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Using the EEDM504D DVOM

Using the EEDM504D DVOM. DVOM stands for:. D IGITAL V OLT O HM M ETER. DVOM – DMM - Multimeter. A DVOM can also be called a digital multi-meter DMM stands for: D igital M ulti M eter The term Multimeter may also be used. Other functions.

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Using the EEDM504D DVOM

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  1. Using the EEDM504D DVOM

  2. DVOM stands for: • DIGITAL • VOLT • OHM • METER

  3. DVOM – DMM - Multimeter • A DVOM can also be called a digital multi-meter • DMM stands for: • Digital • Multi • Meter • The term Multimeter may also be used

  4. Other functions • Besides measuring volts and ohms most DVOMS can also measure : • Amps • Frequency • Duty cycle • Both AC and DC voltage and Amperage can be measured • The EEDM504D DVOM in your toolset can also measure capacitance

  5. Analog meters • Analog meters display electrical measurements using semi-circular dials and needles • Analog meters are not as accurate as DVOM and are harder to read • Due to the low impedance of Analog meters some electronic circuits can be damaged if the meter is used incorrectly • Analog meters are obsolete and rarely used in automotive diagnostic applications

  6. Digital meters • Digital meters display electrical measurements as numbers on a LCD screen • Digital measurements are more accurate than analog and are much easier to read • The high impedance of the meter makes it safe to use on delicate electronic circuits • Features such as ‘Hold’ and ‘Min / Max’ are only available on digital type meters

  7. All DVOMs are sold with a minimum of two test leads - one red and one black Test Leads • The two colors help prevent confusion as to which lead is connected to the terminal sockets • There is no electrical difference between the two color leads

  8. Test leads • The end of the lead is called a probe • The tip of the probe is very sharp so that it can penetrate through any corrosion that may be present at the point in the circuit being tested

  9. The test leads that come with the EEDM504D are CAT II certified for voltages up to 1000Vdc CATII Test Leads • The EEDM504D meter with the supplied test leads should be safe for testing the high voltage electrical systems on hybrid and battery electric vehicles

  10. CAT III rating • This means that the meter is safe to use in high voltage applications such as testing terminal voltage on the battery array of a hybrid vehicle • The test leads used with the DVOM are rated CAT II • The EEDM504D DVOM is rated as CAT III multimeter • The ISO symbol shown here means ‘Danger – High Voltage’ • It serves as a reminder to the technician that there is the potential for electric shock when working with high voltage equipment

  11. ‘Banana’ plugs type jacks • Most DVOMs use sheathed female ‘banana’ type plug sockets to connect the test leads to the meter • This type of socket is found on most DVOM • There are a wide variety of test leads and adapters that will plug right into the DVOM that can be purchased at parts stores or via the internet

  12. Sheathed ‘Banana’ plugs • The ends of the test leads that connect to the DVOM are called ‘banana’ plugs • Sheathed banana plugs protect the technician from electric shock when working on high voltage systems • Unsheathed banana plugs should only be used when working on low voltage system [normal automotive service] Unsheathed Sheathed

  13. Probe tip sleeves • The EEDM504D comes with protector sleeves screwed onto the probe tips • The sleeve prevents accidental shocks from contact with the probe tip • They can be removed when working on low voltage systems

  14. Alligator clips • Two booted alligator clip adapters are included with the meter • The alligator clip adapters screw onto the threads at the probe tips

  15. Alligator clip test leads • Test leads with alligator clip ends are more useful – especially for the ground lead • They can be easily clipped to a jumper wire or paper clip that is in contact with the electrical terminal • They allow the technician to make measurements with one or both hands free … this is especially useful when it is necessary to goose the throttle or toggle a switch while observing voltage, current etc.

  16. Homemade custom test leads • Banana plugs can be purchased at Radio Shack or through the internet • You can easily make your own custom test leads using wire and terminal ends scavenged from old electrical chords and junk found around the shop • This ground clamp test lead was made from the power cord of an old 12 volt drop light

  17. Modular test leads • Modular test leads have a sheathed banana plug at both ends • Different types of probes or clamps may be attached to the lead wire without removing the entire lead wire from the meter

  18. Modular test leads • A wide range of test lead ends are available through parts stores and the internet Insulation piercing adapter Large alligator clip Terminal back probe adapter Standard probe tip Wire end clamping adapter

  19. Back probing electrical connectors • Nearly all the connectors on modern automotive electrical systems are sealed to prevent corrosion at the copper electrical connections • Since there are no exposed places to make an electrical connection for testing a thin metal pin is inserted into the back side of the electrical connector until contact with the copper terminal is made Rubber gasket

  20. Back probing electrical terminals • An inexpensive method of back probing is to insert a paper clip between the wire and rubber gasket that seals the electrical connector • Filing or grinding down the end of the paper clip can make it easier to insert

  21. Back probing electrical terminals • Inexpensive back probe adapters are available for modular test leads that are faster and easier to use than paper clips

  22. Meter Display Screen • The EEDM504D uses a segmented LCD [liquid crystal] screen to display measurements • When the DVOM is first turned on all segments will appear for about 3 seconds • Each time you use the meter you should check to see if all segments are visable

  23. Low Battery Warning • If this symbol is displayed in the upper left corner of the display after the meter has gone through the 3 second LCD display check, the batteries are low and need to be replaced • The meter uses two ‘AAA’ batteries • Do not use NiMh rechargeable batteries – these batteries have a rapid self discharge rate and need charging every month • A set of AAA batteries should last a year or more in normal use • The batteries are accessible by loosening the three #1 Philips screws on the rear cover

  24. Bar graph display • The horizontal graph at the bottom of the display is used to graphically display electrical measurements • When the digits on the display are changing rapidly it is impossible to make any sense of what is happening • The back and forth movement of the graph makes it easy to see the upper and lower limits of the changes

  25. Bar graph display Display Value = 40 • As the value rises additional lines appear on the right side of the graph • When the measured value exceeds 4xxx all of the lines except the first 4 will clear • This allows the bar graph to display more data without being too difficult to read Display Value = 41

  26. Auto – ranging turned on • By default the meter is set to auto ranging • Auto ranging automatically moves the decimal point and display values to the left or right to make the measured value as accurate as possible • When the measured voltage changes from above 10 volts to a level less than 10 volts but more than 1 volt the decimal point moves one position to the left Auto ranging turned on

  27. Auto – ranging turned off • Auto-ranging is turned off by pushing the ‘Range’ button until the decimal point is in the desired location • Auto ranging eliminates the leading zeros so that there is more room for less significant data to the right of the decimal point Auto ranging turned on

  28. Returning back to Auto-Ranging mode • Depress the ‘Range’ button for two seconds until ‘AUTO’ appears on the left side of the display • Auto-ranging is not available in all test modes

  29. Over Limit warning • When the DVOM is set to manual ranging the letters ‘OL’ will appear on the screen if the unit measured is greater than the range currently selected • Testing a voltage that exceeds the range will not damage the DVOM

  30. APO Mode • The APO [Auto Power Off] Mode powers down the display circuit when there has not been any activity for 15 minutes or more • If you are monitoring a circuit for more than 15 minutes you can override the APA mode by pressing the REC button to set the meter to record mode • The APO function is disabled in record mode • Depress and hold the REC button for 3 seconds to exit the APO mode

  31. APO resume • When the DVOM turns itself off after 15 minutes you must turn the function selector to ‘Off’ and then back to any function to resume using the meter

  32. REC mode [MIN / MAX] When in REC mode ‘APO’ is no longer displayed • The REC mode lets you monitor maximum and minimum values over an extended period of time • The REC mode can be used to monitor voltage, amperage and resistance • Only MAX or MIN values can be viewed in REC mode – the current [live] value is not displayed

  33. Delta mode • The relative difference mode [Delta] is used when you want to no the difference between two measurements Battery #1 reference voltage • Connect the test leads to the circuit you want to measure then press the ‘REL’ button

  34. The value that was being measured when the ‘REL’ button was pressed is now held in the meters memory Delta mode • The readings on the display are now the difference between the current measurement and the measurement held in memory Battery #2 Battery #1 reference voltage

  35. Delta mode • When the Delta symbol is displayed on the screen there is a value stored in memory • The reading on the screen is the difference between the recorded value and the currently measured value • The delta function can be used with voltage, amperage and resistance

  36. Function selector knob • The rotary function selector knob allows the technician to select the type of electrical measurement to be made

  37. Function modifier buttons • Additional buttons are arrayed below the LCD screen to change the display type, select alternative functions and to turn some features on and off

  38. ‘Com’ socket • The black test lead is connected to the ‘COM’ socket for all test modes

  39. ‘Volt/Ohm /Hz’ socket • The red test lead is connected to the ‘Volt/Ohm/Hz’ socket • The red lead should be connected to this socket when measuring: • Voltage • Resistance [Ohms] • Frequency [Hz] • Diode test

  40. 10A Socket • The red test lead is connected to the ‘10a’ socket when measuring amperage [without an amp clamp] • Make sure you remove the red lead from the ‘10a’ socket after testing amps • If the lead remains in the ‘10a’ socket when you try to measure volts the internal fuse will be blown and the meter may be damaged !!!!!

  41. MilliAmp / MicroAmp Socket • The socket labeled mAA is used when testing very low circuit amperage – less than .5 amps • You will probably never use this function

  42. Lead connections for voltage measurement • For AC and DC voltage testing the black test lead is connected to the COM socket and red test lead is connected to the V socket

  43. CAUTION! • Do not attempt to make a voltage measurement if a test lead is plugged in the A or mAuA input jack • Instrument damage and/or personal injury may result.

  44. Measuring DC voltage • Connect the black test lead to the ‘COM’ socket • Connect the red test lead to the V socket • Rotate the function selector knob to the DC voltage position

  45. Function – DC Voltage • When this function selector knob is turned to this symbol the meter is set to measure DC voltage • DC [direct current] is found throughout the vehicles electrical system • 95% of the time that you spend with your DVOM will probably be measuring DC voltage • When the DC volt function is selected the meter will read the average voltage in a pulsed DC circuit

  46. Measuring DC voltage • Connect the voltmeter leads in parallel to the circuit being measured Fuse Light switch Negative Terminal The red lead is connected to the higher voltage The black lead is connected to the lower voltage

  47. Absolute voltage measurement • When the black test lead is connected to the battery negative terminal or to chassis ground all voltage measurements will be absolute voltages Light switch Negative Terminal Fuse

  48. Voltage drop measurement • Measuring the difference in voltage from one point in a circuit to another is called Voltage Drop measurement Measured voltage = 0.12 V Absolute voltage = 12.53 V Fuse Switch Positive Terminal Absolute voltage = 12.65 V The red lead is connected to the higher voltage The black lead is connected to the lower voltage

  49. Black lead is connected to a good body ground Measuring Voltage • In this illustration the electrical connector for the parking light bulb has been disconnected to determine if there is voltage at the connector Red lead is connected to the parking light power feed terminal

  50. Voltage drop measurement • Voltage drop measurement is used to find resistance in a circuit • Voltage drop may be measured on both the power side and ground side of a circuit Measured voltage = 0.086 V Negative Terminal Absolute voltage = 0.86 V Fuse Switch Absolute voltage = 0.0 V • If there is no resistance between two points in a circuit the voltage drop should be zero Ground Terminal

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