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Hydro-Probe SE User Guide

1. Hydro Probe SE User Guide HD0278 Rev 2 0 0 55 Appendix B Moisture Calibration Record Sheet 56 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Appendix C Brix Calibration Record Sheet Hydronix Brix Calibration Record Sheet Refer to Hydro Com User Guide HD0273 for full calibration information Instructions e Take a small sample of material where the sensor is located e Whilst taking samples read the Unscaled sensor output from the sensor e Record the sensor Unscaled reading sensor moisture reading and lab moisture in the table below e Data may be used to recalibrate the sensor if there are consistent errors in Brix between the current moisture output from the sensor and the lab Brix Material Location Sensor S N Readings from sensor Lab Sensor Lab Operator name Date Time Unscaled Moisture difference Hydro Probe SE User Guide HD0278 Rev 2 0 0 57 Appendix C Brix Calibration Record Sheet 58 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Appendix D Document Cross Reference 1 Document Cross Reference This section lists all of the other documents that are referred to in this User Guide You may find it beneficial to have a copy available when reading to this guide Document Number Title HD0273 Hydro Com User Guide HD0303 USB Sensor Interface Module User Guide HD0333 Ethernet Adapter User Guide EN0058
2. Brix Curent Calibration Improved Calibration Figure 33 Example of a bad Brix Calibration Seed Point In processes that require a set target point to be indicated when reached i e to begin or end a process this target or Seed Point will be set in terms of either an Unscaled value or Brix value dependent on how the sensor output is configured If simply using the un calibrated Filtered Unscaled output then the target point is set at the desired Unscaled value this will be highly repeatable from batch to batch Hydro Probe SE User Guide HD0278 Rev 2 0 0 41 Chapter 5 Material calibration 4 4 4 5 If the sensor is calibrated to Brix the Seed Point will need to be set in terms of a calibrated Brix value In some applications it may be preferable to relate the target Brix value to a specific fixed Unscaled value This is because the Unscaled value is the most precise measure and will remain constant regardless of any small calibration errors or adjustments of the calibration over time If the Brix calibration is adjusted the current Brix Seed Point will no longer correctly correlate to the previous target point in terms of the Unscaled value If repeatability of the process in terms of an Unscaled measurement is required it is recommended to use the Seed Point function When using the Seed Point function the target Brix value is recalculated using the new calibration data to ensure that it corresponds to the pr
3. Build up of material on Signs of build up Ceramic faceplate Check positioning of sensor face such as dried solid should be kept the sensor deposit on ceramic clean by the action face of material flow Incorrect input calibration Control system Control system Modify control within control system input range accepts output system or range of sensor reconfigure sensor Sensor in alarm condition OmA on 4 20mA range Interference from mobile phones Moisture content of material by oven drying Use of mobile phones close to sensor Must be within working range of sensor No RF sources operating near to sensor Adjust sensor range and or calibration Prevent use within 5m of sensor Average Hold switch has Apply signal to Average moisture Verify with Hydro not operated digital input reading should Com diagnostics change No power to sensor DC power at 15Vdc to 30Vdc Locate fault in junction box power supply wiring No sensor output at control system Measure sensor output current at control system Varies with moisture content Check cabling back to junction box No sensor output at junction box Measure sensor output current at terminals in junction box Varies with moisture content Check sensor output configuration Sensor has shut down Disconnect power for 30 seconds and retry or measure current drawn from power supply Normal
4. 0 5 10 15 20 25 30 35 40 Sensor Unscaled Value Figure 19 Relationship of moisture to Unscaled values In certain materials such as organic products the relationship between Unscaled values and moisture means that a smaller change in Unscaled values gives a large change in the moisture value when operating in Standard Mode This makes the sensor less precise In Figure 19 below calibration line A is less precise than calibration line B When measuring in any material it is important that a small change in moisture level gives a large change in the Unscaled sensor reading This will give the most precise calibrated output However it is also important that the sensor remains capable of measuring over the full range required If the sensor is configured to be too sensitive the sensor will reach it maximum value at a lower moisture level and will be unable to read above this point The working range of the sensor should be checked particularly if the sensor is configured to Mode E or Mode V To determine which mode is the most appropriate it is recommended to run trials for a given material and application For a measurement taken over time it is recommended to record the sensor s output from each of the different measurement modes in the same process Data can easily be recorded using a PC and the Hydronix Hydro Com software these results may then be plotted in a spread sheet When viewed in graph form it is often self evident which m
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6. Electrical installation and communication Chapter 3 3 RS485 multi drop connection The RS485 serial interface enables up to 16 sensors to be connected together via a multi drop network see Figure 8 Each sensor should be connected using a suitable junction box see Chapter 8 Technical specificationfor details RS485 line termination will not normally be required in applications with up to 100 m of cable For longer lengths connect a resistor approximately 100 Ohm in a series with a 1000pF capacitor across each end of the cable It is highly recommended that the RS485 signals be run to the control panel even if they are unlikely to be used as this will facilitate the use of diagnostic software should the need arise in the future S x E x x E x 28 8 8 3 3 8 B o ma G a z a a gt D Ama Q x 2 0 uw a H on lt 3 4 Es u 0975 twisted pair i Sensor cable Junction box Do not connect screen at control cabinet From Pei other sensors control device A EE ere Al Figure 8 RS485 multi drop connections I I I y de al wm mm m an t ee mn Jag PC Control ns ni System Figure 9 Multi Drop RS485 wiring method Hydro Probe SE User Guide HD0278 Rev 2 0 0 19 Chapter 3 Electrical installation and communication 4 Digital input output connections The Hydro Probe SE has two digital inputs the second of which can also be used as an output for a known state Full descriptions of how th
7. Maximum cable run 200m separate to any heavy equipment power cables Grounding The sensor body is connected to the cable shield Ensure equipotential bonding of all exposed metalwork see Chapter 3 In areas of high lightning risk correct and adequate protection should be used Contact Hydronix support for recommended lightning protection Emissions C EEC Declaration of Conformity Electromagnetic Compatibility Directive 2004 108 EC 52 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Appendix A The complete set of default parameters is shown in the table below This applies to firmware version HS0089 Default parameters Parameter Analogue output configuration Range options Default Parameters Output type 0 20mA 4 20mA Compatibility 0 20mA Output variable 1 Filtered moisture Average moisture Filtered Unscaled Average Unscaled Brix Material Temperature Filtered Unscaled Signal processing configuration Output Variable 2 As above Material Temperature High 0 100 20 00 Low 0 100 0 00 Moisture calibration A 0 0000 B 0 2857 C 4 0000 SSD 0 0000 Brix calibration A 101 0000 B 0 1500 C 0 1700 D 2 5000 Unscaled Type Unscaled 2 Type Standard Mode Mode E Mode V As above Standard Mode Mode V Smoothing time 1 0 2 5 5 0 7 5 10 1 sec Slew rate Light Medium Heavy Unused Light Slew rat
8. Sensor has temporarily locked up Power down and re power sensor Sensor functions correctly Check power No power to sensor DC power at junction box 15Vdc to 30Vdc Locate fault in power supply wiring No sensor output at control system Measure sensor output current at control system Milliamp reading within the normal range 0 20mA 4 20mA Varies with moisture content Check cabling back to junction box No sensor output at junction box Measure sensor output current at terminals in junction box Milliamp reading within the normal range 0 20mA 4 20mA Varies with moisture content Check sensor connector pins Sensor MIL Spec connector pins are damaged Internal failure or incorrect configuration Disconnect the sensor cable and check if any pins are damaged Connect the sensor to a PC using the Hydro Com software anda suitable RS485 converter Pins are bent and can be bent to normal to make electrical contact Digital RS485 connection is working Check sensor configuration by connecting toa PC Digital RS485 connection is not working Sensor should be returned to Hydronix for repair 2 Sensor output characteristics A simple test can be performed to check the output from the sensor in air and with the hand Filtered Unscaled Output values shown are approximate RS485 4 20mA 0 20 mA 0 10 V Compatibility mode
9. The sensor reading for measuring moisture in most materials is linear Therefore a calibration line exists which is similar to the one shown below Hydro Probe SE User Guide HD0278 Rev 2 0 0 33 Chapter 5 Material calibration 3 1 20 True X Calibration Line Moisture of material 0 0 100 Sensor Unscaled reading Figure 23 Calibration Line example The equation of the calibration line is defined by a slope B and offset C An SSD input field is also given which allows a second offset to allow for the difference between total moisture and free moisture if needed These values are the calibration coefficients and can be stored inside the sensor if required Using these coefficients the conversion to moisture is Moisture B x Unscaled reading C SSD To determine the calibration line a minimum of two points are required Each point is derived by flowing material over the sensor and finding the sensor s Unscaled reading at the same time taking a sample of material and drying to find its true moisture content This gives Moisture and Unscaled which can be plotted on a graph With at least two points a calibration line can be drawn There are international standards for testing and sampling that are designed to ensure that the moisture content derived is accurate and representative These standards will define accuracy of weighing systems and sampling techniques in order to make the samples representative of
10. F The sensor will not work in frozen materials 1 6 Operating Pressure The Hydro Probe SE will operate from 1 bar Vacuum to 5 bar pressure 1 7 Power supply voltage 15 30 VDC 1 A minimum required for start up normal operating power is 4W Hydro Probe SE User Guide HD0278 Rev 2 0 0 51 Chapter 8 Technical specification 1 8 1 9 Analogue output Two configurable O 20mA or 4 20mA current loop outputs sink available for Unscaled moisture Brix and temperature The sensor output may also be converted to 0 10Vdc using a 500ohm resistor Digital serial communications Opto isolated RS485 2 wire port for serial communications including changing operating parameters and sensor diagnostics Contact Hydronix for read write access to sensor parameters and values Digital inputs One configurable digital input 15 30 V DC activation One configurable digital input output input specification 15 30 V DC output specification open collector output maximum current 500mA over current protection required 2 Connections 2 1 2 2 2 3 Sensor cable Six pairs twisted 12 cores total screened shielded cable with 22 AWG 0 35mm conductors Screen shield Braid with 65 minimum coverage plus aluminium polyester foil Recommended cable types Belden 8306 Alpha 6373 500 Ohm resistor The recommended resistor is an epoxy sealed precision resistor of the following specification 500 Ohm 0 1 0 33W
11. Total Moisture a Free Moisture 20 Unscaled Total Moisture 10 x OU pue 2 O P A OU 20 Unscaled Free Moisture 5 20 30 40 Sensor Unscaled Figure 24 Calibrations using the SSD coefficient 3 2 Hints and safety Wear safety glasses and protective clothing to guard against expulsion of material during the drying process Do not attempt to calibrate the sensor by packing material on the face The readings obtained will not be representative of those from a real application Whilst recording the sensor Unscaled output always sample where the sensor is located Average the sensor s readings using the inbuilt averaging facility Where available use the digital input If no input is available use Hydro Com to control the averaging Ensure the sensor sees a representative sample of material Ensure a representative sample is taken for moisture testing NOTES For full instructions on using Hydro Com refer to the Hydro Com User Guide HD0273 In order to record all calibration data a sample record sheet is included in Appendix B The same principles apply with or without using Hydro Com when calibrating 3 3 Sensor Settings Sensor settings are configured using Hydro Com available free from the Hydronix web site www Hydronix com See the Hydro Com user guide HD0273 for full instructions If the sensor is installed with the digital input wired into the control system then the digital i
12. Sensor exposed 0 4mA OmA OV gt 10V to air Hand on sensor 75 85 15 17 mA 16 18mA 7 5 8 5 V 3 6 2 8V Table 1 Output test values Hydro Probe SE User Guide HD0278 Rev 2 0 0 47 Chapter 7 3 Symptom Incorrect analogue output Sensor diagnostics junction box and PLC for complete length of cable from sensor to PLC wired in correctly Possible explanation Check Required result Action required on failure Wiring problem Wiring at the Twisted pairs used Wire correctly using specified cable in the technical specification Sensor s analogue output is faulty Disconnect the analogue output from the PLC and measure with an ammeter Milliamp reading output similar to as shown in Table 1 Connect sensor to a PC and run Hydro Com Check analogue output on the diagnostics page Force the mA output to known value and check this with an ammeter PLC analogue input card is faulty Disconnect the analogue output from the PLC and measure the analogue output from the sensor using an ammeter Milliamp reading within the normal range 0 20mA 4 20mA Replace analogue input card 4 Symptom Computer does not communicate with the sensor Possible explanation Check Required result Action required on failure No power to sensor DC power at 15Vdc to 30Vdc Locate fault in junction box power supply wiring RS485 incorrectly wired into converte
13. Tab and select the configuration tab The A Band C values are entered in the Material Calibration section Figure 34 Once completed select Write to update the sensor Ensure that the correct sensor is displayed at the top of the screen in red N 3 Hydro Com HS0068 v1 80 EE Language Communicatio unications Help Search Speed Sensor Configuration Address 16 4CC39C32 Hydro Probe SE Material Calibration C SSD Moisture 0 00 0 1778 000 0 00 Calibration Analogue Output Averaging O P Type 4 20mA EN Average Hold Delay 0 y O P variable 1 Filtered Moisture Si Moisture Unscaled O P variable 2 Material Temperature High Limt 20 00 100 00 High 2000 low 000 Low Limit 0 00 on Digital Input Output Signal Processing VP 1use Average Hold gt ida E ei Slew Rate Light I 10 P 2use Unused Digtal Signal Processing Unused Fitering Time 10 Write Figure 34 Hydro Com Configuration Tab Hydro Probe SE User Guide HD0278 Rev 2 0 0 43 Chapter 5 Material calibration 5 2 Good Bad Quadratic Calibrations A good calibration is made when the calibration samples are taken over the working range of the material As many points as possible should be taken to provide higher accuracy Figure 35 is an example of a good calibration All of the points are close to the curve and there is a good spread in the points coveri
14. configuring the sensor There are three types of converter recommended by and available from Hydronix 5 1 RS232 485 converter D type Part no 0049B Manufactured by KK systems this RS232 to RS485 converter is suitable for connecting up to six sensors on a network The converter has a terminal block for connecting the twisted pair RS485 A and B wires and can then be connected directly in to the PC serial communication port Hydronix Part No 0049B RS485 RS232 N to RS485 A Connect ensor to PC Cable RS485 B serial port 6 DIP Switches control the configuration of the converter For both the 0049 and 0049B these should be set to Switch 1 ON Switch 3 OFF Switch 5 OFF Switch 2 OFF Switch 4 ON Switch 6 OFF Figure 12 RS232 485 converter connections 0049B 5 2 RS232 485 converter DIN rail mounting Part no 0049A Manufactured by KK systems this powered RS232 to RS485 converter is suitable for connecting up to 16 sensors on a network The converter has a terminal block for connecting the twisted pair RS485 A and B wires and can then be connected to a PC serial communication port Hydronix Part No 0049A KD485 STD Hydronix Hydronix FA E Sensor Sensor PC 9 way D Type PC ON 1 1 Ok F RS485 A F RS485 A LS or Fennec O 2 2 Qe 6 asasse 14 a Asus gt Control System Tx _3 yO 3 319 Lay a 2 RS232 AX
15. line it is probable that an error was made during the sampling or laboratory process The point can be ignored without removing it from the data set by un ticking the box at the right hand side of the table When a calibration line has been calculated it can be written to the sensor using the Recalculate Seed Point Update Sensor Calibration button Pressing this will display the following screen Figure 31 p Recalculate Seed Point Update Sensor Calibration r Existing Settings Current seed point 80 0 ExistingCoefficients A 101 00 B 0 15 C 0 17 D 2 50 r New Settings New Coefficients A 101 238 B 0 100 C 0 169 D 2 069 New Seed Point 80 0 Calculate New Seed Point Write New Coefficients Figure 31 Recalculate Seed point Update sensor 40 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Material calibration Chapter 5 4 2 4 3 Good bad Brix Calibration A good Brix calibration is achieved by analysing the material over the working range A good spread of points is necessary to provide higher accuracy Figure 32 shows a good calibration will all points close to the best fit curve Unscaled 110 Brix Curent Calibration Improved Calibration Figure 32 Example of a good Brix Calibration Figure 33 is an example of a bad Brix calibration this is evident as the points are not all close to the best fit curve Unscaled 110
16. lt 94 419 full duplex RTS ol 5 5 Host System GND 5 S 6 6 Power Supply O 7 Rutt DIP Switch 7 35v DC Sl 8 Sid Rs232 Settings i a Figure 13 RS232 485 converter connections 0049A Hydro Probe SE User Guide HD0278 Rev 2 0 0 21 Chapter 3 Electrical installation and communication 5 3 USB Sensor Interface Module Part no SIMO1A Manufactured by Hydronix the USB RS485 converter is suitable for connecting any number of sensors on a network The converter has a terminal block for connecting the twisted pair RS485 A and B wires and then connects to a USB port The converter does not require external power although a power supply is supplied and can be connected providing power to the sensor See USB Sensor Interface Module User Guide HD0303 for further information Hydronix Part No SIMO1 B El SE Sensor N gt RS485 sensor connection Interface Module a Sensor power optional 24v DC 24v Connect to 24v DC Power Supply Optional Be t 73 The Sensor Interface Modules is powered from the USB port The external es 24v DC power supply can be used if sensor power is required See user e Les guide HD0303 for further information Figure 14 SIMO1 USB RS485 converter connections Connect to PC USB Port 5 4 Ethernet Adapter Kit Part no EAKO1 Manufactured by Hydronix the Ethernet adapter is suitable for connect
17. see Analogue output setup page 25 There seems to be a scatter in the points have made in my calibration is this problem and is there something can do to improve the calibration result If you have a scattering of points through which you are trying to fit a line then there is a problem with your laboratory test Ensure the sensor is mounted properly in the flow For moisture calibrations use an Average Unscaled value for your calibration The averaging period can be set either with the Average Hold input or using Remote Averaging See Hydro Com User Guide HD0273 for more information The sensor readings are changing erratically or not consistent with the changes in moisture in the material Is there a reason for this A cause of erratic readings may be the build up of material on the sensor measurement surface during the measurement period This may cause the sensor output to remain static for a period of time and to then abruptly change if the material begins to flow For granular or flowing materials check that the flow is consistent and that there is no build up of material on the sensor Hydro Probe SE User Guide HD0278 Rev 2 0 0 45 Chapter 6 Frequently asked questions Q Does the angle of the sensor affect the reading A small change in the angle of the sensor to the flow of a granular material will have a negligible effect on the reading however a larger change gt 5 degrees can affect the readings Th
18. the digital input is low this average value is held constant Brix It is possible for the sensor to output a value that is proportional to the Brix content of a material In such cases the sensor will require calibrating to the given material The calibration requires the relationship between the Unscaled readings of the sensor and the associated Brix value of the material to be defined see Brix Calibration Chapter 5 Section 4 Selecting Brix will configure the sensor to output the calibrated Brix value Material Temperature The Hydro Probe SE has a temperature sensor attached to the metal of the sensing head This can be used to output the current material temperature The output value is set at 0 C equals OmA or 4mA dependent upon the output set up and 100 C equals 20 mA 2 3 Low and High These two values set the moisture range when the output variable is set to Filtered Moisture or Average Moisture The default values are 0 and 20 where 0 20mA OmA represents 0 and 20mA represents 20 26 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Configuration Chapter 4 4 20mA 4mA represents 0 and 20mA represents 20 Where Brix is the selected output variable the default values are O Brix and 20 Brix This should be adjusted to suit the application typically this should be set to 0 Brix and 100 Brix These limits are set for the working range of the moisture Brix and must be matched to the mA to moi
19. 0 An Unscaled value of 0 is the reading in air and 100 would relate to a reading in water Average Unscaled This is the Raw Unscaled variable processed for batch averaging using the averaging parameters If averaging is required it is recommended to use the averaging functionality within the sensor To obtain an average reading the digital input must be configured to Average Hold When this digital input is switched to high the raw Unscaled readings are averaged When the digital input is low this average value is held constant Filtered Moisture It is possible for the sensor to output a value that is proportional to the moisture content of a material In such cases the sensor will require calibrating to the given material The calibration requires the relationship between the Unscaled readings of the sensor and the associated moisture percentage of the material to be defined see Figure 19 Selecting Filtered Moisture will configure the sensor to output the calibrated moisture value Average Moisture If averaging is required it is recommended to use the averaging functionality within the sensor The Average Moisture is the Raw Moisture variable that has been processed for batch averaging using the sensor s averaging parameters To obtain an average reading the digital input must be configured to Average Hold When this digital input is switched high the Raw Moisture readings are averaged When
20. 22 RS232 485 nn Man dune sai as 21 USB Sensor Interface Module 22 Default parameters 53 Digital Inputs Output Average Hold 27 Index Bin EMP arricuta aas 27 29 Data Invalid 27 29 Moisture Temperature oooocnccccnnnocccinnnonccnns 27 Probe OK ange 27 SOUPE He Hier 27 RI WEE 27 DIMENSION Suicida 51 Fault AIM ita a 47 elle DEE 28 Filters Digital Signal Processing 28 Slew Rale iii dit 28 Smoothing Time 28 High Limit See Alarms Hydro Com 17 25 45 Installation Electrica sites nee ur 17 Mechanical 13 Mounting Boss 13 Junction Box ccccccccooococcnnnncnccoonnnonnnncncnnonarannos 19 EOW Dt See Alarms Maintenance nenia n 15 Measurement chamber 15 Measurement Technique 11 Moisture content 36 Parameters Ale e EE 28 le sit riens trust 15 Raw Moisture sie Tornaco anin a a 28 Raw Unscaled 28 Samples International Standards 36 43 Saturated Surface Dry SSD 34 Adsorbed Water 34 Free m lsturenn e ii 34 Total moisture 34 Water Adsorption Value WAV 34 Seed Poltica ca cris 42 Sensor Coment Suicidas 12 POSITION vii ridad eta 13 Sensor Cable an nt did 18 Suitable Applications
21. 3 2 Installing the Sensor silent cdc A lungen 13 3 A ak ENEE 15 Chapter 3 Electrical installation and communication s440s4s40unnnennnnnennnnnnnnnnnnnnnnnnennnnnnnnannnn 17 UNENEE lte D Ke e EI 17 2 117 ee ee EE E E 17 3 RS485 multi drop connection sise 19 4 Digital input output connections suisses 20 5 Gonnectingito RE 21 Ghapter 4 Configuration ci nase iis Cede nantes ke 25 UE e elt line WEE 25 KE ee ee EE KEE 25 SR Re le Ee ene EE 27 4 ISK ste tre tete E E RN E T ne Entre remettre 28 5 Alternative Measurement Modes sn 29 Chapter 5 Material Calibration issues 31 1 Introduction to material calibration eee ee enneeeeeeaeeeeeeaaeeeeeeaaeeeeeeaaeeeeeeaaeeeeeeaaeeeeeeaeeeeneaas 31 2 te ft e Ke Ee ne EE 32 3 Moisture Linear Calibration ss 33 4 Brix Galibration EE 38 5 Quadratic Calibration eros sms Dana te Pat een 43 Chapter 6 Frequently asked questions su 45 Chapter 7 Sensor diagnostics sisi 47 1 Symptom No output from sensor sisi 47 2 Sensor output characteristics ir 47 3 Symptom Incorrect analogue output iii 48 4 Symptom Computer does not communicate with the sensor 48 5 Symptom Near constant material reading 49 6 Symptom Inconsistent or erratic readings that do not track material 50 Chapter 8 Technical specification sisi 51 1 Technical Specifications 51 2 GOMMECTONS serr en ne Lan adh ace Seated lan na ai b pas 52 Appendix A D
22. H 3 I 7 I O TT I I I Di 2 FF 7 EI d LUH S jf i I gt f Calculate Best Fit g 50 60 70 y 80 90 100 110 rix L S Curent Calibration Improved Calibration Recalculate Seed Point Update Sensor Calibration amp Figure 27 Hydro Com new calibration screen To calibrate the sensor a number of Unscaled values need to be correlated to their corresponding Brix value Add Sample Points The Unscaled reading has to be recorded whilst the process is running and a sample needs to be taken of the liquid that the sensor is measuring The sample then needs to have the Brix content calculated in the laboratory and the results can be entered into Hydro Com alongside the Unscaled reading 38 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Material calibration Chapter 5 a Dm B 0 15 C 017 D 25 Average Error 2 2115 ERA ANMANMEEEE LLL tela RRRRRICECC E ANNNENEEEE E la v ly L t le el e et D Sensor 16 Hydro Probe SE y Current Calibration A 10100 C 0 17 Figure 28 Unscaled and Brix values entered into Hydro Com Curent Calibration Once a number of points have been entered into the list Figure 28 the Calculate Best Fit button should be clicked Choose the coefficients to use as a starting point Use default starting point Use existing probe settings as starting point C Use previous best fit calculations as starting poin
23. HPSE Default Values Hydro Probe SE User Guide HD0278 Rev 2 0 0 59 Appendix D Document Cross Reference 60 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Alarms High Limits 29 LOW EIMit 2222 29 Alternative Measurement Modes 29 Effects of selecting different modes 29 Mode E 2 2 38 422 Karen 29 Mode Ve nee 29 Standar Mode ease 29 When to Use cceeeecccc e a e ae 29 Analogue Output Average Moisture C A 26 Average Unscaled 26 Filtered Moisture necesn 26 Filtered Unscaled l a 26 Output type M 25 Averaging Parameters AA 28 Biken bc 11 26 38 42 Cables ele Bis aie ee ra A 17 Calibration oooooccnnnnnononiniccncnnnnnononaninananannna 31 Brie cee Seton EE 38 Coefficients eens 34 Data Storing 2sersneennnennnnnennnnnnnnnnnnn 32 Good bad Brix Calibration 41 Good bad Moisture Calibration 37 Good Bad Quadratic Calibrations 44 In Control System 33 Inside Sensor aececi 33 A ent 33 Procedure coccion ica cir enges 34 Ceramic O eege eu 11 Compatibility 12 Configuration 12 Connection Digital Input Output eessen 20 Multi Grop EE 19 PG POC OU PO 21 Connections oooooccnccncccccnnnonaccncnnnnnnnnnnnnannnnnnna 12 Connector MIESpec He ie 18 Converters Ethernet Adapter
24. Hydro Probe SE User Guide To re order quote part number HD0278 Revision 2 0 0 Revision date July 2014 Copyright Neither the whole or any part of the information contained in nor the product described in this documentation may be adapted or reproduced in any material form except with the prior written approval of Hydronix Limited hereinafter referred to as Hydronix 2014 Hydronix Limited 7 Riverside Business Centre Walnut Tree Close Guildford Surrey GU1 4UG United Kingdom All rights reserved CUSTOMER RESPONSIBILITY The customer in applying the product described in this documentation accepts that the product is a programmable electronic system which is inherently complex and which may not be completely free of errors In doing so the customer therefore undertakes responsibility to ensure that the product is properly installed commissioned operated and maintained by competent and suitably trained persons and in accordance with any instructions or safety precautions made available or good engineering practice and to thoroughly verify the use of the product in the particular application ERRORS IN DOCUMENTATION The product described in this documentation is subject to continuous development and improvement All information of a technical nature and particulars of the product and its use including the information and particulars contained in this documentation are given by Hydronix in good faith Hydronix welcomes com
25. RE i N Cable to Sensor 0975 a eae Description Colour Connector Pin i RS485 A White F l RS485 B Black G Ls OvDCPower Black B 10 100baseT N B gt 24v DC Power Red A CAT5e e it gh Ethernet u FR to EPAO1 A 10 100baseT i Figure 16 Ethernet Power Adapter Kit connections EPK01 Hydro Probe SE N 2 o 17 3 D 2 E 3 z 20 30 40 50 60 70 80 Maximum Air Temperature Figure 17 Maximum number of sensor connections dependent upon ambient temperature NOTE Operation above these limits may cause premature failure of the unit Hydro Probe SE User Guide HD0278 Rev 2 0 0 23 Chapter 3 Electrical installation and communication 24 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Chapter 4 Configuration 1 Configuring the Sensor The Hydro Probe SE has a number of internal parameters which may be used to optimise the sensor for a given application These settings are available to view and change using the Hydro Com software Information for all settings can be found in the Hydro Com User Guide HD0273 Both the Hydro Com software and the User Guide can be downloaded free of charge from www hydronix com All Hydronix sensors operate in the same way and use the same configuration parameters The parameter used will depend on the application For example averaging parameters are typically only used for batch processes 2 Analogue output setup The working range of the two current loop output
26. able to increase this value Options are 0 0 5 1 0 1 5 2 0 and 5 0 seconds High Limit and Low Limit Alarms The High Limit and Low Limit may be set for both the moisture Brix and the sensor Unscaled value The two parameters operate concurrently If the sensor reading falls outside of these limits during sensor averaging the data will be excluded from the average calculation The Bin Empty output will activate when the reading is below the Low Limit The Data Invalid output will activate when the reading is above the High Limit or below the Low Limit 5 Alternative Measurement Modes The Hydro Probe SE has the option of selecting alternative measurement modes The modes have been carefully designed to ensure that the sensor may be configured for maximum sensitivity across a wide variety of materials The default Measurement Mode for the Hydro Probe SE is Standard Mode Options are Mode V Mode E and Standard Mode It is recommended that the modes are only changed after comparing the effectiveness of each mode in the specific application In situ trials may be conducted using the Hydronix Hydro Com software to record data and compare the effectiveness of each mode 5 1 5 2 When to use alternative Measurement Modes The most appropriate mode will be determined by the requirements of the user the application and the material being measured Precision stability and density fluctuations as well as the working mo
27. ading for the entire batch Poor Moisture Calibration Data Poor Moisture Calibration Data 12 12 10 10 ER gs 2 6 E 5 5 3 na 3 5 2 S 2 0 d o 7 20 40 60 80 100 0 20 40 60 80 100 Sensor Unscaled Output Sensor Unscaled Output Figure 26 Examples of poor material calibration points Hydro Probe SE User Guide HD0278 Rev 2 0 0 37 Chapter 5 Material calibration 4 4 1 Brix Calibration The Hydro Probe SE has the ability to derive the Brix content of a liquid from the Unscaled value This is a measure of the amount of dissolved solids that are in a liquid and is mainly used in the food industry The Brix calculation is different from the linear calculation used for moisture To create a calibration line the following equation is used Brix A B e D us where us is the Unscaled value from the sensor This equation gives an exponential curve When using the sensors to measure Brix the sensor must still be calibrated to the process being monitored If Analogue Output 1 is set to output Brix then when the Calibration button is pressed the Brix calibration page will be displayed ae EEN ee Calibration Sensor Sample calibration __ Delte 16 HydoPmbe SE d bacs New Calibration Current Calibration A 101 00 B 0 15 A ho C 017 D 250 0 82 E D 25 Average Error 0 eg Fitered Lab Curent New Unscaled Date Unscaled Bi Probe Bi Probe 110 100 LE d HI d LEE 2 FF PF d FF I
28. an easily be calibrated to automatically calculate the moisture or the Brix content from the value measured and output this to the control system The sensor may be configured remotely when connected to a PC using dedicated Hydronix software A large number of parameters are selectable such as the type of output and the filtering characteristics After installation the sensor is calibrated to the material see Chapter 5 Material calibration For this the sensor can be setup in two ways e Calibration inside sensor Sensor is calibrated internally and outputs true moisture or Brix e Calibration inside control system Sensor outputs an Unscaled reading which is proportional to moisture This can then be used to control to a target figure or by having calibration data inside the control system convert this to the true Moisture Brix The Hydro Probe SE should never be subjected to unnecessary impact damage as it houses sensitive electronics In particular the ceramic faceplate although extremely hardwearing is brittle and may crack if subjected to severe impact CAUTION NEVER HIT THE CERAMIC 2 Measuring Technique The Hydro Probe SE uses the unique Hydronix digital microwave technique that provides a more sensitive measurement compared to analogue techniques Measurements are taken 25 times per second and this enables rapid detection of changes in the material Hydro Probe SE User Guide HD0278 Rev 2 0 0 11 Chapter 1 Int
29. conversion can then be calculated using the linear Unscaled output from the sensor For guidance on setting the output see Chapter 4 Configuring the Sensor 2 1 Calibration inside the Hydro Probe SE Calibration coefficients stored in the yl sensor B C SSD using Hydro Com gt Unscaled US zJ Analogue output represents true moisture or Brix value Control system Figure 21 Calibration inside the Hydro Probe SE The advantages of calibrating inside the Hydro Probe SE are e Advanced free software improving calibration accuracy including diagnostics software e Control system does not need modification to calibrate the sensor e Calibrations can easily be transferred between sensors 2 2 Calibration inside the control system True Moisture Brix Unscaled converted by the Control system software Figure 22 Calibration inside the control system The advantages of calibrating inside the control system are e Direct calibration without the need for an additional computer or RS485 adapter e No need to learn how to use additional software e If it is necessary to replace the sensor a replacement Hydronix sensor can be connected and valid results obtained immediately without connecting the sensor to a PC to update the material calibration e It is possible to have multiple calibrations to handle different materials in the same installation 3 Moisture Linear Calibration
30. ctly installed and in such a manner to ensure representative sampling of the material concerned It is essential that the sensing part of the unit is fully inserted into the main flow of the material It must not be installed in stagnant material or where a build up may occur 2 1 Mounting Arrangement An optional Hydronix manufactured Mounting Boss Part Number 3010 is available to assist with the installation of the Hydro Probe SE in Pressure vessels Figure 3 The Mounting Boss will need to be pressure tight welded to the Vessel It is important to note that the material must flow over the sensing faceplate of the Hydro Probe SE and that the flow must be as consistent as possible with minimal turbulence If installed in a pressurised environment the Mounting Boss must be installed by a competent person in accordance with best practice All welds should be checked for integrity Hydro Probe SE User Guide HD0278 Rev 2 0 0 13 Chapter 2 Mechanical Installation TE 150mm 85mm PC 65mm 30mm Figure 3 Mounting Boss 2 2 Mounting in a Vessel The Hydro Probe SE can be installed in a vessel Mounting Boss Pressure Vessel wall M6 Bolt Hydro Probe SE Mounting Flange Pressure tight weld Gasket Figure 4 Mounting in a pressure vessel orir H Material Flow ze Figure 5 The sensor installed in a storage tank 14 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Mechanical I
31. e Light Medium Heavy Unused Light Hydro Probe SE User Guide HD0278 Rev 2 0 0 53 Appendix Default parameters Averaging configuration Average hold delay 0 0 0 5 1 0 1 5 2 0 5 0 0 0 sec High limit m 0 100 30 00 Low limit m 0 100 0 00 High limit us 0 100 100 00 Low limit us 0 100 0 00 Input Output configuration Input Use 1 Unused Moisture Temp Average hold Moisture temp Input output Use 2 Unused Unused Moisture temp Bin empty Data invalid Probe OK Temperature compensation Electronics temp coeff Factory set Resonator temp coeff Factory set 54 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Appendix B Moisture Calibration Record Sheet Hydronix Moisture Calibration Record Sheet Refer to Hydro Com User Guide HD0273 for full calibration information Instructions e Take a small sample of material where the sensor is located e Whilst taking samples read the Unscaled sensor output from the sensor e Record the sensor Unscaled reading sensor moisture reading and lab moisture in the table below e Data may be used to recalibrate the sensor if there are consistent errors in moisture gt 0 5 between the current moisture output from the sensor and the lab moisture Material Location Sensor S N Readings from sensor Lab Sensor Lab 4 moisture moisture Operator name Date Time Unscaled Moisture difference
32. e moving stream of material e The sensor should not obstruct the material flow e Avoid areas of severe turbulence The optimal signal will be obtained where there is a smooth flow of material over the sensor e Position the sensor so that it is easily accessible for routine maintenance adjustment and cleaning e To prevent damage to the sensor position it as far as reasonably practical from sources of vibration 2 Installing the Sensor The Hydro Probe SE is fitted to the vessel using the Mounting Boss Part number 3010 A suitable hole will need to be cut to permit the installation of the Mounting Boss see Figure 3 for dimensions The Mounting Boss should be pressure tight welded to the vessel by a competent person in accordance with the local regulations and manufacturers recommendations The rubber gasket supplied with the sensor is installed between the Mounting Boss and the Mounting Flange on the sensor to ensure that a pressure tight seal is created see Figure 4 Due to variations in the design of vacuum vessels it is necessary to consult the manufacturer or a qualified person before any holes are cut or welding is attempted During welding the sensor must be removed to protect the electronic circuitry within it The optimum location for the sensor varies depending on the type of installation a number of options are detailed on the following pages Care should be taken to ensure that the Hydro Probe SE has been corre
33. e digital inputs outputs can be configured are included in Chapter 4 The most common use of the digital input is for batch averaging where it is used to indicate the start and end of each batch This is recommended as it provides a representative reading of the full sample during each batch An input is activated using 15 30Vdc into the digital input connection The sensor power supply may be used as an excitation supply for this or alternatively an external source may be used as shown below 3 5 352 E 285 a G o 3 lt Y o a a pe aer li 0975 0975 twisted pair twisted pair Sensor Sensor Cable Cable 15 30Vde Internal excitation External excitation Figure 10 Internal external excitation of digital input 1 amp 2 When the digital output is activated the sensor internally switches pin J to OV This can be used to switch a relay for a signal such as Vessel empty see Chapter 4 Note that the maximum current sink in this case is 500mA and in all cases over current protection should be used S 3 6 ke _ Be lt Active 0975 twisted low pair Sensor output Cable Digital Output switch example using Bin Empty signal to turn on a lamp Figure 11 Activation of digital output 2 20 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Electrical installation and communication Chapter 3 5 Connecting to a PC A converter is required to connect one or more sensors to a PC when checking diagnostics and
34. ed to be entirely stable across the temperature and pressure parameters specified for the sensor in the Technical Specification Chapter 8 Once a good calibration has been determined it is not necessary to re calibrate the sensor under normal circumstances It is recommended to periodically check the validity of the calibration and in the event of there being a fluctuation in the properties of the material an adjustment to the calibration may be required If have to exchange the sensor in my process do have to calibrate my new sensor Normally no assuming the sensor is mounted in exactly the same position Write the calibration data for the material to the new sensor and the moisture readings will be the same It is recommended to verify the calibration by taking a sample as shown in Chapter 5 and checking this calibration point If it lies near to or on the line then the calibration is still valid Preferably this test should be conducted at two or three points across the working moisture brix range If change the material am using do need to recalibrate It is recommended to verify the calibration by taking a sample as shown in Chapter 5 and checking this calibration point If it lies near to or on the line then the calibration is still valid What output variable should set my sensor to This depends on whether the calibration is stored in the sensor or the batch controller and if the digital input is used for batch averaging
35. efault parami eters asn nd di ae eaten 53 Appendix B Moisture Calibration Record Sheet 55 Appendix C Brix Calibration Record Sheet 57 Appendix D Document Cross Reference sisi 59 1 Document Cross Reference sise 59 Hydro Probe SE User Guide HD0278 Rev 2 0 0 7 8 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Figure 26 Figure 27 Figure 28 Figure 29 Figure 30 Figure 31 Figure 32 Figure 33 Figure 34 Figure 35 Figure 36 Table of Figures The Hydro Probe SE at de ate ES lei 10 Connecting the sensor overview iii 12 Mounting Me 14 Mounting in a pressure vessel uusu04s44nenennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn naar 14 The sensor installed in a storage tank 14 Measurement chamber in line with pipeline AA 15 0975 Sensor cable CONNECTIONS si 18 RS485 multi drop connechons sis 19 Multi Drop RS485 wiring method 19 Internal external excitation of digital input 1 amp 2 20 Activation of digital output 2 iii 20 RS232 485 converter connections 0049B rca 21 RS232 485 converter connections 0049A nn 21 SIMO1 USB RS485 converter co
36. evious calibrations Seed Point in terms of the Unscaled value In this way regardless of calibration adjustments the correct Brix value Seed Point will always be shown in relation to the previous underlying target value in terms of Unscaled units Calculate New Seed Point This function can be used if the calibration of a sensor is being adjusted and a fixed point The seed point needs to be adjusted to fit the new calibration It takes a known Brix value entered into the Current seed point box when the original calibration was created and converts it to the value it will be with the new calibration Write New Coefficients This button writes the currently displayed calibration to the sensor enabling the sensor to output a Brix value For full details on the use of Hydro Com see user guide HD0273 42 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Material calibration Chapter 5 5 Quadratic calibration The Hydro Probe SE is able to utilise a quadratic calibration function for use in the rare occasions where a material is non linear The equation used is show below 5 1 Moisture A x Unscaled value B Unscaled value C D Calibration Procedure To calculate the quadratic calibration coefficients it is necessary to use analytical software such as Excel to calculate the coefficients 1 2 3 10 11 Ensure Hydro Com is running with the calibration page open Select the correct sensor from
37. gging period weighing as required applications Incorrect use of Average Hold input Average Hold Modify timings to include main flow and exclude jogging from measurement Inappropriate sensor configuration Operate the Average Hold input Observe sensor behaviour The output should be constant with Average Hold input OFF and changing with the input ON Sensor output configured correctly for the application Inadequate ground connections Metalwork and cable ground connections Ground potential differences must be minimized Ensure equipotential bonding of metalwork 50 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Chapter 8 Technical specification 1 Technical Specification 1 1 Dimensions 447mm 4 x 6 6mm 85 PCD SECH G100mm 663mm 105mm Long Le Flange 1 2 Construction Body Stainless steel 316 Screws Stainless steel 304 Faceplate Silicon Nitride Ceramic O Ring EPDM Food Grade 1 3 Penetration of field Approximately 75 100mm dependent upon material 1 4 Range of moisture For moisture in bulk materials the sensor will measure up to the point of saturation typically 0 20 for most materials For Brix the sensor will measure between 101 Brix and approximately 50 Brix 1 5 Operating temperature range Faceplate 0 100 C 32 212 F 120 C 248 F for short periods i e clean in place cycles Electronics 0 60 C 32 140
38. igh noise applications such as a mixing environment They are less appropriate for low noise environments Options are None Very Light Light Medium Heavy and Very Heavy Filtering Time Smoothing Time The Filtering Time smoothes the signal after it has first passed through the Slew Rate filters and then the DSP filters The filter smoothes the whole signal and will therefore slow the signal response The Filtering Time is defined in seconds Options are 0 1 2 5 5 7 5 10 and a custom time of up to 100 seconds Averaging parameters During averaging the sensor uses the Raw Unscaled value All the filters are unused These parameters determine how the data is processed for batch averaging when using the digital input or remote averaging They are not normally used for continuous processes 4 4 1 Average Hold delay When using the sensor to measure the Moisture Brix content of a material as it is discharged from a vessel there is frequently a short delay between the control signal issued to begin the batch and the material beginning to flow over the sensor Moisture Brix readings during this time should be excluded from the average value as they 28 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Configuration Chapter 4 4 4 2 are likely to be unrepresentative static measurements The Average Hold delay value sets the duration of this initial exclusion period For most applications 0 5 seconds will be adequate but it may be desir
39. in moisture in one material will equate to a different moisture in a different material Because of this it is necessary to calibrate the sensor if a true moisture or Brix value is required Figure 20 left shows the calibration line for three different materials this example is using moisture lt can be seen that for each material when the Unscaled value is at 20 the corresponding Moisture is different For material A an Unscaled value of 20 corresponds to a moisture of 15 at the same Unscaled for Material B the moisture is 10 Note that the relationship between the Brix and the Unscaled value is non linear Not shown 30 Material B Material A 7 Sensor Unscaled Laboratory Result x a Material C 10 5 L gt jo es aoe zn 20 10 gt 30 15 5 40 20 Sensor Unscaled Figure 20 Calibrations for 3 different materials Left and typical calibration data Right Hydro Probe SE User Guide HD0278 Rev 2 0 0 31 Chapter 5 Material calibration A sensor material calibration correlates the Unscaled value to a True moisture or Brix value Figure 20 Right This correlation is determined by measuring the Unscaled value of a material at various moisture or Brix values and collecting a sample of the material The moisture or Brix value in the sample is then determined using an accurate laboratory process The recommended process is detailed in this user guide If an absol
40. ing up to 16 sensors to a standard Ethernet network An optional Ethernet Power Adapter Kit EPKO1 is also available which eliminates the need for additional expensive cables to be run to a remote location which does not have local power If this is not used then the Ethernet adapter will require a local 24v power supply Hydronix Part No EAK01 KOCH gt s Model EA01 Ge WG eet ae paste Ethernet 241 ve Adapter Receive OO Ps E a e Transmit COD ES da wena 10 100baseT CAT5e l Cable to Sensor 0975 Description Colour Connector Pin RS485 A White F RS485 B Black G Ov DC Power Black B 24v DC Power Red A Figure 15 Ethernet Adapter Connections EAK01 22 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Electrical installation and communication Chapter 3 Hydronix Part No EPKO1 IEC Mains Cable 10 100baseT 100 240v AC CATSE 50 60Hz Ethernet to EPIO1 Zeus 10 100baseT i CAT5e N Ethernet KAATO to Network Switch IN Model EA01 Model EPA01 Ethernet Ethernet 24V COJ Power Adapter BEEN Adapter Receive CO i Transmit CO T Bann III CAT5e N wO f l i E
41. ion sus 41 Hydro Com Configuration Tab 43 Example of a good quadratic Calibration ee ceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseneeeeeseeeaeeeseeeaees 44 Examples of bad quadratic calibrations nn 44 Hydro Probe SE User Guide HD0278 Rev 2 0 0 9 MIL Spec Connector Mounting Isolation Flange Ceramic Face Plate Sensing Area Figure 1 The Hydro Probe SE Available accessories 0975 0975 10m 0975 25m 0116 0067 0049A 0049B SIMO1A EAKO1 3010 3020 4m sensor cable 10m sensor cable 25m sensor cable Power supply 30 Watt for up to 4 sensors Terminal box IP56 10 terminals RS232 485 converter DIN rail mounting RS232 485 converter 9 pin D type to terminal block USB Sensor Interface Module including cables and power supply Ethernet Adapter Kit Mounting Boss Gasket 1 supplied with sensor Hydro Com configuration and diagnostics software is available for free download from www hydronix com 10 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Chapter 1 Introduction 1 Introduction The Hydro Probe SE is a digital microwave moisture Brix sensor designed for use in higher temperature environments and pressurised vessels and to have a wear life of many years The Hydro Probe SE measures the material passing in front of the ceramic faceplate Its on board processing provides the options of both an analogue and a digital output which can be easily connected to any control system The sensor c
42. is is due to a change in the compaction or density of the material as it meets the measurement surface When temporarily removing or replacing the sensor the angle of the sensor should be marked and the subsequent installation should adopt the same angle Why does the output read negative moisture or 101 Brix when the sensor is in air A The Unscaled reading of the sensor will read O in air and 100 in water The process of calibrating the sensor equates Unscaled values to a moisture or Brix value A totally dry material will register a number of Unscaled units on the sensor due to its electrical properties If during the calibration process a calibration gradient is produced that indicates that the material when totally dry will have an Unscaled value of 8 this will result in a negative moisture Brix value when the sensor is in air and the Unscaled value drops to zero The Calibrated output is only valid whilst the sensor is exposed to the material Q What is the maximum length of cable can use A See Chapter 8 Technical Specification 46 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Chapter 7 Sensor diagnostics The following tables list the most common faults found when using the sensor If you are unable to diagnose the problem from this information please contact Hydronix technical support support hydronix com 1 Symptom No output from sensor Possible explanation Check Required result Action required on failure
43. isture range are all factors that may determine the choice of measurement mode Mode V is often associated with agricultural and biomass materials It is also suited to other variable or low density materials Mode E is designed to be used for measuring in similar materials to Mode V Mode E is more sensitive than Mode V and therefore the sensor reading may become saturated at a lower moisture percentage This may limit the maximum moisture percentage that the sensor can measure Standard Mode is recommended for use in very wet materials and for Brix The objective is to choose the Mode that gives the most desirable often smoothest signal response and most accurate moisture or Brix determination across the full working range Effects of selecting different Measurement Modes The ability to select the fundamental Measurement Mode enables the user to choose the Mode that reduces the slope of the calibration line see Figure 19 line B The mathematical algorithms employed in the sensor have been specially devised to respond in a different manner dependant on the material being measured All modes will give a stable linear output however line B will give better precision and accuracy Mode V and Mode E will also be less susceptible to density fluctuations Hydro Probe SE User Guide HD0278 Rev 2 0 0 29 Chapter 4 Configuration 6 5 4 3 5 Unscaled units 1 7 2 Moisture Value 1 5 Unscaled units 0 4
44. les differ by 0 3 moisture then one of the samples has not been analysed correctly and the test needs to be restarted 8 Record the average moisture of the three samples in the calibration table The Moisture and Unscaled values make up one calibration point Tick this point to include the values in the calibration 9 Repeat steps 4 8 for additional calibration points It may be best to choose a different time of day or different time of the year to ensure a wide range of moistures are sampled A good calibration is one where the calibration points cover the complete working range of the material and all points lie on or near to a straight line If any calibration points are suspected to be wrong then they can be excluded from calibration by deselecting their corresponding tick box It is generally recommended that a spread of at least 3 will give the best results When the calibration is finished update the new calibration coefficients to the correct sensor by pressing the Write button The B C and SSD values in the sensor frame will then match those values in the calibration frame The moisture output from the sensor should represent true moisture of the material This can be verified by taking further samples and checking the laboratory moisture against the sensor output Calculating the moisture content All calibrations in the user guide refer to the dry weight of the material Moisture Content a
45. ments and suggestions relating to the product and this documentation ACKNOWLEDGEMENTS Hydronix Hydro Probe Hydro Mix Hydro View and Hydro Control are Registered Trade Marks of Hydronix Limited 2 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Hydronix Offices UK Head Office Address 7 Riverside Business Centre Walnut Tree Close Guildford Surrey GU1 4UG Tel 44 1483 468900 Fax 44 1483 468919 Email support hydronix com sales hydronix com Website www hydronix com North American Office Covers North and South America US territories Spain and Portugal Address 692 West Conway Road Suite 24 Harbor Springs MI 47940 USA Tel 1 888 887 4884 Toll Free 1 231 439 5000 Fax 1 888 887 4822 Toll Free 1 231 439 5001 European Office Covers Central Europe Russia and South Africa Tel 49 2563 4858 Fax 49 2563 5016 French Office Tel 33 652 04 89 04 Hydro Probe SE User Guide HD0278 Rev 2 0 0 3 4 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Revision history Revision No Date Description of Change 2 0 0 July 2014 Major Product Update Hydro Probe SE User Guide HD0278 Rev 2 0 0 5 6 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Table of Contents Ghapter TOUS ee EE 11 1 INTO UC ia A a A LA A EEE 11 2 Measuring Technique ss 11 3 Sensor connection and configuration 12 Chapter 2 Mechanical Installation ss 13 1 General to all applications uses 1
46. ng the full moisture range of the material 16 14 12 10 Material Moisture O N P Q T T T T 0 10 20 30 40 50 Sensor Unscaled output Figure 35 Example of a good quadratic calibration Figure 36 shows examples of poor calibrations It is evident that in the left hand calibration graph all of the points are not close to the curve fit and this indicates that there are possible sampling and laboratory errors This calibration would need to be completed again On the right hand graph the points are very close indicating a small spread in moisture of the samples This calibration requires additional calibration points to increase the spread and to improve the accuracy Material Moisture Br on Material Moisture Sensor Unscaled Output Sensor Unscaled Figure 36 Examples of bad quadratic calibrations 44 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Frequently asked questions Hydro Com doesn t detect any sensor when I press search If there are many sensors connected on the RS485 network ensure that each sensor is addressed differently Ensure the sensor is correctly connected that it is powered from a suitable 15 30Vdc source and the RS485 wires are connected through a suitable RS232 485 or USB RS485 converter to the PC On Hydro Com ensure the correct COM port is selected How often should calibrate the sensor The sensor is a precision instrument and is design
47. nnections nursnneensnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nn 22 Ethernet Adapter Connections EAK0O1 nn 22 Ethernet Power Adapter Kit connections EPKO1 ee i ceeeeseeeeeenteeeeeenaeeeeeeaeeeeeeaaeeeeeeaas 23 Maximum number of sensor connections dependent upon ambient temperature 23 Guidance for setting output variables 240rsnn0ennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 25 Relationship of moisture to Unscaled values ooooooccccnociccnonoccccnanonnncnanannnn nan nc nr nana nana 30 Calibrations for 3 different materials Left and typical calibration data Right 31 Calibration inside the Hydro Probe SE 33 Calibration inside the control system 33 Calibration Line example 0 0 A aa 34 Calibrations using the SSD coefficient 35 Example of a good material calibration ooo nncccninnniinnnnnncccnnnaccccnnn arco n arc 37 Examples of poor material calibration points 37 Hydro Com new calibration screen 38 Unscaled and Brix values entered into Hydro Com nn 39 Starting point Selector ie 39 Hydro Com Brix calibration beet 40 Recalculate Seed point Update sensor 2404sn40snsnnnnnnnnnnnnennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 40 Example of a good Brix Calibration 240sn40snnnsnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 41 Example of a bad Brix Calibrat
48. nput should be set to Average Hold set using Hydro Com When the process is running the status should automatically change to Averaging and when stopped it should show Hold The status can be checked using Hydro Com If the digital input is set to None or Moisture Temp a Start Averaging button will be displayed alongside the average Unscaled value in the calibration section of Hydro Com This can be used to start and stop the averaging function Hydro Probe SE User Guide HD0278 Rev 2 0 0 35 Chapter 5 Material calibration 3 4 3 5 Procedure 1 Ensure Hydro Com is running with the calibration page open 2 Create a new calibration 3 Select the correct sensor from the pull down list in the sensor frame 4 Start the material flowing past the sensor and start the averaging function if it is not automatically started then take a sample Enough material should be collected to obtain a representation of the material flowing past the sensor Only take a sample while the sensor is averaging 5 Stop the material flow and then return to the computer stop the averaging if it is not automatic and record the Average Unscaled output which should show the Hold status 6 Mix the collected sample and determine the moisture content of the material using the appropriate lab procedure The sample should be split into 3 equal parts and lab test should be performed on each part 7 Ifthe results of the 3 samp
49. nstallation Chapter 2 2 3 Mounting in a pipeline measurement chamber If the Hydro Probe SE is to be installed in a measurement chamber in line with a pipeline the chamber must remain completely full at all times to achieve reliable results A bypass line should be installed to facilitate any maintenance of the sensor Figure 6 Discharge Isolation ET Valve Y Bypass Valve A Sampling point Li E Isolation Valve m Flow Figure 6 Measurement chamber in line with pipeline 3 Maintenance The sensor should be regularly inspected to ensure that material is not building up on the ceramic faceplate If material is encrusted on the ceramic face plate the ability of the sensor to measure the moisture Brix will be impaired In the majority of cases the build up will be removed during routing cleaning of the vessel Routine cleaning systems can be used to remove encrusted material from the sensor The maximum temperature should be 120 C for short periods only A weak acid solution of Hydrochloric acid 0 5 60 C or an alkaline solution of Sodium Hydroxide 15 can be used to remove excessive material on the ceramic face plate Hydro Probe SE User Guide HD0278 Rev 2 0 0 15 Chapter 2 Mechanical Ins
50. o the following outputs Bin Empty Data Invalid Probe OK This output is energised if the Unscaled value goes below the Low Limits defined in the Averaging section This can be used to signal to an operator when the sensor is in air as the sensor s value goes to zero in air and can indicate a vessel empty state This output is energised if the Unscaled value goes outside of any of the limits defined in the averaging section This may be used to provide a high and low level alarm This option is not currently implemented in this sensor An input is activated using 15 30V DC into the digital input connection The sensor power supply may be used as an excitation supply for this or alternatively an external source may be used as in Figure 10 Hydro Probe SE User Guide HD0278 Rev 2 0 0 27 Chapter 4 Configuration 4 1 4 2 4 3 4 4 Filtering The default filtering parameters can be found in Appendix A The Raw Unscaled reading which is measured 25 times per second may contain a high level of noise due to irregularities in the signal as the material flows As a result this signal requires a certain amount of filtering to make it usable for moisture control The default filtering settings are suitable for most applications however they can be customised if required to suit the application It is not possible to have default filtering settings that are ideally suited to all applications because each will ha
51. ode gives the desired performance characteristics Hydronix can supply additional software to assist with detailed analysis of the measurement modes and optimisation of the sensor filtering parameters if required Hydro Com software and the user guide may be downloaded from www hydronix com When using the sensor to obtain an output signal that is calibrated to moisture an absolute moisture measurement it is recommended to calibrate using the different measurement modes and to compare results see Calibration Chapter 5 For further information please contact the Hydronix support team at support hydronix com 30 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Chapter 5 Material calibration 1 Introduction to material calibration 1 1 The Unscaled Value When it is manufactured each sensor is individually calibrated in a controlled environment so that a zero 0 value relates to the measurement in air and 100 relates to water This is used to give a raw output value from a Hydronix sensor which ranges from 0 to 100 and is called the Unscaled value 1 2 Why Calibrate The Hydro Probe SE measures the electrical properties of a material As the moisture or Brix content changes in the material the sensor s Unscaled value will change accordingly The rate of change of the Unscaled value will vary dependant on the properties of the material Because different materials have different electrical properties the Unscaled value at a certa
52. operation is 70mA 150 mA Check operating temperature is within specified range Hydro Probe SE User Gu ide HD0278 Rev 2 0 0 49 Chapter 7 Internal failure or incorrect configuration Remove sensor clean face and check reading a with ceramic face open and b with hand pressed firmly on ceramic face Activate Average Hold input if required Reading should change over a reasonable range Sensor diagnostics Verify operation with Hydro Com diagnostics material 6 Symptom Inconsistent or erratic readings that do not track Possible explanation Check Required result Action required on failure Build up of material on sensor face Signs of build up such as dried solid deposit on ceramic face Ceramic face should always be kept clean by the action of the material flow Reposition sensor if problem continues Inappropriate calibration Average Hold signal is not in use Ensure calibration values are appropriate to working range Control system is calculating batch average readings Calibration values spread throughout range avoiding extrapolation Average moisture readings must be used in batch Perform further calibration measurements Modify control system and or reconfigure sensor Average Hold signal is operating during the main flow of material from the bin should be active during main flow only not during jo
53. r Converter s wiring instructions and A and B signals are the correct orientation RS485 converter correctly wired Check PC Com port settings Incorrect serial Com Port selected on Hydro Com Com Port menu on Hydro Com All available Com Ports are highlighted on the pull down menu Switch to the correct Com Port Possible Com port number used is higher than 16 and therefore not selectable in the menu on Hydro Com Determine the Com Port number assigned to the actual port by looking at the PC device manager 48 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Sensor diagnostics Com port number is higher than 16 and is not available to use in Hydro Com The Com Port assignments in the PC s Device Manager window Renumber the Com Port used for communication with the sensor to an unused port number between 1 and 10 Chapter 7 Check sensor addresses More than one sensor has the same address number Connect to each sensor individually Sensor is found at an address Renumber this sensor and repeat for all the sensors on the network Try an alternative RS485 RS232 USB if available Possible explanation Check 5 Symptom Near constant material reading Required result Action required on failure Empty bin or sensor uncovered Sensor is covered by material 100mm minimum depth of material Make sure the sensor is in the material
54. ratic term can be used in the calibration equation as shown below Moisture A x Unscaled reading B Unscaled reading C SSD Use of the quadratic coefficient A would only be necessary in complex applications and for most materials the calibration line will be linear in which case A is set to zero For more information on quadratic calibrations and determining the calibration contact the Hydronix Support Department at support hydronix com 2 Storing calibration data There are two ways of storing the calibration data either in the control system or in the Hydro Probe SE Both methods are shown below Calibration inside the sensor will require the coefficient values to be entered using the digital RS485 interface True moisture can then be obtained from the sensor To communicate using the RS485 interface Hydronix has a utility Hydro Com which contains dedicated material calibration pages both for Moisture and Brix The procedures described in section 3 4 are recommended when calibrating the Hydro Probe SE to material These procedures use the Hydro Com utility and the calibration information is stored inside the sensor Whether the calibration data is stored within the sensor or the control system the process is the same 32 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Material calibration Chapter 5 To calibrate outside of the sensor the control system will require its own calibration function and the moisture
55. roduction 3 Sensor connection and configuration As with all Hydronix digital microwave sensors the Hydro Probe SE can be remotely configured using a digital serial connection and a PC running Hydro Com diagnostics software For communication with a PC Hydronix supply RS232 485 converters a USB Sensor Interface Module and an Ethernet Adapter Kit see Chapter 3 The Hydro Probe SE can be connected to a control system in three ways e Analogue output A DC output is configurable to e 4 20 mA e 0 20 mA e 0 10 V output can be achieved using the 500 Ohm resistor supplied with the sensor cable e Digital control an RS485 serial interface USB Sensor Interface Module or Ethernet Adapter permits direct exchange of data and control information between the sensor and the plant control computer e Compatibility mode Not used in this sensor The digital inputs and output enables the moisture to be averaged when material is flowing essential for obtaining representative moisture for process control Power Supply 15v 30vDC 1A min Analogue Outputs 0 20mA 4 20 mA 0 10v Digital Inputs Outputs lt RS485 Serial Comms Figure 2 Connecting the sensor overview 12 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Chapter 2 Mechanical Installation 1 General to all applications Follow the advice below for good sensor positioning e The sensing area of the sensor ceramic face plate should always be positioned in th
56. s can be configured to suit the equipment to which it is connected for example a PLC may require 4 20 mA or 0 10V DC input signal The outputs may also be configured to represent different readings generated by the sensor e g Brix or Moisture Figure 18 may be used to assist in selecting the correct analogue output variable for a given system Calibration inside sensor YES No Averaging in the sensor Averaging in the sensor using digital input using digital input YES No See Note YES S N Filtered Moisture Average Filtered Unscaled Unscaled Average Moisture Note It would be advisable to average in the control system here Figure 18 Guidance for setting output variables 2 1 Output type This defines the type of analogue outputs and has three options 0 20mA The addition of an external 500 Ohm precision resistor converts to 0 10V DC 4 20mA Compatibility This is not used by the Hydro Probe SE Hydro Probe SE User Guide HD0278 Rev 2 0 0 25 Chapter 4 Configuration 2 2 Output variable 1 and 2 These define which sensor readings the analogue output will represent and has 5 options 2 2 1 2 2 2 2 2 3 2 2 4 2 2 5 2 2 6 NOTE This parameter is not used if the output type is set to Compatibility Filtered Unscaled This represents a value which is proportional to moisture and ranges from 0 10
57. sistor supplied with the sensor cable Hydro Probe SE User Guide HD0278 Rev 2 0 0 17 Chapter 3 Electrical installation and communication Sensor cable Part no 0975 connections Twisted Pair MIL spec Sensor connections Cable colour Number pins 1 A 15 30V DC Red 1 OV Black 2 C 1 Digital input Yellow 2 Black Cut back 3 D 1 Analogue Positive Blue 3 E 1 Analogue Return Black 4 F RS485 A White 4 G RS485 B Black 5 d 2 Digital input Green 5 Black Cut back 6 2 Analogue Positive Brown 6 E 2 Analogue Return Black H Screen Screen C Yellow e E 8 a ao x H J Green G Black F White D Blue E Black B Black 0975 twisted pair Sensor Cable Junction box i Do not connect screen BE at control cabinet 500 Ohm resistor for 0 10V ee ll EH le SE SE Positive Return UE ed Positive Return To oV VE S Digital 2 D E Digital i 2 Analogue Output Input SE 1 Analogue Output Input Supply 15 30V DC Output cr i me ee ee ee mmm l ham o mm o mm mn mm m mmm u l n o mm o es ee Control Room Wiring Figure 7 0975 Sensor cable connections Note The cable screen is grounded at the sensor It is important to ensure that the plant where the sensor is installed is properly grounded 18 Hydro Probe SE User Guide HD0278 Rev 2 0 0
58. sture Brix conversion in the batch controller 3 Digital inputs output setup The sensor has two digital inputs output the first can be configured as an input only The second can be either an input or output The first digital input can be set to the following Unused Average Hold Moisture Temperature The status of the input is ignored This is used to control the start and stop period for averaging When the input signal is activated the Raw values Unscaled and Moisture start to average after a delay period set by the Average Hold delay parameter When the input is then deactivated averaging is stopped and the average value is held constant so that it can be read by the batch controller PLC When the input signal is activated once again the average value is reset and averaging commences Gives the user the ability to switch the analogue output between the Unscaled Moisture or Brix whichever is set and temperature This is used when the temperature is required whilst still using only one analogue output With the input active the analogue output will indicate the appropriate moisture variable Unscaled or moisture When the input is activated the analogue output will indicate the material temperature in degrees centigrade Temperature scaling on the analogue output is fixed zero scale 0 or 4mA corresponds to 0 C and full scale 20mA to 100 C The second digital input output can also be set t
59. t Figure 29 Starting point selector A pop up menu Figure 29 will display a choice of methods in which to calculate the line of best fit through your calibration points Each method calculates the line of best fit slightly differently Three methods are given to ensure that the best possible fit may be achieved The most commonly used is Use default starting point The other two methods may also be tried and the results viewed by eye Figure 30 Hydro Probe SE User Guide HD0278 Rev 2 0 0 39 Chapter 5 Material calibration Calibration Sensor Sample calibration v Delete 16 Hydro Probe SE v New Calibration Current Calibration A 1010 B 015 A 101 237 B 0 1000 C 07 D 25 C In ssa D 2 0690 Average Eror 0 3407 o Ets Unscaled 110 100 30 80 70 60 50 40 30 20 10 C M Tr l gt Calculate Best Fit 50 60 70 SS 80 30 rix EE Curent Calibration Improved Calibration Recalculate Seed Point Update Sensor Calibration amp Figure 30 Hydro Com Brix calibration best fit E il PE A eee lt l 1 01701 21 01 01 3 01 01 4 01701 5 8 di d Es ft E lt l i LLL TOTES II C E 2 Cc g i IE g E g 9 i Hydro Com will calculate a line that tries to include all of the points entered It displays the new line as a red line and the last line as a blue line Figure 30 If a point is a long way from the
60. tallation 16 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Electrical installation and communication Hydronix supplies cable 0975 for use with the Hydro Probe SE this is available in different lengths Any extension cable required should be connected to the Hydronix sensor cable using a suitable screened junction box See Chapter 8 for details It is recommended to allow the sensor to stabilise for 15 minutes after applying power before use 1 Installation guidelines Ensure that the cable is of a suitable quality See Chapter 8 Section 2 1 for details Ensure that the RS485 cable is taken back into the control panel This can be used for diagnostic purposes and takes the minimum of effort and cost to connect at the time of installation Route the signal cable away from any power cables Check that the vessel is properly grounded The sensor cable should only be grounded at the sensor end Ensure that the cable screen is not connected at the control panel Ensure that there is continuity of the screen through any junction boxes Keep the number of cable joins to a minimum 2 Analogue outputs Two DC current sources generate analogue signals proportional to separately selectable parameters e g Brix Moisture Unscaled etc See Chapter 4 or the Hydro Com User Guide HD0273 for further details Using the Hydro Com software the outputs may be selected to be 4 20 mA 0 20 mA 0 10 V output can be achieved using the 500 Ohm re
61. the flowing material For more information on sampling please contact Hydronix at support hydronix com or refer to your particular standard Saturated Surface Dry SSD Coefficients for Free Moisture Content In practice it is only practicably possible to obtain oven dried moisture total moisture values for calibration purposes If a free moisture value is required it is necessary to take into consideration adsorbed water within the material Adsorbed water Free moisture Total moisture The SSD Coefficient used in Hydronix procedures and equipment is a value that relates to the water absorption properties of the material sometimes referred to as the Water Absorption Value WAV This value is determined by more complex means than oven drying and may usually be obtained from the material supplier In the Hydro Com calibration settings for the sensor the user may choose to enter the Water Absorption Value into the SSD Coefficient box to obtain a free water moisture value The WAV SSD relates to the properties of the oven dry material and does not change It is treated as an offset in the calibration Figure 24 shows a typical calibration line Total moisture that has been offset using the SSD coefficient set at 5 Free Moisture Oven dried water adsorption value surface moisture moisture SSD offset in the sensor free moisture Total 34 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Material calibration Chapter 5
62. the pull down list in the sensor frame Start the material flowing past the sensor and start the averaging function if it is not automatically started then take a sample Enough material should be collected to obtain a representation of the material flowing past the sensor Only take a sample while the sensor is averaging Stop the material flow and then return to the computer stop the averaging if it is not automatic and record the Average Unscaled output which should show the Hold status Mix the collected sample and determine the moisture content of the material using the appropriate lab procedure The sample should be split into 3 equal parts and the appropriate laboratory test should be performed on each part If the results of the 3 samples differ by more than 0 3 moisture then one of the samples has not been analysed correctly and the test needs to be restarted Take the average of the 3 laboratory samples Record the Average Unscaled value and the laboratory moisture result Repeat steps 4 9 until samples have been taken across the full working range of the material The average Unscaled and lab results should be entered into analytical software to calculate the A B and C coefficients plus the R value The coefficients should be calculated using a second order polynomial Once the coefficients have been calculated enter the A B and C Values into Hydro Com Select the sensor on the main screen Sensor
63. ute moisture or Brix value is required it is necessary to calibrate the sensor However for some processes this is not required and it is more useful to use the Unscaled value as a target or as a measure of the repeatability in a process All installations should be calibrated in situ It is not possible to calibrate without installing the sensor in the process If calibrated the calibration should be periodically checked to ensure that no underlying changes in the material have occurred that may affect the validity of the calibration dataset used 1 3 Material Changes It is important to position the sensor where there is an adequate and consistent flow of material Fluctuations in the composition of the material such as varying blends density or compaction may adversely affect the validity of the calibration See Chapter 2 for mounting advice For further advice regarding specific applications please consult the Hydronix support team support hydronix com 1 4 The Calibration Types The Hydro Probe SE can be calibrated to a moisture percentage or a Brix Value A material calibration for moisture is normally linear and calibrating to this is described in Chapter 5 section 3 For a Brix calibration a different type of line is used and this type of calibration is described in Chapter 5 section 4 There is also a quadratic function for use in the rare cases when the measurement of the material exhibits non linear characteristics a quad
64. ve different characteristics The ideal filter is one that provides a smooth output with a rapid response The Raw Moisture and Raw Unscaled settings should not be used for control purposes The Raw Unscaled reading is processed by the filters in the following order first the Slew Rate Filters limit any step changes in the signal then the Digital Signal Processing Filters remove any high frequency noise from the signal and finally the smoothing filter set using the Filtering Time function smoothes the whole frequency range Each filter is described in detail below Slew Rate Filters The Slew Rate Filters are useful for clipping large spikes or troughs in the sensor reading caused by mechanical interference in a process These filters set rate limits for large positive and negative changes in the raw signal It is possible to set limits for positive and negative changes separately Options are None Light Medium and Heavy The heavier the setting the more the signal will be dampened and the slower the signal response Digital Signal Processing The Digital Signal Processing Filters DSP removes excessive noise from the signal using an advanced algorithm The filter reduces high frequency noise The advantage of this filter is that the DSP filter will treat all signals within a meaningful frequency range as valid The result is a smooth signal that responds rapidly to changes in moisture DSP filters are particularly useful in h
65. x 100 Example 1288 79 1236 e E Moisture Content Je CS x 100 5 7 Note that the moisture calculated here is based upon the dry weight 36 Hydro Probe SE User Guide HD0278 Rev 2 0 0 Material calibration Chapter 5 3 6 Good bad moisture calibration A good calibration is made by measuring samples and taking readings over the full working moisture range of the material As many points as practical should be made as more points provide higher accuracy The graph below shows a good calibration with high linearity Good Moisture Calibration Data 12 aL a gt Gg 5 8 26 at 84 Br o 0 20 40 60 80 100 120 Sensor Unscaled Output Figure 25 Example of a good material calibration Calibration inaccuracy is likely to result if e Too small a sample of material is used for measuring the moisture content e Avery small number of calibration points are used in particular 1 or 2 points e The sub sample tested is not representative of the bulk sample e Samples are taken close to the same moisture content like the calibration graph shown below left A good range is necessary e There is a large scatter in the readings as shown in the calibration graph below right This generally implies an unreliable or inconsistent approach to taking samples for oven drying or poor sensor positioning with inadequate material flow over the sensor e f the averaging facility is not used to ensure representative moisture re

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