Biddle CFL510E_manual 电路图.pdf

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1、MEGGER CFL510E - TDR1000 Time Domain Reflectometer MEGGER User Guide Manuel Utilisateur Bedienungsanleitung Gua del usuario Guida per lutente Gebruikersgids Brugervejledning Kyttohjeet Brukerhndbok Anvndarmanual RadioFans.CN 收音机爱 好者资料库 Introduction6 User Controls and Display8 Operation10 Balance con

2、trol12 Velocity factor12 Pulse widths13 Techniques to improve accuracy14 Test and cable from both ends14 Care and maintenance14 Specification15 Repair and Warranty 18 MeterCenter (800) 230-6008 2 Contents RadioFans.CN 收音机爱 好者资料库 Symbols used on the instrument Caution: Refer to accompanying notes Equ

3、ipment protected throughout by Double or reinforced Insulation Instrument flash tested to 3.7 kV r.m.s. for 1 min. Equipment complies with current EU Directives 3 3.7 RadioFans.CN 收音机爱 好者资料库 SAFETY WARNINGS This instrument meets the safety requirements of IEC 61010 part 1 to 150V cat III. If it is t

4、o be used in situations where hazardous live voltages may be encountered then an additional blocking filter must be used. CAUTION (Risk of electric shock) Although this tester does not generate any hazardous voltages, circuits to which it can be connected could be dangerous due to electric shock haz

5、ard or due to arcing (initiated by short circuit). While every effort has been made by the manufacturer to reduce the hazard, the user must assume responsibility for ensuring his, or her, own safety. 4 The instrument should not be used if any part of it is damaged. Test leads, probes and crocodile c

6、lips must be in good order, clean and with no broken or cracked insulation. Check that all lead connections are correct before making a test. Disconnect the test leads before accessing the battery compartment. Refer to operating instructions for further explanation and precautions. Safety Warnings a

7、nd Precautions must be read and understood before the instrument is used. They must be observed during use. NOTE THE INSTRUMENTS MUST ONLY BE USED BY SUITABLY TRAINED AND COMPETENT PERSONS. 5 Thank you for purchasing this quality AVO product. Before using your new instrument please take the time to

8、read this user guide, ultimately this will save you time, advise you of any precautions you need to take and could prevent damage to yourself and the instrument. The MEGGER TDR1000 is an advanced instrument capable of identifying a wide range of cable faults. The instrument uses a technique called T

9、ime Domain Reflectometry (TDR) which in many ways is similar to radar. Narrow pulses of electrical energy are transmitted along a pair of conductors in a cable. The pulse travels through the cable at a velocity determined by the insulation between the conductors and this resistance to the flow of th

10、e pulse is characterised as impedance for the cable. Changes in cable impedance will cause a proportion of the pulse to be reflected. The pulse velocity is normally described as a fraction of the speed of light and is called the Velocity Factor. By measuring the time between the transmitted pulse an

11、d the reception of the reflected pulse, and multiplying this by the speed of light and the velocity factor, the actual distance to the reflection point can be given. Faulty cables, poor joints or discontinuities will all cause a change in impedance. Impedances higher than the cables cause a normal r

12、eflection; Impedances lower than the cables cause an inverse reflection. Matched terminations absorb all the pulse hence no reflection will occur, the cable appearing endless. Open or Short circuits will reflect all the pulse energy and the TDR will not see the cable beyond that fault. 6 Introductio

13、n As a pulse is transmitted down a cable, the size and shape of that pulse is gradually attenuated by losses in the cable: the pulse gets smaller in height and more spread out. The level of attenuation is determined by the cable type, the condition of the cable and any connections along its length.

14、The limit of how far you can see is determined by the point beyond which you will not discern a reflection. To maximise the instruments range, the TDR1000 has an adjustable gain setting on its input to allow you to discern a reflection from farther away. By combining this variable gain with increasi

15、ng pulse widths, the TDR1000 can discern faults up to 3 Km away. The MEGGER TDR1000 can be used on any cable consisting of at least two insulated metallic elements, one of which may be the armouring or screen of the cable. The TDR1000 has internal matching networks to allow testing of 25 , 50 , 75 a

16、nd 100 cables. (These correspond to power, coaxial data and data/telecoms cable). The instrument can be closely balanced to the cable using the balance control; this allows long lengths of cable to be easily tested. The velocity factor can be adjusted to match the cable, thus allowing an accurate di

17、stance measurement to be directly read from the instrument. To enable a wider range of faults to be detected, the gain of the instrument is adjustable; this allows more minor faults to be identified along the entire length of the cable. Other setting options include changing the distance units betwe

18、en metres and feet, changing the propagation velocity units between a ratio and a distance per microsecond. Display contrast is fully adjustable to compensate for all viewing conditions. A backlight aids viewing in low ambient light conditions. The batteries to power the instrument are housed in the

19、 compartment on the case back, the cover is held in place with two screws. The batteries are held in a carrier, which hold the batteries securely, and allow a quick change of rechargeable battery packs. The instrument can be powered by manganese-alkali, nickel-cadmium or nickel-metal-hydride batteri

20、es. All cells must be of the same type. 7 User Controls and Display: The controls of the TDR have been arranged such that the instrument is easy to use and easy to learn how to use. The instrument controls consist of the following: 1) Instrument Display: The display shows the user the current settin

21、gs of the instrument and the reflected energy trace from the cable connected. 2) Balance: This is an analogue control which allows the user to match the instrument impedance to that of the cable under test more closely, thus enabling faults to be more easily detected. 3) Cursor Left: This control mo

22、ves the cursor left or selects a lower value depending on which mode the instrument is in. 4) Menu: This control is a bi-directional switch and can be used to navigate around the various control options. The control option to be adjusted is shown in reverse video and its name is displayed in the top

23、 left-hand corner of the display. Menu options are cursor, range, VF, V unit, Zo the second is a short circuit at 2000m away. 11 CURSOR0.67R 3000m2000m100 CURSOR0.67R 3000m2000m100 Balance Control Without Balance Control (point 2 in the User Controls and Display section) the transmitted pulse would

24、be visible at the beginning of the trace, swamping any reflections within the pulse length (the dead zone). The balancing circuit attempts to match the characteristic impedance of the cable under test to produce an equivalent pulse. Subtracting this equivalent pulse from the transmitted pulse effect

25、ively removes the dead zone and allows cable features much closer in to be detected. NOTE: In many cases, it will be impossible to completely null the transmitted pulse. Velocity Factor The velocity factor is the scalar that is used to convert the measured time interval into an actual length of cabl

26、e. It can be displayed in one of two ways: a ratio of the transmitted pulse speed to the speed of light, or as a distance per microsecond. When it is displayed as the distance per s (either m/s or ft/s) the velocity factor will be indicated as half the speed of the pulse in the cable. This is becaus

27、e the pulse in fact has to go along the cable to the cable feature and back again which is twice the distance to the feature. If the exact length of a piece of cable of the same type as the C.U.T is known and the reflection from the cable end is visible then a more accurate value can be determined:

28、Locate the reflection caused by the end of the known length of cable with the instrument set on the shortest possible range to see the end of the cable. 12 Locate the start of this reflection as described in the Operation section of this manual. Adjust the velocity factor until the correct cable len

29、gth is shown. The measurement of the distance to the fault can now be made with more confidence that the measurement will be correct. The ability of the instrument to accurately measure the distance to a cable feature relies on the velocity factor being correct, any errors in the velocity factor are

30、 directly proportional to distance measurement errors. Pulse Widths The TDR1000 pulse widths range from 7 ns to 3 s to overcome signal attenuation and enable the instrument to see further down a length of cable. In distance terms for the size of the transmitted pulse, this represents a transmitted p

31、ulse from as small as 1.4m to 602m! (This assumes a velocity factor of 0.67.) Without Balance Control, this would be an enormous dead zone, but with the instrument correctly balanced, faults can be seen well within the pulse width. As the measured distance is taken at the start of the reflected puls

32、e, the size of the pulse width does not affect the accuracy of the measurement. However, if the first feature does not give a complete reflection such that the instrument can see beyond it to a second feature, the ability to discern between features is affected by the pulse widths. If there are mult

33、iple features, the instrument can only fully discern between them if the features are more than the pulse width apart. Hence, for discerning multiple features, the instrument should be used with the shortest range, and so smallest pulse width, that can see both features (refer to the pulse width tab

34、le in the specification). 13 Techniques to improve accuracy To improve on the accuracy of the measurement, numerous methods can be used, depending on the situation encountered. Not every situation can be described, but the following points are effective and the most common and easily implemented met

35、hods. Test the cable from both ends When fault finding a cable it is good practice to test the cable form both ends. Particularly in the case of open circuit faults, the true end of the cable is not visible. Thus, it is harder to estimate whether the answer obtained is realistic. If the measurement

36、is made from both ends, then the combined answer should add up to the expected length of the cable. Even in the case when the true end of the cable is still visible, the reflections after the fault may be too obscure to analyse clearly. In this case, measurement from both ends yields a clearer pictu

37、re as well as improved accuracy. It is also good practice to follow the cable route with a cable tracer, as not all cable runs will be straight. It can save a great deal of time if the exact route of the cable is known as faults will usually be found at points were human intervention has occurred, j

38、unction boxes splices etc. Care and Maintenance Other than replacing the batteries, the instrument has no user serviceable parts. In case of failure it should be returned to your supplier or an approved AVO INTERNATIONAL repair agent. Cleaning the instrument should only be done by wiping with a clea

39、n cloth dampened with soapy water or Isopropyl Alcohol (IPA). 14 Specificaton Except where otherwise stated, this specification applies at an ambient temperature of 20C. General Ranges:10m, 30m, 100m, 300m, 1000m, 3000m (30ft, 90ft, 300ft, 900ft, 3000ft, 9000ft) Accuracy:1% of range pixel at 0.67 VF

40、 Note- The measurement accuracy is for the indicated cursor position only and is conditional on the velocity factor being correct. Resolution:1% of range. Input Protection:The inputs will withstand 150 V d.c. or 150 V a.c. up to 500 Hz. Output pulse:5 volts peak to peak into open circuit. Pulse widt

41、hs determined by range and cable impedance: 255075100 10m7 - 40ns*7ns7ns7ns 30m30 - 50ns*20ns20ns30ns 100m100ns60ns100ns100ns 300m300ns130ns170ns300ns 1000m1000ns520ns680ns1000ns 3000m3000ns2020ns2340ns3000ns*Varied by the gain setting 15 Gain:Set for each range with four user selectable steps. Velo

42、city Factor:Variable from 0.30 to 0.99 in steps of 0.01 Output impedance: User selectable between 25 , 50 , 75 , 100 Balance Adjustment: 0 to 120 Update Rate:Once a second for 5 minutes after last key press. Power Down:Automatic after 5 minutes with no key press. Backlight:Stays on for 1 minute when

43、 activated. Batteries:Six LR6 (AA) type batteries, Manganese- alkali or nickel-cadmium or nickel-metal- hydride cells Nominal voltage: 9V for Alkali of 7.2 V for NiCad. Low battery warning occurs at 6.5 V Battery consumption 100 mA nominal, 140 mA with backlight (20/30 hours continuous use depending

44、 on backlight dependency) Safety:This instrument meets the safety requirements of IEC 61010 part 1 to 150 V cat III. If it is to be used in situations where hazardous live voltages may be encountered then an additional blocking filter must be used. 16 EMC:Complies with Electromagnetic Compatibility

45、Specifications (Light industrial) BS/EN50081-1-1992 BS/EN50082-1-1992 Mechanical:The instrument is designed for use indoors or outdoors and is rated to IP54. Case Dimensions:230 mm long (9 inches) 115 mm wide(4.5 inches) 48 mm deep(2 inches) Instrument weight 0.6kg (1.32lbs) Case material:ABS Connec

46、tors:Two 4mm-safety terminals. Lead:2 metres Display:128 x 64 pixel Graphics LCD. Environmental Operational Temperature: -15C to +50C (5F to 122F) Operational Humidity:95% at 40C (104F) Storage Temperature:-20C to 70C (-4F to158F) Included Accessories Test it shows visible damage; fails to perform t

47、he intended measurements; has been subjected to prolonged storage under unfavourable conditions, or has been subjected to severe transport stresses. NEW INSTRUMENTS ARE GUARANTEED FOR 3 YEARS FROM THE DATE OF PURCHASE BY THE USER. NOTE:Any unauthorized prior repair or adjustment will automatically i

48、nvalidate the Warranty. INSTRUMENT REPAIR AND SPARE PARTS For service requirements for MEGGER Instruments contact: AVO INTERNATIONALorAVO INTERNATIONAL Archcliffe RoadValley Forge Dover Kent, CT17 9EN Corporate Center England2621 Van Buren Avenue Tel: +44 (0) 1304 502243Norristown, PA 19403 Fax: +44

49、 (0) 1304 207342U.S.A. Tel: +1 (610) 676-8579 Fax: +1 (610) 643-8625 Or an approved repair company. Approved Repair Companies A number of independent instrument repair companies have been authorised for repair work on most MEGGER instruments, using genuine MEGGER spare parts. Consult the Appointed Distributor/Agent regarding spare parts, repair facilities, and advice on the best course of action to take. 18 MeterCenter 825 West Queen Creek Road, Suite 2118 - Chandler, AZ 85248 Telephone: (800) 230-6008 Fax: (480) 659-8361 Email: