SU-100 UV sensor

[jot4p]

Hi,

My last 2 sensors SU-100 return values allways > 47 umol/m^2/s-1 during the night..... where is the error ?

Code: Select all

CODE: SELECT ALL
apogee.ON();
apogee.read();
radUV = apogee.radiation;
apogee.OFF();

https://i.ibb.co/02ySkwh/2019-11-26-14- ... Mosaic.png

Answer of APOGEE:

" ... Thanks for the email. The SU-100-SS sensors should read “0” at night. .."

[libelium-dev]

Hi,

We think that it is caused by ADC precision. Could you please copy here the output of the example code to read the SU-100 sensor? Please enable debug mode 2 in WaspSensorXtr.h file before uploading the code to the node.

Regards

[jot4p]

Hi,

https://i.ibb.co/rcdM78f/18h-apogee.png

During the night in Portugal yesterday.

The value is 0.0096 V... I have the same values in 2 diffrente sensors and P&S...

But I have a third old sensor that is correct.. (Agriculture_v20).

[jot4p]

In your code for Apogee_SP510 you have:

Code: Select all

`
::read(void)

if (socket == XTR_SOCKET_F)
	{
		ltc.readADC(ADC_CH2);
		radiationVoltage = ltc.readADC(ADC_CH2);
	}

	radiationVoltage-=0.046;   <<<<<<<<<<<<<<<<<<<THIS HERE...

If I do the same (subtract 0.046) for my sensor (SU-100) I have more "plausible" values... what is this value ?

[jot4p]

I can "hack" the code like this:

Code: Select all

float Apogee_SU100::read(void)
{
	// object to manage ADC
	LTC ltc;

	//Enable SPI isolator for using the ADC
	digitalWrite(SPI_ISO_EN, HIGH);

	// ADC setup
	ltc.begin();

	if (socket == XTR_SOCKET_B)
	{
		ltc.readADC(ADC_CH3);
		radiationVoltage = ltc.readADC(ADC_CH3);
	}
	if (socket == XTR_SOCKET_C)
	{
		ltc.readADC(ADC_CH5);
		radiationVoltage = ltc.readADC(ADC_CH5);
	}
	if (socket == XTR_SOCKET_E)
	{
		ltc.readADC(ADC_CH4);
		radiationVoltage = ltc.readADC(ADC_CH4);
	}
	if (socket == XTR_SOCKET_F)
	{
		ltc.readADC(ADC_CH2);
		radiationVoltage = ltc.readADC(ADC_CH2);
	}

	//Disable SPI isolator for using the ADC
	digitalWrite(SPI_ISO_EN, LOW);

	// check value of the sensor in volts
#if DEBUG_XTR == 2
	PRINT_XTR(F("radiation (V): "));
	USB.printFloat(radiationVoltage, 5);
	USB.println();
#endif

	radiationVoltage-=0.096; //<------------------ change this value here...

	if (radiationVoltage<0){
		radiationVoltage = 0;
	}

	// Conversion from voltage into umol·m-2·s-1
	radiation = radiationVoltage / 0.0002;

	// check value of the sensor in mm
#if DEBUG_XTR == 1
	PRINT_XTR(F("radiation (umol*m-2*s-1): "));
	USB.printFloat(radiation, 5);
	USB.println();
#endif

	// No way to check if sensor missing.
	if (radiation <= 0)
	{
		// measure out of range
		return 0;
	}
	else
	{
		return radiation;
	}

}

[jot4p]

I can "hack" the code like this:

Code: Select all

float Apogee_SU100::read(void)
{
	// object to manage ADC
	LTC ltc;

	//Enable SPI isolator for using the ADC
	digitalWrite(SPI_ISO_EN, HIGH);

	// ADC setup
	ltc.begin();

	if (socket == XTR_SOCKET_B)
	{
		ltc.readADC(ADC_CH3);
		radiationVoltage = ltc.readADC(ADC_CH3);
	}
	if (socket == XTR_SOCKET_C)
	{
		ltc.readADC(ADC_CH5);
		radiationVoltage = ltc.readADC(ADC_CH5);
	}
	if (socket == XTR_SOCKET_E)
	{
		ltc.readADC(ADC_CH4);
		radiationVoltage = ltc.readADC(ADC_CH4);
	}
	if (socket == XTR_SOCKET_F)
	{
		ltc.readADC(ADC_CH2);
		radiationVoltage = ltc.readADC(ADC_CH2);
	}

	//Disable SPI isolator for using the ADC
	digitalWrite(SPI_ISO_EN, LOW);

	// check value of the sensor in volts
#if DEBUG_XTR == 2
	PRINT_XTR(F("radiation (V): "));
	USB.printFloat(radiationVoltage, 5);
	USB.println();
#endif

	radiationVoltage-=0.096; //<------------------ change this value here...

	if (radiationVoltage<0){
		radiationVoltage = 0;
	}

	// Conversion from voltage into umol·m-2·s-1
	radiation = radiationVoltage / 0.0002;

	// check value of the sensor in mm
#if DEBUG_XTR == 1
	PRINT_XTR(F("radiation (umol*m-2*s-1): "));
	USB.printFloat(radiation, 5);
	USB.println();
#endif

	// No way to check if sensor missing.
	if (radiation <= 0)
	{
		// measure out of range
		return 0;
	}
	else
	{
		return radiation;
	}

}

[jot4p]

Sorry for 3 posts... I need options to remove or edit

ERROR: the value of my 0 is 0.0096 not 0.096...

Do you fix this on the next API ? Today I will send this to the correct place with this "HACK" ...

[libelium-dev]

Hi,

That for your collaboration on this issue. We are going to perform some tests to know the offset and we will include it in the next API release.

Regards

[jot4p]

OK... the current version is 43

[libelium-dev]

Hi,

The API v043 was released in November, just before that problem. It will be included in the next API v044.

Regards