User's Manual Optical Dissolved Oxygen Sensor Rev. 01
Contents
1. 8 UART_TXD OUT Receive line of UART 0 3 3 Connector SUBCONN MCBH8M Face view 8 User s Manual Optical Dissolved Oxygen Sensor Rev 01 2 2 Parts of the DO Sensor The following figure shows the basic parts of the DO Sensor Figure 4 Parts of the DO Sensor Table 1 Legend parts of the DO Sensor Position Designation 1 Connector plug 2 Housing 3 Protection cage 4 External temperature sensor 5 Screw for support 6 Support for lenses 7 Convex lens 8 Sensor foil Sensor spot 9 Flat lens 10 O ring 11 Rest for flat lens User s Manual Optical Dissolved Oxygen Sensor Rev 01 3 Installation on CTD The DO Sensor can be connected to a CTD Probe as external sensor For this purpose the DO Sensor must be clamped to the cage of the probe The electrical connection is implemented with a connection cable for underwater operation The operation mode of the DO Sensor must be set to AUTO MODE If the DO sensor is used for profiling measurements the protection cage and the sensor spot should face down The table below shows an example for the electrical interface between DO sensor and CTD Probe It is assumed that the analog output for the external temperature sensor of the DO sensor will be connected to the data acquisition of the CTD It is further assumed that the connection cable between the CTD Probe and the DO Sensor is an 8 pole 1 1 lin2. with p100 O2 mbar 0 2095 patm mbar pH2O T mbar pH2O T mbar 6 112 mbar exp 17 62 T surf C 243 12 C T surf pO2 mbar actual oxygen partial pressure patm mbar barometric pressure which determines the oxygen partial pressure of the medium The setting for the barometric pressure should be adapted according to the conditions during calibration and operation T surf C Surface temperature of the medium In case that no surface temperature sensor is available and the difference between the surface temperature and internal temperature can be neglected the internal temperature sensor of the DO Sensor may alternatively be used Optionally a fixed temperature value can be entered pH2O T mbar saturated water vapor pressure at temperature T 4 1 2 2 Water pressure compensation of measured oxygen partial pressure mbar For use in deep water The measured partial pressure of the sensor foil is slightly dependent from the water pressure The formular for the compensation of the water pressure is Water pressure compensated oxygen partial pressure pO2wpc mbar pO2wpc 1 wp dbar C wp 1 dbar With wp dbar water pressure on the sensor spot C wp 1 dbar water pressure coefficient The water pressure coefficient typically lies in the range from 0 0004 to 0 0006 This yields an increase of 4 to 6 per 1000 dbar or 1000 m water depth User s Manua
3. connector must be left unconnected Protection cage Titan housing Temperature sensor 3 3V Reauiator 910 32V egulator GND Connector Analog output O2 O2 Sensing foil x Light duct OEM Sensor module ET Temp Subconn Sensor spot 2 5 MCBH8M 5 2 Mode control line o UART RXD TXD Figure 3 Internal block diagram of DO Sensor User s Manual Optical Dissolved Oxygen Sensor Rev 01 7 2 1 Connection scheme and pin assignment The DO sensor can be interfaced to a data acquisition device e g a CTD Probe via the electrical connector The connector is SEACONN MCBHa8M type The table below shows the pins and their functions Pin No Name Direction Description Range 1 V 3 3V IN OUT Internal supply voltage As input 3 3 to 5 V for the sensor module As output 3 3 V 2 V 412V IN NONE Supply voltage for the 9 to 32 V Must be left open when 1 is regulator externally supplied 3 GND NONE Reference potential for all signals 4 Analog_Output_A OUT Analog output for the 0 to 2500 mV O2 partial pressure 5 Analog_Output_B OUT Analog output for the 0 to 2500 mV external sensor temperature 6 Auto IN Mode control AUTO MODE GND FULL CONTROL MODE open 7 UART_RXD IN Receive line of UART 0 3 3 V 5 V tolerant
4. convex lens with the sensor spot Perform an oxygen two point calibration Perform a test of the water resistance Replacement of sensor spot without convex lens To change the just the sensor spot without a convex lens proceed as follows Place the DO Sensor so that the sensor head is accessible from the top and the component parts cannot fall down Unscrew the protection cage Unscrew the support for the convex lens with the sensor spot Slide the convex lens with the sensor spot of the flat lens Take care that the flat lens is not extracted from the sensor housing Take care that the O ring and the rest for the flat lens are not displaced There is a risk that the sensor head is no longer waterproof Make the sure that all parts remain in place Carefully cut the sensor spot from the convex lens Free the convex lens of remainders of the glue and clean the convex lens User s Manual Optical Dissolved Oxygen Sensor Rev 01 19 20 Glue a new sensor spot to the center of the convex lens with silicone rubber compound Take care that the active black side of the sensor spot is not covered by any glue Put the convex lens with the new sensor spot on the flat lens Screw the support on the convex lens with the sensor spot Perform an oxygen two point calibration Perform a test of the water resistance User s Manual Optical Dissolved Oxygen Sensor Rev 01 6 Spare parts and consumables Part Remar
5. e for flat lens Sensor spot damaged Replace sensor spot User s Manual Optical Dissolved Oxygen Sensor Rev 01 5 Maintaince 5 1 Replacement of sensor spot with or without convex lens The sensor must be replaced if any of the following conditions is met e The sensing foil is damaged e The analog output voltage for the oxygen partial pressure shows strong noise e The values that are shown for the oxygen partial pressure and the oxygen saturation are obviously wrong even after a two point calibration The sensor spots are available as single spot or as spots glued on a convex lens 5 1 1 Replacement of convex lens with sensor spot To change the sensor spot with a convex lens proceed as follows e Place the DO Sensor so that the sensor spot is accessible from the top and the component parts cannot fall down e Unscrew the protection cage e Unscrew the support for the convex lens with the sensor spot e Slide the convex lens with the sensor spot of the flat lens e Take care that the flat lens is not extracted from the sensor housing 18 User s Manual Optical Dissolved Oxygen Sensor Rev 01 5 1 2 Take care that the O ring and the rest for the flat lens are not displaced There is a risk that the sensor head is no longer waterproof Make the sure that all parts remain in place Put the new sensor spot with convex lens on the flat lens Screw the support on the
6. finished Each flashing of the DO Sensor during operation increases the deviations of the measurement due to the long term drift Do not expose the sensor spot to direct sunlight for longer periods of time Sunlight increases the deviations of the measurement due to the long term drift 4 1 Calculation of engineering units 4 1 1 Basic variables 4 1 1 1 Oxygen partial pressure mbar The oxygen partial pressure is calculated according to the following formula from the analog input voltage Oxygen partial pressure pO2 mbar hPa Analog Output A mV 0 2 mbar mV Range Analog Output A 0 to 2500 mV Range partial pressure pO2 0 to 500 mbar hPa Normally this formula is extended by additional coefficients to compensate for offset and slope error 4 1 1 2 External sensor temperature The external sensor temperature is calculated according to the following formula from the analog input voltage External sensor temperature T i C Analog Output B mV 0 05 C mV 10 C Range Analog Output B 0 to 2500 mV Range External sensor temperature T i 10 to 115 Normally this formula is extended by additional coefficients to compensate for offset and slope error 12 User s Manual Optical Dissolved Oxygen Sensor Rev 01 4 1 2 Extended variables 4 1 2 1 96 air saturation a s The air saturation can be calculated according to the following formulas Definition A a s 100 x pO2 p10002
7. for oxygen partial pressure type OPS 14 User s Manual Optical Dissolved Oxygen Sensor Rev 01 4 4 SDA functions for field calibration procedures 4 4 1 Setting the barometric pressure To get access to the setting for the barometric pressure the user has to perform the following steps e Choose the menu Calibrate Show coeff SST Standard Data Acquisition rev 2 15 25 10 2013 ol x File Recording Replay External isplay Options Help 20 76 205 76 21 54 Presscomp p4 81 98 93 14 2 20 76 205 77 21 5 O2fieldcalb 24 81 98 97 14 2 20 76 205 98 21 53 ME f 1 81 98 95 14 2 20 77 206 10 21 58 21 81 98 97 14 2 20 77 205 60 21 54 99 70 21 88 98 98 14 2 28 77 205 67 21 5 99 73 21 80 98 99 14 2 20 78 205 82 21 53 99 80 21 88 99 03 14 2 20 78 205 98 21 54 99 88 21 79 99 08 14 2 20 78 205 80 21 54 99 79 21 79 99 02 14 2 20 78 205 74 21 52 99 76 21 79 99 85 14 2 28 78 205 71 21 54 99 75 21 79 99 03 19 2 20 77 205 73 21 52 99 796 21 88 98 99 14 2 28 77 205 96 21 51 99 87 21 81 99 02 14 2 20 77 205 73 21 58 99 75 21 81 99 81 14 2 20 77 205 80 21 50 99 79 21 81 99 05 14 2 20 77 206 01 21 53 99 90 21 82 099 18 14 2 Temp 001 T 001 001 RDO 1 Hon dp s CTM880 CTMSO0 CTHS88 CTMS00 8 Display Config 8XO2 OSS ALL CTD800 SPJ DataFile XA251706 6DO 2013 10 28 3T gt e new window titled Calibrational Coefficients for XXXX appears where XXXX denotes the Param
8. 55 99 254 1 28 90 205 22 99 25 1 280 90 2805 39 99 25 1 28 90 205 33 99 26 1 Temp 001 T 001 001 TiR RDO 1 oct S TN LER TS ee ST CTH800 CTHS00 CTHMS80 CTHS68 800 8 gt Display Config SXO2 OSS ALL CTD800 SPJ DataFile 251706 600 2013 10 28 3T gt e new window titled Calibrational Coefficients for XXXX appears where XXXX denotes the Parameter name of a sensor e In the listbox titled Select a sensor choose the appropriate sensor of the calculation type OSS for readings of oxygen saturation optionally OPS for readings of oxygen partial pressure e Within the radio button titled Fieldcalibration of choose the either position Offset or position Slope e Enter the respective target value in the edit field titled Enter desired value e Click the button Calculate offset now resp Calculate slope now e Click the button Save Exit and confirm the following dialogs Calibrational Coefficients for sat 8x02 Selecta probe 8x02 Fieldcalibration of Offset Selecta sensor 25 sat C Slope Calc Type oss Unit Oxygen OPS sensor 2 40000000E 01 Current Value of Sensor Temperature sens 1 20000000E 01 52326556 nm Oxygen VO4 sensor 1 10000000 01 Enter desired value 0 notused 0 00000000 00 04 Spots 1 01183055E 03 teuer yo4 S
9. E 23 E T E A 24 User s Manual Optical Dissolved Oxygen Sensor Rev 01 3 Preface Changes and proprietary information The information description and illustration in this manual are the property of Sea amp Sun Technology GmbH Materials may not be reproduced or disseminated without a prior written consent from SST SST reserves all rights to change specifications and to modify the product without any obligation to change previous installed units This manual is provided for information and is subject to change without notice This user manual provides complete instructions for use and maintenance of the DTS system Please read it prior to deploying the equipment and follow the instructions during setup and installation Notes cautions and warnings Notes Cautions and Warnings have been included in this manual to draw attention to valuable information and to help the user prevent damage to equipment or personnel Notes Cautions and Warnings will be shown in this format This is a NOTE Notes will provide addition information that may be useful to the user This is a CAUTION Cautions provide important information regarding the system Information provided in a Caution Box should not be disregarded This is a WARNING Warnings prove important information regarding the system 4 User s Manual Optical Dissolved Oxygen Sensor Rev 01 About this
10. Optical Dissolved Oxygen Sea amp Sun Marine Tech Sensor d 7 User s Manual Optical Dissolved Oxygen Sensor Rev 01 2013 11 05 Sea amp Sun Marine Tech Sea amp Sun Sea amp Sun Technology GmbH is member of Technology Arndtstrasse 9 13 24610 Trappenkamp Germany Tel 49 4323 910913 Fax 49 4323 910 915 e mail sea sun marine tech com www sea sun marine tech com This page has been intentionally left blank Revisions Revision Date Changes Writer 01 2013 11 05 Initial edition Lyssewski Table of Contents PROVISIONS cenis aia aE 3 Table Of Contents 3 Cc EE MR 4 About this manual 3 25 5 T General Descr tOn e a cm 6 2 Functional D SCIription sesine en enAnnan ireann anaE 7 2 1 Connection scheme and pin assignment sess 8 2 2 Parts of the DO Sensor icon sce ib Pete o nr 9 3 1 dni oca iecit 10 3 1 Functional Cheo KS bet emu flt prete en e ebat dete nimio 11 4 Operation on 12 4 1 Calculation of engineering units e
11. eter name of a sensor e In the listbox titled Select a sensor choose the appropriate sensor of the calculation type 4 e barometric pressure can be edited in the field titled Air press hPa Within the field titled Air press hPa values below 500 are interpreted as pointer to an air pressure sensor Values equal or greater 500 will be interpreted as pressure values in the unit of hPa resp mbar Calibrational Coefficients for V_011 lt 8x02 gt Selecta probe 8x02 Selecta sensor 1 V Oll bd Calc Type Unit mV Coeff A 0 Coeff A 1 Air press hPe notused Spots cal A 0 Spots cal A 1 Fr12388000E 01 425612000E 02 L01300000E 03 0 00000000E 00 3 41500000E 01 1 01507563E 00 X Abort 4 4 2 Performing offset and slope field calibrations To get access to the field calibration functions in the SST SDA software proceed as follows e Choose the menu Calibrate O2 field calib User s Manual Optical Dissolved Oxygen Sensor Rev 01 15 SST Standard Data Acquisition rev 2 15 25 10 2013 ol x File Recording Replay External PEE Display Options 20 88 205 32 99 13 14 20 88 205 24 99 12 1 28 88 205 27 99 17 1 20 88 205 39 99 16 1 20 89 205 67 99 13 1 28 89 205 44 99 18 1 20 89 2805 42 99 15 1 20 89 205 43 99 17 1 20 89 2805 39 99 17 1 20 90 2805 33 99 20 1 28 90 205 48 99 21 1 280 90 205 19 99 23 1 20 90 285
12. eviations increase over the operating time by drift To compensate for the growing deviations a two point calibration should be performed from time to time The sequence of a two point calibration is as follows e Make sure to have the DO Sensor properly interfaced to the SST SDA Software e Adjust the setting for the air pressure in the SST SDA Software according to the conditions during the calibration e Place the DO Sensor in a medium with no oxygen e g water solution with sodium sulfite e Perform an offset calibration in SDA Set the target value to 0 oxygen saturation or 0 mbar oxygen partial pressure e Place the DO Sensor in air saturated water e Perform a slope calibration in SDA Set the target value to 100 oxygen saturation or to the appropriate oxygen partial pressure Thus a complete linear regression for the dependence of the oxygen partial pressure on the output voltage is achieved The offset and slope errors are now compensated It is also possible to skip the offset calibration In this case the error for low oxygen concentrations is not properly compensated and the specified accuracy cannot be assured The SST SDA Software as of version 2 15 offers the following functions for the field calibration e Offset calibration for oxygen saturation calculation type OSS e Slope calibration for oxygen saturation calculation type OSS e Offset calibration for oxygen partial pressure type OPS e Slope calibration
13. k Convex lens with DO Sensor spot 12 5mm DO Sensor spot amp 5mm type 2DGC2 strong optical isolation Silicon Rubber Compound One of eligible supplier is RS electronics No RS692 542 Flowable Fluid O Ring 9 5x1mm Shore 90 Flat lens 12 7 Rest for flat lens amp outer 8 4 x0 1 polyethylene or copper User s Manual Optical Dissolved Oxygen Sensor Rev 01 21 7 Technical Data 7 1 Specifications of the Sensor Dimensions 280 48 mm Weight 900 g Housing material Titan Interface connector Subconn MCBH8M Interfaces 2 x Analog Voltage Output 0 to 2500 mV 1 UART USB Interface Power Supply 9 32 V Power consumption 200 300 mW Operating temperature 0 to 50 C Operating depth 2000 m 6000 m depending on variant Measuring Range O2 partial pressure 0 to 500 mbar Measuring Range O2 saturation 0 to 240 Oxygen measuring principle Lifetime detection of indicator luminescence Excitation wavelength 620 nm orange red Detection wavelength 760 nm near infrared Max sample rate 2 samples per second Oxygen response time t90 6 sec Typical start up time 3 sec Measuring Range Temperature PT100 10 to 115 C Temperature response time 6 sec Analog Outputs Resolution 0 15 mV 14 bit Accuracy typ 4 0 3 mV Range 0 to 2500 mV 22 Use
14. k The cable can be reduced to a 5 8 pin connection or even to a 4 8 pin connection if the analog output for the external sensor temperature is not connected DO Sensor CTD Probe Pin No Name Direction Direction Description 1 V 3 OUT IN Not connected Avoid short circuit with other networks 2 V 12V IN OUT Supply voltage for the DO Sensor 9 to 32V 3 GND NONE NONE GND 4 Analog Output A OUT IN Analog input for the O2 partial pressure 5 Analog Output B OUT IN Analog input for the external sensor temperature 6 AUTO MODE IN OUT GND 7 UART RXD IN IN Not connected Avoid short circuit with other networks 8 UART TXD OUT OUT Not connected Avoid short circuit with other networks 10 User s Manual Optical Dissolved Oxygen Sensor Rev 01 Connector SUBCONN MCBH8M Face view 3 1 Functional Checks Perform the following tests after installation on the CTD probe e Apply the proper supply voltage to the DO Sensor e Check that sensor flashes underneath the sensor foil flash frequency 2 Hz e Check that the voltage between Analog_Output_A A and GND in air at 960 to1040 mbar ambient air pressure is 900 to 1200 mV e Check that the voltage between Analog Output B and GND at 15 C to 30 C temperature is 400 to 900 mV User s Manual Optical Dissolved Oxygen Sensor Rev 01 11 4 Operation CTD Switch the DO Sensor off as soon as the oxygen measurement is
15. l Optical Dissolved Oxygen Sensor Rev 01 13 4 2 Calculation in SST SDA Software The SST SDA Software as of Version 2 15 offers the following calculation types for the calculation of engineering values VO4 Calculates the raw value in the unit of mV of the Analog Output A for the oxygen partial pressure pO2 from the counter value of the AD Converter Additionally it houses 2 field calibration coefficients for the compensation of offset and slope error in the subsequent calculation of the oxygen partial pressure with the calculation type OPS One further coefficient contains the barometric pressure for the subsequent calculation of the 96 oxygen saturation with the calculation type OSS OPS Calculates the oxygen partial pressure pO2 Input variables are the output of a VO4 sensor in the unit millivolt a further coefficient for the compensation of the dependency of the water pressure as well as a pointer to a water pressure sensor The field calibration function for OPS acts back upon the field calibration coefficients of the associated VO4 sensor OSS Calculates the oxygen saturation Input variables are the output of an OPS sensor and a reference to a VO4 sensor supplying the reading for the barometric pressure The field calibration function for OSS acts back upon the field calibration coefficients of the associated VO4 sensor 4 3 Oxygen two point field calibration The output of the sensor is subject to slope and offset errors The d
16. lat lens An external temperature sensor placed outside the housing is connected to the sensor module The sensor module calculates the oxygen partial pressure from the optically scanned signal and the measured temperature A protection cage is attached on that side of the tubular housing where the sensor spot and the temperature sensor reside In AUTO MODE the calculated oxygen partial pressure is converted into an analog voltage The measured temperature is converted into an analog voltage too These analog voltages are output to the electrical connector AUTO MODE is enabled by pulling the mode control line of the sensor module to GND In full control mode the sensor can be operated via an UART line by an external PC application with a manufacturer specific protocol In FULL CONTROL MODE the analog outputs are not working Full control mode is enabled by leaving the mode control line open FULL CONTROL MODE is used for setup of the sensor module at the manufacturer When a voltage of 9 to 32 volt is applied to the input of the internal voltage regulator a voltage of 3 3 volts is generated at the output and fed to the sensor module and back to the related pin of the electrical connector Alternatively a supply voltage of 3 3 to 5 volts can be applied to the output side of the internal voltage generator from the respective pin of the electrical connector In this case the input of the internal voltage generator and its related pin of the electrical
17. manual This manual is to be used with the Optical Dissolved Oxygen Sensor of SST also referenced as optical DO Sensor also called DO Sensor It is intended as user guide for installing operation and maintenance of the DO Sensor User s Manual Optical Dissolved Oxygen Sensor Rev 01 5 1 General Description The SST optical DO Sensor is an oxygen meter for the underwater operation down to 2000 meters There are also variants which are pressure proof for up to 6000 meters The optical DO Sensor measures the partial pressure of the dissolved oxygen in liquids and gases It utilizes a measuring principle based on red light excitation and lifetime detection in the near infrared using luminescent oxygen indicators The oxygen measurement is generally temperature dependent Therefore the optical DO Sensor is equipped with a temperature sensor for the measured medium and a built in temperature compensation Figure 1 Optical DO Sensor with protection cage Figure 2 Optical DO Sensor protection cage dismounted 6 User s Manual Optical Dissolved Oxygen Sensor Rev 01 2 Functional Description The tubular titanium housing of the sensor holds a sensor module and the power supply On a convex optical lens placed outside the housing the sensor spot is fixed The sensor spot is exposed to the measured medium This sensor spot is optically scanned by the sensor module from inside the housing via a light duct and another pressure resistant optical f
18. ner nennen nnne enn 12 4 1 1 Basic Variable8 2 i P EE Ra n Ee De d eat 12 4 1 2 Extended variables a nhan 13 4 2 Calculation in SST SDA Software cccccccsceseececeeeeeeeaeeeeaeeeeeeeeeeaeeesaaesseaeeseneeeseaeeesaeeseaeeeeaes 14 4 3 Oxygen two point field calibration sessssesesseeeeeneeen entente 14 4 4 SDA functions for field calibration procedures 15 4 4 1 Setting the barometric pressure 15 44 2 Performing offset and slope field 15 4 5 Fault Cause Remedy Index ai urne inco Re ete rine teehee 17 S EAE 18 5 1 Replacement of sensor spot with or without convex lens 18 5 1 1 Replacement of convex lens with sensor spot sssseee eee 18 5 1 2 Replacement of sensor spot without convex lens 19 6 Spare parts and consumables eese esee nennen 21 T Technical Data sissies coi eee 22 7 1 Specifications of the Sensor enne en nennen sinn nnns 22 7 2 dtes S MU nr INA S Acn p AUS ML c nr eb ely 23 7 3 Long term Drift E ETEEN E TEE TE AE A
19. pots calfAl 5587007 Save Ext X Abort Calibrational Coefficients for sat lt 8 02 gt Selecta probe Fieldcalibration of Offset Selecta sensor 25 sa Slope Calc Type Unit OxygenOPS sensor 40000000E 01 _ Current Value of Sensor Temperature sens 1 20000000E 01 199 8134544234398 Oxygen VO4 sensor 1 10000000E 01 Enter desired value 100 0 notused 0 00000000E 00 04 Spots cel A0 f 5 20000000E 01 Calculate lope now VO4 Spots 1 962587087 01 X Abort 16 User s Manual Optical Dissolved Oxygen Sensor Rev 01 4 5 Fault Cause Remedy Index Fault Cause Remedy Sensor is not flashing Not proper supply voltage Connect Sensor according to underneath the sensor spot applied connection scheme pin assignment Apply proper voltage Operation mode is not set to Activate AUTO MODE AUTO MODE Connector Connect to GND DO Sensor defect Send DO Sensor to SST for repair Sensor output shows unrealistic values Sensor drift has caused substantial slope and offset errors Perform field calibration two point Sensor output shows strong noise gt 2 oxygen saturation in homogenous medium Sensor spot is bleached out Replace sensor spot Impaired optical path between sensor module and sensor spot Check state and position of e sensor spot e convex lens e flatlens
20. r s Manual Optical Dissolved Oxygen Sensor Rev 01 7 2 The absolute accuracy of the sensor depends on the calibration The following data are valid for a sensor that has been processed by a 2 point calibration without the consideration of long term drift Unit O2 partial pressure mbar 2 of reading but not better than 2 mbar O2 saturation 96 2 of reading but not better than 1 abs 7 3 Long term Drift Optical oxygen sensors show a slight long term drift For fresh sensor spots the drift is proportional to the number of sampled data points The typical absolute drift for fresh sensors spots after 100 000 data samples in aerated solution is 0 296 O2 saturation corresponding to 13 h continuous operation at a sample rate of 2 per second The drift rate of a sensor spot decreases with the operation time however the absolute error increases User s Manual Optical Dissolved Oxygen Sensor Rev 01 23 Appendix 24 User s Manual Optical Dissolved Oxygen Sensor Rev 01
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