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3M

 Advanced Systems Tester 900AST Series

41

Differential and Crosstalk

Use the Differential mode to display only the 

difference between two circuits (usually a ‘good’ 

circuit and a circuit under test).

Use the Crosstalk mode to display the amplitude and 

location of signals that “cross” from one conductor 

to the other. This could be caused by two wires with 

high frequency signals running together for long 

distances and coupling their electrical signals.

For both Differential and Crosstalk, connect the 

Red/Black TDR test leads to the circuit under test 

and connect the Blue/Yellow TDR test leads to the 

reference circuit.

Содержание 900AST Series

Страница 1: ...Advanced Systems Tester 900AST Series Instruction Manual March 2005 78 8135 2559 5 E ...

Страница 2: ......

Страница 3: ...t Edit Custom Cable 9 Controls Contrast Backlight 15 Help 15 High Voltage 16 Functions Voltage 17 Load Test 18 Resistance 19 Soak Test 20 Contact Resistance 21 Toolbox 22 Self Calibration 23 Stored Results 24 Special Resistance 27 Ohms Distance 28 Capacitance 29 Tone 30 Resistance Fault Locate RFL 32 TDR 37 Auto TDR 51 Care and Maintenance 56 Specifications 59 Warranty Information 60 ...

Страница 4: ...holds six AA standard alkaline batteries and should be installed prior to using the unit Please see the Care and Maintenance section for battery installation instructions Always initiate a self calibration see Toolbox Self Calibrate for instructions after installing new batteries The 900AST tester comes with two types of test leads five single conductor test leads red black green yellow and blue fo...

Страница 5: ... format is similar to the following for most functions Test Leads The test lead icons are shown on each of the measurement screens Each lead points to a color dot on the front label that corresponds to the actual test lead and test jack to be used For TDR applications using the special coaxial TDR test lead s the test lead icons indicate which test jacks also denoted by colors to use ...

Страница 6: ... 900AST Series 6 Keypad The 900AST tester keypad has twelve yellow and red Control Keys and nine blue Function Keys Additional blue keys on the keypad are reserved for future expansion and have no designation or current function ...

Страница 7: ...Down Timeout Use the Tab key to select between different options Use the Setup key to change the setup of a function Use the Help key to get context sensitive help with any screen or function Use the Enter key to accept changes or move to the next step in a function Use the Up and Down keys to scroll to different menu options or insert delete characters when editing Use the Left and Right keys to ...

Страница 8: ...oak Test and Contact Resistance functions Use the Toolbox key to access Self Calibration Stored Results Special Resistance and the Ohms to Distance Calculator Use the Capacitance key to measure the capacitance of a component or circuit Use the Tone key to send interrupted tone for circuit identification Use the RFL key to find the distance to a resistance fault between two conductors or a conducto...

Страница 9: ... upper right hand corner of the display gives an indication of the approximate battery capacity Each bar represents one quarter of the full capacity Press to go to the general Setup screen from the Welcome screen System Setup Use the and keys to highlight a menu item units clock format set clock set beep power down timeout or edit create custom cables Press the key to select the highlighted item U...

Страница 10: ...fects all distances displayed in the 900AST tester Degrees Fahrenheit or Centigrade This affects all temperatures used or displayed in the tester TDR Vp Velocity of Propagation or m µs Meters per Microsecond This affects the conductor velocity factor used by the TDR function Vp is normally represented as a fraction of the speed of light and has a value less than one Use the key to accept any chang...

Страница 11: ...rameter Date m d y month day year or d m y day month year The m d y format is used in the US and Canada The d m y format is used in most other countries Time 12 hours or 24 hours This affects the number of hours displayed in the clock The 12 hour clock with a m and p m is used in the US and Canada The 24 hour clock format is used in military services and most other countries Use to accept the chan...

Страница 12: ...m Use the and keys to select the digit to change Use the Blue keys to enter the values Use the and keys to select a m or p m Use to accept the changes and return Press to return to the Welcome Screen without making changes Set Beep Use the Set Beep setup to turn the key beeps on or off Use the key to toggle between on or off Use the key to return ...

Страница 13: ...o set that period as the default After a period of inactivity equal to the default period the unit will beep then automatically power down to preserve battery life Edit Custom Cable This function allows you to create custom cable types for specific applications Select one of the six available customizable cables Custom 1 through Custom 6 to edit Use the key to move between temperature resistance v...

Страница 14: ...urteen characters and digits The label only appears on this screen To use one of the custom cables in an application RFL TDR select the desired cable Custom 1 through Custom 6 in the wire gauge menu of the application Note Velocity of Propagation Vp is the rate at which electrical signals travel through a conductor Vp is expressed as a fraction of the speed of light so it is always less than 1 Met...

Страница 15: ...nd keys to adjust the contrast Press the key again to turn the backlight on or off Please note that use of the backlight decreases available battery capacity Use the key to return Help Press the key at any time on any screen to get context sensitive help with the present function Press the key to return to the previous screen ...

Страница 16: ...ter has been detected between the test leads when the 900 AST tester is not in the Voltage Mode The 900AST tester has opened an internal relay to protect itself from damage Use standard customer safety practices for disconnecting the test leads since a high voltage is present Press the key to restart the 900AST tester ...

Страница 17: ...DC or AC voltage between the Red and Black test leads The readings are live and will vary with the voltage being measured The 900AST tester initially measures DC voltage Press the key to switch from DC to AC voltage measurement Press the key again to switch back from the AC to the DC voltage measurement ...

Страница 18: ...the load as well as a bar graph representing the approximate level of load lamp illumination If the current in the load is greater than 110 mA the following Current Warning screen is displayed This screen indicates that a high current has been detected between the test leads and that the 900AST tester has opened an internal relay to protect itself from damage Use standard safety practices for disc...

Страница 19: ...nt is compensating for any foreign voltage on the line Press the key to remove the voltage compensation Use this mode only if you have first determined there is no DC voltage on the conductor by using the Voltage function The non compensated measurement is slightly faster but it is not as accurate if there is voltage on the conductor The resistance measurement can be affected by moisture on the te...

Страница 20: ...ecting time varying faults such as corrosive bridges Press the key to access the Soak test from the Resistance screen Connect the Red lead to the conductor under test and the Black lead to the fault reference usually ground Use the key to save the active resistance to the Snap Shot area This measurement will not be accurate if there is foreign voltage on the conductor Use the key to return to the ...

Страница 21: ...one side of the circuit and the Green and Yellow test leads to the other side Press the key when you are ready to measure The Contact Resistance measurement may take a few seconds to settle and display a result This measurement is not continuous To retest press the key again If the Contact Resistance is greater than 5 ohms the test returns immediately with an over range indicator Check all test le...

Страница 22: ... menu contains a selection of special functions Use the and keys to move to a desired function then press the key to accept the choice Note The last item in the Toolbox menu Maintenance is reserved for use only during Factory setup and service of the 900AST tester ...

Страница 23: ...ch it will be used Note Initiate a self calibration prior to the very first use of your 900AST tester You will see the following screen as soon as you select Self Calibration from the Toolbox Short the test leads together then press to continue The screen shows Self Calibration Complete when the calibration is done or Self Calibration Failed if the calibration fails In this last case check the tes...

Страница 24: ...n stored No Results Stored will be visible on the screen If one or more sets of test results have been stored the ID number for each will be displayed Use the and keys to highlight the desired stored record Press the key to select the highlighted record and display the stored results list for that record number by type date and time ...

Страница 25: ...s 25 Display Results Use the and keys to highlight the desired stored result Press the key to view the data for the highlighted selection Use the key to delete the selected result Use the key to upload the selected stored test result to a PC ...

Страница 26: ...ress the key to upload all of the saved results Press the key to upload the results of the selected ID Press the key to return to the main Results screen Uploading the test results to a PC requires an IR adapter see Care and Maintenance Both USB and serial ports are supported The 3M communications software package PC Link_900AST is also required Contact the 3M Repair Center at 800 426 8688 Option ...

Страница 27: ...fference in resistance between the two conductors Connect the Red lead to one conductor of the pair and the Green lead to the other conductor Connect the Black lead to a reference wire Note that the reference wire can be a separate wire ground or the shield of the cable Short the other end of the two conductors to each other and to the reference wire Press the key to start the test After the 900AS...

Страница 28: ...ypad and then press the key to select gauge or temperature If you select gauge press the and keys to select the desired gauge If you select temperature enter the value of the desired temperature using the keypad Press when you are ready to convert from Ohms to Distance The screen shows the total conductor length and half the length if you are measuring the distance to the end of a shorted pair Pre...

Страница 29: ...s function measures the capacitance of a circuit or component Connect the Red lead to one side of the circuit and the Black lead to the other side The capacitance is measured continuously If the capacitance cannot be measured the display indicates Press to exit ...

Страница 30: ...on using a tone probe not supplied with the 900AST tester Connect the Red and Black test leads to the conductors under test Press to start sending the ID tone The volume of the tone heard in the 900AST tester speaker may be adjusted Press the and keys to adjust the volume Use to stop sending Note The volume control does not affect the level of the tone sent on the circuit ...

Страница 31: ...ystems Tester 900AST Series 31 Press the key from the Tone screen to change the ID tone Use the keypad to change the frequency The frequency range is 200 to 1000 Hz The output level is fixed at 8 volts peak to peak ...

Страница 32: ...separate good pair of conductors with no faults in the same cable If you prefer you can run a pair of wires to the end of the faulted wire to serve as the separate good pair Once you identify the wires short Strap the far end of the faulted conductor to the two conductors of the separate good pair Press the key The hookup screen will show the last selected wire gauge and temperature Use the key to...

Страница 33: ...nce The reference is the return path for the fault and can be the shield or another wire in the cable Connect the Green and Yellow test leads to the separate good pair Press the key after you make the above connections If no errors in the hook up are detected the 900AST tester will begin the measurement and go to the results screen During the measurement a bar graph of the measurement null voltage...

Страница 34: ...re gauge and temperature are displayed above the bottom bar If the Yield Sign shows beside the results this indicates a possible marginal result due to noise or other external conditions Press to show readings in Ohms instead of distance Press again to return to distance Press to repeat the fault locate on the same conductor s or the key to test a new circuit Press to change the Gauge or Temperatu...

Страница 35: ...ssing or bad 4 The Yellow strap connection is missing or bad The screen will show the combination of errors that have been detected In the case shown above the Yellow lead is not connected Correct the errors and press the key to repeat the hookup test RFL Setup Use RFL Setup to change wire gauge and or the temperature or to enter a known Distance to Strap length Press the key to display the curren...

Страница 36: ...n without saving the changes Press the key again to return to the hookup screen Other RFL Errors If the RFL measurement terminates due to a time out a Yield Sign will be displayed next to the DSTF or RSTF This indicates that the results may not be accurate This could be caused by excessive noise on the circuit If the temperature is known and the specified conductor length is greater than the measu...

Страница 37: ...zation of the coaxial TDR leads to the target environment The TDR test leads plug into the Red Black and Blue Yellow test jacks on the 900AST tester depending on the desired operation TDR Setup The TDR features a setup function that allows you to enter input about the electrical properties of the target conductor or circuit From the TDR Menu press the key to enter the TDR Setup Press the to move b...

Страница 38: ...DR Use Single Trace to view a single conductor or circuit Use Dual Trace to view two separate conductors or circuits at the same time Use Differential to view the difference between two conductors or circuits Use Crosstalk to view the electrical coupling between two conductors or circuits Use Memory to compare a live trace with a trace stored in memory Use Peak to display a history of maximum and ...

Страница 39: ...being tested connect the other TDR test lead to another de energized conductor near the conductor under test TDR pulses occur at such a high frequency that an adjacent conductor can serve effectively as a return for the pulse Ground or cable shield can also be used for the return if desired but this often results in a very noisy trace and is not recommended If a pair of conductors is being tested ...

Страница 40: ...nd Yellow jacks to the reference circuit The circuit under test is displayed at the top of the screen The reference circuit is displayed at the bottom of the screen Any changes in the control parameters affect both traces It is not possible to control each trace independently Dual Trace is used to compare two circuits at the same time usually a faulted and a good circuit ...

Страница 41: ...rosstalk mode to display the amplitude and location of signals that cross from one conductor to the other This could be caused by two wires with high frequency signals running together for long distances and coupling their electrical signals For both Differential and Crosstalk connect the Red Black TDR test leads to the circuit under test and connect the Blue Yellow TDR test leads to the reference...

Страница 42: ... to a stored trace in memory The first screen in memory mode will show a list of the ID numbers for all stored TDR traces Use the and keys to highlight the desired stored result Press the key to select the highlighted result and display the stored results list for that ID number by type TDR date and time You can delete individual stored results by pressing the key ...

Страница 43: ...using the and keys The control settings for the stored trace can be viewed by pressing the or keys but the settings cannot be changed The TDR Memory function includes a Difference Diff control accessible from the memory screen by pressing the key The default is Difference Control OFF Use the or arrow key to turn the Difference Control ON Diff combines the live trace with the stored trace to show t...

Страница 44: ...displays the maximum and minimum traces that occur from the time that the mode is first selected The live trace is also displayed continuously As a new maximum or minimum trace is detected it will replace the previous one on the display If the circuit being tested is stable no intermittent faults then the minimum maximum and live traces should appear as a single trace If any of the control values ...

Страница 45: ...om the left side of the screen to the right side The left side of the screen is at the end of the test leads and the right side is the farthest distance that can be displayed with the selected length Note The length ranges are nominal and based on a Vp of 0 67 If you change the Vp or select a conductor type that has a Vp other than 0 67 the distance indicator at the right side of the display will ...

Страница 46: ...y is shown in the left side box at the top of the TDR screen Pulse Width 3 ns 5 ns 34 ns Pulse Width allows you to select the width of the pulse sent out on the circuit The 900AST tester automatically chooses the best pulse width for each length selected Note that you can change the pulse width independent of the length Use a shorter pulse width to give better resolution of events A shorter pulse ...

Страница 47: ... it contacts the target circuit under test The Start and Stop numbers shown in the distance bar are the distances represented at the left and right side of the screen If you move the cursor to the right side of the screen the screen will pan to the right If you move the cursor to the left side of the screen and the start distance is greater than 0 feet the screen will pan to the left If the cursor...

Страница 48: ...initial event caused by the 100 ohm TDR launch circuit contacting the target can usually be ignored Remember that distance zero 0 begins at the end of the test leads for the TDR function Open Circuit Any open circuit will show up as a peak on the screen A complete open will be the tallest peak you will see You cannot see events past a complete open A partial open circuit caused by situations such ...

Страница 49: ...hort the lower the dip Bridge Tap A bridge tap is a wire that has one or more wires branching off of the main wire The beginning of the bridge tap will look like a resistance fault and an open A dip followed by a peak The distance between the two events is the length of the bridge tap The start of a bridge tap looks like a resistance fault Use the 900AST tester Resistance function to measure the r...

Страница 50: ...e date and time Use the blue keys to enter an alphanumeric ID The ID may have up to twelve digits Because there are not enough keys for all twenty six letters each of the number keys except 1 also functions as letter keys for ID entry Whether a number or letter is entered depends on how many times the key is pressed As an example if the Ohms key is pressed once the number 3 will be displayed If th...

Страница 51: ...te any of the characters that have been entered use the or key to move the cursor under the letter to be changed or deleted To delete the character press the key To change the character press the key of the new character once for a number or several times for a letter Once the ID has been entered press the key to save the current TDR trace information Auto TDR Use the Auto TDR function to have the...

Страница 52: ... in the Auto TDR Setup To change the Vp of a given wire type use the TDR Setup Use the key to accept any changes and return Use the key to return to the Auto TDR screen without making changes When the correct information is displayed on the Auto TDR screen press the key to start the analysis The 900AST performs DC parametric tests to determine if the conductor or cable is shorted open circuited or...

Страница 53: ... captured trace The trace is not live as in the standard TDR mode Changes made to the circuit after the Auto TDR analysis starts will not be detected or displayed Vp can be adjusted while in this mode by using the and keys If the Auto TDR detects an open circuit the cursor is positioned at the location of the open circuit and OPEN is displayed below the trace If the Auto TDR detects a short circui...

Страница 54: ... was no fault found in the selected length If further analysis is needed enter a longer length and retest If multiple events are detected the Auto TDR places the cursor at the most significant event and attempts to classify it Light cursor marks are placed at less significant event locations In the example below the Auto TDR correctly locates an open circuit at the end of the cable Press the key to ...

Страница 55: ...3M Advanced Systems Tester 900AST Series 55 In this case the low impedance anomaly at 24 inches is detected but not classified The Auto TDR displays below the trace ...

Страница 56: ... the pack per the orientation embossed on the battery holder WARNING Do not reverse any batteries or install improperly in pack 4 Reattach the battery holder plug and insert the battery holder in the compartment 5 Replace the battery compartment door and retighten screws Caution Batteries may explode leak or catch fire if exposed to high temperatures or fire Recycle or dispose of properly To preve...

Страница 57: ...The Blue Yellow lead pair is used for RFL and Contact Resistance The coaxial test leads are used only for TDR Keep the test leads clean and dry at all times to insure best accuracy of the measurements Use soap and water to clean them if necessary Replacement Items You may order any of the following replacement items from 3M Contact 3M customer service at 800 426 8688 for more information Accessory...

Страница 58: ...ad broken Improper connections Replace test lead See on screen hookups Resistance 999 MOhm with test leads open Test leads dirty Clean test leads Error messages during Self Calibration Test leads not shorted properly when prompted Test leads broken Check connections Check test leads If the above solutions do not fix the problem the 900AST tester may need repair Please make a note of the conditions...

Страница 59: ...h foreign voltage 0 to 9999 Ω 1 50 Ω 10 K to 99 9 KΩ 1 100 KΩ to 999 KΩ 3 1 M to 9 9 MΩ 3 10 M to 99 MΩ 5 100 M to 990 MΩ 10 Contact Resistance 0 to 5 Ω 0 1 0 01 Ω Special Resistance 0 to 25 Ω 1 of Loop Resistance 0 01 Ω Capacitance 10 nF to 9 9 uF 10 ID Tone 200 to 1000 Hz 1 Hz fixed level interrupted RFL Fault range 0 to 5 MΩ 0 to 500 ΚΩ for specified accuracy Resistance to fault 0 to 15 Ω 0 1 o...

Страница 60: ...current publications or any contrary statements contained on your purchase order shall have no force or effect unless expressly agreed upon in writing by an authorized officer of 3M Warranty Limited Remedy Limited Liability This product will be free from defects in material and manu facture for a period of one 1 year from the time of pur chase 3M MAKES NO OTHER WARRANTIES INCLUDING BUT NOT LIMITED...

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