CS547A Conductivity and Temperature Probe
Contents
1. 1 0 Rs test the initial measurement to then make a more accurate measurement Select Case Rs Case Is lt 1 8 BRHalf Rs 1 mV2500 2 VX1 1 2500 True 0 250 1 0 Rs Rs 1 Rs CS547A Conductivity and Temperature Probe and A547 Interface Case Is lt 9 25 BRFull Rs 1 mV2500 1 VX1 1 2500 True True 0 250 0 001 1 Rs Rs 1 Rs Case Is lt 280 BRFull Rs 1 mV250 1 VX1 1 2500 True True 0 250 0 001 1 Rs Rs 1 Rs EndSelect Subtract resistance errors Rp caused by the blocking capacitors 0 005Kohm and the cable length 0 000032 Kohm ft Rp Rp 0 000032 0 005 Rs Rs Rp EC is then calculated by multiplying the reciprocal of the resistance which is conductance by the cell constant OneOvrRs 1 Rs Ct OneOvrRs CellConstant the following corrects for errors of ionization in the EC measurement If Ct lt 0 474 Then Ct Ct 0 9503 0 0038 Else Ct 0 0289 0 9861 Ct 0 0285 Ct 2 EndIf correct errors in the EC measurement due to temperature Therm107 TempDeg_C 1 3 Vx2 0 _50Hz 1 0 A TempDeg_C 25 Ct100 Ct 100 TC_Proces A TempCoef TC_Proces TC_Proces 100 C25mScm_1 Ct100 TC_Proces end scan loop by calling output table CallTable ECSample NextScan EndProg User Manual 5 1 2 Measurement Programming Edlog Dataloggers Table 1 Program 01 5 Execution Interval seconds Make a preliminary measurement of resistan2. 100 ft The strain relief sleeve is available from Campbell Scientific as part number 7421 Because the CS547A has a slightly positive buoyancy we recommend securing the sensor to a fixed or retractable object or selecting the cable weight option The A547 is usually mounted in the datalogger enclosure The excitation channel used for each EC measurement must be separate from the one used for temperature or measurement errors will result If multiple CS547A A547s are to be wired to a single logger each conductivity excitation must be kept on a separate dedicated EX channel but you can combine several temperature excitations lines onto a single EX port On newer loggers these are labelled as Vx CS547A Conductivity and Temperature Probe and A547 Interface AG AG SE3 SE TEMP EX2 EXTEMP I gt EXI EX COND 3 1H HI COND 5 IL LO COND Ground SHIELD Clear Shield SHIELD En Red Temp En Orange Cond 3 Black Ex Cond EX COND Green Ex Temp EX TEMP Figure 4 1 CS547A Wiring Diagram for Example Below 5 Programming AI example programs may reguire modification by the user to fit the specific application s wiring and programming needs All program examples in this manual are for the CR10 X or CR1000 and assume that datalogger is wired to the A547 interface are as follows the LO COND lead is connected to 1L the HI COND to 1H the EX COND to EX1 the EX TEMP to EX2 and the SE TEMP to SE3 Public Variable Decla
3. Loc Rs 3 8 Z Loc Kc 13 CS547A Conductivity and Temperature Probe and A547 Interface 7 Maintenance Routine maintenance includes thoroughly cleaning the orifice of the CS547A probe with the black nylon brush provided and a little soapy water Rinse thoroughly 8 Analysis of Errors 8 1 EC Measurement Error 1 Bridge Measurement Error lt 1 0 2 Calibration Error bridge measurement lt 0 5 calibration solution lt 1 0 3 Ionization Error of KCI and Na Solutions After Correction lt 2 0 0 45 to 7 0 mS cm lt 8 0 0 005 to 0 45 mS cm Correction of Ionization Errors Figures 8 1 1 and 8 1 2 show the amount of correction applied by the example program to compensate for ionization effects on the measurements Also shown is an ideal correction Factors were derived by measuring the standard solutions described in Section 2 2 with values of 0 0234 0 07 0 4471 07 1 413 2 070 3 920 and 7 0 mS cm 0 E 0 0054 2 E 0 0114 E o 3 0 0151 o O v 0 024 o o lt 0 0254 0 03 0 005 01 015 02 0 25 03 035 04 0 45 05 Measured EC mS cm Applied Ideal Figure 8 1 1 Plot of Ideal and Actual Correction between 0 and 0 44 mS cm 14 User Manual 0 97 0 87 0 71 Applied Correction mS cm Measured EC mS cm Applied k Ideal T 5 6 7 Figure 8 1 2 Plot of Ideal and Actual Correction between 0
4. S L Avda Pompeu Fabra 7 9 Local 1 08024 BARCELONA SPAIN www campbellsci es e info campbellsci es Campbell Scientific Ltd Germany Fahrenheitstrasse13 D 28359 Bremen GERMANY www campbellsci de e info campbellsci de Please visit www campbellsci com to obtain contact information for your local US or International representative
5. life should be removed from the product and also be sent to an appropriate recycling facility Campbell Scientific Ltd can advise on the recycling of the equipment and in some cases arrange collection and the correct disposal of it although charges may apply for some items or territories For further advice or support please contact Campbell Scientific Ltd or your local agent uE CAMPBELL E SCIENTIFIC Campbell Scientific Ltd Campbell Park 80 Hathern Road Shepshed Loughborough LE12 9GX UK Tel 44 0 1509 601141 Fax 44 0 1509 601091 Email support campbellsci co uk www campbellsci co uk Contents PDF viewers note These page numbers refer to the printed version of this document Use the Adobe Acrobat bookmarks tab for links to specific sections O A O 1 1 1 EC Sensor rari acaba LELE ae Sarasin 1 1 2 A547 Interface ssi aL elia 1 2 Specifications ai 2 2 1 CSS54 7A Probe 432222 did 2 2 2 A541 Interface 2 2 3 Temperature Sensor u Lane 3 3 Installation sec ae a 3 3 1 Site Selection ici nni LL aL Aa ni Sein 3 32 MOWINE falla 3 4 Wigo tira 3 5 Programming nu ee 4 9 1 Programming OVeryie Weston se oa 4 5 1 1 Measurement Programming CRBasic Example Code 5 5 1 2 Measurement Programming Edlog Program Example 7 A AR bili ira 11 6 1 Conversioni Factors i rire aaa aaa 11 6 2 Typical Ranges cocinan podle utes A ILA RATA 11 6 3 Factory Calibratio
6. 44 and 7 0 mS cm 8 2 Temperature Measurement Error The overall probe accuracy is a combination of the thermistor s interchangeability specification the precision of the bridge resistors and the polynomial error In a worst case all errors add to an accuracy of 0 4 C over the range of 24 to 48 C and 0 9 C over the range of 38 C to 53 C The major error component is the interchangeability specification of the thermistor tabulated in Table 8 2 1 For the range of 0 to 50 C the interchangeability error is predominantly offset and can be determined with a single point calibration Compensation can then be done with an offset entered in the measurement instruction The bridge resistors are 0 1 tolerance with a 10 ppm temperature coefficient Polynomial errors are tabulated in Table 8 2 2 and plotted in Figure 8 2 1 Table 8 2 1 Thermistor Interchangeability Specification Temperature Temperature C Tolerance C 40 0 40 30 0 40 20 0 32 10 0 25 0 to 50 0 20 Table 8 2 2 Polynomial Error 40 to 56 lt 1 0 C 38 to 53 lt 0 5 C 24 to 48 lt 0 1 C 15 CS547A Conductivity and Temperature Probe and A547 Interface u w Computed Published c rror E 40 30 20 10 0 10 20 30 40 Actual Temperature C Figure 8 2 1 Error Produced by Polynomial Fit to Published Values 9 Deriving a Temperature Compensation Coeffici
7. CS547A Conductivity and Temperature Probe and A547 Interface User Manual Issued 16 11 11 Copyright 1994 2011 Campbell Scientific Inc Printed under licence by Campbell Scientific Ltd CSL 421 Guarantee This eguipment is guaranteed against defects in materials and workmanship This guarantee applies for twelve months from date of delivery We will repair or replace products which prove to be defective during the guarantee period provided they are returned to us prepaid The guarantee will not apply to e Equipment which has been modified or altered in any way without the written permission of Campbell Scientific e Batteries e Any product which has been subjected to misuse neglect acts of God or damage in transit Campbell Scientific will return guaranteed eguipment by surface carrier prepaid Campbell Scientific will not reimburse the claimant for costs incurred in removing and or reinstalling equipment This guarantee and the Company s obligation thereunder is in lieu of all other guarantees expressed or implied including those of suitability and fitness for a particular purpose Campbell Scientific is not liable for conseguential damage Please inform us before returning eguipment and obtain a Repair Reference Number whether the repair is under guarantee or not Please state the faults as clearly as possible and if the product is out of the guarantee period it should be accompanied by a purchase order Ouotations
8. MP 2204 FD EX COND HI COND 3 220u FD 12204 FD i COND LOCOND IC JE R1 SE TEMP TEMP EX TEMP i SHIELD SHIELD Figure 13 2 A547 Interface Circuit Diagram 20 CAMPBELL SCIENTIFIC COMPANIES Campbell Scientific Inc CSD 815 West 1800 North Logan Utah 84321 UNITED STATES www campbellsci com e info campbellsci com Campbell Scientific Africa Pty Ltd CSAf PO Box 2450 Somerset West 7129 SOUTH AFRICA www csafrica co za e sales csafrica co za Campbell Scientific Australia Pty Ltd CSA PO Box 444 Thuringowa Central OLD 4812 AUSTRALIA www campbellsci com au e info campbellsci com au Campbell Scientific do Brazil Ltda CSB Rua Luisa Crapsi Orsi 15 Butant CEP 005543 000 S o Paulo SP BRAZIL www campbellsci com br e suporte campbellsci com br Campbell Scientific Canada Corp CSC 11564 149th Street NW Edmonton Alberta T5M 1W7 CANADA www campbellsci ca e dataloggers campbellsci ca Campbell Scientific Centro Caribe S A CSCC 300N Cementerio Edificio Breller Santo Domingo Heredia 40305 COSTA RICA www campbellsci cc e info campbellsci cc Campbell Scientific Ltd CSL Campbell Park 80 Hathern Road Shepshed Loughborough LE12 9GX UNITED KINGDOM www campbellsci co uk e sales campbellsci co uk Campbell Scientific Ltd France 3 Avenue de la Division Leclerc 92160 ANTONY FRANCE www campbellsci fr e info campbellsci fr Campbell Scientific Spain
9. P95 Subtract resistance errors Rp caused by the blocking capacitors 0 005Kohm and the cable length 0 000032kohm ft Enter cable lead length in nnn below gt 17 Z F P30 1 nnn F Enter cable length in feet 2 00 Exponent of 10 3 5 Z Loc Rp 18 Z X F P37 l 5 X Loc Rp 00032 F 5 Z Loc Rp 19 Z X F P37 1 X Loc Rp 2 F 3 Z Loc Rp 20 Z X F P34 1 29 X Loc Rp 2 005 F 3 5 Z Loc Rp User Manual 21 Z X Y P33 l 1 X Loc Rs 2 5 Y Loc Rp 3 1 Z Loc Rs EC is then calculated by multiplying the reciprocal of resistance which is conductance by the cell constant NOTE The cell constant Kc is printed on the label of each sensor or it can be calculated see Section 6 4 Itis entered in place of nnn below 22 Z 1 X P42 l 1 X Loc Rs 2 2 Z Loc one ovrRs 23 Z X F P37 led X Loc one ovrRs nnn F Enter cell constant 3 3 Z Loc Ct 24 Temp 107 P11 l 1 Reps 2 3 SE Channel 3 2 Excite all reps w E2 4 4 Loc Temp_degC 5 10 Mult 6 0 0 Offset The following program set corrects for errors of ionization in the EC measurement gt 25 IF X lt gt F P89 l 3 X Loc Ct 2 4 lt 3 474 F 4 30 Then Do 26 Z X F P37 1 3 XLoc Ct 2 95031 F 3 3 ZLoc Ct 27 Z X F P34 1 3 XLoc Ct 2 00378 F 3 3 ZLoc Ct 28 Else P94 29 Polynomial P55 1 1 Reps 2 3 X L
10. am is reguired However for rough estimates values between 550 and 750 mg I mS cm_ are typical with the higher values generally being associated with waters high in sulphate concentration USGS Water Supply Paper 1473 p 99 A common practice is to multiply the EC in mS cm by 500 to produce ppm or mg I 6 2 Typical Ranges Single distilled water will have an EC of at least 0 001 mS cm l ECs of melted snow usually range from 0 002 to 0 042 mS cm ECs of stream water usually range from 0 05 to 50 0 mS cm the higher value being close to the EC of sea water USGS Water Supply Paper 1473 p 102 6 3 Factory Calibration The CS547A is shipped with a cell constant calibrated in a 0 01 molal KCI solution at 25 0 C 0 05 C The solution has an EC of 1 408 mS cm 6 4 Field Calibration The cell constant is a dimensional number expressed in units of cm The unit cnr is slightly easier to understand when expressed as cm cm Because it is dimensional the cell constant as determined at any one standard will change only if the physical dimensions inside the CS547A probe change Error due to thermal expansion and contraction is negligible Corrosion and abrasion however have the potential of causing significant errors A field calibration of the CS547A cell constant can be accomplished as follows 1 Make a 0 01 molal KCL solution by dissolving 0 7456 g of reagent grade KCl in 1000 g of distilled water or purchase a calibr
11. ation solution 2 Clean the probe thoroughly with the black nylon brush shipped with the CS547A and a small amount of soapy water Rinse thoroughly with distilled water dry thoroughly and place in the KCI solution 3 Connect the CS547A and A547 or probe and interface to the datalogger using the wiring described in Section 4 Enter the following program into the datalogger The calibration solution temperature must be between 1 C and 35 C the polynomial in step 11 P58 corrects for temperature errors within this range The solution constant of 1 408 mS cm for prepared solution mentioned above entered in step 13 P37 is valid only for a 0 01 molal KCI solution Location 8 Kc cm 1 generated by step 14 will contain the resultant cell constant 11 CS547A Conductivity and Temperature Probe and A547 Interface 6 4 1 CRBasic Program Example CR1000 Datalogger Field Calibration program to determine new Cell Constant Kc for CS547A conductivity probe Public Rs Rp T DimT 25 f of T Public Conductivity Kc Const CalSolution 1 408 for 0 01 molal KCL solution Data Table not reguired for Field Calibration monitor Kc in Public table Main Program BeginProg edit cable length Rp to reflect footage of actual lead length Rp 25 feet Scan 10 Sec 0 0 BrHalf Rs 1 mV2500 2 VX1 1 2500 True 0 250 1 0 Rs Rs 1 Rs correct for resistance of cabling Rs Rs Rp 00032 0 1 0 005 compensa
12. ce for autoranging 1 Full Bridge P6 did Reps 2 13 2500 mV Fast Range 3 1 DIFF Channel 4 1 Excite all reps w Exchan 1 5 2500 mV Excitation 6 1 Loc Rs 7 001 Mult 8 1 Offset 2 BR Transform Rf X 1 X P59 l 1 Reps 2 1 Loc Rs 3 1 Multiplier Rf Test the initial measurement to make a more accurate measurement 3 CASE P93 1 1 Case Loc Rs 4 If Case Location lt F P83 1 1 8 F 2 30 Then Do 5 AC Half Bridge P5 1 1 Reps 2 15 2500 mV Fast Range 322 SE Channel 4 1 Excite all reps w Exchan 1 5 2500 mV Excitation 6 1 Loc Rs 7 1 0 Mult 8 0 0 Offset 6 BR Transform Rf X 1 X P59 l 1 Reps 2 1 Loc Rs 3 1 Multiplier Rf 7 End P95 8 If Case Location lt F P83 1 9 25 F 30 Then Do 9 Full Bridge P6 1 1 Reps 2 15 2500 mV Fast Range 3 1 DIFF Channel 4 1 Excite all reps w Exchan 1 5 2500 mV Excitation CS547A Conductivity and Temperature Probe and A547 Interface 1 Loc Rs 001 Mult 1 Offset 10 BR Transform Rf X 1 X P59 l 1 Reps o jl Loc Rs ces tl Multiplier Rf 11 End P95 12 If Case Location lt F P83 1 280 F 2 30 Then Do 13 Full Bridge P6 sed Reps 14 250 mV Fast Range 1 DIFF Channel 1 Excite all reps w Exchan 1 2500 mV Excitation 1 Loc Rs 001 Mult 1 Offset INN o 14 BR Transform Rf X 1 X P59 l 1 Reps 1 Loc Rs 3 1 Multiplier Rf 15 End P95 16 End
13. d be measured with longer integration periods than 250uSec For CRBasic loggers the Therm107 Integration parameter has options for 60 Hz rejection that impose a long 3mSec integration Sixty and 50 Hz rejection is also available as an option in the Excitation Channel parameter of Instruction 11 for the CR10X CR510 and CR23X dataloggers For the CR10 CR21X and CR7 the 107 should be measured with the AC half bridge Instruction 5 Example 11 1 CR1000 measurement instruction with 60 Hz rejection Therm107 TempDeg_C 1 3 2 0 _60Hz 1 0 0 0 Example 11 2 Sample CR10 X Instructions Using AC Half Bridge 1 AC Half Bridge P5 s Rep 225 7 5 mV 60 Hz rejection Range 3 IN Chan 2 Excite all reps w EXchan 2 2000 mV Excitation 11 Loc Air Temp 800 Mult 0 Offset RI DIN DIE Polynomial P55 Rep 11 X Loc Air Temp 11 F X Loc Air Temp 53 46 CO 90 807 Cl 83 257 C2 52 283 C3 16 723 C4 2 211 C5 1 2 3 4 5 6 T 8 9 Proper entries will vary with program and datalogger channel and input location assignments On the 21X and CR7 use the 15 mV input range and 4000 mV excitation 12 Long Lead Lengths Temperature If the CS547A has lead lengths of more than 300 feet use the DC Half Bridge instruction Instruction 4 with a 2 millisecond delay to measure temperature The delay provides a longer settling time before the measurement is made Do not use the CS547A with long lead length
14. ed by OMEGA Engineering physical chemistry texts and other sources The EC sensor consists of three stainless steel rings mounted in an epoxy tube as shown in Figure 4 1 Resistance of water in the tube is measured by excitation of the centre electrode with positive and negative voltage This electrode configuration eliminates the ground looping problems associated with sensors in electrical contact with earth ground Temperature is measured with a thermistor in a three wire half bridge configuration 1 2 A547 Interface The interface contains the completion resistors and blocking capacitors The interface should be kept in a non condensing environment that is maintained within the temperature range of the unit CS547A Conductivity and Temperature Probe and A547 Interface Figure 1 1 A547 Interface and CS547A Conductivity and Temperature Probe 2 Specifications 2 1 CS547A Probe Construction Size Lx WxH Maximum Cable Length Depth Rating pH Range Electrodes Cell Constant Temp Range of Use EC Range Accuracy 2 2 A547 Interface Size Temperature Rating The probe housing is epoxy 89 mm 3 5 inches x 25 4 mm 1 inch x 19 mm 0 75 inch 305 m 1000 ft The sensor must be ordered with desired length as cable cannot be added to existing probes Maximum 305 m 1000 ft Solution pH of less than 3 0 or greater than 9 0 may damage the stainless steel housing Passivated 316 SS with DC
15. ent 1 Place the CS547A in a sample of the solution to be measured Bring the sample and the probe to 25 C 2 Enter the example program from Section 5 2 in the datalogger and record C at 25 C from Location 3 This number will be C35 in the formula in Step 4 3 Bring the solution and the probe to a temperature t near the temperature at which field measurements will be made This temperature will be t in C in the formula Record C at the new temperature from Location 3 This number will be C in the formula in Step 4 4 Calculate the temperature coefficient TC using the following formula C C s t 25 C35 TC 100 I C Enter TC in the appropriate location nnn as shown in the program segment in Section 5 2 10 Therm107 P11 Instruction Details 16 Understanding the details in this section is not necessary for general operation of the CS547A probe with CSI s dataloggers The Therm107 instruction or P11 in Edlog outputs a precise 2 VAC excitation 4 V with the 21X and measures the voltage drop due to the sensor resistance The thermistor resistance changes with temperature The instruction calculates the ratio of voltage measured to excitation voltage Vs Vx which is related to resistance as shown below Vs Vx 1000 Rs 249000 1000 where Rs is the resistance of the thermistor User Manual See the measurement section of the datalogger manual for more information on bridge measurements Te
16. etermined at a temperature near field conditions See Section 9 for details on how to determine the temperature coefficient If determining the temperature coefficient is not possible use a value of 2 C as a rough estimate 4 Output processing Over large ranges EC is not linear and is best reported as samples using instruction P70 In limited ranges averaging P71 measurements over time may be acceptable Convention requires that the temperature at the time of the measurement be reported 5 1 1 Measurement Programming CRBasic Example Code Program name CS547A CRI i DECLARATIONS MMMM Public Rp CellConstant TempCoef Public Rs Ct Public TempDeg_C Public C25mScm 1 Dim OneOvrRs Ct100 A TC Proces ANNO UTPUT SECTION MMIII DataTable ECSample True 1 Datalnterval 0 60 Min 10 Sample 1 Ct FP2 Sample 1 TempDeg_C FP2 Sample 1 C25mScm_1 FP2 EndTable PROGRAM TTT BeginProg evaluate and edit each of these 3 user specific values Rp 25 edit this value to the actual footage of cable on your sensor CellConstant 1 50 edit this value with the Cell Constant Kc printed on the label of each sensor TempCoef 2 see section 9 of the manual for an explanation of how to more precisely determine the value of this coefficient Scan 5 Sec 3 0 make a preliminary measurement of resistance to determine best range code BrFull Rs 1 mV2500 1 VX1 1 2500 True True 0 250 0 001 1 Rs 1 Rs
17. for repairs can be given on reguest It is the policy of Campbell Scientific to protect the health of its employees and provide a safe working environment in support of this policy a Declaration of Hazardous Material and Decontamination form will be issued for completion When returning equipment the Repair Reference Number must be clearly marked on the outside of the package Complete the Declaration of Hazardous Material and Decontamination form and ensure a completed copy 1s returned with your goods Please note your Repair may not be processed if you do not include a copy of this form and Campbell Scientific Ltd reserves the right to return goods at the customers expense Note that goods sent air freight are subject to Customs clearance fees which Campbell Scientific will charge to customers In many cases these charges are greater than the cost of the repair CAMPBELL SI SCIENTIFIC Campbell Scientific Ltd Campbell Park 80 Hathern Road Shepshed Loughborough LE12 9GX UK Tel 44 0 1509 601141 Fax 44 0 1509 601091 Email support campbellsci co uk www campbellsci co uk PLEASE READ FIRST About this manual Please note that this manual was originally produced by Campbell Scientific Inc primarily for the North American market Some spellings weights and measures may reflect this origin Some useful conversion factors Area 1in sguare inch 645 mm Mass 1 oz ounce 28 35 g 1 Ib pound wei
18. ght 0 454 kg Length 1 in inch 25 4 mm 1 ft foot 304 8 mm Pressure 1 psi Ib in 68 95 mb 1 yard 0 914 m 1 mile 1 609 km Volume 1 UK pint 568 3 ml 1 UK gallon 4 546 litres 1 US gallon 3 785 litres In addition while most of the information in the manual is correct for all countries certain information is specific to the North American market and so may not be applicable to European users Differences include the U S standard external power supply details where some information for example the AC transformer input voltage will not be applicable for British European use Please note however that when a power supply adapter is ordered it will be suitable for use in your country Reference to some radio transmitters digital cell phones and aerials may also not be applicable according to your locality Some brackets shields and enclosure options including wiring are not sold as standard items in the European market in some cases alternatives are offered Details of the alternatives will be covered in separate manuals Part numbers prefixed with a symbol are special order parts for use with non EU variants or for special installations Please quote the full part number with the when ordering Recycling information At the end of this product s life it should not be put in commercial or domestic refuse but sent for recycling Any batteries contained within the product or used during the products
19. isolation capacitors Individually calibrated The cell constant K is found on a label near the termination of the cable 0 to 50 C Approx 0 005 to 7 0 mS em in KCI and Na SO NaHCO and NaCl standards at 25 C 5 of reading 0 44 to 7 0 mS em 10 of reading 0 005 to 0 44 mS cm Dimensions 64 mm 2 5 x 46 mm 1 8 x 23 mm 0 9 Weight 45 g 2 oz 15 C to 50 C User Manual 2 3 Temperature Sensor 3 Installation CAUTION Thermistor Betatherm 100K6A1 Range 0 C to 50 C Accuracy Error 0 4 C See Section 8 2 Rapid heating and cooling of the probe such as leaving it in the sun and then submersing it in a cold stream may cause irreparable damage 3 1 Site Selection 3 2 Mounting 4 Wiring WARNING The EC sensor measures the EC of water inside the hole running through the sensor so detection of rapid changes in EC requires that the probe be flushed continuously This is easy to accommodate in a flowing stream by simply orienting the sensor parallel to the direction of flow In stilling wells and ground wells however diffusion rate of ions limits the response time The housing and sensor cable are made of water impervious durable materials Care should be taken however to mount the probe where contact with abrasives and moving objects will be avoided Strain on cables can be minimized by using a split mesh strain relief sleeve on the cable which is recommended for cables over
20. mperature is calculated using a fifth order polynomial equation correlating Vs Vx with temperature The polynomial coefficients are given in Table 10 2 The polynomial input is Vs Vx 800 Resistance and datalogger output at several temperatures are shown in Table 10 1 Table 10 1 Temperature Resistance and Datalogger Output 0 00 351017 0 06 2 00 315288 1 96 4 00 283558 3 99 6 00 255337 6 02 8 00 230210 8 04 10 00 207807 10 06 12 00 187803 12 07 14 00 169924 14 06 16 00 153923 16 05 18 00 139588 18 02 20 00 126729 19 99 22 00 115179 21 97 24 00 104796 23 95 26 00 95449 25 94 28 00 87026 27 93 30 00 79428 29 95 32 00 72567 31 97 34 00 66365 33 99 36 00 60752 36 02 38 00 55668 38 05 40 00 51058 40 07 42 00 46873 42 07 44 00 43071 44 05 46 00 39613 46 00 48 00 36465 47 91 50 00 33598 49 77 52 00 30983 51 59 54 00 28595 53 35 56 00 26413 55 05 58 00 24419 56 70 60 00 22593 58 28 Table 10 2 Polynomial Coefficients COEFFICIENT VALUE CO 53 4601 C1 9 08067 C2 8 32569 x 10 C3 5 22829 x 10 C4 1 67234 x 10 C5 2 21098 x 10 17 CS547A Conductivity and Temperature Probe and A547 Interface 11 Electrically Noisy Environments AC power lines can be the source of electrical noise If the datalogger is in an electronically noisy environment the 107 temperature measurement shoul
21. n iii 11 6 4 Eteld Callbrationi s iaia eed i ae AA hs E 11 6 4 1 CRBasic Program Example i 12 6 4 2 Edlog Program Example coca eee eee een 12 7 Mamtenance i alia aes 14 8 Analysis of ErrorS eee 14 8 1 EC Measurement Error nono no nnnono nono eee eee ee een 14 8 2 Temperature Measurement Error eee eee een 15 9 Deriving a Temperature Compensation Coerlicienti radiata rapa 16 10 Therm107 P11 Instruction Details 16 11 Electrically Noisy Environments 18 12 Long Lead Lengths Temperature 18 13 CS547A Schematic ecceccecceeeeceeeeeeeeaes 19 Figures Tables 1 1 A547 Interface and CS547A Conductivity and Temperature Probe 2 4 1 CS547A Wiring Diagram for Example Below n 4 8 1 1 Plot of Ideal and Actual Correction between 0 and 0 44 mS cm 14 8 1 2 Plot of Ideal and Actual Correction between 0 44 and 7 0 mS cm 15 8 2 1 Error Produced by Polynomial Fit to Published Values 16 13 1 CS547A Conductivity and Temperature Circuit Diagram 19 13 2 A547 Interface Circuit Diagram iii 20 8 2 1 Thermistor Interchangeability Specification Temperature 15 8 22 Polynomial Errof 2 22 228 202 28 15 10 1 Temperature Resistance and Datal
22. oc Ct 3 3 F X Loc Ct 4 02889 CO 5 98614 Cl 6 02846 C2 CS547A Conductivity and Temperature Probe and A547 Interface 10 7 000000 C3 8 000000 C4 9 000000 CS 30 End P95 This next program set will correct errors in the EC measurement resulting from temperature differences gt 31 Z X F P34 1 4 X Loc Temp_degC 25 F 3 6 ZLoc A 32 Z X F P37 1 3 X Loc Ct 2 100 F 3x y Z Loc Ct100 33 Z X F P37 1 6 X Loc A 2 nnn F Enter TC C to correct cond reading 3 8Z Loc TC Proces 34 Z X F P34 1 8 X Loc TC_Proces 2 100 F 5 Z Loc TC_Proces X Loc Ct100 Y Loc TC_Proces Z Loc C25mScm 1 EC corrected for temperature Output processing convention states that the temperature be reported with the EC measurement gt 36 Do P86 1 10 Set Output Flag High Flag 0 37 Sample P70 l 1 Reps 2 3 Loc Ct 38 Sample P70 Reps 4 Loc Temp_degC 39 Sample P70 s Reps 9 Loc C25mScm 1 Table 2 Program 02 0 0 Execution Interval seconds Table 3 Subroutines End Program User Manual 6 Calibration 6 1 Conversion Factors 1 S Siemens 1 mho 1 ohm Although mS cm and 1S cm l are the commonly used units of EC the SI base unit is S m The result of the example programs is mS cm l EC measurements can be used to estimate dissolved solids For high accuracy calibration to the specific stre
23. ogger Output 17 10 2 Polynomial Coefficient ii 17 CS547A Conductivity and Temperature Probe and A547 Interface 1 Overview 1 1 EC Sensor The CS547A conductivity and temperature probe and A547 interface are designed for measuring the electrical conductivity dissolved solids and temperature of fresh water with Campbell Scientific dataloggers This sensor can be used with any CSI logger that can issue an AC excitation This includes most new CRBasic dataloggers as well as older Edlog loggers Exceptions include the CR200 series the BDR301 and BDR320 loggers which did not have this feature Use with our AM16 32 B multiplexer is possible when needing to measure several of these probes on one datalogger Electrical conductivity EC of a solution is a simple physical property but measurements can be difficult to interpret This manual instructs the user how to make EC measurements with the CS547A Accuracy specifications apply to measurements of EC in water containing KCl Na2SO4 NaHCOs and or NaCl which are typical calibration compounds and to EC not yet compensated for temperature effects Statements made on methods of temperature compensation or estimating dissolved solids are included to introduce common ways of refining and interpreting data but are not definitive Authoritative sources to consult include the USGS Water Supply Paper 1473 The pH and Conductivity Handbook publish
24. rations Input Location Labels Definitions for the following program Rs Solution resistance Rp Resistance of leads cable and blocking caps Ct Solution EC with no temp correction Temp degC Solution temperature in C C25mScm 1 EC corrected for temperature 5 1 Programming Overview Typical datalogger programs to measure the CS547A consist of four parts 1 Measurement of EC and temperature EC Resistance across the electrodes is computed from the results of the BrFull P6 or BrHalf P5 instructions chosen automatically as part of the autoranging feature followed by the Bridge Transformation algorithm P59 2 Correction of ionization errors in EC measurements Ionization caused by the excitation of the EC sensor can cause large errors Campbell Scientific has developed a linear correction for conductivity between 0 005 and 0 44 mS cm and a guadratic correction for conductivity between 0 44 and 7 0 mS em Corrections were determined in standard salt solutions containing KCl Na SO NaHCO3 and NaCl User Manual 3 Correction of temperature errors in EC measurements The effect of temperature on the sample solution can cause large errors in the EC measurement A simple method of correcting for this effect is to assume a linear relationship between temperature and EC This method generally produces values to within 2 to 3 of a measurement made at 25 C The best corrections are made when the temperature coefficient is d
25. s in an electrically noisy environment For all CRBasic loggers as well as CR10X CR510 and CR23X that have 60 and 50 Hz integration options this forces a 3 mSec settling time which accommodates long lead lengths Longer settling times can be entered into the Settling Time parameter Example 12 1 CR1000 measurement instruction with 20 mSec 20000 uSec delay Therm107 TempDeg C 1 3 2 20000 60Hz 1 0 0 0 18 1 Excite Delay Volt SE P4 1 1 Rep 2 DEE 7 5 mV slow range 3 3 IN Chan 4 2 Excite all reps w EXchan 2 dr 2 Delay units 01sec 6 2000 mV Excitation 7 11 Loc Temp C 8 484 Mult 9 0 Offset 2 Polynomial P55 l 1 Rep 2 11 X Loc Temp C 3 11 F X Loc Temp C 4 53 46 CO 5 90 807 Cl 6 83 257 C2 7 52 283 C3 8 16 723 C4 9 2211 C5 Proper entries will vary with program and datalogger channel and input location assignments On the 21X and CR7 use the 15 mV input range and 4000 mV excitation ES User Manual Example 12 2 Sample Program CR10 Using DC Half Bridge with Delay Use a multiplier of 0 2 with a 21X and CR7 13 CS547A Schematic Black Ex Cond CENTER Green Ex Temp Red Temp Orange Cond Figure 13 1 CS547A Conductivity and Temperature Circuit Diagram 19 CS547A Conductivity and Temperature Probe and A547 Interface Datalogger Sensor Connections Connections EXCOND R2 EXTE
26. te for temperature effects Therm107 T 1 3 Vx2 0 50Hz 1 0 0 T 25 T 25 0 01 f of T 0 99124 1 8817 T 25 3 4789 T 2542 3 51 T 253 1 2 T 254 43 T 255 Conductivity 1 f of T CalSolution Kc Conductivity Rs NextScan EndProg 6 4 2 Edlog Program Example 1 AC Half Bridge P5 5 Rep 15 2500 mV fast Range 5000 mV fast for 21X IN Chan Excite all reps w EXchan 1 mV Excitation 5000 mV for 21X Loc Rs Mult Offset er 2 BR Transform Rf X 1 X P59 Rep Loc Rs Multiplier Rf 3 Z F P30 1 nnn F Enter Cable Length in Feet 2 00 Exponent of 10 IE 9 Loc Rp 4 Z X F P37 l 5 Loc Rp 2 00032 F Loc Rp Loc Rp F Loc Rp 12 User Manual 6 Z X F P34 1 5 Loc Rp 2 005 3 5 Loc Rp 7 Z X Y P33 l 1 X Loc Rs 2 5 Y Loc Rp 3 1 Z Loc Rs 8 Temp 107 Probe P11 de 1 Rep 2 3 IN Chan 35 2 Excite all reps w EXchan 2 4 2 Loc t 5 1 Mult 6 0 Offset 9 Z X F P34 l 2 XLoc t 25 F 3 3 Z Loc T25 01 10 Z X F P37 1 3 X Loc T25 01 2 Ol F 3 3 Z Loc T25_01 11 Polynomial P55 l 1 Rep 2 3 X Loc T25 01 3 4 F X Loc f of T 4 99124 CO 5 1 8817 Cl 6 3 4789 C2 7 3 51 C3 8 1 2 C4 9 43 C5 12 Z 1 X P42 l 4 X Loc f of T 2 6 Z Loc one_ovrfT 13 Z X F P37 1 6 X Loc one_ovrfT 2 1 408 F EC of calibration solution 3 7 Z Loc Conductiv 14 Z X Y P36 j 7 X Loc Conductiv 2 1 Y
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