SR-18 MANUAL - Smithsonian Environmental Research Center
Contents
1. 4 W WATCHDOG ALERT estu Men RU NIE ped EU ded Dno 3 152. All of the components within the sensor head unit are environmentally housed for extended year around field operation All components of the sensor head except the PMT are designed to operate without significant temperature effects over a 25 to 55 C ambient temperature range The PMT housing is temperature regulated with a thermostated thermoelectric system A desiccant canister filled with indicating silica gel maintains low humidity inside the sensor head A viewing port in the canister allows the operator to determine when to replace the silica gel The filter wheel turns at 15 RPM and has 2nm half power band width light filters with nominal center wavelengths from 290nm to 324nm Every four seconds a new scan begins The PMT current output which is proportional to the radiation intensity through each filter is converted to a voltage and passed to a precision 20 bit A D converter Data from all light filter channels and the two dark readings are averaged for one minute intervals and along with internal temperature and control information transmitted over three wire RS 232 cable to the data acquisition and control unit The second unit is the external power supply for the sensor head system This power supply provides electrical power both to the head electronics and to the thermoelectric PMT temperature regulator This unit is contained in a weatherproof housing The third unit the data acquisition storage unit consists of an of
3. depleted as indicated by a pale blue pink or white color it should be changed Procedure to change desiccant 1 There are no field serviceable components inside the radiometer Therefore the case should never be opened in the field 2 Unscrew desiccant holder and remove from end plate 3 Locate 0 050 socket head set screw s in threaded area of desiccant holder Some desiccant holders have two set screws 4 Hold canister with wire basket down and the viewing window up to prevent spilling of desiccant 5 Loosen the set screw s that you located in step 3 6 Gently twist basket from main window section of holder IV Normal Maintenance Operations continued 7 10 11 Discard old desiccant or reserve for renewal Desiccant be renewed by heating in an oven until the dark blue color reappears Blow off any desiccant dust from both sections of the holder away from the instrument with dry air Fill the desiccant basket to the brim with fresh indicating desiccant Twist together the two sections of the holder until they mate against the stop tighten the set screw s Reassemble the desiccant holder to the case end plate and screw into place hand tight Data Stream Description Data from SERC 18 Channel Radiometer Each minute of data from the radiometer using version 48 PROM software is 280 bytes This is an example of that one minute s data format where lt CR LF gt refers to a carriage ret
4. 10nm 310 19 0 2698 0 03807 70 87876 M 312nm 312 58 0 2946 0 02197 134 11026 N 314nm 314 29 0 3124 0 01766 176 94704 O 316nm 315 85 0 3273 0 01658 197 46606 31800 318 04 0 3508 0 01734 202 36516 Q 320nm 320 80 0 3807 0 01366 278 71733 R 322nm 321 95 0 4005 0 01224 327 33960 5 324nm 323 72 0 4121 0 01126 365 8883 1 T Dark 2 10 Appendix Command Mode Commands SERC 18 Channel Radiometer Commands Enter Command Mode Ctrl A twice Set time and date Read Temperature Enter Diagnostics Mode Return to Command Mode from Diagnostics Mode Ctrl A twice Exit from Command Mode to Normal Operation Mode Perform a single conversion Ctrl H Set the hour for Sleep Mode 0 23 Set the hour for waking 0 23 Do Not Use 11 Appendix Instrument Case drawing 41004 n 0ot BELOW 300mm 19 MAxcCSO0Omm PRECISION REFERENCE SURFACE amp LOCATOR Wt 26LBS 2KkG SR 18 8200mm 12 Appendix External Power Supply drawing 5 9 225 0259 J100L J100e Wt 18 lbs 9 gt Wt 21 lbs lt 10kg PS1 PS980 Appendix Cabling diagram Interconnection Dingram 1002 VELLOW w 1001 w 1004 120 vac DESS Power Connector To PC Serio Port Externol Supply Power Heo ting Cooling Module 1001 120 VAC power input coble 1002 24 VDC power 8 comtrol coble 1003 H C switche
5. 298 2NM 2593 BARR 9 300 2NM 2593 BARR 11 302 2NM 2593 BARR 10 304 2NM 2593 BARR 9 306 2NM 2693 BARR 9 Dark Zero Channel 1 308 2NM 2593 BARR 12 310 2NM 2593 BARR 10 312 2NM 2493 BARR 11 314 2NM 2493 BARR 9 316 2NM 2593 BARR 10 318 2NM 2593 BARR 10 320 2NM 2493 BARR 10 322 2NM 2593 BARR 10 324 2NM 2493 BARR 10 Dark Zero Channel 2 Measured CWL nm 290 36 291 91 293 90 296 16 207 79 299 99 301 39 303 89 305 94 307 76 310 19 312 58 314 29 315 85 318 04 320 80 321 95 323 72 BW nm 2 13 2 04 2 30 2 20 2 15 2 06 2 17 2 52 2 12 2 34 2 60 2 05 2 43 2 20 2 37 2 71 2 31 2 28 T 0 16 0 16 0 14 0 11 0 12 0 13 0 14 0 18 0 18 0 15 0 10 0 14 0 13 0 15 0 18 0 14 0 18 0 18 Appendix Calibration Constants Calibration of SERC 18 Channel Scanning Radiometer Calibration of UK xx Jul 1996 0 5 N D Nominal EN 74 Mean Filter Measured lamp energy Raw Calibration Channel CWL CWL at CWL Values Constants ID nm nm uW sq cm nm Volts mW sq M nm volt A 290nm 290 36 0 1333 0 20540 6 48987 B 292001 291 91 0 1437 0 26032 5 52007 294nm 293 90 0 1549 0 30028 5 15854 D 296nm 296 16 0 1671 0 18634 8 96753 E 298nm 297 79 0 1804 0 20295 8 88893 F 300nm 299 99 0 1928 0 17191 11 21550 G 302nm 301 39 0 2050 0 06174 33 20214 H 304nm 303 89 0 2224 0 07094 31 35000 I 306nm 305 94 0 2388 0 04358 52 62578 J Dark 1 K 308nm 307 76 0 2507 0 04197 59 73741 L 3
6. 8 For operating purposes the instrument should be leveled to within 10 arc minutes of true level using a machinist s level of a minimum of 90 arc seconds sensitivity or request a G amp B eye level from SERC The leveling is done against a hard surface backplate concrete 4 thick metal plate etc A matching aluminum plate with captive nuts can be supplied by SERC if the client is unable to provide a suitable hard surface waterproof mounting pad The level is placed squarely upon the black occulting ring that surrounds the diffuser This is the reference surface for alignment etc the highest and flattest part of the instrument The four leveling screws are now used to level the instrument II Installation Instructions continued When level two inch hold down screws along with a flat washer and a lock washer are inserted and snugged up to keep the instrument from moving The level should be rechecked and the assembly re adjusted using the leveling screw if needed loosening or tightening the mounting screws as required B Set up external power supply This power supply is designed to be mounted with its cooling fins positioned vertically to increase convection cooling The power supply has two nearly universal mounting brackets These brackets can be used to mount the supply to any vertical surface or vertical shaft or pipe C Set up data acquisition system D Install cabli
7. See II Installation Instructions the radiometer system is ready to begin collecting data Within three minutes after the SR 18 is cabled and powered it will begin to collect data and transmit that data over its communications cable See Section V Data Stream Description for information on the format of the data and on how much data is transmitted from the radiometer When the SR 18 is first powered its internal operating program begins running This program first undertakes initialization and checking functions and then waits for the start of a minute to begin data collection Because of these start up functions and the wait period a period of up to three minutes may pass before the SR 18 sends any data down its communication cable See Section IV Normal Maintenance Operations for daily and weekly checks and maintenance operations Data Acquisition The SERC SR 18 is designed for flexibility in data acquisition which will allow a variety of data acquisition schemes to be used There are several standard schemes currently in use SERC uses an in house data acquisition program that captures data and allows the option of writing that data to a file on the PC It shows the last acquired reading in a box at the bottom of the bottom of the window It also shows the last reading as a reduced spectra and a daily plot of one filter using the calibrations for that unit Details of the acquisition program are in a separate document Any serial c
8. User Manual for Smithsonian SERC 18 Channel UVB Scanning Radiometer Model SR 18 Date of Issue 20 Dec 2006 Smithsonian Institution Smithsonian Environmental Research Center SERC Solar Radiation Laboratory 647 Contee s Wharf Road P O Box 28 Edgewater MD 21037 0028 443 482 2200 FAX 443 482 2380 USER MANUAL for SMITHSONIAN SERC 18 CHANNEL UVB SCANNING RADIOMETER Table of Contents I Instrument Description iss con ea aro uec meni m dee 1 II Installation Instuctlons 6s o tre Esca b sweets b audi dte a ens md 2 III Operation Instructions m 4 IV Normal Maintenance Operations aoc esee cst eerte te Qe 6 V Data Stream Description 8 Appendix Light filters 1n this mistr ment 9 Calibration Constants 10 Command Mode Commands 11 Instrument Case drawing isset tn 12 External Power Supply 13 opea tasse ii eiae Pea p pcd tede 14 Instrument Description The radiometer sensor head unit is a weatherproof housing with cosine corrected diffuser for light sampling a filter wheel with 18 2nm nominal band pass interference filters mounted in the periphery a collimator and a solar blind R 1657 photomultiplier tube PMT
9. d power coble W 1004 communicotions coble 14 Index cables cabline Ne 14 installation 05222222 e Er err per eno temer rua evo eese t TI 3 calibration COnstants i dio P ER EE ERO I ED b E de D ED Ee E RITE 10 channel GA 8 clock ctor tts Caii ableiten bise lits nates se Raa ease erat cs tone rade d 5 set sleep wake secet etri 5 Command Mode dtum cas apte 5 commands ees eie edt oo dtt 11 D data CESCHD UGIL C eese ose t iio satio MEE 1 8 ce sete hii Ee iter edv as 8 EE 4 bere t tta mt cn dre tris 6 F filters adoro 1 1 40500116 227284 9 Installation 2 instrument M 1 Mamtenance operations C MEE 6 1 PL
10. f the shelf PC running in an office environment with a hard drive a 3 5 inch floppy disk drive serial port and a modem network connector running under a Windows 9x operating system Data would routinely be downloaded from the hard drive to the removable floppy or transmitted via modem network or Internet to the data management facility II Installation Instructions Set up radiometer head SR 18 The set up of solar radiation monitoring devices is a subject beyond the scope of this manual Most importantly the operating location should have an unobstructed a view of the sky as possible from horizon to horizon Refer to Instrument Case drawing in the appendix of this manual for dimensions of the instrument case The radiometer should be mounted on a user provided solid mounting stand The SERC SR 18 18 channel UV B radiometer has been mechanically upgraded to easily level the unit under field conditions The instrument now has a 12 x 12 x 4 thick aluminum leveling baseplate attached The baseplate has four leveling screws located one at each corner The plate also has precision locating holes used by SERC in opto mechanical alignment and during calibration and re calibrations of the instrument This upgrade assures the repeatability of the position location during subsequent calibrations DO NOT remove the baseplate DO NOT loosen the mounting hardware holding the radiometer to the leveling baseplate Leveling the SR 1
11. fter the SR 18 sends this message it will attempt to begin data collection and transmission in a normal manner again If several WATCHDOG ALERT messages occur in a row they can occur as frequently as every two seconds or up to three minutes apart the operator should turn off the 120V AC power to the SR 18 leave the power off for at least 30 seconds and then turn on the power again If WATCHDOG ALERT messages again occur the SR 18 will require non field maintenance Normal Maintenance Operations A Observe for normal operation 1 Instrument should be checked daily for normal operation Items to check a Is data being collected normally in standard data format see Section V Data Stream Description Are date and time correct in the data stream Are there 14 data sets per minute Is the STATUS indicator 0 Is the TEMP between 0 and 60 If any abnormalities are noted in the operation of the radiometer contact service depot There are no field serviceable components inside the radiometer The instrument must be returned to the service center for depot level maintenance B Clean diffuser 1 Diffuser light entrance port should be cleaned with clear water and wiped dry with a soft cloth at least once a week Daily CLEANING is required under high pollen or dust conditions In below freezing weather alcohol should be used in place of water Check desiccant for dark blue color If desiccant is
12. ing in full duplex mode This can be done using Hyper terminal Send the Control A code twice After receipt of the double Ctrl A command the SR 18 will wait until the end of the current minute and then enter Command Mode When the SR 18 enters Command Mode it will send a list of its current settings down the communications line In Command Mode this list of settings will look like this example COMMAND MODE Sleep Time 00 00 00 Wake Time 00 00 00 DATE DDMMYY TIME HHMMSS Enter command Sleep Time is the time that the SR 18 will stop taking data each day and Wake Time is the time that the SR 18 will begin taking data each day Normally one should not set sleep time The date and time shown are the current SR 18 values See the Appendix in this document for SR 18 commands available in Command Mode Diagnostics Mode causes the SR 18 to send the value for each channel for each scan down the communications line along with the date and time of that scan To exit from Command Mode and return to normal data collection press Ctrl G The SR 18 acquisition program incorporates these commands in the menu bar at the top of the screen Re setting time and date can be done without stopping and starting the acquisition program During normal data collection the SR 18 may also send a diagnostic message WATCHDOG ALERT This message means that there was an operating problem in the current minute of data collection A
13. ng Refer to SR 18 Interconnection Diagram and Instrument Case and External Power Supply drawings in the Appendix of this document Note and follow the color coding of the cable connectors as shown on interconnection diagram 1 Install cables from external power supply to SR 18 a Install W 1002 cable from external power supply to SR 18 main case b Install W 1003 cable from external power supply to SR 18 heating cooling module 2 Install W 1004 communications cable from 5 18 to data acquisition system d Install W 1001 120 VAC power input cable to external power supply At the data acquisition end of the serial data cable is a converter module with a female DE 9 connector This connector connects serial RS 232 signals to the data acquisition system The protocol of the signal is 9600 bps 8 data bits NO parity 1 stop bit 9600 8 N 1 E Turr on procedure When 120 VAC power is applied to the external power supply and the two cables W 1002 and W 1003 are connected from the supply to the SR 18 the radiometer will begin to operate and collect data in its normal scan mode In this mode data will be sent from the SR 18 over the communications cable W 1004 every minute The 5 18 contains a battery backed clock which has been set during manufacture so that the operator need now do nothing more to begin collecting data Operating Instructions After the SR 18 system has been installed leveled cabled and powered
14. ommunications program running on a PC such as Hyperterm which captures data and allows the option to write that data to a file on the PC can be used to acquire data from the SR 18 For every minute the SR 18 is in standard operating mode it transmits three lines of data The first line consists of the instrument ID and current date and time The time indicates the time at the end of the minute which was just recorded the minute for which the following data refers The second line contains twenty channels of light data Each channel includes a channel ID Indicator character A through T a sign character or and a seven digit plus decimal voltage value That voltage is the mean of all the scans normally 14 made during that minute for that channel That voltage is proportional to the spectral irradiance in that channel s filter pass band and can be converted to power milli watts per square meter per nanometer by multiplying the voltage by that channel s calibration constant See Appendix The third line consists of diagnostic information Operating Instructions continued The SR 18 includes its own battery backed clock which should be set to local standard time There is a provision to set the clock and to do several other diagnostic and function setting tasks This function is called Command Mode and is accessible to the operator by sending the SR 18 a Control A code twice up the communications line which is operat
15. urn and line feed character pair A G S UK DATE 00 12576 00 05314 00 01582N 4 170896 1 00 00 UJ H4 DATA SETS 00 01696T 00 014 00 1241 7016 R LF 14404C4 064241 0135604 00042 CR LF STATUS 00 0390804 00 11544 99 00 01418P4 0 TEMP 00 10206 00 00046K4 00 0144604 39 57 FSC Including CR LF characters Total 280 bytes minute ID line is 30 bytes 16 800 bytes per hour data line is 202 bytes 302 400 bytes for an 18 hour day Status line is 48 bytes SR 18 CHANNEL DESIGNATIONS Channel ID dQomwWonozzumwm Uuuomummuauv s Nominal Filter Center Wavelength 290nm 292nm 294nm 296nm 298nm 300nm 302nm 304nm 306nm Dark Zero 1 308nm 310nm 312nm 314nm 316nm 318nm 320nm 322nm 324nm Dark Zero 2 00 045621 00 01594 00 09530F 00 07946 00 03476 00 01806 Li 000 8 1 LE Appendix Light Filters Sample Light Filters Installed in SERC 18 Channel UVB Radiometer UK Filter run 30JUL96 Nominal CWL Channel nm 2 290 292 294 296 298 300 302 304 306 308 310 312 314 316 318 320 222 324 0 5 N D neutral density filters in these channels Filter name 0 5ND filter 290 2 2593 BARR 5 292 2NM 2593 BARR 4 294 2NM 2593 BARR 9 296 2NM 2593 BARR 9
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