and the Arduino is powered with a USB connected to the computer.
The Arduino and the Bosch CJ125 controller are both powered by a common 5V. So if we do not use the built in 5V voltage regulator of the Arduino it will instead use the 5V from the computers USB which can be very unreliable.
dgleason wrote:
02 May 2019 22:49
When viewed in the Arduino Serial Monitor, the output looks like this:
STATUS,1,10495,1010,168,791
This actually shows the symptom of a low 5V, since the ADC values are much higher than normal it shows that the ADC reference is off. They are so high you will not get a reading since they are considered invalid. Typically you should expect an ADC value of 854 ± 1% in free air.

From the technical manual, 3.2 – Alternative Power Input:
By using a jumper on X7, the power input from the Arduino (or compatible) board is directly connected to power input of the Lambda Shield. This can be used either to power the Arduino from the Lambda Shield. Or power the Lambda Shield (heater) from the Arduino. In either case the 5V is always common.

Image
Either put a traditional jumper (blue) or a jumper wire (red) to connect the 12V power source to the Arduino. This will also enable the 5V voltage regulator of the Arduino and give you a stable 5V which will improve the readings.

WARNING! - Never connect more than one power source at any time when using this feature.
dgleason wrote:
02 May 2019 22:49
When I hold a lighter to the sensors, the oxygen reading drops as low as 0.5%.
The error is almost insignificant the closer you get to 0% oxygen, i.e. λ = 1.
dgleason wrote:
02 May 2019 22:49
I am concerned that the sensor is legitimately reading 26%, but the code is refusing to output anything above 20.95%.
Correct, with a more accurate 5V you should be able to get trustworthy readings. Unless you are measuring a gas containing more oxygen than air the code should be sufficient.

Please let me know if this solved your problem.
Best Regards,
Christian Bylund
Bylund Automotive AB

dgleason
Posts: 14
Joined: 18 Apr 2019 21:45

Re: Lambda GUI not reading

Post by dgleason » 17 Jun 2019 17:35

When you say "Never connect more than one power source at any time when using this feature", does that mean that I should not plug in the 12V power source to the board and a USB to the Arduino/computer at the same time?

If so, how can I use the GUI while the sensor is powered?

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Christian_Bylund
Posts: 52
Joined: 07 Mar 2015 18:09

Re: Lambda GUI not reading

Post by Christian_Bylund » 17 Jun 2019 21:41

dgleason wrote:
17 Jun 2019 17:35
When you say "Never connect more than one power source at any time when using this feature", does that mean that I should not plug in the 12V power source to the board and a USB to the Arduino/computer at the same time?

If so, how can I use the GUI while the sensor is powered?
Sorry that it was unclear, with power source I meant connections to the DC-jacks. So never connect two DC-jacks at the same time. Use one or the other.

You are definitely supposed to use the USB. I hope that it clarified my statement.
Best Regards,
Christian Bylund
Bylund Automotive AB

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