Product Manual - Eco
Contents
1. A resistance to earth measurement will actually comprise 3 components the resistance of the electrode itself the resistance of the ground rod or anode material for example including test leads the electrode earth contact resistance and the resistance of the surrounding earth Typically the resistance of the surrounding earth is the largest component of the resistance to earth measurement The three electrodes are positioned in a straight line 1deally as indicated in Figure 3 below Page 11 of 38 3 ELECTRODE APPLICATION ELECTRODE GROUNDING ROD or ANODE RESISTANCE TO EARTH MEASUREMENT RESISTANCE Ohms Potential Current Electrode Electrode Anode or Grounding Rod Figure 3 As indicated in Figure 3 a jumper wire is connected between the C1 and P1 terminals on the MILLER 400D and test leads connect the Potential Electrode and the Current Electrode to terminals P2 and C2 respectively Finally a test lead connects the electrode under test a ground rod or an anode for example to the C1 terminal With this configuration the MILLER 400D passes a current between the test electrode and the Current Electrode and generates a resistance reading based on the voltage dropped between the electrode under test and the Potential Electrode The magnitude of the resistance reading will be a function of the separation distance between the electrode under test and the Potential Electrode with2. the resultant resistance value In such cases the load appearing across the input terminals of the meter is not purely resistive but has reactive components as well In particular an effective shunt capacitor due to the test leads being in close proximity will bleed off some of the current current that would have otherwise flowed through the resistive soil leading to inaccurate resistance values High resistance readings are particularly affected by the shunt capacitance since the output currents are so small in such cases and the current leakage effect is therefore magnified The solution to this issue is to make sure that the test leads are physically separated from each other in cases where the soil resistance is greater than 1MQ So for example in the case of the M C Miller 4 test lead reel the test leads should be physically separated from each other ties removed if very high gt 1MQ resistances are to be measured Note This should only be an issue for soil with essentially zero moisture content since a IMQ soil resistance translates to a 1 000 x 105 O cm soil resistivity for a 5 feet pin spacing for example
3. 010 resolution or LCD shows 0 XXXO Note Data received by a PC will always Resolution 0 01 resolution have highest resolution regardless of display format Assuming that a Bluetooth enabled PDA or PC is available the above five parameters can be modified from their default values or settings using the Miller 400D Configuration Program In the absence of a Bluetooth enabled PDA or PC the Miller 400D will operate in the factory configured mode with the default values or settings being applicable Page 19 of 38 After installing the Configuration Program from the CD that was supplied with the Miller 400D onto your PC or PDA and opening the application the window shown below will be displayed r File Miller 400D A Bluetooth connection is initiated by the Configuration Program via the following procedure With the PDA or PC within range within 30 feet of the Miller 400D left mouse click or tap on the Miller 400D menu and click or tap on the Connect option as indicated below Page 20 of 38 3 Miller 400D Configuration Pro O54 The following message will be displayed Make sure that the Miller 400D is turned ON At this point depress the Read button on the Miller 400D which turns the unit ON and immediately click or tap on the Yes button in response to the message Note A few seconds are required to establish a connection Also the above proces
4. continue adding data to the file To do so click or tap on the Open Survey File button and highlight the name of the survey file to be opened and click or tap on the Open button on the Open ProCP Soil Resisitivity Survey window At this point the window shown below the Survey Screen will be displayed Page 28 of 38 IPro CP Soil Resistivity Miller 400D is connected X File Miller 400 Help Options Pin Spacing Pipeline Name m Location Type Station N C Use Metric Choose a Location method Calc Pipe Loc From GPS _ Include Altitude Reading Interval feet E Add Manually Entered Locations Note all numbers are in feet MCM Survey Options Field Pipeline Name Enter a name for the pipeline over which the survey is being conducted if known Location Type By clicking or tapping on the drop down menu button in the Location Type field a selection can be made regarding how locations are displayed Station Milepost or Miles plus Feet or their metric equivalents Use Metric Make this selection for metric distance units rather than U S distance units With this box checked all distances will be in metric units Select one of the following options regarding stationing measurement location information along the pipeline Calc Pipe Loc From GPS With this option the distance between the previous measurement location and the current measurem
5. identifying a previously created folder perhaps located in your My Documents folder as the target folder for the survey file A target folder for the survey file is selected by clicking on the Browse for Folder button indicated by the arrow on the window shown below In the example window see below a previously created folder named SR Surveys is highlighted to be the parent folder for soil resistivity survey files Page 26 of 38 x tN Pro CP Soil Resistivity Miller 400D is Not connected mX File Miller 400 Help Select the Target folder for this New Survey Remote Display Remote monitoring stuff O Resume Shop Test Stuff Soil Box Stuff SR Surveys Stripper Data loggers c Symantec ec Training Courses Materials eke new raider ox cae J Following target folder identification enter a name for the survey file as indicated in the window shown below and click or tap on the Accept button In the example shown the survey file name is MCM survey Page 27 of 38 IPro CP Soil Resistivity Miller 400D is connected la File Miller 400 Help New Survey Options Survey Name MCM Survey Survey Folder C Documents and Settings Robert My E a After selecting Accept the window shown below the Options Screen will be displayed Re opening a pre existing survey file A pre existing saved survey file can be re opened perhaps to
6. respect to a fixed position for the Current Electrode Page 12 of 38 A characteristic resistance versus distance plot is illustrated in Figure 4 below A characterisitic resistance versus distance plot assuming that the Current Electrode see Figure3 is far enough away from the electrode under test L Z LL ETZ 7 o lt p gt Aw TE lt i 3c T S Y bral d o c ul S E oe o ac Distance between the electrode under test and the Potential Electrode see Figure 3 feet Figure 4 This type of plot assumes that the Current Electrode see Figure 3 is positioned far enough away from the electrode under test so that a plateau region is obtained in the plot A 100 foot separation is typically recommended However it is suggested that a resistance versus distance curve be generated for any given situation in order to verify the existence of a plateau type region which will allow an accurate determination of the electrode to earth resistance Assuming that a plateau type region is obtained the resistance to earth value for the electrode under test will be the resistance value on the plot corresponding to the plateau region as illustrated in Figure 4 A general rule of thumb which assumes that the Current Electrode is positioned sufficiently far away from the electrode under test is that if the Page 13 of 38 Potential Electrode is positioned at a distance from
7. P1 and P2 directly to the electrodes with separate test leads thus eliminating the jumper wires Such a configuration eliminates any voltage drop in the test leads due to current flow in the leads which would appear in series with the voltage drop occurring between the electrodes in the case of the configuration shown in Figure 5 The reading displayed on the MILLER 400D will be a direct measurement of resistance comprising 2 components the resistance to earth contribution of each electrode which itself comprises 3 components see the 3 Page 15 of 38 Electrode Application section above and the earth s resistance between the two electrodes SECTION 5 STATUS INDICATORS amp ERROR CODES Status Indicators There are 3 status indicators on the MILLER 400D A light bar in the LCD positioned opposite each of 3 icons will indicate particular scenarios The 3 icons are shown below and are located to the left hand side of the LCD From top to bottom the icons represent the battery the noise status and the Bluetooth radio ve 3 Battery Indicator The battery indicator provides a warning that it s time to replace the batteries in the MILLER 400D see the Maintenance amp Calibration Section Section 6 for details The indicator bar opposite the battery icon will be ON when there is only 20 of the charge remaining and the indicator will flash ON and OFF when there is 10 or less charge remaining When the battery c
8. Page 1 of 38 MILLER 400D DIGITAL RESISTANCE METER USER S MANUAL Revised September 7 2010 MICMILLER co M C Miller Co Inc 11640 U S Highway 1 Sebastian FL 32958 U S A Telephone 772 794 9448 Website www mcmiller com Page 2 of 38 CONTENTS Section le Description ioes seeren anera e cease bed Op dau Ya ace 3 Section 2 How to Take Resistance Readings Manually 4 Section 3 Logging Resistance Readings on a Bluetooth Enabled Computer PDA Laptop etc cece cece ee ence ees 5 Section 4 AAppICdtols course Set eer ht REOR PE Rd DRE NAE AR 6 4 Electrode Applications esee 6 Earth Resistivity Measurement 00000 c eevee cence 6 Soil Sample Resistivity Measurement 000 000 8 3 Electrode Application eser oer retta doe e AU ae 10 2 Electrode Application 25er eu acceder mire erbe ei da 13 Section 5 Status Indicators and Error Codes ss 15 Section 6 Maintenance amp Calibration cece cece ee eee eee ees 17 Appendix 1 How to Change Settings from their default values Using the Miller 400D Configuration Program 18 Appendix 2 How to use the ProCP Soil Resistivity Survey Program in conjunction with the Miller 400D 23 Appendix 3 Influence of test lead proximity on the accuracy of AC resistance meter readings ssssuuuuss 38 FCC Statement The Miller 400D Resistance Meter meets
9. Page 24 of 38 With the PDA or PC within range within 30 feet of the Miller 400D left mouse click or tap on the Miller 400D menu and click or tap on the Connect option as indicated below e Pro CP Soil Resistivity Miller 400D is Not connected sd E3 File Miller 400 Help New Survey File m Open Survey File The following message will be displayed Make sure that the Miller 400D is turned ON At this point depress the Read button on the Miller 400D which turns the unit ON and immediately click or tap on the Yes button in response to the message Note The above process may have to be repeated more than once for a Bluetooth connection to be established Approximately 16 seconds are required to establish a connection and to have the software be in control of the Bluetooth radio in the Miller 400D unit The window shown below will be displayed when a Bluetooth connection has been successfully established Please note the header indication Miller 400D is connected on the window Page 25 of 38 Pro CP Soil Resistivity Miller 400D is connected Jog File Miller 400 Help New Survey File Open Survey File Creating a new survey file or re opening a pre existing survey file Creating a new survey file A new soil resistivity survey file is established by clicking or tapping on the New Survey File button on the above window and
10. Pipe Loc From GPS Manually Entered Locations Note all numbers are in feet MCM Survey Survey Screen After making Options and Pin Spacing selections click or tap on the Survey button lower right hand corner which will pull up the survey screen An example survey screen is shown below for the case of 3 pin spacing values having been entered 20 feet 10 feet and 5 feet Page 31 of 38 IPro CP Soil Resistivity Miller 400D is connected m Eg File Miller 400 Help Note all calculated readings are in ohm cm Location Current Pin Spacing 20 00 1 3 20 00 feet FA Grab Resistance Meter Value R Calculated Value P gt Value from Device Remarks C Known Station Survey Direction 2000 00 feet surveyed MCM Survey As indicated in the above window the software is ready to acquire the meter value resistance value associated with the first of three pin spacings 20 foot pin spacing in this example case A selection should be made for the Survey Direction either Downstream or Upstream This selection is important with regard to the first two Location Method options namely the Calc Pipe Loc from GPS and Reading Interval options Downstream implies that the stationing will be increasing with each logged reading and Upstream implies that the stationing will be decreasing with each logged reading Note For the Upstream selection it
11. ast qo MCM Survey As indicated above the acquired resistance value in this example for the 10 foot pin spacing is 10 1Q and the calculated resistivity value is 19 347 4Q cm The calculated resistivity value 19 347 4O cm in this example case is saved by clicking or tapping on the Log Reading button At that point the third prompt screen automatically appears as shown below and the resistance value acquired by clicking or tapping on the Grab Resistance Value from Device button or depressing the Read button on the Miller 400D will be displayed in the Meter Value field Page 35 of 38 IPro CP Soil Resistivity Miller 400D is connected Joke File Miller 400 Help Note all calculated readings are in ohm cm Location Current Pin Spacing 20 00 3 3 5 00 feet F3 Grab Resistance Meter Value R Calculated Value P Value from Device 15 1 14487 6 Remarks Known Station Survey Direction 2000 00 feet surveyed MCM Survey The window above shows the acquired resistance value 15 1Q and the calculated resistivity value 14 487 6O cm for the 5 foot pin spacing example the third of 3 pin spacing readings Clicking or tapping on the Log Reading button will save the final calculated resistivity value for this location site and a fresh prompt screen will be presented for the next location next site The Delete Last Site Location button can be used t
12. ayed By depressing the read button twice rather than once continuous resistance readings will be initiated In the continuous mode a resistance reading will be taken and displayed every 3 seconds The process is terminated by depressing the read button a third time Also the process will self terminate after 10 readings by default Although this mode consumes more battery power it may be desirable to observe the resistance reading as a function of time for some period of time in order to check for consistency The read button can also be used to initiate a self calibration process please see the Maintenance amp Calibration Section Section 6 SECTION 3 LOGGING RESISTANCE READINGS ON A BLUETOOTH ENABLED COMPUTER PDA LAPTOP ETC A Bluetooth enabled computer can be programmed to acquire resistance readings directly from the MILLER 400D and with electrodes and test leads appropriately connected to the meter as indicated in the Application Section Section 4 resistance readings can be logged via a software application For instance the MILLER 400D is supplied with an over the pipe soil resistivity survey program known as ProCP Soil Resistivity which is based on the 4 pin Wenner Methodology Please see Appendix 2 for information on this software application Page 6 of 38 SECTION 4 APPLICATIONS 4 ELECTRODE APPLICATIONS 1 Earth Resistivity Measurement This application uses 4 electrodes pins The electr
13. cted by any stray interference signals having frequencies other than 82 2Hz that may be present in the earth during the measurement The MILLER 400D runs on a set of replaceable D size alkaline batteries so there is no requirement to periodically re charge the unit or to plug the unit into a power source Furthermore due to its extremely low power consumption design the MILLER 400D can perform 10 000 single resistance readings for example on a fresh set of batteries SECTION 2 HOW TO TAKE RESISTANCE READINGS MANUALLY The Read Button is used to initiate a resistance measurement once electrodes and test leads are appropriately connected to the MILLER 400D as indicated in the Applications Section Section 4 A single resistance reading is initiated by depressing the read button once momentarily for a period of less than 2 seconds The Q symbol on the LCD will flash On and Off when a reading is being E r performed When the reading has been accomplished the value will be displayed and the appropriate units highlighted MQ KQ or Q Page 5 of 38 The LCD will be as indicated in cases M where the measured resistance is 3 higher than 10MQ The resistance reading will be displayed for a period of time 1 minute by default after which the LCD will go blank until the read button is momentarily depressed again to take another reading Another reading can also be initiated while the previous reading value is being displ
14. ctrode Application e The resistance to earth of a buried electrode such as a ground rod or an anode for example 3 Electrode Application e The resistance between two buried electrodes such as two ground rods or two anodes 2 Electrode Application The MILLER 400D has a resistance measurement range with automatic ranging from 0 01Q to 10M O Over the range 0 01 to IMQ the specified meter accuracy is 1 6 1 LS display digit 0 01Q and over the range 1MQ to 10MQ the specified accuracy is 5 1 LS display digit Note For load resistances gt 1 MQ in addition to internal meter errors errors associated with test lead proximity can also be significant please see Appendix 3 for details It should be noted however that these accuracy Page 4 of 38 specifications assume a low electrode pin earth contact resistance during the measurement In this regard it is recommended that the electrodes pins be firmly driven into the earth pins cannot be loose and in dry soils it is recommended that the soil around the pins be moistened in order that reliable low resistance contact be made to the surrounding soil The voltage source inside the MILLER 400D that supplies the current used in the resistance measurement is a 12 V rms crystal controlled 82 2Hz square wave oscillator and the internal ammeter and voltmeter use very narrow band pass filters centered at 82 2Hz What this means is that resistance measurements are unaffe
15. current FCC radio frequency exposure guidelines and complies with Part 15 of the FCC Rules FCC Equipment Authorization ID POOWML C40 Page 3 of 38 SECTION 1 DESCRIPTION When combined with appropriate electrodes pins and test leads the MILLER 400D can be used to measure earth resistance with the push of a button There is no need to adjust dials or select ranges the MILLER 400D automatically provides a direct resistance reading In addition to taking and recording readings manually see Section 2 a Bluetooth enabled computer PDA laptop etc can be programmed to acquire resistance readings directly from the Miller 400D since the resistance meter has a built in Bluetooth interface see Section 3 In the latter case the PDA or PC which is in control of the Bluetooth link commands the Miller 400D to take a reading and the resistance value is sent automatically to the PDA or PC Depending on the application 4 Electrode 3 Electrode or 2 Electrode the MILLER 400D can be used to determine the following e The average earth resistivity to a specific depth with the application of an appropriate multiplier to convert resistance to resistivity based on the electrode separation distance 4 Electrode Application e Theresistivity ofa soil sample or ofa liquid via an electrolyte soil liquid box with the application of an appropriate multiplier to convert resistance to resistivity depending on the box geometry 4 Ele
16. ded by 100 In the above example the resistivity would be 659 73 ohm m Note The above formula is accurate only if the electrode depth d is small relative to the electrode spacing S An S value equal to or greater than 20 times the d value is recommended This means that if d is 1 foot for example then S has to be at least 20 feet or if d is 0 3 meter then S has to be at least 6 meters The Wenner Method 1s the basis of an ASTM Standard Test Method ASTM G57 06 2 Soil Sample or Liquid Resistivity Measurement This application also uses 4 electrodes however in this case the electrodes are an integral part of an electrolyte box which is more commonly referred to as a soil box For this application the MILLER 400D can be used in conjunction with one of M C Miller s soil boxes catalog 37008 or catalog 37006 and 4 test leads catalog 37009 A schematic of the test arrangement is illustrated in Figure 2 below Page 9 of 38 4 ELECTRODE APPLICATION SOIL or LIQUID RESISTIVITY MEASUREMENT VIA AN ELECTROLYTE BOX RESISTANCE Ohms Pm ELECTROLYTE SOIL or LIQUID BOX Figure 2 For this application the test leads are connected to the MILLER 400D as shown in Figure 2 With this arrangement the MILLER 400D displays the resistance of the soil sample or of the liquid that fills the electrolyte box based on the magnitude of the current flowing between terminals C1 and C2 and the volta
17. e noise indicator will be observed during the Continuous Reading Mode in which readings are presented at 3 second intervals continuously should either of the following two scenarios occur A new resistance value is larger than twice the previous value or a new resistance value is smaller than half of the previous value Such scenarios could occur if the test leads are disturbed during the continuous reading process for example In this case readings should also be ignored Bluetooth Indicator If a Bluetooth enabled PDA or PC is being used to log resistance data generated by the MILLER 400D the Bluetooth Indicator will be ON when a link has been established between the MILLER 400D and the PDA or PC Error Codes The following are the error codes that may be displayed on the LCD Ero Erl Detected an internal power supply failure Er2 Detected an internal communications failure when sending Er3 Detected an internal communications failure when receiving Er4 Detected a calibration error Should any of above codes be displayed please contact the M C Miller Company Page 17 of 38 SECTION 6 MAINTENANCE amp CALIBRATION Other than changing the batteries the MILLER 400D requires no maintenance The procedure to change the 5 D size alkaline batteries in the unit is as follows Unscrew both battery holder covers rotate covers clockwise to unscrew and remove the old batteries Install five 1 5Volt D size alkaline batteries po
18. ent location is calculated by the software and a station number is presented for the current Page 29 of 38 position based on the station number of the previous measurement location The starting station number if known is entered on the survey screen prior to logging the first reading see below Note A straight line will be assumed between any two GPS locations for the purposes of the calculations Also if the include altitude option is not selected it will be assumed that there is no altitude change between the two locations involved in a distance calculation And if the include altitude option is selected the accuracy of the altitude data will significantly impact the accuracy of a calculated distance between two locations Reading Interval feet or meters With this option the entered Reading Interval distance is added to the stationing each time a reading is logged for the case of Downstream surveys and the entered Reading Interval distance is subtracted from the stationing each time a reading is logged for the case of Upstream surveys This is an ideal selection if survey flags for example have been laid out ahead of the soil resistivity survey based on measured distances and soil resistance readings are to be taken at each flagged location say every 200 feet for example The starting station number if known is entered on the survey screen prior to logging the first reading see below Man
19. ge dropped between terminals P1 and P2 In general for a particular volume of soil sample or liquid as defined by the geometric constraints of the electrolyte box the sample s resistivity can be calculated from the resistance value displayed by the MILLER 400D using the following formula p RA L Page 10 of 38 where p is the resistivity in ohm cm R is the resistance in ohms A is the cross sectional area of the current electrodes in cm squared and L is the separation between the potential electrodes in cm Consequently the ratio A L represents a multiplication factor that needs to be applied to the resistance reading in order to obtain the sample s resistivity value Conveniently for both M C Miller soil boxes the A L ratio is exactly 1cm Consequently when M C Miller soil boxes are used the reading in ohms or kQ displayed on the MILLER 400D becomes the resistivity value in ohm cm or kO cm If the resistivity value is required to be expressed in ohm m rather than ohm cm the ohm cm value is divided by 100 For example a resistivity value of 2500 ohm cm would be equivalent to 25 ohm m 3 ELECTRODE APPLICATION The 3 Electrode Application can be used to measure the resistance to earth of a buried electrode such as a buried ground rod or a buried anode In this case two of the electrodes are pins driven into the earth and the third electrode is the test electrode itself for example a ground rod or an anode
20. harge is at a critically low level the unit will not perform a resistance measurement Consequently it is recommended that batteries be replaced when the battery indicator first lights up Noise Indicator Generally speaking readings taken by the MILLER 400D are not affected by external noise sources since the unit employs narrow band pass filters centered at 82 2Hz which makes interference from 50Hz 60Hz 100Hz or 120Hz signals for example highly unlikely However to guarantee accurate resistance measurements the MILLER 400D examines all signals appearing at its input terminals and the noise indicator alerts the user to specific issues as follows Page 16 of 38 Flashing On and Off presentation Indicates that the unit has detected a large voltage 7235V at its input terminals in front of the filter Should such large external sources appear across the input terminals the unit will disconnect itself Any displayed resistance values on the LCD should be ignored when the noise indicator is flashing On and Off Note Once the over voltage is removed the unit should be re started by momentarily depressing the Read button Steady ON presentation Indicates that the unit has detected external interference signals after the filter when its internal voltage source has been switched off This situation would imply that the resistance measurement is compromised and the reading should be ignored Also the Steady ON presentation of th
21. ired resistance value is manually logged in turn The window below shows the acquired resistance value 5 0Q and the calculated resistivity value 19 248 1Q cm for the 20 foot pin spacing example the first of 3 pin spacing readings Page 33 of 38 Pro CP Soil Resistivity Miller 400D is connected max File Miller 400 Help x Note all calculated readings are in ohm cm Location Curent Pin Spacing 5 Wi GPs 20 00 feet Grab Resistance Meter Value R Calculated Value P Value from Device 5 0 19248 1 Remarks v Known Station Survey Direction 1000 00 feet surveyed Delete Last 5 Qo MCM Survey The calculated resistivity value 19 248 1O cm in this example case is saved by clicking or tapping on the Log Reading button At that point the second prompt screen automatically appears as shown below and the resistance value acquired by clicking or tapping on the Grab Resistance Value from Device button or depressing the Read button on the Miller 400D will be displayed in the Meter Value field Page 34 of 38 IPro CP Soil Resistivity Miller 400D is connected JoE3 File Miller 400 Help Note all calculated readings are in ohm cm Location Current Pin Spacing 20 00 2 3 3 Wi ces 10 00 feet Grab Resistance Meter Value R Calculated Value P gt Value from Device 10 1 19347 4 Remarks Known Station Survey Direction 2000 00 feet surveyed Delete L
22. is important to enter a start station number that is sufficiently large so that the last data collection location on the survey still corresponds to a positive station number For the case of the Manually Entered Locations option it is not necessary to select the Survey Direction as only actual station numbers will be entered for each measurement location For this case the box labeled Known Station will be automatically checked as indicated on the above window since all locations will have known station numbers Page 32 of 38 The start station number should be entered if known and a reading acquired by clicking on the Grab Resistance Value from Device button on the survey screen Alternatively the Read button on the Miller 400D meter can be depressed after first placing the curser in the Meter Value field Note The reading acquisition time is approximately 5 seconds in either case The acquired resistance reading will appear in the Meter Value R field and the calculated resistivity value based on the pin spacing will appear in the Calculated Value p field All calculated resistivity values are in ohm cm units Enter any textual remarks in the Remarks field A resistivity value is saved by clicking or tapping on the Log Reading button Multiple Pin Spacing Readings In the case of multiple pin spacing readings each calculated resistivity value based on each successively acqu
23. ll allow the Bluetooth radio in the Miller 400D to switch OFF power saving mode after the LCD shuts down WARNING If the software disconnection process is not carried out within range of the Miller 400D the Bluetooth radio will remain ON even when the LCD automatically shuts down Page 23 of 38 Appendix 2 How to Use the ProCP Soil Resistivity Survey Program in Conjunction with the Miller 400D Resistance Meter The MILLER 400D is supplied with an over the pipe soil resistivity software program known as ProCP Soil Resistivity which is based on the 4 pin Wenner Methodology see Section 4 Earth Resistivity Measurement The program needs to be run on a Bluetooth enabled PDA or PC Also if a GPS receiver is integrated with the PDA or PC GPS location data are logged automatically at soil resistivity measurement sites After installing the program from the CD supplied with the Miller 400D either the PC version or the PDA version and opening the program the window shown below will be displayed iPro CP Soil Resistivity Miller 400D is Not connected EJ File Miller 400 Help New Survey File m Open Survey File As indicated on the header of the above window the Miller 400D 1s currently not connected via Bluetooth to the PDA or PC The Bluetooth connection is initiated and subsequently maintained by the software program ProCP Soil Resistivity using the following procedure
24. o remove the resistivity value s saved at the last site if readings need to be re taken for example Note If readings are to be re taken at the deleted site check the currently displayed station number and manually enter the station number of the current site do over site location if the currently displayed station number is not appropriate Saved resistivity values can be viewed via the Edit Data button and values can be edited also if necessary Page 36 of 38 Exporting Survey Data to Excel The soil resistivity data logged on a survey can be exported to Excel for future processing using the following procedure Note The export process can be performed while connected to or disconnected from the Miller 400D unit As indicated in the window below an Export to Excel option is available via the File menu Pro CP Soil Resistivity Miller 400D is connected m X a E File Miller 400 Help New i Note all calculated readings are in ohm cm Open Curent Pin Spacing 1 3 j 2000 fee E Meter Value R Calculated Value P Remarks C Known Station Survey Direction 2000 00 feet surveyed MCM Survey IMPORTANT FINAL STEP It is important at the completion of a survey to disconnect the software application from the Miller 400D unit while the PDA or PC is in range of the unit Note Disconnecting the Bluetooth connection will allow the Bluetooth radio in the Miller 400D
25. odes are driven down into the earth the same distance and are evenly spaced in a straight line A schematic of this arrangement is illustrated in Figure 1 below 4 ELECTRODE APPLICATION EARTH RESISTIVITY MEASUREMENT RESISTANCE Ohms Figure 1 The MILLER 400D can be used in conjunction with M C Miller s 4 lead color coded test reel catalog 44700 and four heavy duty stainless steel electrodes soil pins catalog 44720 The test leads are connected to the MILLER 400D as shown in Figure 1 With this arrangement the MILLER 400D displays the earth s average resistance to a depth equal to the electrode spacing S based on the magnitude of the current flowing Page 7 of 38 between terminals C1 and C2 and the voltage dropped between terminals P1 and P2 Note For load resistances gt 1MQ in addition to internal meter errors errors associated with test lead proximity can also be significant please see Appendix 3 for details Dr Frank Wenner of the U S Bureau of Standards developed the theory behind this test in 1915 1 He showed that if the electrode pin depth d is kept small relative to the separation between the electrodes S the earth s average resistivity to a depth equal to the electrode spacing S can be obtained by applying the following formula p 2naSsR where R is the resistance value in ohms as displayed on the MILLER 400D p is the resistivity in ohm cm az is the constant 3 1416 and S is
26. s may have to be repeated more than once for a Bluetooth connection to be established When a connection is established the window shown below will be displayed Page 21 of 38 Miller 400D Configuration Pro OE3 Miller 400D C Keep Bluetooth On After LCD Shuts Off C Always Calibrate Before Each Reading L High Resolution for LCD Display on Device 10 Number of Continuous Readings LCD Auto Shutoff In Minutes After Last Action Reading Changes to the power saving default settings can be made if necessary via the above window Also a reading can be initiated and the meter reading can be displayed on the above window either by clicking or tapping on the Display Resistance Reading button or by depressing the Read button on the Miller 400D The reading acquisition time is 3 5 seconds See the window below for an example Page 22 of 38 Miller 400D Configuration Pro 1 File Miller 400D C Keep Bluetooth On After LCD Shuts Off C Always Calibrate Before Each Reading L High Resolution for LCD Display on Device 10 Number of Continuous Readings LCD Auto Shutoff In Minutes After Last Action Reading Display Resistance Reading Finally click or tap on the Save Configuration button if any changes were made and then select the Disconnect option from the Miller 400D menu while in range of the Miller 400D Note Disconnecting the Bluetooth connection wi
27. sitive terminals facing out 3 batteries in one holder and 2 batteries in the other and replace the battery holder covers rotate covers counter clockwise With respect to calibration the MILLER 400D is self calibrating and the user can select to have the unit calibrate itself before every measurement or can select to have the unit self calibrate at his her request default setting If the latter selection is made the self calibration process is initiated by depressing the Read button for a period of 10 seconds When performing an auto self calibration the LCD will be as shown below Ah The Q symbol located at the bottom right hand corner of the LCD will flash ON and OFF during the calibration process and will stop flashing when the re calibration sequence is complete approximately a 10 second process The unit self calibrates after the batteries have been replaced Reference 1 F Wenner A Method of Measuring Earth Resistivity Bulletin of Bureau of Standards Report 258 Vol 12 No 3 Oct 11 1915 Page 18 of 38 Appendix 1 How to Change Settings Using the Miller 400D Configuration Program The Miller 400D Resistance Meter is supplied with factory settings default settings for a group of five parameters The five parameters are defined in the table below and their default values or settings are indicated Parameter Explanation of Parameter Default Value Set
28. the electrode separation in cm Typically the electrode pin spacing is not measured in centimeters but rather in feet in the U S or in meters in most other countries U S Example electrode spacing measured in feet Since there are 30 38 centimeters in 1 foot the above formula can be written as p Q cm 2r x 30 38 x electrode spacing in feet x R ohms or p Q cm 191 5 x electrode spacing in feet x R ohms So for example if the MILLER 400D displays a resistance value of 15 ohms for an electrode pin spacing of 20 feet the earth s average resistivity value to a depth of 20 feet would be p 191 5 x 20 x 15 57 450 ohm cm If the resistivity value is required to be expressed in ohm m rather than ohm cm the ohm cm value is divided by 100 In the above example the resistivity would be 574 5 ohm m Page 8 of 38 Metric Example electrode spacing measured in meters Since there are 100 centimeters in 1 meter the above formula can be written as p Q cm 22 x 100 x electrode spacing in meters x R ohms or p Q cm 628 32 x electrode spacing in meters x R ohms So for example if the MILLER 400D displays a resistance value of 15 ohms for an electrode pin spacing of 7 meters the earth s average resistivity value to a depth of 7 meters would be p 628 32 x 7x 15 65 973 6 ohm cm If the resistivity value is required to be expressed in ohm m rather than ohm cm the ohm cm value is divi
29. the test electrode of 0 62 x D where D is the distance between the electrode under test and the Current Electrode the resistance reading observed will correspond to the resistance to earth value for the electrode under test This particular configuration is illustrated in Figure 3 For example if the distance between the electrode under test and the Current Electrode is 100 feet the Potential Electrode should be positioned 62 feet from the electrode under test However again it is suggested that resistance versus distance plots be generated in each instance 2 ELECTRODE APPLICATION The 2 Electrode Application can be used to measure the resistance between two buried electrodes such as two ground rods or two anodes for example In this case the two electrodes are the two buried components Figure 5 below illustrates the measurement configuration Page 14 of 38 2 ELECTRODE APPLICATION RESISTANCE MEASUREMENT BETWEEN TWO ELECTRODES GROUND RODS or ANODES RESISTANCE Ohms Anode or Anode or Grounding Rod Grounding Rod Figure 5 As indicated in Figure 5 in this configuration jumper wires are connected between terminals C1 and P1 and between terminals C2 and P2 In addition test leads connect one of the electrodes to terminal C1 and the other electrode to terminal C2 Another configuration option which is recommended for use when measuring small resistances is to connect the potential terminals
30. ting Number of Continuous In the Continuous Reading Mode see Section 2 a Readings new reading is displayed every 3 seconds When 10 readings the selected number of readings have been taken Range of values 3 255 the process will self terminate readings Auto Shut Down In the Single Reading Mode see section 2 the Time LCD shuts down reading value is no longer 1 minute displayed after a set period of time in order to Range of Values 1 10 conserve power minutes Bluetooth Radio Setting In the default setting Bluetooth radio ON upon demand which is the power saving mode the Bluetooth Options Radio Always ON or Bluetooth radio is turned ON and OFF by the Radio ON Radio ON Upon Demand software applications either the Configuration Upon Program or the ProCP Soil Resistivity Program Demand Self Calibration Setting In the power saving default setting Calibrate on Demand the self calibration process is initiated by Options Calibrate on use of the Read button see Section 6 With the Self Calibrate Demand or Calibrate before other option a calibration process a 10 second om Demand each Reading Sequence event is initiated each time a reading is requested Single Reading Mode or at the start of each Continuous Reading Mode cycle Resolution Setting for R lt 1Q In the default setting the LCD will display the resistance value in the format 0 X XO With the LCD shows Options LCD shows 0 0012 other setting the display will be in the format 0
31. to switch OFF power saving mode after the LCD shuts down Page 37 of 38 WARNING If the software disconnection process is not carried out within range of the Miller 400D the Bluetooth radio will remain ON even when the LCD automatically shuts down Select the Disconnect option from the Miller 400D menu while in range of the Miller 400D Page 38 of 38 Appendix 3 Influence of Test Lead Proximity leads separate or bound together on the Accuracy of Resistance Readings as measured by an AC Resistance Meter Resistance Meter Miller 400D 4 Terminal Digital Resistance Meter Experimental Test Leads Four 12 feet long cables 16 AWG insulated wire Test Lead Configurations Case 1 test leads physically separate Case 2 test leads bound together via ties Resistance reading with Resistance reading with Test lead test leads separated test leads bound together proximity related from each other measurement error 7 3MQ 6 4MQ 12 3 4 7 MQ 4 4MQ 6 4 1 0MQ 996KQ 0 4 502KQ 501KQ 0 2 50 1KQ 50 1KQ Zero 5 06KQ 5 06KQ Zero 5 110 5 110 Zero For load resistances greater than 1 MQ in addition to internal meter errors errors associated with test lead proximity can also be significant as indicated above When test leads are in close physical contact with each other mutual capacitance and mutual inductance effects can impact the current and voltage respectively and hence
32. ually Entered Locations With this option the user enters a station number at each measurement location prior to logging each reading The starting station number is entered on the survey screen prior to logging the first reading see below Pin Spacing Field Any number of Pin Spacing values can be entered which means that any number of soil resistance readings can be taken at each measurement location for soil resistivity versus depth profiling purposes Enter a value for the first pin spacing in feet or meters in the field opposite the Add button and click or tap on the Add button This will place the pin spacing value into the Pin Spacing field Repeat this process for each of your pin spacing values Page 30 of 38 The window shown below indicates how the pin spacing values appear for the example case of 3 entered values 20 feet 10 feet and 5 feet Note Pin spacing values should be entered in the order in which the resistance readings are planned to be taken since the reading prompts will appear automatically in the same listed order see the Survey Screen section below Note Highlighted pin spacings can be removed from the Pin Spacing field using the Remove button f Pro CP Soil Resistivity Miller 400D is connected m X File Miller 400 Help Options Pin Spacing Pipeline Name vw be i m 5 Location Type Station iv C Use Metric Choose a Location method Calc
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