1500 user manual 1-7 - Environmental Systems & Services
Contents
1. 1 000 microSiemens For practical applications it is not desirable to use two probes Im apart Instead a probe can be manufactured into a compact probe containing both electrodes The measuring principle remains the same How does the 1500 conductivity sensor work The 1500 EC sensor employs a unique measuring technique Instead of electrical contact probes it uses an inductive or magnetic method to determine conductivity Two coils are placed a known distance apart One coil has an oscillating current applied that forms a magnetic field inside the coil centre The other coil receives the magnetic flux produced inside the transmit coil However because of the coll arrangement the receiving coil will only receive signal if a conductor is placed in the middle of the coils If water is allowed to flow through the coil centre impurities in the form of dissolved salts will once again provide the necessary magnetic coupling 1500 user manual 1 7 doc 2 Figure 1 EC measurement using magnetic coupling Rx coil Tx coil Magnetic flux is concentrated in the middle of coils Conductive water flowing through middle increases magnetic coupling between transmit and receive coils Figure 1 1500 Sensor measurement principle The above diagram shows how the sensor works Transmit Tx coil forms a magnetic flux inside the coil pair Conductive water increases the magnetic coupling which is seen as a transfer of oscillating current in receiv2. 1500 user manual 1 7 doc 3 Sensor description Figure 2 Sensor dimensions Sensor head O 56 mm 20 mm 262 mm The 1500 sensor is a fully submersible device used for measuring water conductivity It is constructed from durable machined plastic components and epoxy resins For reliability there are no wetted metal components to corrode making this sensor suitable for high conductivity high dissolved solids application and even for water with high acidity The 1500 EC sensor is designed for very long term deployment at unattended monitoring stations The sensor head is fully epoxy encapsulated and has a hole through the middle to allow the flow of water through it lt is here that the water provides magnetic coupling for the measurement to take place An 8mm diameter submersible rated cable is hardwired to the back of the sensor length specified during ordering Although care must be taken to secure the sensor at all times the sensor may be suspended from the cable for short periods such as during installation Once installed and powered the sensor will measure conductivity from zero to full scale as indicated on the sensor body in microSiemens The dry end of the cable has four wires for supply ground and current output signals Connectors can be fitted for direct connection to ES amp S equipment such as the 3500 logger or custom connectors can be fitted upon request There are no moving parts on the 1500 EC
3. Example program to read SDI 12 The following program can be used with the Campbell Scientific CR1000 logger Program name CR1000 sample display reading CR1 Date written 3 06 2009 using the CRBasic programming tool from Campbell Scientific LoggerNet 3 4 1 This program is used to test the SDI 12 Interface using a Campbells CR1000 logger Sensor powered from 12V terminal and a G terminal and with SDI 12 ton Cl terminal Logger Cla s 9reecns gt sensor SDL 12 12V red Sensor Power ve G bLack Sensor Ground The program below will collect data each second from the four SDI 12 Interface channels Use one of the Data Displays from the loggerNet Connect Screen Set the table cells to sdidata 1 to sdidata 4 The information from each of the four channels of the SDI 12 Sensor Engine will be displayed and updated every second Public sdidata 4 sdidatall conductivity sdidata 2 temperature sdidata 3 not used sdidata 4 temperature of SDI IF uprocessor BeginProg SCAN iroa 2y 0 SDIt2 Recorder sdidata ly 0 TM a 2 000 0 NextScan EndProg 1500 user manual 1 7 doc 14 Maintenance The 1500 sensor will require little periodic maintenance to ensure that measurements remain accurate While all wetted components are no metallic and cannot corrode in high salt or acidity liquids Debris silt and algae lodged in the hole can cause inaccurate readings lt is recommended the
4. from plastic Figure 6 Sensor installation 1500 user manual 1 7 doc T EC1500 Model Types EC1500 4 20mA The diagram below shows the electrical circuit equivalent of a 4 20mA output 1500 EC sensor The 1500 EC sensor has two 3 wire current loop devices EC out 4 20mA Yen load RL Common A ys Y Veil sen load RL vv Temp out 4 20mA Figure 7 EC1500 4 20mA electrical equivalent circuit A single cable is hardwired to the 1500 sensor The diagram below shows the configuration and typical connection of the sensor to power and controlling equipment switched 12Vdc 4 20mA EC out 4 20mA temperature out not used common 0V Figure 8 EC1500 4 20mA conductor designation The EC1500 Sensor is used in 4 20 mA mode only the Green wire is not required amp the Blue and Yellow wires are EC and Temperature 4 20 mA outputs The red wire is 12V power and the black wire is Gnd Conductor Conductor Requirement Colour Designation 3 pin red switched 12vdc input 80 mA blue 4 20mA output EC Source current CB Bl black common OV yellow 4 20mA output Temp Source current B plug2 D green Not used EE ee 1500 user manual 1 7 doc 8 EC1500S SDI 12 The EC1500S sensor is an SDI 12 sensor SDI I O Gnd Figure 9 EC1500S electrical equivalent circuit A single cable is hardwired to the 1500 sensor The diagram below shows the configurat
5. sensor and no serviceable components This sensor is a dual output 3 wire current loop device as detailed in the Installation section 1500 user manual 1 7 doc 4 Installation Site Selection Before installing a 1500 EC sensor it is recommended a suitable site be selected first The installation and maintenance complexity as well as the reliability of the instrument in critical applications depends on the site chosen and the length of cable required can then be determined Well chosen sites slow flowing water no stratification minimal or no accumulation of debris around sensor easy and safe access away from waterway traffic sensor head is always submerged in at least 200mm of water sensor head is at least 100mm from bottom and at least 50mm from any metal sensor cannot be dislodged during high flows Avoid sites with very low or stagnant water flows where debris can accumulate inside sensor head excessive air bubbles in water difficult or unsafe access high siltation rates where sensor will be exposed in air during low flows The following is also recommended for EC sensor installation e Install the sensor out of direct sunlight especially when in shallow water Sunlight will heat the sensor head to produce a false temperature and compensated EC reading e Algae will tend to grow within the sensor hole This can be minimized by covering the sensor with a shield to make the head as d
6. 30 C Temperature range 10 to 60 C storage operating O to 50 C Zero amp Full Scale Setting 0 1 of full scale setting Response Time 2 seconds to full accuracy Type Magnetic inductive coupling SDI 12 Output EC in uS cm standard The SDI 12 output of the EC1500S and EC1500S4 can also be scaled at the factory to read 4 20 Check with factory 4 20mA Output__ Scaled to maximum range 1500 Analogue 4 20MA current 1500S S4 Scaled SDI 12 4 20 Example for 20000US cm probe 20000 ptt ttt tT LA AHI IIA HILO tte ty Ey Ty pe tt Pett ttt LA A ATT ptt tt Tt yt tty SERRE 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 4 20mA or SDI 12 value 18000 conductivity uS cm D O O oO L E TE TE IT IT TE Ir IE In general the transfer function is Conductivity Cm R 4 uS cm where Cm Max range R reading So for Cm 20000US cm Conductivity 1250 R 4 uS cm Power Supply 10 15 V unregulated current capability gt 500MA Surge Dimensions 0 3mAh per reading on average typical Secondary surge protection Can absorb 0 6J of energy 1500 262 long 56 dia mm 1500S S4 240 long 46 dia 106 long 56 dia mm 1500 user manual 1 7 doc 16 Ordering information Item description Electrical conductivity sensor Cable hardwired to sensor 10 meters std other cable length available on request Connector 2x 3 pin male plugs fitted to 1510 cable with V splice to se
7. EC1500 ELECTRICAL CONDUCTIVITY SENSOR 1500 4 20mA output 1500S SDI 12 interface 150054 combined 4 20mA amp SDI 12 environmental systems amp services PRODUCT USER MANUAL II www esands com 8 River Street Richmond VIC 3121 Australia T 61 3 8420 8999 F 61 3 8420 8900 environmental esands com ES amp S Quality Assurance Statement ISO9001 accreditation ES amp S is currently an AS NZS ISO9001 2008 certified organisation This certification is evidence that sound practices are used to get high quality instrumentation to your organization within a reasonable time interval Standard practices are used for all areas of manufacture beginning with the efficient procurement of incoming orders right through to shipment Stringent quality assurance procedures are applied to all aspects of manufacturing including the calibration of scientific instruments against NATA traceable references Every sensor is accompanied by a test and calibration certificate that can be used as reference information as well as evidence of sensor accuracy Terms of Warranty The warranty covers part or complete replacement repair or substitution of new instrumentation that has failed in part or completely within the warranty period While every effort has been made to supply robust and user friendly instrumentation the warranty does not cover instruments incorrectly installed misused or operated in conditions outside those specified The wa
8. ark as possible No sunlight means no algae e Silt can accumulate in the sensor hole Install the sensor so water can flow through the hole Typically most sites that are already equipped with hydrographic instrumentation can be used for installation of the 1500 EC sensor EC1500 Model Types There are three EC1500 models e EC1500 4 20m output Only e EC1500S SDI 12 output Only e EC1500S4 SDI 12 amp 4 20mA output 1500 user manual 1 7 doc 5 Installation Orientation For correct installation the following installation restrictions apply Y Figure 3 Sensor orientation With the exception of the head with hole trough it the rest of the sensor can be completely covered If 50mm ID poly tube is used for installation a suitable compression gland is available from irrigation hardware suppliers The sensor outside diameter is smaller than the compression gland internal diameter and can be clamped easily and securely using this method When this system is used the sensor head must protrude from the gland by as least 60mm Sensor Clearance Correct orientation of the sensor will help to reduce the build up of silt and debris within the hole in the center of the EC head Where algal blooms are likely it is recommended the sensor is covered with a sun shield keeping the sensor in the shade thereby reducing algae buildup When installing a shield ensure the shield clears the sensor head by at least 50mm The shield should i
9. asurement and respond with CRC on n 4 wet subsequent ODO command N i OC Begin a concurrent measurement Same as OM 00034 r n command but no service request is issued Begin a concurrent measurement and respond a ae with CRC on subsequent ODO command NN Get data is called after a OM OMC OC OCCI and OV commands If called after the OV Response to OV ODO command then the single result is the version 0 2 0 r n number otherwise it returns 4 results namely the Otherwise 3 sensor voltages and the internal temperature 0 1 1 2 2 3 3 25 0 r n of the interface OXSET Set and store one of the calibration coefficients indexed by m p where m is the measurement OXACK An VAR m p VAL l and n is the parameter Retrieve and store the calibration coefficients OXLOAD indexed by m p where m is the measurement OXACK rin VAR M N and n is the parameter to a string buffer ready to be retrieved by the OXGET command Retrieve the string buffer that was filled from the A a previous OXLOAD command nr If no error OXOK r n Possible errors OXER BAD OXER Retrieve a string for the last error generated by COMMANDInNn the use of an X command OXER BAD MEASUREMENT INDEX r n OXER BAD COEF INDEX r n Internal Temperature Sensor Models EC155S and EC1500S4 have an internal temperature sensor however for higher accuracy it must be calibrated by the end user 1500 user manual 1 7 doc 13
10. d air compressor module and levelpro 6100 advanced liquid level sensor to form a fully self contained hydrostatic pressure sensor designed to measure water and liquid levels reliably and accurately Dipmeter The Water Level Indicators Dipmeters are typically used to measure the depth of water levels in boreholes standpipes or observation wells environmental systems amp services 8 River Street Richmond Victoria 3121 AUSTRALIA T 61 3 8420 8999 F 61 3 8420 8900 environmental esands com www esands com
11. deally be installed 100mm from the sensor and cover the sensor sufficiently from direct sunlight A shield will also prevent excessive temperature variations 1500 user manual 1 7 doc 6 Site preparation Before the sensor can be installed the site must be prepared to ensure the sensor will be secured protected and serviceable The following recommendation is based on typical installation methods practiced by today s hydrographers Several variations of this method are used to suit particular applications Please study the diagram below Site preparation involves the installation of a larger plastic tube along the waterway bank as shown The tube should ideally be continuous but may also be made from sections One end of the tube must be installed into the water ensuring the sensor optical path will not be obstructed according to the previous section Sensor Clearance The other end can be terminated in a junction pit that is large enough so that the sensor can be inserted from the pit Typically an underground electrical pit is used as this also allows a sensor carrier assembly to be inserted easily The pit must be installed on a stable part of the bank that cannot erode Site shelter es Figure 5 Sensor installation Junction pit Sensor tube with sensor installed atend See detail waterway He 4 bank Pa ALU Detail A Guide tube Sensor is Optional guide Cable tie or strapped to side of tube disks made similar devices
12. er Rx coil The degree of transfer is an indication of water conductivity What is temperature compensation Like resistance conductivity changes with temperature The lower the temperature the less the conductivity and this is because electrons find it harder to flow through dissociated salt molecules at lower temperature This makes measurement confusing when actually trying to determine the water conductivity over a temperature range To overcome this effect conductivity measurements at any temperature are output as if the temperature is 25 C and is called temperature compensated output The relationship between compensated and non compensated raw output is linear and simply put a percentage is added or subtracted from the raw measurement to determine compensated output For the 1500 EC sensor the compensation is set at approximately 2 per C For temperatures below 25 C the proportion is subtracted and is added for temperatures above 25 C Of course the temperature needs to be measured for compensation and therefore the 1500 EC sensor has an internal temperature sensor As an additional feature the 1500 EC sensor also has a separate temperature output available to loggers and controllers as a 4 20mA signal Temperature compensation operates between 0 and 50 C the typical expected water temperature for most environmental conditions Corrected EC 25 C in uS cm Raw E C Reading in uS cm 1 0 02 Sample Temperature 25 C
13. erifier Note that the EC1500581and EC1500 S4 are 11 cm longer than the 4 20mA EC1 500 Note that some of the earlier EC 15005 had an SDI 12 interface with the output data scaled 4 20 1500 user manual 1 7 doc 11 SDI 12 Commands The commands assume that the sensor address is O but any address could be substituted into the commands below r n is carriage return and line feed characters Calibration coefficients are modified by extended X commands and are indexed by a 2 dimensional array where the first zero based index is the measurement index and the second is the parameter Measurement Sensor 0 Sensor 2 Sensor 3 Temperature Each measurement has 3 parameters Parameter Default Value Offset 1 0 resistor gain Rs Rp Rp Example To calibrate the output of the second sensor such that it s voltage is multiplied by 2 and an offset of 3 is added to the result using the following transfer function out 2 x 3 the following two extended commands would be used OXSET VAR 1 0 3 OXSET VAR 1 1 2 1500 user manual 1 7 doc 12 SDI 12 Command Table Command Description Typical Response 2 ni address of a single sensor on the SDI 12 DAN Ol Ping returns same address O r n oV Verify command Subsequent ODO command 00001 r n will return the version of the Interface Begin a measurement Subsequent 0DO OM command will return the 3 measurements and O0034 r n the temperature Begin a me
14. ion and typical connection of the sensor to power and controlling equipment switched 12Vdc not used Be not used u m SDI 12 in out common OV Conductor Conductor Requirement Colour Designation 3 pin Red switched 12vdc input 80 mA typ A Blue Not used B B Black common OV Yellow B plug2 D Green SDI 12 in out SDI data E 1500 user manual 1 7 doc 9 EC1500S4 Combined SDI 12 and 4 20mA sensor electrical connection 12 volts de _ The EC150084 is SDI I O an SDI 12 sensor EN i plus two 3 wire Y Y current loop EC out 4 20mA devices load R ss Common O load RL lt 7 Temp out 4 20mA Figure 11 EC150084 electrical equivalent circuit switched 12Vdc 4 20mA EC out 4 20mA temperature out SDI 12 in out common 0V Conductor Conductor Requirement ES amp S Colour Designation 3 Zu we red switched 12vdc input 80mA min blue 4 20mA output EC Source max 120Q load Dee Note 1 black OV dc yellow 4 20mA output Temp Source max 1200 load CIS Note 1 green SDI 12 in out E Note 1 The 4 20mA output of the EC150054 MUST have a load resistor of 0 120R If the 4 20mA output is not used connect the blue and yellow wires to common 1500 user manual 1 7 doc 10 1500 4 20mA Interface EC1500 and EC1500S4 To obtain a measurement from the 1500 sensor Install the sensor according to recommendations in Section Installation Apply p
15. nsor cable Connector 5 pin male plug fitted to 1510 cable Extension cable with 5 pin male plug and 5 pin female jack meters code 1500 1510 1520 1530 1540 Note For EC with SDI 12 output add S to the above ordering codes Example SDI 12 Electrical conductivity sensor 1500S Contact Details Environmental Systems amp Services Pty Ltd Address 8 River Street Richmond Victoria 3121 Australia PO Box 939 Hawthorn Victoria 3122 Phone 03 8420 8999 Fax 03 8420 8900 Int l phone 61 3 8420 8999 Int fax 61 3 8420 8900 email environmental esands com web www esands com 1500 user manual 1 7 doc 17 essS DELIVERING WATER MONITORING SOLUTIONS 2600 Turbidity Sensor The ES amp S Turbidity sensor is a miniature backscatter nephelometer that detects turbidity and suspended solids in water Applications include rivers streams irrigation runoff water quality sediment transportation aquaculture waste water quality EPA compliance monitoring The 2600 is NOW AVAILABLE with SDI 12 LevelPro 6100 The LevelPro 6100 advanced liquid level sensor is used to measure water level determination 0 70 metres Applications include river irrigation water level tidal monitoring groundwater level amp landfill monitoring dam tank reservoir levels waste water monitoring food warning systems process industry liquid level PumpPro 6150 The PumpPro 6150 combines an integrate
16. ower to the sensor 1500 2 x 4 20mA current output will be produced at the respective outputs 1500S Conductivity data is available on the SDI 12 bus A current output signal will be available for measurement after 1 second For power conserving applications the sensor can be switched off immediately after the reading is attained The sensor can also be left on continuously if required The 4 20mA current output will be available for reading 1 second after switched power is applied With proper care and routine maintenance the sensor can be left operating unattended for several months Of course as each application will be different it is recommended that the total time between services is determined experimentally 1500S SDI 12 Interface EC1500S and EC1500S4 The SDI 12 interface of the EC1500S and EC1500S4 handles all of the communication and power down features of the SDI 12 protocol All standard SDI 12 commands are supported In addition extended commands can be used to calibrate sensor outputs Each of the measurements can be scaled and offset with user supplied calibration coefficients The factory sets these parameters so the output is in uS cm Any changes to these parameters should take into account their factory calibration values as these have been established by measurement for each sensor The SDI 12 Interface also has an on board temperature sensor The interface has been fully tested with the NR Systems SDI 12 V
17. purities Pure water has extremely low conductivity resistance of greater than 10 megaohms meaning it allows very little electrical current to flow As soon as impurities in the form of dissolved salts enter the water resistance decreases flow of electricity increases and therefore conductivity increases By measuring the conductivity the amount of dissolved solids can be easily determined While an EC sensor cannot determine the type of dissolved salts it can provide a good indicator of how suitable the water is for a large number of uses For example and EC sensor installed in a river downstream of a farming area can provide valuable information about how much the water is being contaminated by fertilizer runoff during rain events It the same water is being used for viticultural irrigation salt content must be low to ensure plantations are not endangered by water that is too salty How is conductivity measured Measuring conductivity is very straight forward Simply place two electrical probes Im apart into the water sample Apply a known voltage to the probes and measure the current flowing through the probes Using the formula V IR the resistance of the water sample can be determined To convert to conductivity take the inverse of resistance le R V I then Conductivity 1 R in Siemens or 1 ohms For example apply IV to the probes Im apart and current flow is 0 001A resistance Is 1 000 onms Conductivity is 1 milliSiemens or
18. rranty does not cover shipment costs for instrumentation installation or removal and under no circumstances whatsoever indirect or consequential losses caused by the failed instrumentation ES amp S believes the warranty conditions to be fair and just and in accordance with standard business practices worldwide ES amp S reserves the right to arbitrate any warranty issues and will ensure that warranty issues are treated with the highest standards of professional conduct At ES amp S we believe your investment in our products and services is a good decision and we will therefore ensure all your requirements are met at all times both now and in the future Contents Conductivity measurement background What is conductivity How is conductivity measured How does the 1500 electrical conductivity sensor work What is temperature compensation Sensor description Installation Site selection Site preparation Sensor installation Sensor electrical connection Operation Maintenance General Calibration check Specifications Ordering information Contact details 1500 user manual 1 7 doc Background information What is electrical conductivity Electrical conductivity is a measure of how easily an electrical current can flow through a substance lt is easily measured by low cost meters and is the inverse of resistance Conductivity plays a major role in water quality measurement as it is a direct indicator of dissolved im
19. sensor is checked during every visit or at least every 3 6 months You may find the sensor will not require any maintenance for even longer periods however warmer climates or high silt laded rivers and streams can accelerate these effects General Ensure the sensor is not affected by debris silt or algae or marine growth The sensor should be removed from Its installed location for a thorough inspection Using the recommended installation method outlined in the section Installation removal should be easy and maintenance staff do not need to enter the waterway Ensure the installation is sound and the sensor is still secure from moving and there are no obvious signs of erosion or damage Calibration check The sensor output can be checked against a reference instrument if if is available Ideally the measurement should be taken in the same solution as the sensor while the sensor Is installed If there is a large difference an installation problem may be highlighted All sensor measurements should be within the specified accuracy compare the sensor measurement to that of the reference instrument ensure the reference instrument calibration error is also known 1500 user manual 1 7 doc 15 Specifications Range Accuracy Standard ranges of 500 1000 2000 5000 10000 20000 50000 60000 US cm Other ranges available on request EC Linearity lt 3 of full scale Temperature lt 0 2 C of FS over the range 0 to
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