XDATA Instrument Compatibility Table

Manufacturer	Name	ID	Identify	Decode	Detected	Introduced
EnSci	Ozonesonde	0x01	:heavy_check_mark:	:heavy_check_mark:	:x:	01/04/2009
Vaisala	OIF411	0x05	:heavy_check_mark:	:heavy_check_mark:	:heavy_check_mark:
EnSci	CFH	0x08	:heavy_check_mark:	:x:	:heavy_check_mark:	01/04/2009
NOAA	FPH	0x10	:heavy_check_mark:	:x:	:heavy_check_mark:	01/04/2009
ETH Zurich	COBALD	0x19	:heavy_check_mark:	:heavy_check_mark:	:heavy_check_mark:	01/04/2009
Anasphere	SLW	0x28	:heavy_check_mark:	:x:	:x:	11/08/2011
NOAA	POPS	0x38	:heavy_check_mark:	:x:	:x:	04/06/2014
Particles Plus	OPC	0x39	:heavy_check_mark:	:x:	:x:	07/01/2015
Scienterra	WVS	0x3A	:x:	:x:	:x:	Never flown
ETH Zurich	PCFH	0x3C	:heavy_check_mark:	:heavy_check_mark:	:heavy_check_mark:	26/10/2015
Central Aerological Observatory	FLASH-B	0x3D	:heavy_check_mark:	:heavy_check_mark:	:x:	15/11/2016
NOAA	TRAPS	0x3E	:heavy_check_mark:	:x:	:x:	27/01/2017
Meisei Electric	SKYDEW	0x3F	:heavy_check_mark:	:heavy_check_mark:	:x:	22/05/2017
GasLab	CICANUM	0x41	:heavy_check_mark:	:x:	:x:	04/06/2018
NOAA	POPS	0x45	:heavy_check_mark:	:x:	:x:	30/08/2019
KNMI	Tachometer	0x80	:heavy_check_mark:	:heavy_check_mark:	:heavy_check_mark:	Unknown?

This table is mainly sourced from the NOAA XDATA Instrument ID Allocation table.

EnSci Ozonesonde Notes

The EnSci ECC Ozonesonde is available in three models which are compatible with all major radiosondes. The ECC Ozonesonde can calculate the amount of Ozone using an electrochemical concentration cell (ECC). The ECC Ozonesonde has a single data format with a length of 16 characters.

Ozonesonde Measurement XDATA Format

Sample data: 01010349FDC54296 (16 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	01	1	-	1
Instrument Number	2	2	01	1	-	1
Cell Current	4	4	0349	841	*0.001	0.841 uA
Pump Temperature	8	4	FDC5 (signed)	-571	*0.01	-5.71°C
Pump Current	12	2	42	66	-	66 mA
Battery Voltage	14	2	96	150	*0.1	15.0 V

Ozonesonde Ozone Partial Pressure Calculation

We are using the same calculations as the OIF411 for an approximate value.

Vaisala OIF411 Notes

The Vaisala OIF411 is an Ozone Interface Board that is used with the Science Pump Corporation ECC-6A or EN-SCI Z Ozone sensors. These two sensors are largely similar designs both using an electrochemical concentration cell (ECC) design to measure the amount of Ozone. The OIF411 has two data formats with lengths of 20 and 21 characters for measurements and diagnostics respectively.

OIF411 Measurement XDATA Format

Sample data: 050108CA186A0750B637CR (20 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	05	5	-	5
Instrument Number	2	2	01	1	-	1
Ozone Pump Temperature	4	4	08CA (signed)	2250	*0.01	22.5°C
Ozone Current	8	5	186A0	100000	*0.0001	10.0000 uA
Battery Voltage	13	2	75	117	*0.1	11.7 V
Ozone Pump Current	15	3	0B6	182	-	182 mA
External Voltage	18	2	37	55	*0.1	5.5 V

OIF411 Diagnostics XDATA Format

Sample data: 0501G12345670000000AICR (21 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	05	5	-	5
Instrument Number	2	2	01	1	-	1
Serial Number	4	8	G1234567	-	-	G1234567
Diagnostics Word	12	4	0000	-	Table A1	Default value, no diagnostics bits active
Software Version	16	4	000A	10	*0.01	0.10

Table A1

Code	Diagnostics Message
0000	Default value, no diagnostics bits active
0004	Ozone pump temperature below −5 °C.
0400	Ozone pump battery voltage (+VBatt) is not connected to OIF411.
0404	Both “Ozone pump temperature below −5 ºC” and “Ozone pump battery voltage (+VBatt) is not connected to OIF411” are active at the same time.

OIF411 Ozone Partial Pressure Calculation

Complete information on performing O3 partial pressure calculations can be found in Section 4.3.3 the OIF411 user guide - this section is a summary only.

The calculation for partial pressure is as follows:

The Ozone current (I) and airflow temperature (Tp) are obtained directly from the telemetry, noting that Tp must be converted to Kelvin (+273.15). The ozone pump flow rate (t) and ozone sensor background current (Ibg) are measured before launch, and are not sent in the telemetry. There are also other correction parameters used such as the pump efficiency correction (Cef), which vary depending on the actual ozone sensor in use (remember the Vaisala OIF411 is an interface board - the actual sensor units are made by others).

To get an approximation of partial pressure, we can set Ibg=0 uA, and use a 'nominal' figure of 28.5 seconds for the pump flow rate (based on flow rate data provided by the Australian Bureau of Meteorology). This results in a value within +/- 1 mPa of the 'truth' data. Without the calibration information, this is the best we can do.

ETH Zurich COBALD Notes

The Compact Optical Backscatter Aerosol Detector is a lightweight backscatter instrument used to determine aerosol information including particle size and density. The COBALD is currently deployed at 17 sites worldwide with the majority of flights taking place at Jülich, Lindenberg (Germany), and Payerne, Zurich (Switzerland). The COBALD uses a single format XDATA measurement packet 30 characters long.

COBALD Measurement XDATA Format

Sample data: 190213FFFE005FCF00359943912CCA (30 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	19	19	-	19
Instrument Number	2	2	02	2	-	2
Sonde Number	4	3	13F	319	-	319
Internal Temperature	7	3	FFE (signed)	-2	*0.125	-0.25°C
Blue Backscatter	10	6	005FCF (signed)	24527	-	24527
Red Backscatter	16	6	003599 (signed)	13721	-	13721
Blue Monitor	22	4	4391 (signed)	17297	-	17297
Red Monitor	26	4	2CCA (signed)	11466	-	11466

ETH Zurich PCFH Notes

The Peltier Cooled Frost point Hygrometer is a lightweight water vapor instrument. The PCFH uses five XDATA packet types measuring 32, 26, 30, and 18 characters long. The type of packet can be identified by the two character PacketID found at positions 5-6 in each packet.

PacketID	Packet Type
00	Individual instrument identification (10 s)
01	Regular one second data, sub-sensor 1
02	Regular one second data, sub-sensor 2
03	Regular five second data
04	Instrument status (10 s)

PCFH Diagnostics XDATA Format (00)

Sample data: 3C010000011B062221 (18 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	3C	60	-	60
Instrument Number	2	2	01	1	-	1
PacketID	4	2	00	0	-	0
Serial Number	6	4	0001	1	-	1
Temperature PCB date	10	2	1B	-	Table B1	Nov 2017
Main PCB date	12	2	06	-	Table B1	Jun 2016
Controller FW date	14	2	22	-	Table B1	Feb 2018
FPGA FW date	16	2	21	-	Table B1	Jan 2018

Table B1

The two-character date value can be split into a year and month character where the resulting date is equal to 2016 + the year character and the month corresponds to the month character where January = 1 and December = 12.

Value	Year Character	Month Character	Year	Month	Result
1B	1	11	2017	November	Nov 2017
06	0	6	2016	June	Jun 2016
22	2	2	2018	Febuary	Feb 2018
21	2	1	2018	January	Jan 2018

PCFH Measurement XDATA Format (01/02)

Sample data: 3C0101434A062C5CD4A5747B81486C93 (32 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	3C	60	-	60
Instrument Number	2	2	01	1	-	1
PacketID	4	2	01	1	-	1
Timestamp	6	2	43	-	-	-
Frost Point Mirror Temperature	8	3	4A0	1184	*0.05 - 125	-65.80°C
Peltier Hot Side Temperature	11	3	62C	1580	*0.05 - 125	-46.00°C
Air Temperature	14	3	5CD	1485	*0.05 - 125	-50.75°C
Anticipated Frost Point Mirror Temperature	17	3	4A5	1189	*0.05 - 125	-65.55°C
Frost Point Mirror Reflectance	20	4	747B	29819	/32768	0.910
Reference Surface Reflectance	24	4	8148	33096	/32768	1.010
Reference Surface Heating Current	28	2	6C	108	/2.56	42.19% FS
Peltier Current	30	2	93 (signed)	-109	/64	-1.703A

PCFH Measurement XDATA Format (03)

Sample data: 3C0103456076175EC5FC9DF9B1 (26 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	3C	60	-	60
Instrument Number	2	2	01	1	-	1
PacketID	4	2	03	3	-	3
Timestamp	6	2	45	-	-	-
Heat Sink Temperature 1	8	3	607	1543	*0.05 - 125	-47.85°C
Reference Surface Temperature 1	11	3	617	1559	*0.05 - 125	-47.05°C
Heat Sink Temperature 2	14	3	5EC	1516	*0.05 - 125	-49.20°C
Reference Surface Temperature 2	17	3	5FC	1532	*0.05 - 125	-48.40°C
Thermocouple Reference Temperature	20	3	9DF	2527	*0.05 - 125	1.35°C
Reserved Temperature	23	3	9B1	2481	*0.05 - 125	-0.95°C

PCFH Measurement XDATA Format (04)

Sample data: 3C0104A427104E203A9861A8AB6A65 (30 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	3C	60	-	60
Instrument Number	2	2	01	1	-	1
PacketID	4	2	04	4	-	4
Timestamp	6	2	A4	-	-	-
Clean Frost Point Mirror Reflectance 1	8	4	2710	10000	*0.001	10.000
Clean Reference Surface Reflectance 1	12	4	4E20	20000	*0.001	20.000
Clean Frost Point Mirror Reflectance 2	16	4	3A98	15000	*0.001	15.000
Clean Reference Surface Reflectance 2	20	4	61A8	25000	*0.001	25.000
6V Analog Supply Battery Voltage	24	2	AB	171	*0.02 + 2.5	5.92 V
4.5V Logic Supply Battery Voltage	26	2	6A	106	*0.02 + 2.5	4.62 V
4.5V Peltier & Heater Supply Battery Voltage	28	2	65	101	*0.02 + 2.5	4.52 V

Central Aerological Observatory FLASH-B Notes

The Fluorescent Lyman-Alpha Stratospheric Hygrometer for Balloon (FLASH-B) is an instrument from the Central Aerological Observatory that uses the fluorescent method to determine the water vapor mixing ratio. The FLASH-B uses a single XDATA packet measuring 35 characters long.

FLASH-B Measurement XDATA Format

Sample data: 3D0204E20001407D00E4205DC24406B1012 (38 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	3D	61	-	61
Instrument Number	2	2	02	2	-	2
Photomultiplier Counts	5	4	4E20	20000	Counts	-
Photomultiplier Background Counts	9	4	0014	20	-	20
Photomultiplier Temperature	13	4	07D0	2000	Temperature	26.32°C
Battery Voltage	17	4	0E42	3650	*0.005185	12.69 V
YUV Lamp Current	21	4	05DC	1500	*0.0101688	9.15 mA
PMT Voltage	25	4	2440	9280	*0.36966	1137.8 V
Firmware Version	29	2	6B	107	*0.1	10.7
Production Year	31	2	10	16	-	16
Hardware Version	33	2	12	18	-	18

FLASH-B Photomultiplier Counts

To calculate the photomultiplier counts six values are required including the pressure and temperature from the attached sonde and two calibration values that are not transmitted in telemetry.

TBD

FLASH-B Photomultiplier Temperature

The FLASH-B photomultiplier temperature in degrees celcius can be determined using the following equation.

Temperature = (-21.103 * log((_photomultiplier_temperature * 0.0183) / (2.49856 - (_photomultiplier_temperature * 0.00061)))) + 97.106

Meisei Electric SKYDEW Notes

The Peltier-based chilled-mirror hygrometer SKYDEW is an instrument from Meisei Electric used to determine the atmospheric water vapor using the thermodynamic measurement principle. The SKYDEW uses a single XDATA packet measuring 38 characters long with a rotating parameter included in each packet.

SKYDEW Measurement XDATA Format

Sample data: 3F0144A75446416100160ECAFFFF6EC8000006 (38 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	3F	63	-	63
Instrument Number	2	2	01	1	-	1
Mirror Temperature AD Value	4	4	44A7	17575	Temperature	17575
Scattered Light Level	8	4	5546	21830	*0.0000625	1.3484 V
Reference Resistance	12	4	4161	16737	-	16737
Offset Value	16	4	0016	22	-	22
Peltier Current	20	4	0ECA	3786	*0.00040649414 - 1.5)*2	0.078 A
Heatsink Temperature	24	2	FF	255	Temperature	-2.88°C
Circuit Board Temperature	26	2	FF	255	Temperature	-2.78°C
Battery	28	2	6E	110	-	110
PID	30	2	C8	200	-	200
Parameter	32	4	0000	0	-	0
Parameter Type	36	2	06	6	Parameters	6

SKYDEW Parameters

The SKYDEW transmits a single parameter each XDATA packet out of a total of 10 different parameters. The parameter is 4 characters while the parameter type is identified by the two-character parameter type field.

Parameter Type	Parameter Name	Comment
00	Serial Number	Unique serial number for the SKYDEW
01	Coefficient B	Coefficient for calculating the resistance
02	Coefficent C	Coefficient for calculating the resistance
03	Coefficent D	Coefficient for calculating the mirror temperature
04	Coefficent E	Coefficient for calculating the mirror temperature
05	Firmware Version	Firmware version of the SKYDEW

SKYDEW Mirror Temperature

The SKYDEW uses the PT100 platinum resistance thermometer to determine the mirror temperature and seven transmitted values are required to calculate the temperature in degrees.

Value	Size
Mirror Temperature AD Value	4
Reference Resistance	4
Offset Value	4
Coefficient B	4
Coefficient E	4
Coefficient D	4
Coefficient E	4

PT100 Resistance

The first step is to determine the resistance of the PT100.

B = -((Coefficient_B - 11000)/10000)
C = -((Coefficient_C - 11000)/10000)

Resistance = B * (100 * (Mirror_Temperature_AD_Value - Offset_Value) / (Reference_Resistance - Offset_Value)) + C

Mirror Temperature

We can now use this resistance value and the other two coefficients to calculate the mirror temperature in degrees.

D = -((Coefficient_D - 11000)/10000)
E = -((Coefficient_E - 11000)/10000)

TemperatureTemp = ((-0.0000269887 * Resistance^3) + (0.00179841 * Resistance^2) + (2.28094 * Resistance) - 243.379)
Temperature = TemperatureTemp - ((D * TemperatureTemp) + E)

SKYDEW Heat Sink Temperature

The heat sink temperature in degrees can be determined using the following formula.

Temperature = (((((log(((heatsink_temperature / 8192) * 141.9) / (3.3 - (heatsink_temperature / 8192) * 3.3) / 6)) / 3390) + 1) / 273.16)^-1 -276.16)

SKYDEW Circuit Board Temperature

Temperature = (((((log(((circuit_board_temperature / 8192) * 39.6) / (3.3 - (circuit_board_temperature / 8192) * 3.3) / 6)) / 3390) + 1) / 273.16)^-1 -276.16)

KNMI Tachometer Notes

KNMI has developed a small Arduino board for the Vaisala OIF411, which measures the motor turns of the pump of the ozone sonde using a light barrier. The board is powered directly from the 3V battery of the RS41. On the backside of the OIF411 therefor is a cable soldered which connects PIN 5 from the Radiosonde connector to PIN 4 of the additional sensor input.

The goal is to increase the precision of the measurement since the motor does not turns always exactly 40 times per second as it should. The transmission of the measurement occurs every 400 turns, so approximately every 10 seconds.

Delta is the time it takes the engine to turn 400 times. To calculate the revolutions per second in this timespan, divide 400 by delta.

The temperature sensor is currently not soldered to the board, so the value is always approximately the same.

KNMI Tachometer XDATA Format

Sample data: 80022B5A1EE4001384A407F8 (24 characters)

Field	Position	Length	Hexadecimal	Decimal	Conversion	Result
Instrument ID	0	2	80	80	-	80
Instrument Number	2	2	02	2	-	2
Tachometer Uptime	4	8	2B5A1EE4	727326436	* 8 / 1000000	5818.611488 seconds
Tachometer Delta	12	8	001384A4	1279140	* 8 / 1000000	10.23312 seconds
Temperature Sensor (not in use)	20	4	07F8	2040	-	?